al_grab_font_from_bitmap(3)al_grab_font_from_bitmap(3)NAMEal_grab_font_from_bitmap - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro_font.h>
ALLEGRO_FONT *al_grab_font_from_bitmap(ALLEGRO_BITMAP *bmp,
int ranges_n, const int ranges[])
DESCRIPTION
Creates a new font from an Allegro bitmap. You can delete the bitmap
after the function returns as the font will contain a copy for itself.
Parameters:
· bmp: The bitmap with the glyphs drawn onto it
· n: Number of unicode ranges in the bitmap.
· ranges: 'n' pairs of first and last unicode point to map glyphs to
for each range.
The bitmap format is as in the following example, which contains three
glyphs for 1, 2 and 3.
.............
. 1 .222.333.
. 1 . 2. 3.
. 1 .222.333.
. 1 .2 . 3.
. 1 .222.333.
.............
In the above illustration, the dot is for pixels having the background
color. It is determined by the color of the top left pixel in the bit‐
map. There should be a border of at least 1 pixel with this color to
the bitmap edge and between all glyphs.
Each glyph is inside a rectangle of pixels not containing the back‐
ground color. The height of all glyph rectangles should be the same,
but the width can vary.
The placement of the rectangles does not matter, except that glyphs are
scanned from left to right and top to bottom to match them to the spec‐
ified unicode codepoints.
The glyphs will simply be drawn using al_draw_bitmap(3), so usually you
will want the rectangles filled with full transparency and the glyphs
drawn in opaque white.
Examples:
int ranges[] = {32, 126};
al_grab_font_from_bitmap(bitmap, 1, ranges)
int ranges[] = {
0x0020, 0x007F, /* ASCII */
0x00A1, 0x00FF, /* Latin 1 */
0x0100, 0x017F, /* Extended-A */
0x20AC, 0x20AC}; /* Euro */
al_grab_font_from_bitmap(bitmap, 4, ranges)
The first example will grab glyphs for the 95 standard printable ASCII
characters, beginning with the space character (32) and ending with the
tilde character (126). The second example will map the first 96 glyphs
found in the bitmap to ASCII range, the next 95 glyphs to Latin 1, the
next 128 glyphs to Extended-A, and the last glyph to the Euro charac‐
ter. (This is just the characters found in the Allegro 4 font.)
SEE ALSOal_load_bitmap(3), al_grab_font_from_bitmap(3)Allegro reference manualal_grab_font_from_bitmap(3)
