D2D1SIZEF

D2D1_SIZE_F is a data structure used in the Direct2D API to represent a two-dimensional size with floating-point components. It is defined in the Direct2D header files and is commonly used to pass width and height values in rendering-related calls. The structure contains two members: width and height, both of type FLOAT, which is typically a 32-bit floating-point type.

In practice, D2D1_SIZE_F stores sizes in device-independent pixels (DIPs), though the exact mapping to physical pixels depends on the render target’s DPI. This makes D2D1_SIZE_F suitable for DPI-aware layouts and resource descriptions where fractional sizes are needed.

Initialization and usage examples: in C, a D2D1_SIZE_F variable can be initialized with an aggregate initializer, such as D2D1_SIZE_F s = { 100.0f, 50.0f }; In C++, there is a helper function D2D1::SizeF(width, height) that returns a D2D1_SIZE_F initialized with the given values, providing a convenient alternative to direct struct initialization.

Relation to related types: D2D1_SIZE_F is the floating-point counterpart to D2D1_SIZE_U, which uses unsigned integers for width and height. This distinction allows developers to choose the appropriate representation based on whether fractional sizes are needed.

Typical contexts for use include describing the size of resources, layouts, bitmaps, gradients, or other rendering targets where a precise, floating-point dimension is required. As a plain POD (plain-old-data) structure, D2D1_SIZE_F has no methods or behavior beyond storing its two size components.

See also: D2D1_RECT_F, D2D1_POINT_2F, D2D1_SIZE_U, and the helper namespace D2D1::SizeF.