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-rw-r--r--internal/media/imaging.go623
1 files changed, 623 insertions, 0 deletions
diff --git a/internal/media/imaging.go b/internal/media/imaging.go
new file mode 100644
index 000000000..a9f73a066
--- /dev/null
+++ b/internal/media/imaging.go
@@ -0,0 +1,623 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+package media
+
+import (
+ "image"
+ "image/color"
+ "math"
+)
+
+// NOTE:
+// the following code is borrowed from
+// github.com/disintegration/imaging
+// and collapses in some places for our
+// particular usecases and with parallel()
+// function (spans work across goroutines)
+// removed, instead working synchronously.
+//
+// at gotosocial we take particular
+// care about where we spawn goroutines
+// to ensure we're in control of the
+// amount of concurrency in relation
+// to the amount configured by user.
+
+// resizeDownLinear resizes image to given width x height using linear resampling.
+// This is specifically optimized for resizing down (i.e. smaller), else is noop.
+func resizeDownLinear(img image.Image, width, height int) image.Image {
+ srcW, srcH := img.Bounds().Dx(), img.Bounds().Dy()
+ if srcW <= 0 || srcH <= 0 ||
+ width < 0 || height < 0 {
+ return &image.NRGBA{}
+ }
+
+ if width == 0 {
+ // If no width is given, use aspect preserving width.
+ tmp := float64(height) * float64(srcW) / float64(srcH)
+ width = int(math.Max(1.0, math.Floor(tmp+0.5)))
+ }
+
+ if height == 0 {
+ // If no height is given, use aspect preserving height.
+ tmp := float64(width) * float64(srcH) / float64(srcW)
+ height = int(math.Max(1.0, math.Floor(tmp+0.5)))
+ }
+
+ if width < srcW {
+ // Width is smaller, resize horizontally.
+ img = resizeHorizontalLinear(img, width)
+ }
+
+ if height < srcH {
+ // Height is smaller, resize vertically.
+ img = resizeVerticalLinear(img, height)
+ }
+
+ return img
+}
+
+// flipH flips the image horizontally (left to right).
+func flipH(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.w
+ dstH := src.h
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcY := y
+ src.scan(0, srcY, src.w, srcY+1, dst.Pix[i:i+rowSize])
+ reverse(dst.Pix[i : i+rowSize])
+ }
+ return dst
+}
+
+// flipV flips the image vertically (from top to bottom).
+func flipV(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.w
+ dstH := src.h
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcY := dstH - y - 1
+ src.scan(0, srcY, src.w, srcY+1, dst.Pix[i:i+rowSize])
+ }
+ return dst
+}
+
+// rotate90 rotates the image 90 counter-clockwise.
+func rotate90(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.h
+ dstH := src.w
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcX := dstH - y - 1
+ src.scan(srcX, 0, srcX+1, src.h, dst.Pix[i:i+rowSize])
+ }
+ return dst
+}
+
+// rotate180 rotates the image 180 counter-clockwise.
+func rotate180(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.w
+ dstH := src.h
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcY := dstH - y - 1
+ src.scan(0, srcY, src.w, srcY+1, dst.Pix[i:i+rowSize])
+ reverse(dst.Pix[i : i+rowSize])
+ }
+ return dst
+}
+
+// rotate270 rotates the image 270 counter-clockwise.
+func rotate270(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.h
+ dstH := src.w
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcX := y
+ src.scan(srcX, 0, srcX+1, src.h, dst.Pix[i:i+rowSize])
+ reverse(dst.Pix[i : i+rowSize])
+ }
+ return dst
+}
+
+// transpose flips the image horizontally and rotates 90 counter-clockwise.
+func transpose(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.h
+ dstH := src.w
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcX := y
+ src.scan(srcX, 0, srcX+1, src.h, dst.Pix[i:i+rowSize])
+ }
+ return dst
+}
+
+// transverse flips the image vertically and rotates 90 counter-clockwise.
+func transverse(img image.Image) image.Image {
+ src := newScanner(img)
+ dstW := src.h
+ dstH := src.w
+ rowSize := dstW * 4
+ dst := image.NewNRGBA(image.Rect(0, 0, dstW, dstH))
+ for y := 0; y < dstH; y++ {
+ i := y * dst.Stride
+ srcX := dstH - y - 1
+ src.scan(srcX, 0, srcX+1, src.h, dst.Pix[i:i+rowSize])
+ reverse(dst.Pix[i : i+rowSize])
+ }
+ return dst
+}
+
+// resizeHorizontalLinear resizes image to given width using linear resampling.
+func resizeHorizontalLinear(img image.Image, dstWidth int) image.Image {
+ src := newScanner(img)
+ dst := image.NewRGBA(image.Rect(0, 0, dstWidth, src.h))
+ weights := precomputeWeightsLinear(dstWidth, src.w)
+ scanLine := make([]uint8, src.w*4)
+ for y := 0; y < src.h; y++ {
+ src.scan(0, y, src.w, y+1, scanLine)
+ j0 := y * dst.Stride
+ for x := range weights {
+ var r, g, b, a float64
+ for _, w := range weights[x] {
+ i := w.index * 4
+ s := scanLine[i : i+4 : i+4]
+ aw := float64(s[3]) * w.weight
+ r += float64(s[0]) * aw
+ g += float64(s[1]) * aw
+ b += float64(s[2]) * aw
+ a += aw
+ }
+ if a != 0 {
+ aInv := 1 / a
+ j := j0 + x*4
+ d := dst.Pix[j : j+4 : j+4]
+ d[0] = clampFloat(r * aInv)
+ d[1] = clampFloat(g * aInv)
+ d[2] = clampFloat(b * aInv)
+ d[3] = clampFloat(a)
+ }
+ }
+ }
+ return dst
+}
+
+// resizeVerticalLinear resizes image to given height using linear resampling.
+func resizeVerticalLinear(img image.Image, height int) image.Image {
+ src := newScanner(img)
+ dst := image.NewNRGBA(image.Rect(0, 0, src.w, height))
+ weights := precomputeWeightsLinear(height, src.h)
+ scanLine := make([]uint8, src.h*4)
+ for x := 0; x < src.w; x++ {
+ src.scan(x, 0, x+1, src.h, scanLine)
+ for y := range weights {
+ var r, g, b, a float64
+ for _, w := range weights[y] {
+ i := w.index * 4
+ s := scanLine[i : i+4 : i+4]
+ aw := float64(s[3]) * w.weight
+ r += float64(s[0]) * aw
+ g += float64(s[1]) * aw
+ b += float64(s[2]) * aw
+ a += aw
+ }
+ if a != 0 {
+ aInv := 1 / a
+ j := y*dst.Stride + x*4
+ d := dst.Pix[j : j+4 : j+4]
+ d[0] = clampFloat(r * aInv)
+ d[1] = clampFloat(g * aInv)
+ d[2] = clampFloat(b * aInv)
+ d[3] = clampFloat(a)
+ }
+ }
+ }
+ return dst
+}
+
+type indexWeight struct {
+ index int
+ weight float64
+}
+
+func precomputeWeightsLinear(dstSize, srcSize int) [][]indexWeight {
+ du := float64(srcSize) / float64(dstSize)
+ scale := du
+ if scale < 1.0 {
+ scale = 1.0
+ }
+
+ ru := math.Ceil(scale)
+ out := make([][]indexWeight, dstSize)
+ tmp := make([]indexWeight, 0, dstSize*int(ru+2)*2)
+
+ for v := 0; v < dstSize; v++ {
+ fu := (float64(v)+0.5)*du - 0.5
+
+ begin := int(math.Ceil(fu - ru))
+ if begin < 0 {
+ begin = 0
+ }
+ end := int(math.Floor(fu + ru))
+ if end > srcSize-1 {
+ end = srcSize - 1
+ }
+
+ var sum float64
+ for u := begin; u <= end; u++ {
+ w := resampleLinear((float64(u) - fu) / scale)
+ if w != 0 {
+ sum += w
+ tmp = append(tmp, indexWeight{index: u, weight: w})
+ }
+ }
+ if sum != 0 {
+ for i := range tmp {
+ tmp[i].weight /= sum
+ }
+ }
+
+ out[v] = tmp
+ tmp = tmp[len(tmp):]
+ }
+
+ return out
+}
+
+// resampleLinear is the resample kernel func for linear filtering.
+func resampleLinear(x float64) float64 {
+ x = math.Abs(x)
+ if x < 1.0 {
+ return 1.0 - x
+ }
+ return 0
+}
+
+// scanner wraps an image.Image for
+// easier size access and image type
+// agnostic access to data at coords.
+type scanner struct {
+ image image.Image
+ w, h int
+ palette []color.NRGBA
+}
+
+// newScanner wraps an image.Image in scanner{} type.
+func newScanner(img image.Image) *scanner {
+ b := img.Bounds()
+ s := &scanner{
+ image: img,
+
+ w: b.Dx(),
+ h: b.Dy(),
+ }
+ if img, ok := img.(*image.Paletted); ok {
+ s.palette = make([]color.NRGBA, len(img.Palette))
+ for i := 0; i < len(img.Palette); i++ {
+ s.palette[i] = color.NRGBAModel.Convert(img.Palette[i]).(color.NRGBA)
+ }
+ }
+ return s
+}
+
+// scan scans the given rectangular region of the image into dst.
+func (s *scanner) scan(x1, y1, x2, y2 int, dst []uint8) {
+ switch img := s.image.(type) {
+ case *image.NRGBA:
+ size := (x2 - x1) * 4
+ j := 0
+ i := y1*img.Stride + x1*4
+ if size == 4 {
+ for y := y1; y < y2; y++ {
+ d := dst[j : j+4 : j+4]
+ s := img.Pix[i : i+4 : i+4]
+ d[0] = s[0]
+ d[1] = s[1]
+ d[2] = s[2]
+ d[3] = s[3]
+ j += size
+ i += img.Stride
+ }
+ } else {
+ for y := y1; y < y2; y++ {
+ copy(dst[j:j+size], img.Pix[i:i+size])
+ j += size
+ i += img.Stride
+ }
+ }
+
+ case *image.NRGBA64:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1*8
+ for x := x1; x < x2; x++ {
+ s := img.Pix[i : i+8 : i+8]
+ d := dst[j : j+4 : j+4]
+ d[0] = s[0]
+ d[1] = s[2]
+ d[2] = s[4]
+ d[3] = s[6]
+ j += 4
+ i += 8
+ }
+ }
+
+ case *image.RGBA:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1*4
+ for x := x1; x < x2; x++ {
+ d := dst[j : j+4 : j+4]
+ a := img.Pix[i+3]
+ switch a {
+ case 0:
+ d[0] = 0
+ d[1] = 0
+ d[2] = 0
+ d[3] = a
+ case 0xff:
+ s := img.Pix[i : i+4 : i+4]
+ d[0] = s[0]
+ d[1] = s[1]
+ d[2] = s[2]
+ d[3] = a
+ default:
+ s := img.Pix[i : i+4 : i+4]
+ r16 := uint16(s[0])
+ g16 := uint16(s[1])
+ b16 := uint16(s[2])
+ a16 := uint16(a)
+ d[0] = uint8(r16 * 0xff / a16)
+ d[1] = uint8(g16 * 0xff / a16)
+ d[2] = uint8(b16 * 0xff / a16)
+ d[3] = a
+ }
+ j += 4
+ i += 4
+ }
+ }
+
+ case *image.RGBA64:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1*8
+ for x := x1; x < x2; x++ {
+ s := img.Pix[i : i+8 : i+8]
+ d := dst[j : j+4 : j+4]
+ a := s[6]
+ switch a {
+ case 0:
+ d[0] = 0
+ d[1] = 0
+ d[2] = 0
+ case 0xff:
+ d[0] = s[0]
+ d[1] = s[2]
+ d[2] = s[4]
+ default:
+ r32 := uint32(s[0])<<8 | uint32(s[1])
+ g32 := uint32(s[2])<<8 | uint32(s[3])
+ b32 := uint32(s[4])<<8 | uint32(s[5])
+ a32 := uint32(s[6])<<8 | uint32(s[7])
+ d[0] = uint8((r32 * 0xffff / a32) >> 8)
+ d[1] = uint8((g32 * 0xffff / a32) >> 8)
+ d[2] = uint8((b32 * 0xffff / a32) >> 8)
+ }
+ d[3] = a
+ j += 4
+ i += 8
+ }
+ }
+
+ case *image.Gray:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1
+ for x := x1; x < x2; x++ {
+ c := img.Pix[i]
+ d := dst[j : j+4 : j+4]
+ d[0] = c
+ d[1] = c
+ d[2] = c
+ d[3] = 0xff
+ j += 4
+ i++
+ }
+ }
+
+ case *image.Gray16:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1*2
+ for x := x1; x < x2; x++ {
+ c := img.Pix[i]
+ d := dst[j : j+4 : j+4]
+ d[0] = c
+ d[1] = c
+ d[2] = c
+ d[3] = 0xff
+ j += 4
+ i += 2
+ }
+ }
+
+ case *image.YCbCr:
+ j := 0
+ x1 += img.Rect.Min.X
+ x2 += img.Rect.Min.X
+ y1 += img.Rect.Min.Y
+ y2 += img.Rect.Min.Y
+
+ hy := img.Rect.Min.Y / 2
+ hx := img.Rect.Min.X / 2
+ for y := y1; y < y2; y++ {
+ iy := (y-img.Rect.Min.Y)*img.YStride + (x1 - img.Rect.Min.X)
+
+ var yBase int
+ switch img.SubsampleRatio {
+ case image.YCbCrSubsampleRatio444, image.YCbCrSubsampleRatio422:
+ yBase = (y - img.Rect.Min.Y) * img.CStride
+ case image.YCbCrSubsampleRatio420, image.YCbCrSubsampleRatio440:
+ yBase = (y/2 - hy) * img.CStride
+ }
+
+ for x := x1; x < x2; x++ {
+ var ic int
+ switch img.SubsampleRatio {
+ case image.YCbCrSubsampleRatio444, image.YCbCrSubsampleRatio440:
+ ic = yBase + (x - img.Rect.Min.X)
+ case image.YCbCrSubsampleRatio422, image.YCbCrSubsampleRatio420:
+ ic = yBase + (x/2 - hx)
+ default:
+ ic = img.COffset(x, y)
+ }
+
+ yy1 := int32(img.Y[iy]) * 0x10101
+ cb1 := int32(img.Cb[ic]) - 128
+ cr1 := int32(img.Cr[ic]) - 128
+
+ r := yy1 + 91881*cr1
+ if uint32(r)&0xff000000 == 0 {
+ r >>= 16
+ } else {
+ r = ^(r >> 31)
+ }
+
+ g := yy1 - 22554*cb1 - 46802*cr1
+ if uint32(g)&0xff000000 == 0 {
+ g >>= 16
+ } else {
+ g = ^(g >> 31)
+ }
+
+ b := yy1 + 116130*cb1
+ if uint32(b)&0xff000000 == 0 {
+ b >>= 16
+ } else {
+ b = ^(b >> 31)
+ }
+
+ d := dst[j : j+4 : j+4]
+ d[0] = uint8(r)
+ d[1] = uint8(g)
+ d[2] = uint8(b)
+ d[3] = 0xff
+
+ iy++
+ j += 4
+ }
+ }
+
+ case *image.Paletted:
+ j := 0
+ for y := y1; y < y2; y++ {
+ i := y*img.Stride + x1
+ for x := x1; x < x2; x++ {
+ c := s.palette[img.Pix[i]]
+ d := dst[j : j+4 : j+4]
+ d[0] = c.R
+ d[1] = c.G
+ d[2] = c.B
+ d[3] = c.A
+ j += 4
+ i++
+ }
+ }
+
+ default:
+ j := 0
+ b := s.image.Bounds()
+ x1 += b.Min.X
+ x2 += b.Min.X
+ y1 += b.Min.Y
+ y2 += b.Min.Y
+ for y := y1; y < y2; y++ {
+ for x := x1; x < x2; x++ {
+ r16, g16, b16, a16 := s.image.At(x, y).RGBA()
+ d := dst[j : j+4 : j+4]
+ switch a16 {
+ case 0xffff:
+ d[0] = uint8(r16 >> 8)
+ d[1] = uint8(g16 >> 8)
+ d[2] = uint8(b16 >> 8)
+ d[3] = 0xff
+ case 0:
+ d[0] = 0
+ d[1] = 0
+ d[2] = 0
+ d[3] = 0
+ default:
+ d[0] = uint8(((r16 * 0xffff) / a16) >> 8)
+ d[1] = uint8(((g16 * 0xffff) / a16) >> 8)
+ d[2] = uint8(((b16 * 0xffff) / a16) >> 8)
+ d[3] = uint8(a16 >> 8)
+ }
+ j += 4
+ }
+ }
+ }
+}
+
+// reverse reverses the data
+// in contained pixel slice.
+func reverse(pix []uint8) {
+ if len(pix) <= 4 {
+ return
+ }
+ i := 0
+ j := len(pix) - 4
+ for i < j {
+ pi := pix[i : i+4 : i+4]
+ pj := pix[j : j+4 : j+4]
+ pi[0], pj[0] = pj[0], pi[0]
+ pi[1], pj[1] = pj[1], pi[1]
+ pi[2], pj[2] = pj[2], pi[2]
+ pi[3], pj[3] = pj[3], pi[3]
+ i += 4
+ j -= 4
+ }
+}
+
+// clampFloat rounds and clamps float64 value to fit into uint8.
+func clampFloat(x float64) uint8 {
+ v := int64(x + 0.5)
+ if v > 255 {
+ return 255
+ }
+ if v > 0 {
+ return uint8(v)
+ }
+ return 0
+}
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-31 08:52:35 +0000