PixelSurround

typedef struct _PixelSurround PixelSurround;

enum PixelSurroundMode

typedef enum
{
  PIXEL_SURROUND_SMEAR,
  PIXEL_SURROUND_BACKGROUND
} PixelSurroundMode;

pixel_surround_new ()

PixelSurround*      pixel_surround_new                  (TileManager *tiles,
                                                         gint width,
                                                         gint height,
                                                         PixelSurroundMode mode);

PixelSurround provides you a contiguous read-only view of the area surrounding a pixel. It is an efficient pixel access strategy for interpolation algorithms.

pixel_surround_set_bg ()

void                pixel_surround_set_bg               (PixelSurround *surround,
                                                         const guchar *bg);

This sets the color that the PixelSurround uses when in PIXEL_SURROUND_BACKGROUND mode for pixels that are not covered by the tile manager.

pixel_surround_lock ()

const guchar*       pixel_surround_lock                 (PixelSurround *surround,
                                                         gint x,
                                                         gint y,
                                                         gint *rowstride);

Gives access to a region of pixels. The upper left corner is specified by the x and y parameters. The size of the region is determined by the dimensions given when creating the surround.

When you don't need to read from the pixels any longer, you should unlock the surround using pixel_surround_unlock(). If you need a different region, just call pixel_surround_lock() again.

pixel_surround_release ()

void                pixel_surround_release              (PixelSurround *surround);

Unlocks pixels locked by surround. See pixel_surround_lock().

pixel_surround_destroy ()

void                pixel_surround_destroy              (PixelSurround *surround);

Unlocks pixels and frees any resources allocated for surround. You must not use surround any longer after calling this function.