nf-uxtheme-bufferedpaintsetalpha.md

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NF:uxtheme.BufferedPaintSetAlpha	BufferedPaintSetAlpha function (uxtheme.h)	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).	BufferedPaintSetAlpha BufferedPaintSetAlpha function [Windows Controls] _shell_BufferedPaintSetAlpha _shell_BufferedPaintSetAlpha_cpp controls.BufferedPaintSetAlpha controls._shell_BufferedPaintSetAlpha uxtheme/BufferedPaintSetAlpha	controls\BufferedPaintSetAlpha.htm	Controls	VS|Controls|~\controls\userex\functions\bufferedpaintsetalpha.htm	12/05/2018	BufferedPaintSetAlpha, BufferedPaintSetAlpha function [Windows Controls], _shell_BufferedPaintSetAlpha, _shell_BufferedPaintSetAlpha_cpp, controls.BufferedPaintSetAlpha, controls._shell_BufferedPaintSetAlpha, uxtheme/BufferedPaintSetAlpha	uxtheme.h		Windows	Windows Vista [desktop apps only]	Windows Server 2008 [desktop apps only]											UxTheme.dll		Windows			19H1	BufferedPaintSetAlpha uxtheme/BufferedPaintSetAlpha	c++	APIRef kbSyntax	DllExport	UxTheme.dll	BufferedPaintSetAlpha

BufferedPaintSetAlpha function

-description

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).

-parameters

-param hBufferedPaint

Type: HPAINTBUFFER

The handle of the buffered paint context, obtained through BeginBufferedPaint.

-param prc [in]

Type: const RECT*

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.

-param alpha

Type: BYTE

The alpha value to set. The alpha value can range from zero (fully transparent) to 255 (fully opaque).

-returns

Type: HRESULT

If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

-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.