1set_write_alpha_blender(3)      Allegro manual      set_write_alpha_blender(3)
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NAME

6       set_write_alpha_blender  -  Enables  the  special alpha-channel editing
7       mode. Allegro game programming library.
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SYNOPSIS

10       #include <allegro.h>
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13       void set_write_alpha_blender();
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DESCRIPTION

16       Enables the special alpha-channel editing mode, which is used for draw‐
17       ing  alpha  channels  over the top of an existing 32-bit RGB sprite, to
18       turn it into an RGBA format image. After calling this function, you can
19       set  the drawing mode to DRAW_MODE_TRANS and then write draw color val‐
20       ues (0-255) onto a 32-bit image.  This  will  leave  the  color  values
21       unchanged,  but  alter  the  alpha  to whatever values you are writing.
22       After enabling this mode you can also use draw_trans_sprite() to super‐
23       impose an 8-bit alpha mask over the top of an existing 32-bit sprite.
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SEE ALSO

27       set_alpha_blender(3),   draw_trans_sprite(3),   drawing_mode(3),  exal‐
28       pha(3), extrans(3)
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32Allegro                          version 4.2.2      set_write_alpha_blender(3)
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