ALLEGRO_LOCKED_REGION (3alleg5)

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

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;

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

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format indicates the pixel format of the data.

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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).

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

al_lock_bitmap(3alleg5), al_lock_bitmap_region(3alleg5), al_unlock_bitmap(3alleg5), ALLEGRO_PIXEL_FORMAT(3alleg5)