GdiTransparentBlt function (wingdi.h)
The GdiTransparentBlt function performs a bit-block transfer of the color data corresponding to a rectangle of pixels from the specified source device context into a destination device context.
Syntax
BOOL GdiTransparentBlt(
[in] HDC hdcDest,
[in] int xoriginDest,
[in] int yoriginDest,
[in] int wDest,
[in] int hDest,
[in] HDC hdcSrc,
[in] int xoriginSrc,
[in] int yoriginSrc,
[in] int wSrc,
[in] int hSrc,
[in] UINT crTransparent
);
Parameters
[in] hdcDest
A handle to the destination device context.
[in] xoriginDest
The x-coordinate, in logical units, of the upper-left corner of the destination rectangle.
[in] yoriginDest
The y-coordinate, in logical units, of the upper-left corner of the destination rectangle.
[in] wDest
The width, in logical units, of the destination rectangle.
[in] hDest
The height, in logical units, of the destination rectangle.
[in] hdcSrc
A handle to the source device context.
[in] xoriginSrc
The x-coordinate, in logical units, of the source rectangle.
[in] yoriginSrc
The y-coordinate, in logical units, of the source rectangle.
[in] wSrc
The width, in logical units, of the source rectangle.
[in] hSrc
The height, in logical units, of the source rectangle.
[in] crTransparent
The RGB color in the source bitmap to treat as transparent.
Return value
If the function succeeds, the return value is TRUE.
If the function fails, the return value is FALSE.
Remarks
The GdiTransparentBlt function works with compatible bitmaps (DDBs).
The GdiTransparentBlt function supports all formats of source bitmaps. However, for 32 bpp bitmaps, it just copies the alpha value over. Use AlphaBlend to specify 32 bits-per-pixel bitmaps with transparency.
If the source and destination rectangles are not the same size, the source bitmap is stretched to match the destination rectangle. When the SetStretchBltMode function is used, the iStretchMode modes of BLACKONWHITE and WHITEONBLACK are converted to COLORONCOLOR for the GdiTransparentBlt function.
The destination device context specifies the transformation type for the destination coordinates. The source device context specifies the transformation type for the source coordinates.
GdiTransparentBlt does not mirror a bitmap if either the width or height, of either the source or destination, is negative.
When used in a multiple monitor system, both hdcSrc and hdcDest must refer to the same device or the function will fail. To transfer data between DCs for different devices, convert the memory bitmap to a DIB by calling GetDIBits. To display the DIB to the second device, call SetDIBits or StretchDIBits.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | wingdi.h (include Windows.h) |
| Library | Gdi32.lib |
| DLL | Gdi32.dll |