Post

sharp caps out at affine, but libvips itself doesn't: vips mapim takes an arbitrary coordinate map, so a 3x3 homography works — wasm-vips exposes it too. In the browser a perspective warp is just a textured quad in WebGL, or cv.warpPerspective in opencv.js. No cloud round-trip needed.

22 July

libvips has arbitrary 2D transforms, though I don't think sharp exposes them.

Michael G

@g12n.de

libvips.orgVips.Image.mapimReference for Vips.Image.mapim

It's vips_quadratic or vips_mapim … maybe. Right? The documentation is a bit esoteric. www.libvips.org/API/8.17/met... Yeah, sharp has a lot of issues open for that topic. github.com/lovell/sharp... github.com/lovell/sharp... … Which are not really helped along by devs pointing to vips_affine.

stackoverflow.comHow to perform perspective distort transformation in VIPS?Is it possible to do the following ImageMagick perspective distort command using VIPS? If so, what would the command be (using ruby-vips)? $ convert my_file.png -matte -virtual-pixel transparent +

Oh, perspective distort example in this ancient stackoverflow answer: stackoverflow.com/a/50219715/8...

Yes, `mapim`. You can use `xyz` to make an image where the value of a pixel is its coordinate, then transform that with the formula for your transformation. There's an example in pyvips: github.com/libvips/pyvi...