Merge branch 'master' of https://github.com/matrixik/resize into matrixik-master
This commit is contained in:
commit
079ed2e48a
55
thumbnail.go
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55
thumbnail.go
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/*
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Copyright (c) 2012, Jan Schlicht <jan.schlicht@gmail.com>
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Permission to use, copy, modify, and/or distribute this software for any purpose
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with or without fee is hereby granted, provided that the above copyright notice
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and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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*/
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package resize
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import (
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"image"
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)
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// Thumbnail will downscale provided image to max width and height preserving
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// original aspect ratio and using the interpolation function interp.
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// It will return original image, without processing it, if original sizes
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// are already smaller than provided constraints.
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func Thumbnail(maxWidth, maxHeight uint, img image.Image, interp InterpolationFunction) image.Image {
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origBounds := img.Bounds()
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origWidth := uint(origBounds.Dx())
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origHeight := uint(origBounds.Dy())
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newWidth, newHeight := origWidth, origHeight
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// Return original image if it have same or smaller size as constraints
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if maxWidth >= origWidth && maxHeight >= origHeight {
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return img
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}
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// Preserve aspect ratio
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if origWidth > maxWidth {
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newHeight = uint(origHeight * maxWidth / origWidth)
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if newHeight < 1 {
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newHeight = 1
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}
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newWidth = maxWidth
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}
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if newHeight > maxHeight {
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newWidth = uint(newWidth * maxHeight / newHeight)
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if newWidth < 1 {
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newWidth = 1
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}
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newHeight = maxHeight
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}
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return Resize(newWidth, newHeight, img, interp)
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}
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47
thumbnail_test.go
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thumbnail_test.go
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package resize
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import (
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"image"
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"runtime"
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"testing"
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)
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func init() {
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runtime.GOMAXPROCS(runtime.NumCPU())
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}
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var thumbnailTests = []struct {
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origWidth int
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origHeight int
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maxWidth uint
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maxHeight uint
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expectedWidth uint
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expectedHeight uint
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}{
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{5, 5, 10, 10, 5, 5},
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{10, 10, 5, 5, 5, 5},
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{10, 50, 10, 10, 2, 10},
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{50, 10, 10, 10, 10, 2},
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{50, 100, 60, 90, 45, 90},
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{120, 100, 60, 90, 60, 50},
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{200, 250, 200, 150, 120, 150},
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}
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func TestThumbnail(t *testing.T) {
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for i, tt := range thumbnailTests {
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img := image.NewGray16(image.Rect(0, 0, tt.origWidth, tt.origHeight))
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outImg := Thumbnail(tt.maxWidth, tt.maxHeight, img, NearestNeighbor)
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newWidth := uint(outImg.Bounds().Dx())
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newHeight := uint(outImg.Bounds().Dy())
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if newWidth != tt.expectedWidth ||
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newHeight != tt.expectedHeight {
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t.Errorf("%d. Thumbnail(%v, %v, img, NearestNeighbor) => "+
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"width: %v, height: %v, want width: %v, height: %v",
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i, tt.maxWidth, tt.maxHeight,
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newWidth, newHeight, tt.expectedWidth, tt.expectedHeight,
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)
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}
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}
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}
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