// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

#include "precomp.h"

#include "DxRenderer.hpp"
#include "CustomTextLayout.h"

#include "../../interactivity/win32/CustomWindowMessages.h"
#include "../../types/inc/Viewport.hpp"
#include "../../inc/unicode.hpp"
#include "../../inc/DefaultSettings.h"
#include <VersionHelpers.h>

#include "ScreenPixelShader.h"
#include "ScreenVertexShader.h"
#include <DirectXMath.h>
#include <d3dcompiler.h>
#include <DirectXColors.h>

using namespace DirectX;

std::atomic<size_t> Microsoft::Console::Render::DxEngine::_tracelogCount{ 0 };
#pragma warning(suppress : 26477) // We don't control tracelogging macros
TRACELOGGING_DEFINE_PROVIDER(g_hDxRenderProvider,
                             "Microsoft.Windows.Terminal.Renderer.DirectX",
                             // {c93e739e-ae50-5a14-78e7-f171e947535d}
                             (0xc93e739e, 0xae50, 0x5a14, 0x78, 0xe7, 0xf1, 0x71, 0xe9, 0x47, 0x53, 0x5d), );

// Quad where we draw the terminal.
// pos is world space coordinates where origin is at the center of screen.
// tex is texel coordinates where origin is top left.
// Layout the quad as a triangle strip where the _screenQuadVertices are place like so.
// 2 0
// 3 1
struct ShaderInput
{
    XMFLOAT3 pos;
    XMFLOAT2 tex;
} const _screenQuadVertices[] = {
    { XMFLOAT3(1.f, 1.f, 0.f), XMFLOAT2(1.f, 0.f) },
    { XMFLOAT3(1.f, -1.f, 0.f), XMFLOAT2(1.f, 1.f) },
    { XMFLOAT3(-1.f, 1.f, 0.f), XMFLOAT2(0.f, 0.f) },
    { XMFLOAT3(-1.f, -1.f, 0.f), XMFLOAT2(0.f, 1.f) },
};

D3D11_INPUT_ELEMENT_DESC _shaderInputLayout[] = {
    { "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 },
    { "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, D3D11_APPEND_ALIGNED_ELEMENT, D3D11_INPUT_PER_VERTEX_DATA, 0 }
};

#pragma hdrstop

static constexpr float POINTS_PER_INCH = 72.0f;
static constexpr std::wstring_view FALLBACK_FONT_FACES[] = { L"Consolas", L"Lucida Console", L"Courier New" };
static constexpr std::wstring_view FALLBACK_LOCALE = L"en-us";

using namespace Microsoft::Console::Render;
using namespace Microsoft::Console::Types;

// Routine Description:
// - Constructs a DirectX-based renderer for console text
//   which primarily uses DirectWrite on a Direct2D surface
#pragma warning(suppress : 26455)
// TODO GH 2683: The default constructor should not throw.
DxEngine::DxEngine() :
    RenderEngineBase(),
    _invalidateFullRows{ true },
    _invalidMap{},
    _invalidScroll{},
    _firstFrame{ true },
    _presentParams{ 0 },
    _presentReady{ false },
    _presentScroll{ 0 },
    _presentDirty{ 0 },
    _presentOffset{ 0 },
    _isEnabled{ false },
    _isPainting{ false },
    _displaySizePixels{},
    _foregroundColor{ 0 },
    _backgroundColor{ 0 },
    _selectionBackground{},
    _glyphCell{},
    _boxDrawingEffect{},
    _haveDeviceResources{ false },
    _swapChainDesc{ 0 },
    _swapChainFrameLatencyWaitableObject{ INVALID_HANDLE_VALUE },
    _recreateDeviceRequested{ false },
    _retroTerminalEffects{ false },
    _forceFullRepaintRendering{ false },
    _softwareRendering{ false },
    _antialiasingMode{ D2D1_TEXT_ANTIALIAS_MODE_GRAYSCALE },
    _defaultTextBackgroundOpacity{ 1.0f },
    _hwndTarget{ static_cast<HWND>(INVALID_HANDLE_VALUE) },
    _sizeTarget{},
    _dpi{ USER_DEFAULT_SCREEN_DPI },
    _scale{ 1.0f },
    _prevScale{ 1.0f },
    _chainMode{ SwapChainMode::ForComposition },
    _customLayout{},
    _customRenderer{ ::Microsoft::WRL::Make<CustomTextRenderer>() },
    _drawingContext{}
{
    const auto was = _tracelogCount.fetch_add(1);
    if (0 == was)
    {
        TraceLoggingRegister(g_hDxRenderProvider);
    }

    THROW_IF_FAILED(D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, IID_PPV_ARGS(&_d2dFactory)));

    THROW_IF_FAILED(DWriteCreateFactory(
        DWRITE_FACTORY_TYPE_SHARED,
        __uuidof(_dwriteFactory),
        reinterpret_cast<IUnknown**>(_dwriteFactory.GetAddressOf())));

    // Initialize our default selection color to DEFAULT_FOREGROUND, but make
    // sure to set to to a D2D1::ColorF
    SetSelectionBackground(DEFAULT_FOREGROUND);
}

// Routine Description:
// - Destroys an instance of the DirectX rendering engine
DxEngine::~DxEngine()
{
    _ReleaseDeviceResources();

    const auto was = _tracelogCount.fetch_sub(1);
    if (1 == was)
    {
        TraceLoggingUnregister(g_hDxRenderProvider);
    }
}

// Routine Description:
// - Sets this engine to enabled allowing painting and presentation to occur
// Arguments:
// - <none>
// Return Value:
// - Generally S_OK, but might return a DirectX or memory error if
//   resources need to be created or adjusted when enabling to prepare for draw
//   Can give invalid state if you enable an enabled class.
[[nodiscard]] HRESULT DxEngine::Enable() noexcept
{
    return _EnableDisplayAccess(true);
}

// Routine Description:
// - Sets this engine to disabled to prevent painting and presentation from occurring
// Arguments:
// - <none>
// Return Value:
// - Should be OK. We might close/free resources, but that shouldn't error.
//   Can give invalid state if you disable a disabled class.
[[nodiscard]] HRESULT DxEngine::Disable() noexcept
{
    return _EnableDisplayAccess(false);
}

// Routine Description:
// - Helper to enable/disable painting/display access/presentation in a unified
//   manner between enable/disable functions.
// Arguments:
// - outputEnabled - true to enable, false to disable
// Return Value:
// - Generally OK. Can return invalid state if you set to the state that is already
//   active (enabling enabled, disabling disabled).
[[nodiscard]] HRESULT DxEngine::_EnableDisplayAccess(const bool outputEnabled) noexcept
{
    // Invalid state if we're setting it to the same as what we already have.
    RETURN_HR_IF(E_NOT_VALID_STATE, outputEnabled == _isEnabled);

    _isEnabled = outputEnabled;
    if (!_isEnabled)
    {
        _ReleaseDeviceResources();
    }

    return S_OK;
}

// Routine Description:
// - Compiles a shader source into binary blob.
// Arguments:
// - source - Shader source
// - target - What kind of shader this is
// - entry - Entry function of shader
// Return Value:
// - Compiled binary. Errors are thrown and logged.
inline Microsoft::WRL::ComPtr<ID3DBlob>
_CompileShader(
    std::string source,
    std::string target,
    std::string entry = "main")
{
#ifdef __INSIDE_WINDOWS
    THROW_HR(E_UNEXPECTED);
    return 0;
#else
    Microsoft::WRL::ComPtr<ID3DBlob> code{};
    Microsoft::WRL::ComPtr<ID3DBlob> error{};

    const HRESULT hr = D3DCompile(
        source.c_str(),
        source.size(),
        nullptr,
        nullptr,
        nullptr,
        entry.c_str(),
        target.c_str(),
        0,
        0,
        &code,
        &error);

    if (FAILED(hr))
    {
        LOG_HR_MSG(hr, "D3DCompile failed with %x.", static_cast<int>(hr));
        if (error)
        {
            LOG_HR_MSG(hr, "D3DCompile error\n%*S", static_cast<int>(error->GetBufferSize()), static_cast<PWCHAR>(error->GetBufferPointer()));
        }

        THROW_HR(hr);
    }

    return code;
#endif
}

// Routine Description:
// - Setup D3D objects for doing shader things for terminal effects.
// Arguments:
// Return Value:
// - HRESULT status.
HRESULT DxEngine::_SetupTerminalEffects()
{
    ::Microsoft::WRL::ComPtr<ID3D11Texture2D> swapBuffer;
    RETURN_IF_FAILED(_dxgiSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&swapBuffer));

    // Setup render target.
    RETURN_IF_FAILED(_d3dDevice->CreateRenderTargetView(swapBuffer.Get(), nullptr, &_renderTargetView));

    // Setup _framebufferCapture, to where we'll copy current frame when rendering effects.
    D3D11_TEXTURE2D_DESC framebufferCaptureDesc{};
    swapBuffer->GetDesc(&framebufferCaptureDesc);
    WI_SetFlag(framebufferCaptureDesc.BindFlags, D3D11_BIND_SHADER_RESOURCE);
    RETURN_IF_FAILED(_d3dDevice->CreateTexture2D(&framebufferCaptureDesc, nullptr, &_framebufferCapture));

    // Setup the viewport.
    D3D11_VIEWPORT vp;
    vp.Width = _displaySizePixels.width<float>();
    vp.Height = _displaySizePixels.height<float>();
    vp.MinDepth = 0.0f;
    vp.MaxDepth = 1.0f;
    vp.TopLeftX = 0;
    vp.TopLeftY = 0;
    _d3dDeviceContext->RSSetViewports(1, &vp);

    // Prepare shaders.
    auto vertexBlob = _CompileShader(screenVertexShaderString, "vs_5_0");
    auto pixelBlob = _CompileShader(screenPixelShaderString, "ps_5_0");
    // TODO:GH#3928 move the shader files to to hlsl files and package their
    // build output to UWP app and load with these.
    // ::Microsoft::WRL::ComPtr<ID3DBlob> vertexBlob, pixelBlob;
    // RETURN_IF_FAILED(D3DReadFileToBlob(L"ScreenVertexShader.cso", &vertexBlob));
    // RETURN_IF_FAILED(D3DReadFileToBlob(L"ScreenPixelShader.cso", &pixelBlob));

    RETURN_IF_FAILED(_d3dDevice->CreateVertexShader(
        vertexBlob->GetBufferPointer(),
        vertexBlob->GetBufferSize(),
        nullptr,
        &_vertexShader));

    RETURN_IF_FAILED(_d3dDevice->CreatePixelShader(
        pixelBlob->GetBufferPointer(),
        pixelBlob->GetBufferSize(),
        nullptr,
        &_pixelShader));

    RETURN_IF_FAILED(_d3dDevice->CreateInputLayout(
        static_cast<const D3D11_INPUT_ELEMENT_DESC*>(_shaderInputLayout),
        ARRAYSIZE(_shaderInputLayout),
        vertexBlob->GetBufferPointer(),
        vertexBlob->GetBufferSize(),
        &_vertexLayout));

    // Create vertex buffer for screen quad.
    D3D11_BUFFER_DESC bd{};
    bd.Usage = D3D11_USAGE_DEFAULT;
    bd.ByteWidth = sizeof(ShaderInput) * ARRAYSIZE(_screenQuadVertices);
    bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;
    bd.CPUAccessFlags = 0;

    D3D11_SUBRESOURCE_DATA InitData{};
    InitData.pSysMem = static_cast<const void*>(_screenQuadVertices);

    RETURN_IF_FAILED(_d3dDevice->CreateBuffer(&bd, &InitData, &_screenQuadVertexBuffer));

    D3D11_BUFFER_DESC pixelShaderSettingsBufferDesc{};
    pixelShaderSettingsBufferDesc.Usage = D3D11_USAGE_DEFAULT;
    pixelShaderSettingsBufferDesc.ByteWidth = sizeof(_pixelShaderSettings);
    pixelShaderSettingsBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;

    _ComputePixelShaderSettings();

    D3D11_SUBRESOURCE_DATA pixelShaderSettingsInitData{};
    pixelShaderSettingsInitData.pSysMem = &_pixelShaderSettings;

    RETURN_IF_FAILED(_d3dDevice->CreateBuffer(&pixelShaderSettingsBufferDesc, &pixelShaderSettingsInitData, &_pixelShaderSettingsBuffer));

    // Sampler state is needed to use texture as input to shader.
    D3D11_SAMPLER_DESC samplerDesc{};
    samplerDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;
    samplerDesc.AddressU = D3D11_TEXTURE_ADDRESS_CLAMP;
    samplerDesc.AddressV = D3D11_TEXTURE_ADDRESS_CLAMP;
    samplerDesc.AddressW = D3D11_TEXTURE_ADDRESS_CLAMP;
    samplerDesc.MipLODBias = 0.0f;
    samplerDesc.MaxAnisotropy = 1;
    samplerDesc.ComparisonFunc = D3D11_COMPARISON_ALWAYS;
    samplerDesc.BorderColor[0] = 0;
    samplerDesc.BorderColor[1] = 0;
    samplerDesc.BorderColor[2] = 0;
    samplerDesc.BorderColor[3] = 0;
    samplerDesc.MinLOD = 0;
    samplerDesc.MaxLOD = D3D11_FLOAT32_MAX;

    // Create the texture sampler state.
    RETURN_IF_FAILED(_d3dDevice->CreateSamplerState(&samplerDesc, &_samplerState));

    return S_OK;
}

// Routine Description:
// - Puts the correct values in _pixelShaderSettings, so the struct can be
//   passed the GPU.
// Arguments:
// - <none>
// Return Value:
// - <none>
void DxEngine::_ComputePixelShaderSettings() noexcept
{
    // Retro scan lines alternate every pixel row at 100% scaling.
    _pixelShaderSettings.ScaledScanLinePeriod = _scale * 1.0f;

    // Gaussian distribution sigma used for blurring.
    _pixelShaderSettings.ScaledGaussianSigma = _scale * 2.0f;
}

// Routine Description;
// - Creates device-specific resources required for drawing
//   which generally means those that are represented on the GPU and can
//   vary based on the monitor, display adapter, etc.
// - These may need to be recreated during the course of painting a frame
//   should something about that hardware pipeline change.
// - Will free device resources that already existed as first operation.
// Arguments:
// - createSwapChain - If true, we create the entire rendering pipeline
//                   - If false, we just set up the adapter.
// Return Value:
// - Could be any DirectX/D3D/D2D/DXGI/DWrite error or memory issue.
[[nodiscard]] HRESULT DxEngine::_CreateDeviceResources(const bool createSwapChain) noexcept
try
{
    if (_haveDeviceResources)
    {
        _ReleaseDeviceResources();
    }

    auto freeOnFail = wil::scope_exit([&]() noexcept { _ReleaseDeviceResources(); });

    RETURN_IF_FAILED(CreateDXGIFactory1(IID_PPV_ARGS(&_dxgiFactory2)));

    const DWORD DeviceFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT |
                              // clang-format off
// This causes problems for folks who do not have the whole DirectX SDK installed
// when they try to run the rest of the project in debug mode.
// As such, I'm leaving this flag here for people doing DX-specific work to toggle it
// only when they need it and shutting it off otherwise.
// Find out more about the debug layer here:
// https://docs.microsoft.com/en-us/windows/desktop/direct3d11/overviews-direct3d-11-devices-layers
// You can find out how to install it here:
// https://docs.microsoft.com/en-us/windows/uwp/gaming/use-the-directx-runtime-and-visual-studio-graphics-diagnostic-features
                              // clang-format on
                              // D3D11_CREATE_DEVICE_DEBUG |
                              D3D11_CREATE_DEVICE_SINGLETHREADED;

    const std::array<D3D_FEATURE_LEVEL, 5> FeatureLevels{ D3D_FEATURE_LEVEL_11_1,
                                                          D3D_FEATURE_LEVEL_11_0,
                                                          D3D_FEATURE_LEVEL_10_1,
                                                          D3D_FEATURE_LEVEL_10_0,
                                                          D3D_FEATURE_LEVEL_9_1 };

    // Trying hardware first for maximum performance, then trying WARP (software) renderer second
    // in case we're running inside a downlevel VM where hardware passthrough isn't enabled like
    // for Windows 7 in a VM.
    HRESULT hardwareResult = E_NOT_SET;

    // If we're not forcing software rendering, try hardware first.
    // Otherwise, let the error state fall down and create with the software renderer directly.
    if (!_softwareRendering)
    {
        hardwareResult = D3D11CreateDevice(nullptr,
                                           D3D_DRIVER_TYPE_HARDWARE,
                                           nullptr,
                                           DeviceFlags,
                                           FeatureLevels.data(),
                                           gsl::narrow_cast<UINT>(FeatureLevels.size()),
                                           D3D11_SDK_VERSION,
                                           &_d3dDevice,
                                           nullptr,
                                           &_d3dDeviceContext);
    }

    if (FAILED(hardwareResult))
    {
        RETURN_IF_FAILED(D3D11CreateDevice(nullptr,
                                           D3D_DRIVER_TYPE_WARP,
                                           nullptr,
                                           DeviceFlags,
                                           FeatureLevels.data(),
                                           gsl::narrow_cast<UINT>(FeatureLevels.size()),
                                           D3D11_SDK_VERSION,
                                           &_d3dDevice,
                                           nullptr,
                                           &_d3dDeviceContext));
    }

    _displaySizePixels = _GetClientSize();

    // Get the other device types so we have deeper access to more functionality
    // in our pipeline than by just walking straight from the D3D device.

    RETURN_IF_FAILED(_d3dDevice.As(&_dxgiDevice));
    RETURN_IF_FAILED(_d2dFactory->CreateDevice(_dxgiDevice.Get(), _d2dDevice.ReleaseAndGetAddressOf()));

    // Create a device context out of it (supercedes render targets)
    RETURN_IF_FAILED(_d2dDevice->CreateDeviceContext(D2D1_DEVICE_CONTEXT_OPTIONS_NONE, &_d2dDeviceContext));

    if (createSwapChain)
    {
        _swapChainDesc = { 0 };
        _swapChainDesc.Flags = 0;

        // requires DXGI 1.3 which was introduced in Windows 8.1
        WI_SetFlagIf(_swapChainDesc.Flags, DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT, IsWindows8Point1OrGreater());

        _swapChainDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
        _swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
        _swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
        _swapChainDesc.BufferCount = 2;
        _swapChainDesc.SampleDesc.Count = 1;
        _swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
        _swapChainDesc.Scaling = DXGI_SCALING_NONE;

        switch (_chainMode)
        {
        case SwapChainMode::ForHwnd:
        {
            // use the HWND's dimensions for the swap chain dimensions.
            RECT rect = { 0 };
            RETURN_IF_WIN32_BOOL_FALSE(GetClientRect(_hwndTarget, &rect));

            _swapChainDesc.Width = rect.right - rect.left;
            _swapChainDesc.Height = rect.bottom - rect.top;

            // We can't do alpha for HWNDs. Set to ignore. It will fail otherwise.
            _swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_IGNORE;
            const auto createSwapChainResult = _dxgiFactory2->CreateSwapChainForHwnd(_d3dDevice.Get(),
                                                                                     _hwndTarget,
                                                                                     &_swapChainDesc,
                                                                                     nullptr,
                                                                                     nullptr,
                                                                                     &_dxgiSwapChain);
            if (FAILED(createSwapChainResult))
            {
                _swapChainDesc.Scaling = DXGI_SCALING_STRETCH;
                RETURN_IF_FAILED(_dxgiFactory2->CreateSwapChainForHwnd(_d3dDevice.Get(),
                                                                       _hwndTarget,
                                                                       &_swapChainDesc,
                                                                       nullptr,
                                                                       nullptr,
                                                                       &_dxgiSwapChain));
            }

            break;
        }
        case SwapChainMode::ForComposition:
        {
            // Use the given target size for compositions.
            _swapChainDesc.Width = _displaySizePixels.width<UINT>();
            _swapChainDesc.Height = _displaySizePixels.height<UINT>();

            // We're doing advanced composition pretty much for the purpose of pretty alpha, so turn it on.
            _swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;
            // It's 100% required to use scaling mode stretch for composition. There is no other choice.
            _swapChainDesc.Scaling = DXGI_SCALING_STRETCH;

            RETURN_IF_FAILED(_dxgiFactory2->CreateSwapChainForComposition(_d3dDevice.Get(),
                                                                          &_swapChainDesc,
                                                                          nullptr,
                                                                          &_dxgiSwapChain));
            break;
        }
        default:
            THROW_HR(E_NOTIMPL);
        }

        if (IsWindows8Point1OrGreater())
        {
            ::Microsoft::WRL::ComPtr<IDXGISwapChain2> swapChain2;
            const HRESULT asResult = _dxgiSwapChain.As(&swapChain2);
            if (SUCCEEDED(asResult))
            {
                _swapChainFrameLatencyWaitableObject = wil::unique_handle{ swapChain2->GetFrameLatencyWaitableObject() };
            }
            else
            {
                LOG_HR_MSG(asResult, "Failed to obtain IDXGISwapChain2 from swap chain");
            }
        }

        if (_retroTerminalEffects)
        {
            const HRESULT hr = _SetupTerminalEffects();
            if (FAILED(hr))
            {
                _retroTerminalEffects = false;
                LOG_HR_MSG(hr, "Failed to setup terminal effects. Disabling.");
            }
        }

        // With a new swap chain, mark the entire thing as invalid.
        RETURN_IF_FAILED(InvalidateAll());

        // This is our first frame on this new target.
        _firstFrame = true;

        RETURN_IF_FAILED(_PrepareRenderTarget());
    }

    _haveDeviceResources = true;
    if (_isPainting)
    {
        // TODO: MSFT: 21169176 - remove this or restore the "try a few times to render" code... I think
        _d2dDeviceContext->BeginDraw();
    }

    freeOnFail.release(); // don't need to release if we made it to the bottom and everything was good.

    // Notify that swap chain changed.

    if (_pfn)
    {
        try
        {
            _pfn();
        }
        CATCH_LOG(); // A failure in the notification function isn't a failure to prepare, so just log it and go on.
    }

    return S_OK;
}
CATCH_RETURN();

static constexpr D2D1_ALPHA_MODE _dxgiAlphaToD2d1Alpha(DXGI_ALPHA_MODE mode) noexcept
{
    switch (mode)
    {
    case DXGI_ALPHA_MODE_PREMULTIPLIED:
        return D2D1_ALPHA_MODE_PREMULTIPLIED;
    case DXGI_ALPHA_MODE_STRAIGHT:
        return D2D1_ALPHA_MODE_STRAIGHT;
    case DXGI_ALPHA_MODE_IGNORE:
        return D2D1_ALPHA_MODE_IGNORE;
    case DXGI_ALPHA_MODE_FORCE_DWORD:
        return D2D1_ALPHA_MODE_FORCE_DWORD;
    default:
    case DXGI_ALPHA_MODE_UNSPECIFIED:
        return D2D1_ALPHA_MODE_UNKNOWN;
    }
}

[[nodiscard]] HRESULT DxEngine::_PrepareRenderTarget() noexcept
{
    try
    {
        // Pull surface out of swap chain.
        RETURN_IF_FAILED(_dxgiSwapChain->GetBuffer(0, IID_PPV_ARGS(&_dxgiSurface)));

        // Make a bitmap and bind it to the swap chain surface
        const auto bitmapProperties = D2D1::BitmapProperties1(
            D2D1_BITMAP_OPTIONS_TARGET | D2D1_BITMAP_OPTIONS_CANNOT_DRAW,
            D2D1::PixelFormat(_swapChainDesc.Format, _dxgiAlphaToD2d1Alpha(_swapChainDesc.AlphaMode)));

        RETURN_IF_FAILED(_d2dDeviceContext->CreateBitmapFromDxgiSurface(_dxgiSurface.Get(), bitmapProperties, &_d2dBitmap));

        // Assign that bitmap as the target of the D2D device context. Draw commands hit the context
        // and are backed by the bitmap which is bound to the swap chain which goes on to be presented.
        // (The foot bone connected to the leg bone,
        //  The leg bone connected to the knee bone,
        //  The knee bone connected to the thigh bone
        //  ... and so on)

        _d2dDeviceContext->SetTarget(_d2dBitmap.Get());

        // We need the AntialiasMode for non-text object to be Aliased to ensure
        //  that background boxes line up with each other and don't leave behind
        //  stray colors.
        // See GH#3626 for more details.
        _d2dDeviceContext->SetAntialiasMode(D2D1_ANTIALIAS_MODE_ALIASED);
        _d2dDeviceContext->SetTextAntialiasMode(_antialiasingMode);

        RETURN_IF_FAILED(_d2dDeviceContext->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::DarkRed),
                                                                  &_d2dBrushBackground));

        RETURN_IF_FAILED(_d2dDeviceContext->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::White),
                                                                  &_d2dBrushForeground));

        const D2D1_STROKE_STYLE_PROPERTIES strokeStyleProperties{
            D2D1_CAP_STYLE_SQUARE, // startCap
            D2D1_CAP_STYLE_SQUARE, // endCap
            D2D1_CAP_STYLE_SQUARE, // dashCap
            D2D1_LINE_JOIN_MITER, // lineJoin
            0.f, // miterLimit
            D2D1_DASH_STYLE_SOLID, // dashStyle
            0.f, // dashOffset
        };
        RETURN_IF_FAILED(_d2dFactory->CreateStrokeStyle(&strokeStyleProperties, nullptr, 0, &_strokeStyle));

        // If in composition mode, apply scaling factor matrix
        if (_chainMode == SwapChainMode::ForComposition)
        {
            DXGI_MATRIX_3X2_F inverseScale = { 0 };
            inverseScale._11 = 1.0f / _scale;
            inverseScale._22 = inverseScale._11;

            ::Microsoft::WRL::ComPtr<IDXGISwapChain2> sc2;
            RETURN_IF_FAILED(_dxgiSwapChain.As(&sc2));
            RETURN_IF_FAILED(sc2->SetMatrixTransform(&inverseScale));
        }

        _prevScale = _scale;
        return S_OK;
    }
    CATCH_RETURN();
}

// Routine Description:
// - Releases device-specific resources (typically held on the GPU)
// Arguments:
// - <none>
// Return Value:
// - <none>
void DxEngine::_ReleaseDeviceResources() noexcept
{
    try
    {
        _haveDeviceResources = false;

        _pixelShaderSettingsBuffer.Reset();

        _d2dBrushForeground.Reset();
        _d2dBrushBackground.Reset();

        _d2dBitmap.Reset();

        if (nullptr != _d2dDeviceContext.Get() && _isPainting)
        {
            _d2dDeviceContext->EndDraw();
        }

        _d2dDeviceContext.Reset();

        _dxgiSurface.Reset();
        _dxgiSwapChain.Reset();
        _swapChainFrameLatencyWaitableObject.reset();

        _d2dDevice.Reset();
        _dxgiDevice.Reset();

        if (nullptr != _d3dDeviceContext.Get())
        {
            // To ensure the swap chain goes away we must unbind any views from the
            // D3D pipeline
            _d3dDeviceContext->OMSetRenderTargets(0, nullptr, nullptr);
        }
        _d3dDeviceContext.Reset();

        _d3dDevice.Reset();

        _dxgiFactory2.Reset();
    }
    CATCH_LOG();
}

// Routine Description:
// - Calculates whether or not we should force grayscale AA based on the
//   current renderer state.
// Arguments:
// - <none> - Uses internal state of _antialiasingMode, _defaultTextBackgroundOpacity,
//            _backgroundColor, and _defaultBackgroundColor.
// Return Value:
// - True if we must render this text in grayscale AA as cleartype simply won't work. False otherwise.
[[nodiscard]] bool DxEngine::_ShouldForceGrayscaleAA() noexcept
{
    // GH#5098: If we're rendering with cleartype text, we need to always
    // render onto an opaque background. If our background's opacity is
    // 1.0f, that's great, we can use that. Otherwise, we need to force the
    // text renderer to render this text in grayscale. In
    // UpdateDrawingBrushes, we'll set the backgroundColor's a channel to
    // 1.0 if we're in cleartype mode and the background's opacity is 1.0.
    // Otherwise, at this point, the _backgroundColor's alpha is <1.0.
    //
    // Currently, only text with the default background color uses an alpha
    // of 0, every other background uses 1.0
    //
    // DANGER: Layers slow us down. Only do this in the specific case where
    // someone has chosen the slower ClearType antialiasing (versus the faster
    // grayscale antialiasing)
    const bool usingCleartype = _antialiasingMode == D2D1_TEXT_ANTIALIAS_MODE_CLEARTYPE;
    const bool usingTransparency = _defaultTextBackgroundOpacity != 1.0f;
    // Another way of naming "bgIsDefault" is "bgHasTransparency"
    const auto bgIsDefault = (_backgroundColor.a == _defaultBackgroundColor.a) &&
                             (_backgroundColor.r == _defaultBackgroundColor.r) &&
                             (_backgroundColor.g == _defaultBackgroundColor.g) &&
                             (_backgroundColor.b == _defaultBackgroundColor.b);
    const bool forceGrayscaleAA = usingCleartype &&
                                  usingTransparency &&
                                  bgIsDefault;

    return forceGrayscaleAA;
}

// Routine Description:
// - Helper to create a DirectWrite text layout object
//   out of a string.
// Arguments:
// - string - The text to attempt to layout
// - stringLength - Length of string above in characters
// - ppTextLayout - Location to receive new layout object
// Return Value:
// - S_OK if layout created successfully, otherwise a DirectWrite error
[[nodiscard]] HRESULT DxEngine::_CreateTextLayout(
    _In_reads_(stringLength) PCWCHAR string,
    _In_ size_t stringLength,
    _Out_ IDWriteTextLayout** ppTextLayout) noexcept
try
{
    return _dwriteFactory->CreateTextLayout(string,
                                            gsl::narrow<UINT32>(stringLength),
                                            _dwriteTextFormat.Get(),
                                            _displaySizePixels.width<float>(),
                                            _glyphCell.height() != 0 ? _glyphCell.height<float>() : _displaySizePixels.height<float>(),
                                            ppTextLayout);
}
CATCH_RETURN()

// Routine Description:
// - Sets the target window handle for our display pipeline
// - We will take over the surface of this window for drawing
// Arguments:
// - hwnd - Window handle
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::SetHwnd(const HWND hwnd) noexcept
{
    _hwndTarget = hwnd;
    _chainMode = SwapChainMode::ForHwnd;
    return S_OK;
}

[[nodiscard]] HRESULT DxEngine::SetWindowSize(const SIZE Pixels) noexcept
try
{
    _sizeTarget = Pixels;

    _invalidMap.resize(_sizeTarget / _glyphCell, true);
    return S_OK;
}
CATCH_RETURN();

void DxEngine::SetCallback(std::function<void()> pfn)
{
    _pfn = pfn;
}

bool DxEngine::GetRetroTerminalEffects() const noexcept
{
    return _retroTerminalEffects;
}

void DxEngine::SetRetroTerminalEffects(bool enable) noexcept
try
{
    if (_retroTerminalEffects != enable)
    {
        _retroTerminalEffects = enable;
        _recreateDeviceRequested = true;
        LOG_IF_FAILED(InvalidateAll());
    }
}
CATCH_LOG()

void DxEngine::SetForceFullRepaintRendering(bool enable) noexcept
try
{
    if (_forceFullRepaintRendering != enable)
    {
        _forceFullRepaintRendering = enable;
        LOG_IF_FAILED(InvalidateAll());
    }
}
CATCH_LOG()

void DxEngine::SetSoftwareRendering(bool enable) noexcept
try
{
    if (_softwareRendering != enable)
    {
        _softwareRendering = enable;
        _recreateDeviceRequested = true;
        LOG_IF_FAILED(InvalidateAll());
    }
}
CATCH_LOG()

Microsoft::WRL::ComPtr<IDXGISwapChain1> DxEngine::GetSwapChain()
{
    if (_dxgiSwapChain.Get() == nullptr)
    {
        THROW_IF_FAILED(_CreateDeviceResources(true));
    }

    return _dxgiSwapChain;
}

void DxEngine::_InvalidateRectangle(const til::rectangle& rc)
{
    auto invalidate = rc;

    if (_invalidateFullRows)
    {
        invalidate = til::rectangle{ til::point{ static_cast<ptrdiff_t>(0), rc.top() }, til::size{ _invalidMap.size().width(), rc.height() } };
    }

    _invalidMap.set(invalidate);
}

// Routine Description:
// - Invalidates a rectangle described in characters
// Arguments:
// - psrRegion - Character rectangle
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::Invalidate(const SMALL_RECT* const psrRegion) noexcept
try
{
    RETURN_HR_IF_NULL(E_INVALIDARG, psrRegion);

    _InvalidateRectangle(Viewport::FromExclusive(*psrRegion).ToInclusive());

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Invalidates one specific character coordinate
// Arguments:
// - pcoordCursor - single point in the character cell grid
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::InvalidateCursor(const COORD* const pcoordCursor) noexcept
try
{
    RETURN_HR_IF_NULL(E_INVALIDARG, pcoordCursor);

    _InvalidateRectangle(til::rectangle{ *pcoordCursor, til::size{ 1, 1 } });

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Invalidates a rectangle describing a pixel area on the display
// Arguments:
// - prcDirtyClient - pixel rectangle
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::InvalidateSystem(const RECT* const prcDirtyClient) noexcept
try
{
    RETURN_HR_IF_NULL(E_INVALIDARG, prcDirtyClient);

    // Dirty client is in pixels. Use divide specialization against glyph factor to make conversion
    // to cells.
    _InvalidateRectangle(til::rectangle{ *prcDirtyClient }.scale_down(_glyphCell));

    return S_OK;
}
CATCH_RETURN();

// Routine Description:
// - Invalidates a series of character rectangles
// Arguments:
// - rectangles - One or more rectangles describing character positions on the grid
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::InvalidateSelection(const std::vector<SMALL_RECT>& rectangles) noexcept
{
    for (const auto& rect : rectangles)
    {
        RETURN_IF_FAILED(Invalidate(&rect));
    }
    return S_OK;
}

// Routine Description:
// - Scrolls the existing dirty region (if it exists) and
//   invalidates the area that is uncovered in the window.
// Arguments:
// - pcoordDelta - The number of characters to move and uncover.
//               - -Y is up, Y is down, -X is left, X is right.
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::InvalidateScroll(const COORD* const pcoordDelta) noexcept
try
{
    RETURN_HR_IF(E_INVALIDARG, !pcoordDelta);

    const til::point deltaCells{ *pcoordDelta };

    if (deltaCells != til::point{ 0, 0 })
    {
        // Shift the contents of the map and fill in revealed area.
        _invalidMap.translate(deltaCells, true);
        _invalidScroll += deltaCells;
    }

    return S_OK;
}
CATCH_RETURN();

// Routine Description:
// - Invalidates the entire window area
// Arguments:
// - <none>
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::InvalidateAll() noexcept
try
{
    _invalidMap.set_all();

    // Since everything is invalidated here, mark this as a "first frame", so
    // that we won't use incremental drawing on it. The caller of this intended
    // for _everything_ to get redrawn, so setting _firstFrame will force us to
    // redraw the entire frame. This will make sure that things like the gutters
    // get cleared correctly.
    //
    // Invalidating everything is supposed to happen with resizes of the
    // entire canvas, changes of the font, and other such adjustments.
    _firstFrame = true;
    return S_OK;
}
CATCH_RETURN();

// Routine Description:
// - This currently has no effect in this renderer.
// Arguments:
// - pForcePaint - Always filled with false
// Return Value:
// - S_FALSE because we don't use this.
[[nodiscard]] HRESULT DxEngine::InvalidateCircling(_Out_ bool* const pForcePaint) noexcept
{
    RETURN_HR_IF_NULL(E_INVALIDARG, pForcePaint);

    *pForcePaint = false;
    return S_FALSE;
}

// Routine Description:
// - Gets the area in pixels of the surface we are targeting
// Arguments:
// - <none>
// Return Value:
// - X by Y area in pixels of the surface
[[nodiscard]] til::size DxEngine::_GetClientSize() const
{
    switch (_chainMode)
    {
    case SwapChainMode::ForHwnd:
    {
        RECT clientRect = { 0 };
        LOG_IF_WIN32_BOOL_FALSE(GetClientRect(_hwndTarget, &clientRect));

        return til::rectangle{ clientRect }.size();
    }
    case SwapChainMode::ForComposition:
    {
        return _sizeTarget;
    }
    default:
        FAIL_FAST_HR(E_NOTIMPL);
    }
}

// Routine Description:
// - Helper to multiply all parameters of a rectangle by the font size
//   to convert from characters to pixels.
// Arguments:
// - cellsToPixels - rectangle to update
// - fontSize - scaling factors
// Return Value:
// - <none> - Updates reference
void _ScaleByFont(RECT& cellsToPixels, SIZE fontSize) noexcept
{
    cellsToPixels.left *= fontSize.cx;
    cellsToPixels.right *= fontSize.cx;
    cellsToPixels.top *= fontSize.cy;
    cellsToPixels.bottom *= fontSize.cy;
}

// Routine Description:
// - This is unused by this renderer.
// Arguments:
// - pForcePaint - always filled with false.
// Return Value:
// - S_FALSE because this is unused.
[[nodiscard]] HRESULT DxEngine::PrepareForTeardown(_Out_ bool* const pForcePaint) noexcept
{
    RETURN_HR_IF_NULL(E_INVALIDARG, pForcePaint);

    *pForcePaint = false;
    return S_FALSE;
}

// Routine description:
// - Prepares the surfaces for painting and begins a drawing batch
// Arguments:
// - <none>
// Return Value:
// - Any DirectX error, a memory error, etc.
[[nodiscard]] HRESULT DxEngine::StartPaint() noexcept
try
{
    RETURN_HR_IF(E_NOT_VALID_STATE, _isPainting); // invalid to start a paint while painting.

    // If someone explicitly requested differential rendering off, then we need to invalidate everything
    // so the entire frame is repainted.
    //
    // If retro terminal effects are on, we must invalidate everything for them to draw correctly.
    // Yes, this will further impact the performance of retro terminal effects.
    // But we're talking about running the entire display pipeline through a shader for
    // cosmetic effect, so performance isn't likely the top concern with this feature.
    if (_forceFullRepaintRendering || _retroTerminalEffects)
    {
        _invalidMap.set_all();
    }

    if (TraceLoggingProviderEnabled(g_hDxRenderProvider, WINEVENT_LEVEL_VERBOSE, 0))
    {
        const auto invalidatedStr = _invalidMap.to_string();
        const auto invalidated = invalidatedStr.c_str();

#pragma warning(suppress : 26477 26485 26494 26482 26446 26447) // We don't control TraceLoggingWrite
        TraceLoggingWrite(g_hDxRenderProvider,
                          "Invalid",
                          TraceLoggingWideString(invalidated),
                          TraceLoggingLevel(WINEVENT_LEVEL_VERBOSE));
    }

    if (_isEnabled)
    {
        const auto clientSize = _GetClientSize();

        // If we don't have device resources or if someone has requested that we
        // recreate the device... then make new resources. (Create will dump the old ones.)
        if (!_haveDeviceResources || _recreateDeviceRequested)
        {
            RETURN_IF_FAILED(_CreateDeviceResources(true));
            _recreateDeviceRequested = false;
        }
        else if (_displaySizePixels != clientSize || _prevScale != _scale)
        {
            // OK, we're going to play a dangerous game here for the sake of optimizing resize
            // First, set up a complete clear of all device resources if something goes terribly wrong.
            auto resetDeviceResourcesOnFailure = wil::scope_exit([&]() noexcept {
                _ReleaseDeviceResources();
            });

            // Now let go of a few of the device resources that get in the way of resizing buffers in the swap chain
            _dxgiSurface.Reset();
            _d2dDeviceContext->SetTarget(nullptr);
            _d2dBitmap.Reset();

            // Change the buffer size and recreate the render target (and surface)
            RETURN_IF_FAILED(_dxgiSwapChain->ResizeBuffers(2, clientSize.width<UINT>(), clientSize.height<UINT>(), _swapChainDesc.Format, _swapChainDesc.Flags));
            RETURN_IF_FAILED(_PrepareRenderTarget());

            // OK we made it past the parts that can cause errors. We can release our failure handler.
            resetDeviceResourcesOnFailure.release();

            // And persist the new size.
            _displaySizePixels = clientSize;

            // Mark this as the first frame on the new target. We can't use incremental drawing on the first frame.
            _firstFrame = true;
        }

        _d2dDeviceContext->BeginDraw();
        _isPainting = true;

        {
            // Get the baseline for this font as that's where we draw from
            DWRITE_LINE_SPACING spacing;
            RETURN_IF_FAILED(_dwriteTextFormat->GetLineSpacing(&spacing.method, &spacing.height, &spacing.baseline));

            // Assemble the drawing context information
            _drawingContext = std::make_unique<DrawingContext>(_d2dDeviceContext.Get(),
                                                               _d2dBrushForeground.Get(),
                                                               _d2dBrushBackground.Get(),
                                                               _ShouldForceGrayscaleAA(),
                                                               _dwriteFactory.Get(),
                                                               spacing,
                                                               _glyphCell,
                                                               _d2dDeviceContext->GetSize(),
                                                               std::nullopt,
                                                               D2D1_DRAW_TEXT_OPTIONS_ENABLE_COLOR_FONT);
        }
    }

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Ends batch drawing and captures any state necessary for presentation
// Arguments:
// - <none>
// Return Value:
// - Any DirectX error, a memory error, etc.
[[nodiscard]] HRESULT DxEngine::EndPaint() noexcept
try
{
    RETURN_HR_IF(E_INVALIDARG, !_isPainting); // invalid to end paint when we're not painting

    HRESULT hr = S_OK;

    if (_haveDeviceResources)
    {
        _isPainting = false;

        // If there's still a clip hanging around, remove it. We're all done.
        LOG_IF_FAILED(_customRenderer->EndClip(_drawingContext.get()));

        hr = _d2dDeviceContext->EndDraw();

        if (SUCCEEDED(hr))
        {
            if (_invalidScroll != til::point{ 0, 0 })
            {
                // Copy `til::rectangles` into RECT map.
                _presentDirty.assign(_invalidMap.begin(), _invalidMap.end());

                // Scale all dirty rectangles into pixels
                std::transform(_presentDirty.begin(), _presentDirty.end(), _presentDirty.begin(), [&](til::rectangle rc) {
                    return rc.scale_up(_glyphCell);
                });

                // Invalid scroll is in characters, convert it to pixels.
                const auto scrollPixels = (_invalidScroll * _glyphCell);

                // The scroll rect is the entire field of cells, but in pixels.
                til::rectangle scrollArea{ _invalidMap.size() * _glyphCell };

                // Reduce the size of the rectangle by the scroll.
                scrollArea -= til::size{} - scrollPixels;

                // Assign the area to the present storage
                _presentScroll = scrollArea;

                // Pass the offset.
                _presentOffset = scrollPixels;

                // Now fill up the parameters structure from the member variables.
                _presentParams.DirtyRectsCount = gsl::narrow<UINT>(_presentDirty.size());
                _presentParams.pDirtyRects = _presentDirty.data();

                _presentParams.pScrollOffset = &_presentOffset;
                _presentParams.pScrollRect = &_presentScroll;

                // The scroll rect will be empty if we scrolled >= 1 full screen size.
                // Present1 doesn't like that. So clear it out. Everything will be dirty anyway.
                if (IsRectEmpty(&_presentScroll))
                {
                    _presentParams.pScrollRect = nullptr;
                    _presentParams.pScrollOffset = nullptr;
                }
            }

            _presentReady = true;
        }
        else
        {
            _presentReady = false;
            _ReleaseDeviceResources();
        }
    }

    _invalidMap.reset_all();

    _invalidScroll = {};

    return hr;
}
CATCH_RETURN()

// Routine Description:
// - Copies the front surface of the swap chain (the one being displayed)
//   to the back surface of the swap chain (the one we draw on next)
//   so we can draw on top of what's already there.
// Arguments:
// - <none>
// Return Value:
// - Any DirectX error, a memory error, etc.
[[nodiscard]] HRESULT DxEngine::_CopyFrontToBack() noexcept
{
    try
    {
        Microsoft::WRL::ComPtr<ID3D11Resource> backBuffer;
        Microsoft::WRL::ComPtr<ID3D11Resource> frontBuffer;

        RETURN_IF_FAILED(_dxgiSwapChain->GetBuffer(0, IID_PPV_ARGS(&backBuffer)));
        RETURN_IF_FAILED(_dxgiSwapChain->GetBuffer(1, IID_PPV_ARGS(&frontBuffer)));

        _d3dDeviceContext->CopyResource(backBuffer.Get(), frontBuffer.Get());
    }
    CATCH_RETURN();

    return S_OK;
}

// Method Description:
// - Blocks until the engine is able to render without blocking.
// - See https://docs.microsoft.com/en-us/windows/uwp/gaming/reduce-latency-with-dxgi-1-3-swap-chains.
void DxEngine::WaitUntilCanRender() noexcept
{
    if (!_swapChainFrameLatencyWaitableObject)
    {
        return;
    }

    const auto ret = WaitForSingleObjectEx(
        _swapChainFrameLatencyWaitableObject.get(),
        1000, // 1 second timeout (shouldn't ever occur)
        true);
    if (ret != WAIT_OBJECT_0)
    {
        LOG_WIN32_MSG(ret, "Waiting for swap chain frame latency waitable object returned error or timeout.");
    }
}

// Routine Description:
// - Takes queued drawing information and presents it to the screen.
// - This is separated out so it can be done outside the lock as it's expensive.
// Arguments:
// - <none>
// Return Value:
// - S_OK on success, E_PENDING to indicate a retry or a relevant DirectX error
[[nodiscard]] HRESULT DxEngine::Present() noexcept
{
    if (_presentReady)
    {
        if (_retroTerminalEffects)
        {
            const HRESULT hr2 = _PaintTerminalEffects();
            if (FAILED(hr2))
            {
                _retroTerminalEffects = false;
                LOG_HR_MSG(hr2, "Failed to paint terminal effects. Disabling.");
            }
        }

        try
        {
            HRESULT hr = S_OK;

            bool recreate = false;

            // On anything but the first frame, try partial presentation.
            // We'll do it first because if it fails, we'll try again with full presentation.
            if (!_firstFrame)
            {
                hr = _dxgiSwapChain->Present1(1, 0, &_presentParams);

                // These two error codes are indicated for destroy-and-recreate
                // If we were told to destroy-and-recreate, we're going to skip straight into doing that
                // and not try again with full presentation.
                recreate = hr == DXGI_ERROR_DEVICE_REMOVED || hr == DXGI_ERROR_DEVICE_RESET;

                // Log this as we actually don't expect it to happen, we just will try again
                // below for robustness of our drawing.
                if (FAILED(hr) && !recreate)
                {
                    LOG_HR(hr);
                }
            }

            // If it's the first frame through, we cannot do partial presentation.
            // Also if partial presentation failed above and we weren't told to skip straight to
            // device recreation.
            // In both of these circumstances, do a full presentation.
            if (_firstFrame || (FAILED(hr) && !recreate))
            {
                hr = _dxgiSwapChain->Present(1, 0);
                _firstFrame = false;

                // These two error codes are indicated for destroy-and-recreate
                recreate = hr == DXGI_ERROR_DEVICE_REMOVED || hr == DXGI_ERROR_DEVICE_RESET;
            }

            // Now check for failure cases from either presentation mode.
            if (FAILED(hr))
            {
                // If we were told to recreate the device surface, do that.
                if (recreate)
                {
                    // We don't need to end painting here, as the renderer has done it for us.
                    _ReleaseDeviceResources();
                    FAIL_FAST_IF_FAILED(InvalidateAll());
                    return E_PENDING; // Indicate a retry to the renderer.
                }
                // Otherwise, we don't know what to do with this error. Report it.
                else
                {
                    FAIL_FAST_HR(hr);
                }
            }

            // Finally copy the front image (being presented now) onto the backing buffer
            // (where we are about to draw the next frame) so we can draw only the differences
            // next frame.
            RETURN_IF_FAILED(_CopyFrontToBack());
            _presentReady = false;

            _presentDirty.clear();
            _presentOffset = { 0 };
            _presentScroll = { 0 };
            _presentParams = { 0 };
        }
        CATCH_RETURN();
    }

    return S_OK;
}

// Routine Description:
// - This is currently unused.
// Arguments:
// - <none>
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::ScrollFrame() noexcept
{
    return S_OK;
}

// Routine Description:
// - This paints in the back most layer of the frame with the background color.
// Arguments:
// - <none>
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::PaintBackground() noexcept
try
{
    D2D1_COLOR_F nothing{ 0 };
    if (_chainMode == SwapChainMode::ForHwnd)
    {
        // When we're drawing over an HWND target, we need to fully paint the background color.
        nothing = _backgroundColor;
    }

    // If the entire thing is invalid, just use one big clear operation.
    if (_invalidMap.all())
    {
        _d2dDeviceContext->Clear(nothing);
    }
    else
    {
        // Runs are counts of cells.
        // Use a transform by the size of one cell to convert cells-to-pixels
        // as we clear.
        _d2dDeviceContext->SetTransform(D2D1::Matrix3x2F::Scale(_glyphCell));
        for (const auto& rect : _invalidMap.runs())
        {
            // Use aliased.
            // For graphics reasons, it'll look better because it will ensure that
            // the edges are cut nice and sharp (not blended by anti-aliasing).
            // For performance reasons, it takes a lot less work to not
            // do anti-alias blending.
            _d2dDeviceContext->PushAxisAlignedClip(rect, D2D1_ANTIALIAS_MODE_ALIASED);
            _d2dDeviceContext->Clear(nothing);
            _d2dDeviceContext->PopAxisAlignedClip();
        }
        _d2dDeviceContext->SetTransform(D2D1::Matrix3x2F::Identity());
    }

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Places one line of text onto the screen at the given position
// Arguments:
// - clusters - Iterable collection of cluster information (text and columns it should consume)
// - coord - Character coordinate position in the cell grid
// - fTrimLeft - Whether or not to trim off the left half of a double wide character
// Return Value:
// - S_OK or relevant DirectX error
[[nodiscard]] HRESULT DxEngine::PaintBufferLine(gsl::span<const Cluster> const clusters,
                                                COORD const coord,
                                                const bool /*trimLeft*/,
                                                const bool /*lineWrapped*/) noexcept
try
{
    // Calculate positioning of our origin.
    const D2D1_POINT_2F origin = til::point{ coord } * _glyphCell;

    // Create the text layout
    RETURN_IF_FAILED(_customLayout->Reset());
    RETURN_IF_FAILED(_customLayout->AppendClusters(clusters));

    // Layout then render the text
    RETURN_IF_FAILED(_customLayout->Draw(_drawingContext.get(), _customRenderer.Get(), origin.x, origin.y));

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Paints lines around cells (draws in pieces of the grid)
// Arguments:
// - lines - Which grid lines (top, left, bottom, right) to draw
// - color - The color to use for drawing the lines
// - cchLine - Length of the line to draw in character cells
// - coordTarget - The X,Y character position in the grid where we should start drawing
//               - We will draw rightward (+X) from here
// Return Value:
// - S_OK or relevant DirectX error
[[nodiscard]] HRESULT DxEngine::PaintBufferGridLines(GridLines const lines,
                                                     COLORREF const color,
                                                     size_t const cchLine,
                                                     COORD const coordTarget) noexcept
try
{
    const auto existingColor = _d2dBrushForeground->GetColor();
    const auto restoreBrushOnExit = wil::scope_exit([&]() noexcept { _d2dBrushForeground->SetColor(existingColor); });

    _d2dBrushForeground->SetColor(_ColorFFromColorRef(color));

    const auto font = _glyphCell;
    D2D_POINT_2F target = til::point{ coordTarget } * font;

    D2D_POINT_2F start = { 0 };
    D2D_POINT_2F end = { 0 };

    for (size_t i = 0; i < cchLine; i++)
    {
        // 0.5 pixel offset for crisp lines
        start = { target.x + 0.5f, target.y + 0.5f };

        if (lines & GridLines::Top)
        {
            end = start;
            end.x += font.width();

            _d2dDeviceContext->DrawLine(start, end, _d2dBrushForeground.Get(), 1.0f, _strokeStyle.Get());
        }

        if (lines & GridLines::Left)
        {
            end = start;
            end.y += font.height();

            _d2dDeviceContext->DrawLine(start, end, _d2dBrushForeground.Get(), 1.0f, _strokeStyle.Get());
        }

        // NOTE: Watch out for inclusive/exclusive rectangles here.
        // We have to remove 1 from the font size for the bottom and right lines to ensure that the
        // starting point remains within the clipping rectangle.
        // For example, if we're drawing a letter at 0,0 and the font size is 8x16....
        // The bottom left corner inclusive is at 0,15 which is Y (0) + Font Height (16) - 1 = 15.
        // The top right corner inclusive is at 7,0 which is X (0) + Font Height (8) - 1 = 7.

        // 0.5 pixel offset for crisp lines; -0.5 on the Y to fit _in_ the cell, not outside it.
        start = { target.x + 0.5f, target.y + font.height() - 0.5f };

        if (lines & GridLines::Bottom)
        {
            end = start;
            end.x += font.width() - 1.f;

            _d2dDeviceContext->DrawLine(start, end, _d2dBrushForeground.Get(), 1.0f, _strokeStyle.Get());
        }

        start = { target.x + font.width() - 0.5f, target.y + 0.5f };

        if (lines & GridLines::Right)
        {
            end = start;
            end.y += font.height() - 1.f;

            _d2dDeviceContext->DrawLine(start, end, _d2dBrushForeground.Get(), 1.0f, _strokeStyle.Get());
        }

        // Move to the next character in this run.
        target.x += font.width();
    }

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Paints an overlay highlight on a portion of the frame to represent selected text
// Arguments:
//  - rect - Rectangle to invert or highlight to make the selection area
// Return Value:
// - S_OK or relevant DirectX error.
[[nodiscard]] HRESULT DxEngine::PaintSelection(const SMALL_RECT rect) noexcept
try
{
    // If a clip rectangle is in place from drawing the text layer, remove it here.
    LOG_IF_FAILED(_customRenderer->EndClip(_drawingContext.get()));

    const auto existingColor = _d2dBrushForeground->GetColor();

    _d2dBrushForeground->SetColor(_selectionBackground);
    const auto resetColorOnExit = wil::scope_exit([&]() noexcept { _d2dBrushForeground->SetColor(existingColor); });

    const D2D1_RECT_F draw = til::rectangle{ Viewport::FromExclusive(rect).ToInclusive() }.scale_up(_glyphCell);

    _d2dDeviceContext->FillRectangle(draw, _d2dBrushForeground.Get());

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Does nothing. Our cursor is drawn in CustomTextRenderer::DrawGlyphRun,
//   either above or below the text.
// Arguments:
// - options - unused
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::PaintCursor(const CursorOptions& /*options*/) noexcept
{
    return S_OK;
}

// Routine Description:
// - Paint terminal effects.
// Arguments:
// Return Value:
// - S_OK or relevant DirectX error.
[[nodiscard]] HRESULT DxEngine::_PaintTerminalEffects() noexcept
try
{
    // Should have been initialized.
    RETURN_HR_IF(E_NOT_VALID_STATE, !_framebufferCapture);

    // Capture current frame in swap chain to a texture.
    ::Microsoft::WRL::ComPtr<ID3D11Texture2D> swapBuffer;
    RETURN_IF_FAILED(_dxgiSwapChain->GetBuffer(0, IID_PPV_ARGS(&swapBuffer)));
    _d3dDeviceContext->CopyResource(_framebufferCapture.Get(), swapBuffer.Get());

    // Prepare captured texture as input resource to shader program.
    D3D11_TEXTURE2D_DESC desc;
    _framebufferCapture->GetDesc(&desc);

    D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;
    srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
    srvDesc.Texture2D.MostDetailedMip = 0;
    srvDesc.Texture2D.MipLevels = desc.MipLevels;
    srvDesc.Format = desc.Format;

    ::Microsoft::WRL::ComPtr<ID3D11ShaderResourceView> shaderResource;
    RETURN_IF_FAILED(_d3dDevice->CreateShaderResourceView(_framebufferCapture.Get(), &srvDesc, &shaderResource));

    // Render the screen quad with shader effects.
    const UINT stride = sizeof(ShaderInput);
    const UINT offset = 0;

    _d3dDeviceContext->OMSetRenderTargets(1, _renderTargetView.GetAddressOf(), nullptr);
    _d3dDeviceContext->IASetVertexBuffers(0, 1, _screenQuadVertexBuffer.GetAddressOf(), &stride, &offset);
    _d3dDeviceContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
    _d3dDeviceContext->IASetInputLayout(_vertexLayout.Get());
    _d3dDeviceContext->VSSetShader(_vertexShader.Get(), nullptr, 0);
    _d3dDeviceContext->PSSetShader(_pixelShader.Get(), nullptr, 0);
    _d3dDeviceContext->PSSetShaderResources(0, 1, shaderResource.GetAddressOf());
    _d3dDeviceContext->PSSetSamplers(0, 1, _samplerState.GetAddressOf());
    _d3dDeviceContext->PSSetConstantBuffers(0, 1, _pixelShaderSettingsBuffer.GetAddressOf());
    _d3dDeviceContext->Draw(ARRAYSIZE(_screenQuadVertices), 0);

    return S_OK;
}
CATCH_RETURN()

// Routine Description:
// - Updates the default brush colors used for drawing
// Arguments:
// - textAttributes - Text attributes to use for the brush color
// - pData - The interface to console data structures required for rendering
// - isSettingDefaultBrushes - Lets us know that these are the default brushes to paint the swapchain background or selection
// Return Value:
// - S_OK or relevant DirectX error.
[[nodiscard]] HRESULT DxEngine::UpdateDrawingBrushes(const TextAttribute& textAttributes,
                                                     const gsl::not_null<IRenderData*> pData,
                                                     const bool isSettingDefaultBrushes) noexcept
{
    // GH#5098: If we're rendering with cleartype text, we need to always render
    // onto an opaque background. If our background's opacity is 1.0f, that's
    // great, we can actually use cleartype in that case. In that scenario
    // (cleartype && opacity == 1.0), we'll force the opacity bits of the
    // COLORREF to 0xff so we draw as cleartype. In any other case, leave the
    // opacity bits unchanged. PaintBufferLine will later do some logic to
    // determine if we should paint the text as grayscale or not.
    const bool usingCleartype = _antialiasingMode == D2D1_TEXT_ANTIALIAS_MODE_CLEARTYPE;
    const bool usingTransparency = _defaultTextBackgroundOpacity != 1.0f;
    const bool forceOpaqueBG = usingCleartype && !usingTransparency;

    const auto [colorForeground, colorBackground] = pData->GetAttributeColors(textAttributes);

    _foregroundColor = _ColorFFromColorRef(OPACITY_OPAQUE | colorForeground);
    _backgroundColor = _ColorFFromColorRef((forceOpaqueBG ? OPACITY_OPAQUE : 0) | colorBackground);

    _d2dBrushForeground->SetColor(_foregroundColor);
    _d2dBrushBackground->SetColor(_backgroundColor);

    // If this flag is set, then we need to update the default brushes too and the swap chain background.
    if (isSettingDefaultBrushes)
    {
        _defaultForegroundColor = _foregroundColor;
        _defaultBackgroundColor = _backgroundColor;

        // If we have a swap chain, set the background color there too so the area
        // outside the chain on a resize can be filled in with an appropriate color value.
        /*if (_dxgiSwapChain)
        {
            const auto dxgiColor = s_RgbaFromColorF(_defaultBackgroundColor);
            RETURN_IF_FAILED(_dxgiSwapChain->SetBackgroundColor(&dxgiColor));
        }*/
    }

    // If we have a drawing context, it may be choosing its antialiasing based
    // on the colors. Update it if it exists.
    // We only need to do this here because this is called all the time on painting frames
    // and will update it in a timely fashion. Changing the AA mode or opacity do affect
    // it, but we will always hit updating the drawing brushes so we don't
    // need to update this in those locations.
    if (_drawingContext)
    {
        _drawingContext->forceGrayscaleAA = _ShouldForceGrayscaleAA();
    }

    return S_OK;
}

// Routine Description:
// - Updates the font used for drawing
// Arguments:
// - pfiFontInfoDesired - Information specifying the font that is requested
// - fiFontInfo - Filled with the nearest font actually chosen for drawing
// Return Value:
// - S_OK or relevant DirectX error
[[nodiscard]] HRESULT DxEngine::UpdateFont(const FontInfoDesired& pfiFontInfoDesired, FontInfo& fiFontInfo) noexcept
try
{
    RETURN_IF_FAILED(_GetProposedFont(pfiFontInfoDesired,
                                      fiFontInfo,
                                      _dpi,
                                      _dwriteTextFormat,
                                      _dwriteTextAnalyzer,
                                      _dwriteFontFace));

    _glyphCell = fiFontInfo.GetSize();

    // Calculate and cache the box effect for the base font. Scale is 1.0f because the base font is exactly the scale we want already.
    RETURN_IF_FAILED(CustomTextLayout::s_CalculateBoxEffect(_dwriteTextFormat.Get(), _glyphCell.width(), _dwriteFontFace.Get(), 1.0f, &_boxDrawingEffect));

    // Prepare the text layout
    _customLayout = WRL::Make<CustomTextLayout>(_dwriteFactory.Get(), _dwriteTextAnalyzer.Get(), _dwriteTextFormat.Get(), _dwriteFontFace.Get(), _glyphCell.width(), _boxDrawingEffect.Get());

    return S_OK;
}
CATCH_RETURN();

[[nodiscard]] Viewport DxEngine::GetViewportInCharacters(const Viewport& viewInPixels) noexcept
{
    const short widthInChars = gsl::narrow_cast<short>(viewInPixels.Width() / _glyphCell.width());
    const short heightInChars = gsl::narrow_cast<short>(viewInPixels.Height() / _glyphCell.height());

    return Viewport::FromDimensions(viewInPixels.Origin(), { widthInChars, heightInChars });
}

// Routine Description:
// - Sets the DPI in this renderer
// Arguments:
// - iDpi - DPI
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::UpdateDpi(int const iDpi) noexcept
{
    _dpi = iDpi;

    // The scale factor may be necessary for composition contexts, so save it once here.
    _scale = _dpi / static_cast<float>(USER_DEFAULT_SCREEN_DPI);

    RETURN_IF_FAILED(InvalidateAll());

    if (_retroTerminalEffects && _d3dDeviceContext && _pixelShaderSettingsBuffer)
    {
        _ComputePixelShaderSettings();
        try
        {
            _d3dDeviceContext->UpdateSubresource(_pixelShaderSettingsBuffer.Get(), 0, nullptr, &_pixelShaderSettings, 0, 0);
        }
        CATCH_RETURN();
    }

    return S_OK;
}

// Method Description:
// - Get the current scale factor of this renderer. The actual DPI the renderer
//   is USER_DEFAULT_SCREEN_DPI * GetScaling()
// Arguments:
// - <none>
// Return Value:
// - the scaling multiplier of this render engine
float DxEngine::GetScaling() const noexcept
{
    return _scale;
}

// Method Description:
// - This method will update our internal reference for how big the viewport is.
//      Does nothing for DX.
// Arguments:
// - srNewViewport - The bounds of the new viewport.
// Return Value:
// - HRESULT S_OK
[[nodiscard]] HRESULT DxEngine::UpdateViewport(const SMALL_RECT /*srNewViewport*/) noexcept
{
    return S_OK;
}

// Routine Description:
// - Currently unused by this renderer
// Arguments:
// - pfiFontInfoDesired - <unused>
// - pfiFontInfo - <unused>
// - iDpi - <unused>
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::GetProposedFont(const FontInfoDesired& pfiFontInfoDesired,
                                                FontInfo& pfiFontInfo,
                                                int const iDpi) noexcept
{
    Microsoft::WRL::ComPtr<IDWriteTextFormat> format;
    Microsoft::WRL::ComPtr<IDWriteTextAnalyzer1> analyzer;
    Microsoft::WRL::ComPtr<IDWriteFontFace1> face;

    return _GetProposedFont(pfiFontInfoDesired,
                            pfiFontInfo,
                            iDpi,
                            format,
                            analyzer,
                            face);
}

// Routine Description:
// - Gets the area that we currently believe is dirty within the character cell grid
// Arguments:
// - <none>
// Return Value:
// - Rectangle describing dirty area in characters.
[[nodiscard]] std::vector<til::rectangle> DxEngine::GetDirtyArea()
{
    return _invalidMap.runs();
}

// Routine Description:
// - Gets the current font size
// Arguments:
// - pFontSize - Filled with the font size.
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::GetFontSize(_Out_ COORD* const pFontSize) noexcept
try
{
    *pFontSize = _glyphCell;
    return S_OK;
}
CATCH_RETURN();

// Routine Description:
// - Currently unused by this renderer.
// Arguments:
// - glyph - The glyph run to process for column width.
// - pResult - True if it should take two columns. False if it should take one.
// Return Value:
// - S_OK or relevant DirectWrite error.
[[nodiscard]] HRESULT DxEngine::IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept
try
{
    RETURN_HR_IF_NULL(E_INVALIDARG, pResult);

    const Cluster cluster(glyph, 0); // columns don't matter, we're doing analysis not layout.

    RETURN_IF_FAILED(_customLayout->Reset());
    RETURN_IF_FAILED(_customLayout->AppendClusters({ &cluster, 1 }));

    UINT32 columns = 0;
    RETURN_IF_FAILED(_customLayout->GetColumns(&columns));

    *pResult = columns != 1;

    return S_OK;
}
CATCH_RETURN();

// Method Description:
// - Updates the window's title string.
// Arguments:
// - newTitle: the new string to use for the title of the window
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
{
    if (_hwndTarget != INVALID_HANDLE_VALUE)
    {
        return PostMessageW(_hwndTarget, CM_UPDATE_TITLE, 0, 0) ? S_OK : E_FAIL;
    }
    return S_FALSE;
}

// Routine Description:
// - Attempts to locate the font given, but then begins falling back if we cannot find it.
// - We'll try to fall back to Consolas with the given weight/stretch/style first,
//   then try Consolas again with normal weight/stretch/style,
//   and if nothing works, then we'll throw an error.
// Arguments:
// - familyName - The font name we should be looking for
// - weight - The weight (bold, light, etc.)
// - stretch - The stretch of the font is the spacing between each letter
// - style - Normal, italic, etc.
// Return Value:
// - Smart pointer holding interface reference for queryable font data.
[[nodiscard]] Microsoft::WRL::ComPtr<IDWriteFontFace1> DxEngine::_ResolveFontFaceWithFallback(std::wstring& familyName,
                                                                                              DWRITE_FONT_WEIGHT& weight,
                                                                                              DWRITE_FONT_STRETCH& stretch,
                                                                                              DWRITE_FONT_STYLE& style,
                                                                                              std::wstring& localeName) const
{
    auto face = _FindFontFace(familyName, weight, stretch, style, localeName);

    if (!face)
    {
        for (const auto fallbackFace : FALLBACK_FONT_FACES)
        {
            familyName = fallbackFace;
            face = _FindFontFace(familyName, weight, stretch, style, localeName);

            if (face)
            {
                break;
            }

            familyName = fallbackFace;
            weight = DWRITE_FONT_WEIGHT_NORMAL;
            stretch = DWRITE_FONT_STRETCH_NORMAL;
            style = DWRITE_FONT_STYLE_NORMAL;
            face = _FindFontFace(familyName, weight, stretch, style, localeName);

            if (face)
            {
                break;
            }
        }
    }

    THROW_HR_IF_NULL(E_FAIL, face);

    return face;
}

// Routine Description:
// - Locates a suitable font face from the given information
// Arguments:
// - familyName - The font name we should be looking for
// - weight - The weight (bold, light, etc.)
// - stretch - The stretch of the font is the spacing between each letter
// - style - Normal, italic, etc.
// Return Value:
// - Smart pointer holding interface reference for queryable font data.
[[nodiscard]] Microsoft::WRL::ComPtr<IDWriteFontFace1> DxEngine::_FindFontFace(std::wstring& familyName,
                                                                               DWRITE_FONT_WEIGHT& weight,
                                                                               DWRITE_FONT_STRETCH& stretch,
                                                                               DWRITE_FONT_STYLE& style,
                                                                               std::wstring& localeName) const
{
    Microsoft::WRL::ComPtr<IDWriteFontFace1> fontFace;

    Microsoft::WRL::ComPtr<IDWriteFontCollection> fontCollection;
    THROW_IF_FAILED(_dwriteFactory->GetSystemFontCollection(&fontCollection, false));

    UINT32 familyIndex;
    BOOL familyExists;
    THROW_IF_FAILED(fontCollection->FindFamilyName(familyName.data(), &familyIndex, &familyExists));

    if (familyExists)
    {
        Microsoft::WRL::ComPtr<IDWriteFontFamily> fontFamily;
        THROW_IF_FAILED(fontCollection->GetFontFamily(familyIndex, &fontFamily));

        Microsoft::WRL::ComPtr<IDWriteFont> font;
        THROW_IF_FAILED(fontFamily->GetFirstMatchingFont(weight, stretch, style, &font));

        Microsoft::WRL::ComPtr<IDWriteFontFace> fontFace0;
        THROW_IF_FAILED(font->CreateFontFace(&fontFace0));

        THROW_IF_FAILED(fontFace0.As(&fontFace));

        // Retrieve metrics in case the font we created was different than what was requested.
        weight = font->GetWeight();
        stretch = font->GetStretch();
        style = font->GetStyle();

        // Dig the family name out at the end to return it.
        familyName = _GetFontFamilyName(fontFamily.Get(), localeName);
    }

    return fontFace;
}

// Routine Description:
// - Helper to retrieve the user's locale preference or fallback to the default.
// Arguments:
// - <none>
// Return Value:
// - A locale that can be used on construction of assorted DX objects that want to know one.
[[nodiscard]] std::wstring DxEngine::_GetLocaleName() const
{
    std::array<wchar_t, LOCALE_NAME_MAX_LENGTH> localeName;

    const auto returnCode = GetUserDefaultLocaleName(localeName.data(), gsl::narrow<int>(localeName.size()));
    if (returnCode)
    {
        return { localeName.data() };
    }
    else
    {
        return { FALLBACK_LOCALE.data(), FALLBACK_LOCALE.size() };
    }
}

// Routine Description:
// - Retrieves the font family name out of the given object in the given locale.
// - If we can't find a valid name for the given locale, we'll fallback and report it back.
// Arguments:
// - fontFamily - DirectWrite font family object
// - localeName - The locale in which the name should be retrieved.
//              - If fallback occurred, this is updated to what we retrieved instead.
// Return Value:
// - Localized string name of the font family
[[nodiscard]] std::wstring DxEngine::_GetFontFamilyName(gsl::not_null<IDWriteFontFamily*> const fontFamily,
                                                        std::wstring& localeName) const
{
    // See: https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nn-dwrite-idwritefontcollection
    Microsoft::WRL::ComPtr<IDWriteLocalizedStrings> familyNames;
    THROW_IF_FAILED(fontFamily->GetFamilyNames(&familyNames));

    // First we have to find the right family name for the locale. We're going to bias toward what the caller
    // requested, but fallback if we need to and reply with the locale we ended up choosing.
    UINT32 index = 0;
    BOOL exists = false;

    // This returns S_OK whether or not it finds a locale name. Check exists field instead.
    // If it returns an error, it's a real problem, not an absence of this locale name.
    // https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-findlocalename
    THROW_IF_FAILED(familyNames->FindLocaleName(localeName.data(), &index, &exists));

    // If we tried and it still doesn't exist, try with the fallback locale.
    if (!exists)
    {
        localeName = FALLBACK_LOCALE;
        THROW_IF_FAILED(familyNames->FindLocaleName(localeName.data(), &index, &exists));
    }

    // If it still doesn't exist, we're going to try index 0.
    if (!exists)
    {
        index = 0;

        // Get the locale name out so at least the caller knows what locale this name goes with.
        UINT32 length = 0;
        THROW_IF_FAILED(familyNames->GetLocaleNameLength(index, &length));
        localeName.resize(length);

        // https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-getlocalenamelength
        // https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-getlocalename
        // GetLocaleNameLength does not include space for null terminator, but GetLocaleName needs it so add one.
        THROW_IF_FAILED(familyNames->GetLocaleName(index, localeName.data(), length + 1));
    }

    // OK, now that we've decided which family name and the locale that it's in... let's go get it.
    UINT32 length = 0;
    THROW_IF_FAILED(familyNames->GetStringLength(index, &length));

    // Make our output buffer and resize it so it is allocated.
    std::wstring retVal;
    retVal.resize(length);

    // FINALLY, go fetch the string name.
    // https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-getstringlength
    // https://docs.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-idwritelocalizedstrings-getstring
    // Once again, GetStringLength is without the null, but GetString needs the null. So add one.
    THROW_IF_FAILED(familyNames->GetString(index, retVal.data(), length + 1));

    // and return it.
    return retVal;
}

// Routine Description:
// - Updates the font used for drawing
// Arguments:
// - desired - Information specifying the font that is requested
// - actual - Filled with the nearest font actually chosen for drawing
// - dpi - The DPI of the screen
// Return Value:
// - S_OK or relevant DirectX error
[[nodiscard]] HRESULT DxEngine::_GetProposedFont(const FontInfoDesired& desired,
                                                 FontInfo& actual,
                                                 const int dpi,
                                                 Microsoft::WRL::ComPtr<IDWriteTextFormat>& textFormat,
                                                 Microsoft::WRL::ComPtr<IDWriteTextAnalyzer1>& textAnalyzer,
                                                 Microsoft::WRL::ComPtr<IDWriteFontFace1>& fontFace) const noexcept
{
    try
    {
        std::wstring fontName(desired.GetFaceName());
        DWRITE_FONT_WEIGHT weight = static_cast<DWRITE_FONT_WEIGHT>(desired.GetWeight());
        DWRITE_FONT_STYLE style = DWRITE_FONT_STYLE_NORMAL;
        DWRITE_FONT_STRETCH stretch = DWRITE_FONT_STRETCH_NORMAL;
        std::wstring localeName = _GetLocaleName();

        // _ResolveFontFaceWithFallback overrides the last argument with the locale name of the font,
        // but we should use the system's locale to render the text.
        std::wstring fontLocaleName = localeName;
        const auto face = _ResolveFontFaceWithFallback(fontName, weight, stretch, style, fontLocaleName);

        DWRITE_FONT_METRICS1 fontMetrics;
        face->GetMetrics(&fontMetrics);

        const UINT32 spaceCodePoint = L'M';
        UINT16 spaceGlyphIndex;
        THROW_IF_FAILED(face->GetGlyphIndicesW(&spaceCodePoint, 1, &spaceGlyphIndex));

        INT32 advanceInDesignUnits;
        THROW_IF_FAILED(face->GetDesignGlyphAdvances(1, &spaceGlyphIndex, &advanceInDesignUnits));

        DWRITE_GLYPH_METRICS spaceMetrics = { 0 };
        THROW_IF_FAILED(face->GetDesignGlyphMetrics(&spaceGlyphIndex, 1, &spaceMetrics));

        // The math here is actually:
        // Requested Size in Points * DPI scaling factor * Points to Pixels scaling factor.
        // - DPI = dots per inch
        // - PPI = points per inch or "points" as usually seen when choosing a font size
        // - The DPI scaling factor is the current monitor DPI divided by 96, the default DPI.
        // - The Points to Pixels factor is based on the typography definition of 72 points per inch.
        //    As such, converting requires taking the 96 pixel per inch default and dividing by the 72 points per inch
        //    to get a factor of 1 and 1/3.
        // This turns into something like:
        // - 12 ppi font * (96 dpi / 96 dpi) * (96 dpi / 72 points per inch) = 16 pixels tall font for 100% display (96 dpi is 100%)
        // - 12 ppi font * (144 dpi / 96 dpi) * (96 dpi / 72 points per inch) = 24 pixels tall font for 150% display (144 dpi is 150%)
        // - 12 ppi font * (192 dpi / 96 dpi) * (96 dpi / 72 points per inch) = 32 pixels tall font for 200% display (192 dpi is 200%)
        float heightDesired = static_cast<float>(desired.GetEngineSize().Y) * static_cast<float>(USER_DEFAULT_SCREEN_DPI) / POINTS_PER_INCH;

        // The advance is the number of pixels left-to-right (X dimension) for the given font.
        // We're finding a proportional factor here with the design units in "ems", not an actual pixel measurement.

        // Now we play trickery with the font size. Scale by the DPI to get the height we expect.
        heightDesired *= (static_cast<float>(dpi) / static_cast<float>(USER_DEFAULT_SCREEN_DPI));

        const float widthAdvance = static_cast<float>(advanceInDesignUnits) / fontMetrics.designUnitsPerEm;

        // Use the real pixel height desired by the "em" factor for the width to get the number of pixels
        // we will need per character in width. This will almost certainly result in fractional X-dimension pixels.
        const float widthApprox = heightDesired * widthAdvance;

        // Since we can't deal with columns of the presentation grid being fractional pixels in width, round to the nearest whole pixel.
        const float widthExact = round(widthApprox);

        // Now reverse the "em" factor from above to turn the exact pixel width into a (probably) fractional
        // height in pixels of each character. It's easier for us to pad out height and align vertically
        // than it is horizontally.
        const auto fontSize = widthExact / widthAdvance;

        // Now figure out the basic properties of the character height which include ascent and descent
        // for this specific font size.
        const float ascent = (fontSize * fontMetrics.ascent) / fontMetrics.designUnitsPerEm;
        const float descent = (fontSize * fontMetrics.descent) / fontMetrics.designUnitsPerEm;

        // Get the gap.
        const float gap = (fontSize * fontMetrics.lineGap) / fontMetrics.designUnitsPerEm;
        const float halfGap = gap / 2;

        // We're going to build a line spacing object here to track all of this data in our format.
        DWRITE_LINE_SPACING lineSpacing = {};
        lineSpacing.method = DWRITE_LINE_SPACING_METHOD_UNIFORM;

        // We need to make sure the baseline falls on a round pixel (not a fractional pixel).
        // If the baseline is fractional, the text appears blurry, especially at small scales.
        // Since we also need to make sure the bounding box as a whole is round pixels
        // (because the entire console system maths in full cell units),
        // we're just going to ceiling up the ascent and descent to make a full pixel amount
        // and set the baseline to the full round pixel ascent value.
        //
        // For reference, for the letters "ag":
        // ...
        //          gggggg      bottom of previous line
        //
        // -----------------    <===========================================|
        //                         | topSideBearing       |  1/2 lineGap    |
        // aaaaaa   ggggggg     <-------------------------|-------------|   |
        //      a   g    g                                |             |   |
        //  aaaaa   ggggg                                 |<-ascent     |   |
        // a    a   g                                     |             |   |---- lineHeight
        // aaaaa a  gggggg      <----baseline, verticalOriginY----------|---|
        //          g     g                               |<-descent    |   |
        //          gggggg      <-------------------------|-------------|   |
        //                         | bottomSideBearing    | 1/2 lineGap     |
        // -----------------    <===========================================|
        //
        // aaaaaa   ggggggg     top of next line
        // ...
        //
        // Also note...
        // We're going to add half the line gap to the ascent and half the line gap to the descent
        // to ensure that the spacing is balanced vertically.
        // Generally speaking, the line gap is added to the ascent by DirectWrite itself for
        // horizontally drawn text which can place the baseline and glyphs "lower" in the drawing
        // box than would be desired for proper alignment of things like line and box characters
        // which will try to sit centered in the area and touch perfectly with their neighbors.

        const auto fullPixelAscent = ceil(ascent + halfGap);
        const auto fullPixelDescent = ceil(descent + halfGap);
        lineSpacing.height = fullPixelAscent + fullPixelDescent;
        lineSpacing.baseline = fullPixelAscent;

        // According to MSDN (https://docs.microsoft.com/en-us/windows/win32/api/dwrite_3/ne-dwrite_3-dwrite_font_line_gap_usage)
        // Setting "ENABLED" means we've included the line gapping in the spacing numbers given.
        lineSpacing.fontLineGapUsage = DWRITE_FONT_LINE_GAP_USAGE_ENABLED;

        // Create the font with the fractional pixel height size.
        // It should have an integer pixel width by our math above.
        // Then below, apply the line spacing to the format to position the floating point pixel height characters
        // into a cell that has an integer pixel height leaving some padding above/below as necessary to round them out.
        Microsoft::WRL::ComPtr<IDWriteTextFormat> format;
        THROW_IF_FAILED(_dwriteFactory->CreateTextFormat(fontName.data(),
                                                         nullptr,
                                                         weight,
                                                         style,
                                                         stretch,
                                                         fontSize,
                                                         localeName.data(),
                                                         &format));

        THROW_IF_FAILED(format.As(&textFormat));

        Microsoft::WRL::ComPtr<IDWriteTextAnalyzer> analyzer;
        THROW_IF_FAILED(_dwriteFactory->CreateTextAnalyzer(&analyzer));
        THROW_IF_FAILED(analyzer.As(&textAnalyzer));

        fontFace = face;

        THROW_IF_FAILED(textFormat->SetLineSpacing(lineSpacing.method, lineSpacing.height, lineSpacing.baseline));
        THROW_IF_FAILED(textFormat->SetParagraphAlignment(DWRITE_PARAGRAPH_ALIGNMENT_NEAR));
        THROW_IF_FAILED(textFormat->SetWordWrapping(DWRITE_WORD_WRAPPING_NO_WRAP));

        // The scaled size needs to represent the pixel box that each character will fit within for the purposes
        // of hit testing math and other such multiplication/division.
        COORD coordSize = { 0 };
        coordSize.X = gsl::narrow<SHORT>(widthExact);
        coordSize.Y = gsl::narrow_cast<SHORT>(lineSpacing.height);

        // Unscaled is for the purposes of re-communicating this font back to the renderer again later.
        // As such, we need to give the same original size parameter back here without padding
        // or rounding or scaling manipulation.
        const COORD unscaled = desired.GetEngineSize();

        const COORD scaled = coordSize;

        actual.SetFromEngine(fontName,
                             desired.GetFamily(),
                             textFormat->GetFontWeight(),
                             false,
                             scaled,
                             unscaled);
    }
    CATCH_RETURN();

    return S_OK;
}

// Routine Description:
// - Helps convert a GDI COLORREF into a Direct2D ColorF
// Arguments:
// - color - GDI color
// Return Value:
// - D2D color
[[nodiscard]] D2D1_COLOR_F DxEngine::_ColorFFromColorRef(const COLORREF color) noexcept
{
    // Converts BGR color order to RGB.
    const UINT32 rgb = ((color & 0x0000FF) << 16) | (color & 0x00FF00) | ((color & 0xFF0000) >> 16);

    switch (_chainMode)
    {
    case SwapChainMode::ForHwnd:
    {
        return D2D1::ColorF(rgb);
    }
    case SwapChainMode::ForComposition:
    {
        // Get the A value we've snuck into the highest byte
        const BYTE a = ((color >> 24) & 0xFF);
        const float aFloat = a / 255.0f;

        return D2D1::ColorF(rgb, aFloat);
    }
    default:
        FAIL_FAST_HR(E_NOTIMPL);
    }
}

// Routine Description:
// - Updates the selection background color of the DxEngine
// Arguments:
// - color - GDI Color
// Return Value:
// - N/A
void DxEngine::SetSelectionBackground(const COLORREF color, const float alpha) noexcept
{
    _selectionBackground = D2D1::ColorF(GetRValue(color) / 255.0f,
                                        GetGValue(color) / 255.0f,
                                        GetBValue(color) / 255.0f,
                                        alpha);
}

// Routine Description:
// - Changes the antialiasing mode of the renderer. This must be called before
//   _PrepareRenderTarget, otherwise the renderer will default to
//   D2D1_TEXT_ANTIALIAS_MODE_GRAYSCALE.
// Arguments:
// - antialiasingMode: a value from the D2D1_TEXT_ANTIALIAS_MODE enum. See:
//          https://docs.microsoft.com/en-us/windows/win32/api/d2d1/ne-d2d1-d2d1_text_antialias_mode
// Return Value:
// - N/A
void DxEngine::SetAntialiasingMode(const D2D1_TEXT_ANTIALIAS_MODE antialiasingMode) noexcept
try
{
    if (_antialiasingMode != antialiasingMode)
    {
        _antialiasingMode = antialiasingMode;
        LOG_IF_FAILED(InvalidateAll());
    }
}
CATCH_LOG()

// Method Description:
// - Update our tracker of the opacity of our background. We can only
//   effectively render cleartype text onto fully-opaque backgrounds. If we're
//   rendering onto a transparent surface (like acrylic), then cleartype won't
//   work correctly, and will actually just additively blend with the
//   background. This is here to support GH#5098.
// Arguments:
// - opacity: the new opacity of our background, on [0.0f, 1.0f]
// Return Value:
// - <none>
void DxEngine::SetDefaultTextBackgroundOpacity(const float opacity) noexcept
try
{
    _defaultTextBackgroundOpacity = opacity;

    // Make sure we redraw all the cells, to update whether they're actually
    // drawn with cleartype or not.
    // We don't terribly care if this fails.
    LOG_IF_FAILED(InvalidateAll());
}
CATCH_LOG()

// Method Description:
// - Informs this render engine about certain state for this frame at the
//   beginning of this frame. We'll use it to get information about the cursor
//   before PaintCursor is called. This enables the DX renderer to draw the
//   cursor underneath the text.
// - This is called every frame. When the cursor is Off or out of frame, the
//   info's cursorInfo will be set to std::nullopt;
// Arguments:
// - info - a RenderFrameInfo with information about the state of the cursor in this frame.
// Return Value:
// - S_OK
[[nodiscard]] HRESULT DxEngine::PrepareRenderInfo(const RenderFrameInfo& info) noexcept
{
    _drawingContext->cursorInfo = info.cursorInfo;
    return S_OK;
}
