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author | Sem <sembrestels@riseup.net> | 2012-08-02 21:44:44 +0200 |
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committer | Sem <sembrestels@riseup.net> | 2012-08-02 21:44:44 +0200 |
commit | dad0209bbd7994b623bc0126e3e37b1f521d2977 (patch) | |
tree | 1e954b32439cbfc2acbbd63ed62dc372a260f37e /vendors/jquery-file-upload/server/gae-go/resize/resize.go | |
parent | fa81c487488064f684649272a6579079d3a88e2c (diff) | |
parent | 28b1669c4b1afaed7429da2cc9580340dcb13b6e (diff) | |
download | elgg-dad0209bbd7994b623bc0126e3e37b1f521d2977.tar.gz elgg-dad0209bbd7994b623bc0126e3e37b1f521d2977.tar.bz2 |
Merge branch 'jquery-uploader' of git://github.com/sembrestels/Tidypics
Conflicts:
start.php
views/default/photos/css.php
Diffstat (limited to 'vendors/jquery-file-upload/server/gae-go/resize/resize.go')
-rw-r--r-- | vendors/jquery-file-upload/server/gae-go/resize/resize.go | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/vendors/jquery-file-upload/server/gae-go/resize/resize.go b/vendors/jquery-file-upload/server/gae-go/resize/resize.go new file mode 100644 index 000000000..dcb627870 --- /dev/null +++ b/vendors/jquery-file-upload/server/gae-go/resize/resize.go @@ -0,0 +1,247 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package resize + +import ( + "image" + "image/color" +) + +// Resize returns a scaled copy of the image slice r of m. +// The returned image has width w and height h. +func Resize(m image.Image, r image.Rectangle, w, h int) image.Image { + if w < 0 || h < 0 { + return nil + } + if w == 0 || h == 0 || r.Dx() <= 0 || r.Dy() <= 0 { + return image.NewRGBA64(image.Rect(0, 0, w, h)) + } + switch m := m.(type) { + case *image.RGBA: + return resizeRGBA(m, r, w, h) + case *image.YCbCr: + if m, ok := resizeYCbCr(m, r, w, h); ok { + return m + } + } + ww, hh := uint64(w), uint64(h) + dx, dy := uint64(r.Dx()), uint64(r.Dy()) + // The scaling algorithm is to nearest-neighbor magnify the dx * dy source + // to a (ww*dx) * (hh*dy) intermediate image and then minify the intermediate + // image back down to a ww * hh destination with a simple box filter. + // The intermediate image is implied, we do not physically allocate a slice + // of length ww*dx*hh*dy. + // For example, consider a 4*3 source image. Label its pixels from a-l: + // abcd + // efgh + // ijkl + // To resize this to a 3*2 destination image, the intermediate is 12*6. + // Whitespace has been added to delineate the destination pixels: + // aaab bbcc cddd + // aaab bbcc cddd + // eeef ffgg ghhh + // + // eeef ffgg ghhh + // iiij jjkk klll + // iiij jjkk klll + // Thus, the 'b' source pixel contributes one third of its value to the + // (0, 0) destination pixel and two thirds to (1, 0). + // The implementation is a two-step process. First, the source pixels are + // iterated over and each source pixel's contribution to 1 or more + // destination pixels are summed. Second, the sums are divided by a scaling + // factor to yield the destination pixels. + // TODO: By interleaving the two steps, instead of doing all of + // step 1 first and all of step 2 second, we could allocate a smaller sum + // slice of length 4*w*2 instead of 4*w*h, although the resultant code + // would become more complicated. + n, sum := dx*dy, make([]uint64, 4*w*h) + for y := r.Min.Y; y < r.Max.Y; y++ { + for x := r.Min.X; x < r.Max.X; x++ { + // Get the source pixel. + r32, g32, b32, a32 := m.At(x, y).RGBA() + r64 := uint64(r32) + g64 := uint64(g32) + b64 := uint64(b32) + a64 := uint64(a32) + // Spread the source pixel over 1 or more destination rows. + py := uint64(y) * hh + for remy := hh; remy > 0; { + qy := dy - (py % dy) + if qy > remy { + qy = remy + } + // Spread the source pixel over 1 or more destination columns. + px := uint64(x) * ww + index := 4 * ((py/dy)*ww + (px / dx)) + for remx := ww; remx > 0; { + qx := dx - (px % dx) + if qx > remx { + qx = remx + } + sum[index+0] += r64 * qx * qy + sum[index+1] += g64 * qx * qy + sum[index+2] += b64 * qx * qy + sum[index+3] += a64 * qx * qy + index += 4 + px += qx + remx -= qx + } + py += qy + remy -= qy + } + } + } + return average(sum, w, h, n*0x0101) +} + +// average convert the sums to averages and returns the result. +func average(sum []uint64, w, h int, n uint64) image.Image { + ret := image.NewRGBA(image.Rect(0, 0, w, h)) + for y := 0; y < h; y++ { + for x := 0; x < w; x++ { + index := 4 * (y*w + x) + ret.SetRGBA(x, y, color.RGBA{ + uint8(sum[index+0] / n), + uint8(sum[index+1] / n), + uint8(sum[index+2] / n), + uint8(sum[index+3] / n), + }) + } + } + return ret +} + +// resizeYCbCr returns a scaled copy of the YCbCr image slice r of m. +// The returned image has width w and height h. +func resizeYCbCr(m *image.YCbCr, r image.Rectangle, w, h int) (image.Image, bool) { + var verticalRes int + switch m.SubsampleRatio { + case image.YCbCrSubsampleRatio420: + verticalRes = 2 + case image.YCbCrSubsampleRatio422: + verticalRes = 1 + default: + return nil, false + } + ww, hh := uint64(w), uint64(h) + dx, dy := uint64(r.Dx()), uint64(r.Dy()) + // See comment in Resize. + n, sum := dx*dy, make([]uint64, 4*w*h) + for y := r.Min.Y; y < r.Max.Y; y++ { + Y := m.Y[y*m.YStride:] + Cb := m.Cb[y/verticalRes*m.CStride:] + Cr := m.Cr[y/verticalRes*m.CStride:] + for x := r.Min.X; x < r.Max.X; x++ { + // Get the source pixel. + r8, g8, b8 := color.YCbCrToRGB(Y[x], Cb[x/2], Cr[x/2]) + r64 := uint64(r8) + g64 := uint64(g8) + b64 := uint64(b8) + // Spread the source pixel over 1 or more destination rows. + py := uint64(y) * hh + for remy := hh; remy > 0; { + qy := dy - (py % dy) + if qy > remy { + qy = remy + } + // Spread the source pixel over 1 or more destination columns. + px := uint64(x) * ww + index := 4 * ((py/dy)*ww + (px / dx)) + for remx := ww; remx > 0; { + qx := dx - (px % dx) + if qx > remx { + qx = remx + } + qxy := qx * qy + sum[index+0] += r64 * qxy + sum[index+1] += g64 * qxy + sum[index+2] += b64 * qxy + sum[index+3] += 0xFFFF * qxy + index += 4 + px += qx + remx -= qx + } + py += qy + remy -= qy + } + } + } + return average(sum, w, h, n), true +} + +// resizeRGBA returns a scaled copy of the RGBA image slice r of m. +// The returned image has width w and height h. +func resizeRGBA(m *image.RGBA, r image.Rectangle, w, h int) image.Image { + ww, hh := uint64(w), uint64(h) + dx, dy := uint64(r.Dx()), uint64(r.Dy()) + // See comment in Resize. + n, sum := dx*dy, make([]uint64, 4*w*h) + for y := r.Min.Y; y < r.Max.Y; y++ { + pixOffset := m.PixOffset(r.Min.X, y) + for x := r.Min.X; x < r.Max.X; x++ { + // Get the source pixel. + r64 := uint64(m.Pix[pixOffset+0]) + g64 := uint64(m.Pix[pixOffset+1]) + b64 := uint64(m.Pix[pixOffset+2]) + a64 := uint64(m.Pix[pixOffset+3]) + pixOffset += 4 + // Spread the source pixel over 1 or more destination rows. + py := uint64(y) * hh + for remy := hh; remy > 0; { + qy := dy - (py % dy) + if qy > remy { + qy = remy + } + // Spread the source pixel over 1 or more destination columns. + px := uint64(x) * ww + index := 4 * ((py/dy)*ww + (px / dx)) + for remx := ww; remx > 0; { + qx := dx - (px % dx) + if qx > remx { + qx = remx + } + qxy := qx * qy + sum[index+0] += r64 * qxy + sum[index+1] += g64 * qxy + sum[index+2] += b64 * qxy + sum[index+3] += a64 * qxy + index += 4 + px += qx + remx -= qx + } + py += qy + remy -= qy + } + } + } + return average(sum, w, h, n) +} + +// Resample returns a resampled copy of the image slice r of m. +// The returned image has width w and height h. +func Resample(m image.Image, r image.Rectangle, w, h int) image.Image { + if w < 0 || h < 0 { + return nil + } + if w == 0 || h == 0 || r.Dx() <= 0 || r.Dy() <= 0 { + return image.NewRGBA64(image.Rect(0, 0, w, h)) + } + curw, curh := r.Dx(), r.Dy() + img := image.NewRGBA(image.Rect(0, 0, w, h)) + for y := 0; y < h; y++ { + for x := 0; x < w; x++ { + // Get a source pixel. + subx := x * curw / w + suby := y * curh / h + r32, g32, b32, a32 := m.At(subx, suby).RGBA() + r := uint8(r32 >> 8) + g := uint8(g32 >> 8) + b := uint8(b32 >> 8) + a := uint8(a32 >> 8) + img.SetRGBA(x, y, color.RGBA{r, g, b, a}) + } + } + return img +} |