Direct2D Overview

Direct2D is a 2D graphics API that provides high performance, hardware-accelerated, and vector-based rendering of 2D graphics and rich text. It is designed for applications that require efficient and high-quality 2D drawing capabilities, such as user interfaces, games, and multimedia applications.

Key Features

Hardware Acceleration: Leverages the GPU for significant performance gains in rendering complex graphics.
Vector-Based Rendering: Supports scalable graphics, ensuring crisp output at any resolution.
Rich Set of Drawing Primitives: Includes support for shapes, lines, paths, text, images, and gradients.
Effects and Filters: Offers a wide range of built-in image effects and a framework for creating custom effects.
Integration: Seamlessly integrates with other Windows graphics technologies like Direct3D and GDI.
Text Rendering: Provides advanced text layout and rendering capabilities, including anti-aliasing and ClearType.

Core Concepts

Device and Device Context

The foundation of Direct2D rendering involves a Device, which represents the rendering hardware, and a Device Context, which is the object used to perform drawing operations. You obtain a device context from the device and use it to issue drawing commands.


// Example of creating a device context (simplified)
ID2D1Factory* pFactory;
D2D1CreateFactory(D2D1_FACTORY_TYPE_MULTI_THREADED, &pFactory);

// ... obtain HWND from your application ...
HWND hwnd = ...;
D2D1_RENDER_TARGET_PROPERTIES renderTargetProperties = D2D1::RenderTargetProperties();
ID2D1HwndRenderTarget* pRenderTarget;
pFactory->CreateHwndRenderTarget(
    renderTargetProperties,
    D2D1::HwndRenderTargetProperties(hwnd, D2D1::SizeU(width, height)),
    &pRenderTarget
);

// Now pRenderTarget is your device context.

Bitmaps

Direct2D allows you to create and render bitmaps. You can load images from files or create them dynamically. Bitmaps can be drawn directly to the render target or used as sources for effects.


// Example of creating a bitmap from a file (simplified)
IWICBitmapDecoder* pDecoder = NULL;
IWICBitmapFrameDecode* pSource = NULL;
IWICFormatConverter* pConverter = NULL;
ID2D1Bitmap* pBitmap = NULL;

// ... load WIC bitmap ...

pRenderTarget->CreateBitmapFromWicBitmap(pSource, &pBitmap);

// Draw the bitmap
pRenderTarget->BeginDraw();
pRenderTarget->DrawBitmap(pBitmap);
pRenderTarget->EndDraw();

Geometry

Direct2D provides robust support for vector geometry. You can define geometric shapes like rectangles, ellipses, paths, and arcs, and then render them using various brushes.


// Example of drawing a rectangle with a solid color brush
ID2D1SolidColorBrush* pBrush;
pRenderTarget->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::Blue), &pBrush);

D2D1_RECT_F rect = D2D1::RectF(50.0f, 50.0f, 150.0f, 150.0f);
pRenderTarget->FillRectangle(rect, pBrush);

pBrush->Release();

Next Steps

Explore the Getting Started section to set up your development environment, or dive into specific Concepts to understand the core components of Direct2D.