I didn't know about image/draw, thank you! The linked doc has a very helpful example and references a a good blog post.
Am Dienstag, 5. September 2017 04:46:24 UTC+2 schrieb James Fargher: > > I think your ImageSetter is already in the standard library > https://golang.org/pkg/image/draw/#Image It's a little bit subtle because > different packages have the immutable Image and mutable Image > > It might save you some work by using golang.org/x/image library which > already has affine transforms. > https://godoc.org/golang.org/x/image/draw#Kernel.Transform > > On 4 September 2017 at 08:54, Florian Florensen <fl...@posteo.de > <javascript:>> wrote: > >> Hello, >> >> I'd like to rotate, scale, ... images by moving pixels using affine >> transformations. For example, the get a points x, y position after a >> translating it by m, n pixels, you can just add m resp n to x and y: >> >> x' = x + m >> y' = y + n >> >> >> So the task is basically just to iterate over the images pixels. This was >> done by directly accessing the Pix-slice >> <https://golang.org/pkg/image/#Paletted>, but not every every in-memory >> image has this field. >> >> The current solution uses reflection and is extracting the Set >> function (and, as a nice side effect, a new image with the same type and >> resolution as the input image): >> >> func getSet(im image.Image) (func(int, int, color.Color), image.Image, >> error) { >> set := func(x, y int, c color.Color) {} >> switch tmp := im.(type) { >> case *image.Alpha: >> im = image.NewAlpha(tmp.Rect) >> set = im.(*image.Alpha).Set >> ... >> default: >> return nil, nil, fmt.Errorf("%T has no function Set", im) >> } >> return set, im, nil >> } >> >> My favourited approach would be to use an interface which adds Set it to >> image.Image. This works, but I obviously can't just throw an image.Image in. >> >> type ImageSetter interface { >> image.Image >> Set(int, int, color.Color) >> } >> >> What would be a go-like solution for this task? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
