gotosocial/internal/media/imaging.go
Markus Unterwaditzer 275a3f8636 [chore] Upgrade golangci-lint, ignore existing int overflow warnings
There is a new lint for unchecked int casts. Integer overflows are bad,
but the old code that triggers this lint seems to be perfectly fine.
Instead of disabling the lint entirely for new code as well, grandfather
in existing code.
2024-10-12 10:30:08 +02:00

624 lines
14 KiB
Go

// 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) //nolint:gosec
d[1] = uint8(g16 * 0xff / a16) //nolint:gosec
d[2] = uint8(b16 * 0xff / a16) //nolint:gosec
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) //nolint:gosec
d[1] = uint8((g32 * 0xffff / a32) >> 8) //nolint:gosec
d[2] = uint8((b32 * 0xffff / a32) >> 8) //nolint:gosec
}
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 { //nolint:gosec
r >>= 16
} else {
r = ^(r >> 31)
}
g := yy1 - 22554*cb1 - 46802*cr1
if uint32(g)&0xff000000 == 0 { //nolint:gosec
g >>= 16
} else {
g = ^(g >> 31)
}
b := yy1 + 116130*cb1
if uint32(b)&0xff000000 == 0 { //nolint:gosec
b >>= 16
} else {
b = ^(b >> 31)
}
d := dst[j : j+4 : j+4]
d[0] = uint8(r) //nolint:gosec
d[1] = uint8(g) //nolint:gosec
d[2] = uint8(b) //nolint:gosec
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) //nolint:gosec
d[1] = uint8(g16 >> 8) //nolint:gosec
d[2] = uint8(b16 >> 8) //nolint:gosec
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) //nolint:gosec
d[1] = uint8(((g16 * 0xffff) / a16) >> 8) //nolint:gosec
d[2] = uint8(((b16 * 0xffff) / a16) >> 8) //nolint:gosec
d[3] = uint8(a16 >> 8) //nolint:gosec
}
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
}