41 lines
1.2 KiB
Go
41 lines
1.2 KiB
Go
package crop
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import (
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"errors"
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goutil "git.gutmet.org/goutil.git/misc"
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"image"
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)
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func boundInt(i, min, max int) int {
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return goutil.IntMin(goutil.IntMax(i, min), max)
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}
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func bound(p image.Point, bounds image.Rectangle) image.Point {
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min := bounds.Min
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max := bounds.Max
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return image.Point{X: boundInt(p.X, min.X, max.X), Y: boundInt(p.Y, min.Y, max.Y)}
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}
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type subImageSupport interface {
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SubImage(rec image.Rectangle) image.Image
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}
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func Crop(img image.Image, topleft image.Point, w int, h int) (image.Image, error) {
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bounds := img.Bounds()
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topleft = bound(topleft, bounds)
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bottomright := bound(image.Point{X: topleft.X + w, Y: topleft.Y + h}, bounds)
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croparea := image.Rect(topleft.X, topleft.Y, bottomright.X, bottomright.Y)
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if timg, ok := img.(subImageSupport); ok {
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return timg.SubImage(croparea), nil
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} else {
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return nil, errors.New("Crop: image format does not support 'SubImage' method (cropping not supported)")
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}
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}
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func CropCenter(img image.Image, w int, h int) (image.Image, error) {
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bounds := img.Bounds()
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center := image.Point{X: bounds.Min.X + bounds.Dx()/2, Y: bounds.Min.Y + bounds.Dy()/2}
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topleft := image.Point{X: center.X - w/2, Y: center.Y - h/2}
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return Crop(img, topleft, w, h)
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}
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