Method

VipsImagemapim

Declaration [src] 

int
vips_mapim (
  VipsImage* in,
  VipsImage** out,
  VipsImage* index,
  ...
)

Description [src]

Optional arguments:

  • interpolate: interpolate pixels with this
  • extend: VipsExtend how to generate new pixels
  • background: VipsArrayDouble colour for new pixels
  • premultiplied: %gboolean, images are already premultiplied

This operator resamples in using index to look up pixels. out is the same size as index, with each pixel being fetched from that position in in. That is:

out[x, y] = in[index[x, y]]

If index has one band, that band must be complex. Otherwise, index must have two bands of any format.

Coordinates in index are in pixels, with (0, 0) being the top-left corner of in, and with y increasing down the image. Use vips_xyz() to build index images.

interpolate defaults to bilinear.

By default, new pixels are filled with background. This defaults to zero (black). You can set other extend types with extend. #VIPS_EXTEND_COPY is better for image upsizing.

Image are normally treated as unpremultiplied, so this operation can be used directly on PNG images. If your images have been through vips_premultiply(), set premultiplied.

This operation does not change xres or yres. The image resolution needs to be updated by the application.

See vips_maplut() for a 1D equivalent of this operation.

See also: vips_xyz(), vips_affine(), vips_resize(), vips_maplut(), VipsInterpolate.

This method is not directly available to language bindings.

Parameters

out

Type: VipsImage

Output image.

The argument will be set by the function.
The caller of the method takes ownership of the returned data, and is responsible for freeing it.
index

Type: VipsImage

Index image.

The data is owned by the caller of the method.
...

Type: 

NULL-terminated list of optional named arguments.

Return value

Type: int

0 on success, -1 on error.