Sets the alpha to a specified value in a given rectangle. The alpha controls the amount of transparency applied when blending with the buffer onto the destination target device context (DC).
Syntax
HRESULT BufferedPaintSetAlpha(
HPAINTBUFFER hBufferedPaint,
const RECT *prc,
BYTE alpha
);
Parameters
- hBufferedPaint
-
The handle of the buffered paint context, obtained through BeginBufferedPaint.
- prc
-
[in] A pointer to a >RECT structure that specifies the rectangle in which to set the alpha. Set this parameter to NULL to specify the entire buffer.
- alpha
-
The alpha value to set. The alpha value can range from zero (fully transparent) to 255 (fully opaque).
Return Value
Returns S_OK if successful, or an error value otherwise.
Remarks
This function sets the alpha value for each pixel in the target rectangle. Passing an alpha value of 255 makes pixels fully opaque. The BufferedPaintMakeOpaque macro, which is defined in uxtheme.h, sets alpha values to 255. It is typically used to call GDI to draw into a memory buffer and then to make it opaque in order to draw it on glass.
Function Information
| Stock Implementation | UxTheme.dll |
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| Custom Implementation | No |
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| Header | uxtheme.h |
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| Import library | None |
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| Minimum operating systems |
Windows Vista |
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