excolmap(3alleg4)                Allegro manual                excolmap(3alleg4)

       excolmap - Creating graphical effects with color mapping tables. Allegro
       game programming library.

       #include <allegro.h>

       Example excolmap

       This program demonstrates how to create custom graphic effects with the
       create_color_table function. Allegro drawing routines are affected by any
       color table you might have set up. In the first part of this example, a
       greyscale color table is set. The result is that a simple rectfill call,
       instead of drawing a rectangle with color zero, uses the already drawn
       pixels to determine the pixel to be drawn (read the comment of
       return_grey_color() for a precise description of the algorithm). In the
       second part of the test, the color table is changed to be an inverse
       table, meaning that any pixel drawn will be shown as its color values had
       been inverted.

       BITMAP(3alleg4), COLOR_MAP(3alleg4), END_OF_MAIN(3alleg4),
       PALETTE(3alleg4), RGB(3alleg4), RGB_MAP(3alleg4), SCREEN_H(3alleg4),
       SCREEN_W(3alleg4), allegro_error(3alleg4), allegro_init(3alleg4),
       allegro_message(3alleg4), blit(3alleg4), circlefill(3alleg4),
       clear_keybuf(3alleg4), color_map(3alleg4), create_bitmap(3alleg4),
       create_color_table(3alleg4), create_rgb_table(3alleg4),
       destroy_bitmap(3alleg4), drawing_mode(3alleg4), font(3alleg4),
       generate_332_palette(3alleg4), install_keyboard(3alleg4),
       keypressed(3alleg4), makecol(3alleg4), rectfill(3alleg4), rest(3alleg4),
       rgb_map(3alleg4), screen(3alleg4), set_gfx_mode(3alleg4),
       set_palette(3alleg4), textout_centre_ex(3alleg4), vsync(3alleg4)

Allegro                           version 4.4.3                excolmap(3alleg4)