SetAlpha Macro

Microchip Graphics Library

SetAlpha Macro

#define SetAlpha(alpha) (_alpha = alpha)

Overview

This macro sets the alpha value. Enabling this feature requires the macros USE_ALPHABLEND_LITE defined in the GraphicsConfig.h. See USE_ALPHABLEND_LITE for information on supported primitive rendering functions.

Input Parameters

Description

alpha

Defines the alpha blending percentage of the new color set by SetColor() to the existing pixel color. Valid values for alpha for pure primitive layer implementation are:

100 : no alpha blending, color set by last SetColor() call will replace the pixels.
75 : alpha blending with new color set by last SetColor() call will be alpha blended with 75% to the existing pixel colors.
50 : alpha blending with new color set by last SetColor() call will be alpha blended with 50% to the existing pixel colors.
25 : alpha blending with new color set by last SetColor() call will be alpha blended with 25% to the existing pixel colors.

Returns

None

Side Effects

none

Example

Copy Code

SetAlpha(50);       // set alpha level
SetColor(BLUE);     // set color to use
Bar(5,10,30,50);    // render an alpha blended Bar

Library API > Graphics Primitive Layer API > Alpha Blending Functions > SetAlpha Macro

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