al_hold_bitmap_drawing(3)al_hold_bitmap_drawing(3)NAMEal_hold_bitmap_drawing - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro.h>
void al_hold_bitmap_drawing(bool hold)
DESCRIPTION
Enables or disables deferred bitmap drawing. This allows for efficient
drawing of many bitmaps that share a parent bitmap, such as sub-bitmaps
from a tilesheet or simply identical bitmaps. Drawing bitmaps that do
not share a parent is less efficient, so it is advisable to stagger
bitmap drawing calls such that the parent bitmap is the same for large
number of those calls. While deferred bitmap drawing is enabled, the
only functions that can be used are the bitmap drawing functions and
font drawing functions. Changing the state such as the blending modes
will result in undefined behaviour. One exception to this rule are the
transformations. It is possible to set a new transformation while the
drawing is held.
No drawing is guaranteed to take place until you disable the hold.
Thus, the idiom of this function's usage is to enable the deferred bit‐
map drawing, draw as many bitmaps as possible, taking care to stagger
bitmaps that share parent bitmaps, and then disable deferred drawing.
As mentioned above, this function also works with bitmap and truetype
fonts, so if multiple lines of text need to be drawn, this function can
speed things up.
SEE ALSOal_is_bitmap_drawing_held(3)Allegro reference manualal_hold_bitmap_drawing(3)
