ALLEGRO_LOCKED_REGION(3)

NAME

ALLEGRO_LOCKED_REGION - Allegro 5 API

SYNOPSIS

    #include <allegro5/allegro.h>
    typedef struct ALLEGRO_LOCKED_REGION ALLEGRO_LOCKED_REGION;

DESCRIPTION

Users who wish to manually edit or read from a bitmap are required to lock it first. The ALLEGRO_LOCKED_REGION structure represents the locked region of the bitmap. This call will work with any bitmap, including memory bitmaps.

    typedef struct ALLEGRO_LOCKED_REGION {
       void *data;
       int format;
       int pitch;
       int pixel_size;
    } ALLEGRO_LOCKED_REGION;

•   data points to the leftmost pixel of the first row (row 0) of the locked region.

•   format indicates the pixel format of the data.

•   pitch gives the size in bytes of a single row (also known as the stride). The pitch may be greater than width * pixel_size due to padding; this is not uncommon. It is also not uncommon for the pitch to be negative (the bitmap may be upside down).

•   pixel_size is the number of bytes used to represent a single pixel.

SEE ALSO

al_lock_bitmap(3), al_lock_bitmap_region(3), al_unlock_bitmap(3), ALLEGRO_PIXEL_FORMAT(3)