D2D1RectF

D2D1_RECT_F, commonly referred to as D2D1_RECT_F or in documentation as D2D1_RECT_F, is a structure used by the Direct2D API to define an axis-aligned rectangle with floating-point coordinates. It provides a floating-point alternative to the integer rectangle types in Windows, and its coordinates are expressed in device-independent pixels (DIPs) relative to a render target.

The structure contains four members: left, top, right, and bottom, all of type FLOAT. The rectangle is specified by the upper-left corner (left, top) and the lower-right corner (right, bottom). A valid rectangle satisfies right >= left and bottom >= top. Since the coordinates are floating-point, the rectangle can represent fractional positions and dimensions, which is useful for high-DPI rendering and transforms.

D2D1_RECT_F is commonly used to describe drawing extents, clipping regions, and hit-testing bounds within Direct2D operations. It can be created directly by assigning values to its members, or by using helper constructors such as D2D1::RectF(left, top, right, bottom) to construct a D2D1_RECT_F instance in a single call.

In practice, D2D1_RECT_F complements the integer D2D1_RECT_L type and is widely used with methods that take a rectangle parameter, including drawing, filling, and clipping operations on render targets and geometry interfaces. When interchanging between integer and floating-point rectangles, conversions may be needed to align with pixel boundaries or transform results.

See also: D2D1_RECT_L, D2D1::RectF, ID2D1RenderTarget methods that accept D2D1_RECT_F.