al_create_bitmap - Allegro 5 API
ALLEGRO_BITMAP *al_create_bitmap(int w, int h)
Creates a new bitmap using the bitmap format and flags for the current thread.
Blitting between bitmaps of differing formats, or blitting between memory
bitmaps and display bitmaps may be slow.
Unless you set the ALLEGRO_MEMORY_BITMAP flag, the bitmap is created for the
current display. Blitting to another display may be slow.
If a display bitmap is created, there may be limitations on the allowed
dimensions. For example a DirectX or OpenGL backend usually has a maximum
allowed texture size - so if bitmap creation fails for very large dimensions,
you may want to re-try with a smaller bitmap. Some platforms also dictate a
minimum texture size, which is relevant if you plan to use this bitmap with
the primitives addon. If you try to create a bitmap smaller than this, this
call will not fail but the returned bitmap will be a section of a larger
bitmap with the minimum size. The minimum size that will work on all platforms
is 32 by 32.
Some platforms do not directly support display bitmaps whose dimensions are not
powers of two. Allegro handles this by creating a larger bitmap that has
dimensions that are powers of two and then returning a section of that bitmap
with the dimensions you requested. This can be relevant if you plan to use
this bitmap with the primitives addon but shouldn't be an issue otherwise.
al_set_new_bitmap_format(3), al_set_new_bitmap_flags(3), al_clone_bitmap(3),