AgentSkillsCN

direct2d-rendering

在Windows平台上，运用Direct2D与DirectWrite图形渲染模式。在实现2D图形、文本渲染、硬件加速绘图、处理设备丢失，或与ID2D1DeviceContext协同工作时使用此功能。

SKILL.md
--- frontmatter
name: direct2d-rendering
description: Direct2D and DirectWrite graphics rendering patterns for Windows. Use when implementing 2D graphics, text rendering, hardware-accelerated drawing, handling device loss, or working with ID2D1DeviceContext.
metadata:
  author: DualTail
  version: "1.0"

Direct2D/DirectWrite Rendering

Graphics Stack

  • •Direct2D 1.1 - Hardware-accelerated 2D graphics
  • •DirectWrite - Advanced text rendering
  • •Direct3D 11 - GPU resources and swap chain
  • •DXGI 1.3 - Display management

Key Patterns

Creating Resources

cpp
wil::com_ptr<ID2D1SolidColorBrush> _brush;
THROW_IF_FAILED(_d2dContext->CreateSolidColorBrush(
    D2D1::ColorF(D2D1::ColorF::Black), &_brush));

BeginDraw/EndDraw with RAII

cpp
{
    HRESULT hr = S_OK;
    {
        _d2dContext->BeginDraw();
        auto endDraw = wil::scope_exit([&] { hr = _d2dContext->EndDraw(); });
        
        _d2dContext->Clear(D2D1::ColorF(1.0f, 1.0f, 1.0f));
        // Drawing operations...
    }
    
    if (hr == D2DERR_RECREATE_TARGET) 
    {
        RecreateDeviceResources();
    }
}

Text with DirectWrite

cpp
wil::com_ptr<IDWriteTextLayout> layout;
THROW_IF_FAILED(_dwriteFactory->CreateTextLayout(
    text.c_str(), static_cast<UINT32>(text.length()),
    _textFormat.get(), maxWidth, maxHeight, &layout));

_d2dContext->DrawTextLayout(D2D1::Point2F(x, y), layout.get(), _brush.get());

Best Practices

  1. •Validate device state before rendering
  2. •Handle D2DERR_RECREATE_TARGET for device loss
  3. •Cache brushes and layouts - minimize recreation
  4. •Use dirty region updates for performance
  5. •Handle DPI changes - recalculate layouts

DPI Awareness

cpp
void OnDpiChanged(UINT dpi) 
{
    _d2dContext->SetDpi(static_cast<float>(dpi), static_cast<float>(dpi));
    IconCache::SetDpi(dpi);
    RecreateDeviceDependentResources();
}

Text Rendering (ColorTextView)

  • •Use IDWriteTextLayout for complex text scenarios
  • •Implement virtualization for large documents
  • •Cache frequently used resources (brushes, layouts)
  • •Handle Unicode properly with UTF-16 encoding
  • •Optimize for smooth scrolling with async layout updates

Performance Considerations

  • •Async Operations: Use thread pools for heavy computations
  • •Caching: Implement LRU caches for expensive resources
  • •Memory: Monitor usage, implement cleanup strategies
  • •Rendering: Use offscreen rendering and dirty region updates
  • •Measurements: Profile performance-critical paths

Device Loss Handling

cpp
HRESULT hr = _d2dContext->EndDraw();
if (hr == D2DERR_RECREATE_TARGET) {
    // Device lost - recreate all device-dependent resources
    DiscardDeviceResources();
    CreateDeviceResources();
} else if (FAILED(hr)) {
    // Other error - log and handle
    Debug::Error(L"EndDraw failed: {:#x}", hr);
}