Vips_resize() normally uses VIPS_KERNEL_LANCZOS3 for the final reduce, you

The default value is 2.0 (very close to fair resampling To speed up downsizing by having vips_shrink() to shrink See also: vips_shrink(), vips_resize(), VipsInterpolate. This operation does not change xres or yres. If your images have been through vips_premultiply(), Image are normally treated as unpremultiplied, so this operation can be usedĭirectly on PNG images. You can set other extend types with extend Is just large enough to cover the whole of theīy default, new pixels are filled with background Is a four-element int array of left, top, width, height. The section of the output space defined by oarea X and Y are the coordinates in output image. X = a * ( x + idx ) + b * ( y + idy ) + odx Y = c * ( x + idx ) + d * ( y + idy ) + doy where : x and y are the coordinates in input image. To control the types of error that will cause loading to fail. To set the rendering intent for any ICC transform. Input image has no ICC profile, or if the profile embedded in the Will be transformed to the target colourspace before writing to the To the filename of an ICC profile, the image This can give better results, but canĪlso be far slower, since tricks like JPEG shrink-on-load cannot be used in Shrinking is normally done in sRGB colourspace. Normally any orientation tags on the input image (such as EXIF tags) are Is VIPS_SIZE_FORCE, the image aspect ratio will be broken and the To VIPS_SIZE_DOWN, the operation will only downsize and will just To VIPS_SIZE_UP, the operation will only upsize and will just Normally the operation will upsize or downsize as required to fit the image , then the output image will fill the whole of the width To a very large number to ignore that dimension. Specify a separate height with the height The output image will fit within a square of size width To thumbnail all pages or frames, pass n=-1 to the loader in Vips_thumbnail_source() to thumbnail from an arbitrary byte source.īy default, libvips will only the first frame of animated or multipage See vips_thumbnail_buffer() to thumbnail from a memory buffer, or The output should be high quality, and the operation should be Shrink-on-load features available in the file import library, using a block Shrinking is done in three stages: using any : VipsFailOn, load error types to fail on : gchararray, fallback import ICC profile : gboolean, perform shrink in linear light : VipsInteresting, shrink and crop to fill target : gboolean, don't rotate upright using orientation tag : VipsSize, upsize, downsize, both or force Is only there for emergencies, don't use it unless you really have to.Īs a separate thing, ` vips_mapim() can apply arbitrary 2D image transforms Shrink-on-load, giving a (potentially) huge speedup. Because loadĪnd resize happen together, it can exploit tricks like JPEG and TIFF Vips_affine() and others to implement a general, high-quality imageįinally, vips_thumbnail() combines load and resize in one operation, and addsĬolour management and correct handling of alpha transparency. It strings together combinations of vips_shrink(), vips_reduce(), Next, vips_resize() specialises in the common task of image reduce andĮnlarge. It will give poor results for small size reductions: It's very fast and uses an adaptive kernel for Vips_reduce() is like vips_affine(), but it can only shrink images, it can'tĮnlarge, rotate, or skew. Good results for very large shrinks: you'll see aliasing. Use to generate pixels, see vips_interpolate_new().

Sort of 2D transform which preserves straight lines so any combination of These operations build on each other in a set of layers.įirst, vips_affine() applies an affine transform to an image.

Image resizer api