vips_region_new ()

VipsRegion *vips_region_new (VipsImage *image);

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

See also:vips_region_prepare().

[constructor]

vips_region_buffer ()

intvips_region_buffer (VipsRegion *reg,constVipsRect *r);

The region is transformed so that at leastr pixels are available as amemory buffer that can be written to.

vips_region_image ()

intvips_region_image (VipsRegion *reg,constVipsRect *r);

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

vips_region_region ()

intvips_region_region (VipsRegion *reg,VipsRegion *dest,constVipsRect *r,int x,int y);

MakeVIPS_REGION_ADDR() onreg go todest instead.

r is the part ofreg which you want to be able to address (thiseffectively becomes the valid field), (x,y) is the top LH corner of thecorresponding area indest.

Performs all clipping necessary to ensure thatreg->valid is indeedvalid.

If the region we attach to is moved or destroyed, we can be left withdangling pointers! If the region we attach to is on another image, thetwo images must have the same sizeof(pel).

vips_region_equalsregion ()

intvips_region_equalsregion (VipsRegion *reg1,VipsRegion *reg2);

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

123

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

vips_region_position ()

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

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

vips_region_paint ()

voidvips_region_paint (VipsRegion *reg,constVipsRect *r,int value);

Paintsvalue intoreg covering rectangler.r is clipped againstreg->valid.

For int images,value ispassed tomemset(), 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 againstreg->valid.

See also:vips_region_black().

vips_region_paint_pel ()

voidvips_region_paint_pel (VipsRegion *reg,constVipsRect *r,constVipsPel *ink);

Paintsink intoreg covering rectangler.r is clipped againstreg->valid.

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

See also:vips_region_paint().

vips_region_black ()

voidvips_region_black (VipsRegion *reg);

Paints 0 into the valid part ofreg.

See also:vips_region_paint().

vips_region_copy ()

voidvips_region_copy (VipsRegion *reg,VipsRegion *dest,constVipsRect *r,int x,int y);

Copy from one region to another. Copy arear from insidereg todest,positioning the area of pixels atx,y. The two regions must have pixelswhich are the same size.

See also:vips_region_paint().

vips_region_shrink_method ()

intvips_region_shrink_method (VipsRegion *from,VipsRegion *to,constVipsRect *target,VipsRegionShrink method);

Write the pixelstarget into from the x2 larger area infrom.Non-complex uncoded images and LABQ only. Images with alpha (seevips_image_hasalpha()) shrink with pixels scaled by alpha to avoid fringing.

method selects the method used to do the 2x2 shrink.

See also:vips_region_copy().

vips_region_shrink ()

intvips_region_shrink (VipsRegion *from,VipsRegion *to,constVipsRect *target);

Write the pixelstarget into from the x2 larger area infrom.Non-complex uncoded images and LABQ only. Images with alpha (seevips_image_hasalpha()) shrink with pixels scaled by alpha to avoid fringing.

This is a compatibility stub that just callsvips_region_shrink_method().

See also:vips_region_shrink_method().

[skip]

vips_region_prepare ()

intvips_region_prepare (VipsRegion *reg,constVipsRect *r);

vips_region_prepare() fillsreg with pixels. After calling,you can address at least the arear withVIPS_REGION_ADDR() and getvalid pixels.

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

Usevips_sink_screen() to calculate an area of pixels in thebackground.

See also:vips_sink_screen(),vips_region_prepare_to().

vips_region_prepare_to ()

intvips_region_prepare_to (VipsRegion *reg,VipsRegion *dest,constVipsRect *r,int x,int y);

Likevips_region_prepare(): fillreg with the pixels in arear.

Unlikevips_region_prepare(), rather than writing the result toreg, thepixels are written intodest at offsetx,y.

Also unlikevips_region_prepare(),dest is not set up for writing foryou withvips_region_buffer(). You canpointdest at anything, and pixels really will be written there.This makesvips_region_prepare_to() useful for making the ends ofpipelines.

See also:vips_region_prepare(),vips_sink_disc().

vips_region_fetch ()

VipsPel *vips_region_fetch (VipsRegion *region,int left,int top,int width,int height,size_t *len);

Generate an area of pixels and return a copy. The result must be freedwithg_free(). The requested area must be completely inside the image.

This is equivalent tovips_region_prepare(), followed by a memcpy. It isconvenient for language bindings.

vips_region_width ()

intvips_region_width (VipsRegion *region);

vips_region_height ()

intvips_region_height (VipsRegion *region);

vips_region_invalidate ()

voidvips_region_invalidate (VipsRegion *reg);

Mark a region as containing invalid pixels. Calling this function meansthat the next timevips_region_prepare() is called, the region will berecalculated.

This is faster than callingvips_image_invalidate_all(), but obviously onlyaffects a single region.

See also:vips_image_invalidate_all(),vips_region_prepare().

VIPS_COUNT_PIXELS()

#define VIPS_COUNT_PIXELS(R, N) vips__region_count_pixels(R, N)

VIPS_REGION_LSKIP()

#define             VIPS_REGION_LSKIP(R)

VIPS_REGION_N_ELEMENTS()

#define             VIPS_REGION_N_ELEMENTS(R)

VIPS_REGION_SIZEOF_ELEMENT()

#define             VIPS_REGION_SIZEOF_ELEMENT(R)

VIPS_REGION_SIZEOF_PEL()

#define             VIPS_REGION_SIZEOF_PEL(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 theVipsRect (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 theVipsRegion, thatis, the pixel at (R->valid.left,R->valid.top).

See also:vips_region_prepare().

enum VipsRegionShrink

How to calculate the output pixels when shrinking a 2x2 region.