FT800 Series Programmer Guide
Version 2.1
Document Reference No.: BRT_000030 Clearance No.: BRT#037
119
Copyright © Bridgetek Limited
4.24
COLOR_A
Set the current color alpha
Encoding
31 24 23 8 7 0
0x10
Reserved
alpha
Parameters
alpha
Alpha for the current color. The initial value is 255
Description
Sets the alpha value applied to drawn elements - points, lines, and bitmaps. How
the alpha value affects image pixels depends on BLEND_FUNC; the default behavior
is a transparent blend.
Examples
Drawing three characters with transparency 255, 128, and 64:
dl( BEGIN(BITMAPS) );
dl( VERTEX2II(50, 30, 31, 0x47) );
dl( COLOR_A( 128 ) );
dl( VERTEX2II(58, 38, 31, 0x47) );
dl( COLOR_A( 64 ) );
dl( VERTEX2II(66, 46, 31, 0x47) );
Graphics context
The value of alpha is part of the graphics context, as described in section 4.1
See also
COLOR_RGB, BLEND_FUNC
