vips_region_new ()

VipsRegion *
vips_region_new (VipsImage *image);

Create a region. VipsRegion s start out empty, you need to call vips_region_prepare() to fill them with pixels.

See also: vips_region_prepare().

vips_region_buffer ()

int
vips_region_buffer (VipsRegion *reg,
                    VipsRect *r);

The region is transformed so that at least r pixels are available as a memory buffer.

vips_region_image ()

int
vips_region_image (VipsRegion *reg,
                   VipsRect *r);

The region is transformed so that at least r pixels are available directly from the image. The image needs to be a memory buffer or represent a file on disc that has been mapped or can be mapped.

vips_region_region ()

int
vips_region_region (VipsRegion *reg,
                    VipsRegion *dest,
                    VipsRect *r,
                    int x,
                    int y);

Make VIPS_REGION_ADDR() on reg go to dest instead.

r is the part of reg which you want to be able to address (this effectively becomes the valid field), (x , y ) is the top LH corner of the corresponding area in dest .

Performs all clipping necessary to ensure that reg->valid is indeed valid.

If the region we attach to is modified, we can be left with dangling pointers! If the region we attach to is on another image, the two images must have the same sizeof( pel ).

vips_region_equalsregion ()

int
vips_region_equalsregion (VipsRegion *reg1,
                          VipsRegion *reg2);

Do two regions point to the same piece of image? ie.

	VIPS_REGION_ADDR( reg1, x, y ) == VIPS_REGION_ADDR( reg2, x, y ) &&
	*VIPS_REGION_ADDR( reg1, x, y ) == 
		*VIPS_REGION_ADDR( reg2, x, y ) for all x, y, reg1, reg2.

vips_region_position ()

int
vips_region_position (VipsRegion *reg,
                      int x,
                      int y);

Set the position of a region. This only affects reg->valid, ie. the way pixels are addressed, not reg->data, the pixels which are addressed. Clip against the size of the image. Do not allow negative positions, or positions outside the image.

vips_region_paint ()

void
vips_region_paint (VipsRegion *reg,
                   VipsRect *r,
                   int value);

Paints value into reg covering rectangle r . For int images, value is passed to memset(), so it usually needs to be 0 or 255. For float images, value is cast to a float and copied in to each band element.

r is clipped against reg->valid .

See also: vips_region_black().

vips_region_paint_pel ()

void
vips_region_paint_pel (VipsRegion *reg,
                       VipsRect *r,
                       VipsPel *ink);

Paints ink into reg covering rectangle r . r is clipped against reg->valid .

ink should be a byte array of the same size as an image pixel containing the binary value to write into the pixels.

See also: vips_region_paint().

vips_region_black ()

void
vips_region_black (VipsRegion *reg);

Paints 0 into the valid part of reg .

See also: vips_region_paint().

vips_region_copy ()

void
vips_region_copy (VipsRegion *reg,
                  VipsRegion *dest,
                  VipsRect *r,
                  int x,
                  int y);

Copy from one region to another. Copy area r from inside reg to dest , positioning the area of pixels at x , y . The two regions must have pixels which are the same size.

See also: vips_region_paint().

vips_region_prepare ()

int
vips_region_prepare (VipsRegion *reg,
                     VipsRect *r);

vips_region_prepare() fills reg with pixels. After calling, you can address at least the area r with VIPS_REGION_ADDR() and get valid pixels.

vips_region_prepare() runs in-line, that is, computation is done by the calling thread, no new threads are involved, and computation blocks until the pixels are ready.

Use vips_sink_screen() to calculate an area of pixels in the background.

See also: vips_sink_screen(), vips_region_prepare_to().

vips_region_prepare_to ()

int
vips_region_prepare_to (VipsRegion *reg,
                        VipsRegion *dest,
                        VipsRect *r,
                        int x,
                        int y);

Like vips_region_prepare(): fill reg with data, ready to be read from by our caller. Unlike vips_region_prepare(), rather than allocating memory local to reg for the result, we guarantee that we will fill the pixels in dest at offset x , y . In other words, we generate an extra copy operation if necessary.

Also unlike vips_region_prepare(), dest is not set up for writing for you with vips_region_buffer(). You can point dest at anything, and pixels really will be written there. This makes vips_region_prepare_to() useful for making the ends of pipelines, since it (effectively) makes a break in the pipe.

See also: vips_region_prepare(), vips_sink_disc().

vips_region_prepare_many ()

int
vips_region_prepare_many (VipsRegion **reg,
                          VipsRect *r);

vips_region_invalidate ()

void
vips_region_invalidate (VipsRegion *reg);

Mark a region as containing invalid pixels. Calling this function means that the next time vips_region_prepare() is called, the region will be recalculated.

This is faster than calling vips_image_invalidate_all(), but obviously only affects a single region.

See also: vips_image_invalidate_all(), vips_region_prepare().

vips_region_dump_all ()

void
vips_region_dump_all (void);

VIPS_REGION_LSKIP()

#define             VIPS_REGION_LSKIP( R )

VIPS_REGION_N_ELEMENTS()

#define             VIPS_REGION_N_ELEMENTS( R )

VIPS_REGION_SIZEOF_LINE()

#define             VIPS_REGION_SIZEOF_LINE( R )

VIPS_REGION_ADDR()

#define             VIPS_REGION_ADDR( R, X, Y )

This macro returns a pointer to a pixel in a region. The (X , Y ) coordinates need to be within the VipsRect (R->valid ).

If DEBUG is defined, you get a version that checks bounds for you.

See also: vips_region_prepare().

VIPS_REGION_ADDR_TOPLEFT()

#define VIPS_REGION_ADDR_TOPLEFT( R ) ((R)->data)

This macro returns a pointer to the top-left pixel in the VipsRegion, that is, the pixel at (R->valid.left , R->valid.top ).

See also: vips_region_prepare().