mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-30 14:09:42 -05:00
387 lines
9 KiB
Go
Vendored
387 lines
9 KiB
Go
Vendored
/*
|
|
Copyright (c) 2014, Charlie Vieth <charlie.vieth@gmail.com>
|
|
|
|
Permission to use, copy, modify, and/or distribute this software for any purpose
|
|
with or without fee is hereby granted, provided that the above copyright notice
|
|
and this permission notice appear in all copies.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
|
|
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
|
FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
|
|
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
|
|
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
|
|
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
|
|
THIS SOFTWARE.
|
|
*/
|
|
|
|
package resize
|
|
|
|
import (
|
|
"image"
|
|
"image/color"
|
|
)
|
|
|
|
// ycc is an in memory YCbCr image. The Y, Cb and Cr samples are held in a
|
|
// single slice to increase resizing performance.
|
|
type ycc struct {
|
|
// Pix holds the image's pixels, in Y, Cb, Cr order. The pixel at
|
|
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*3].
|
|
Pix []uint8
|
|
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
|
|
Stride int
|
|
// Rect is the image's bounds.
|
|
Rect image.Rectangle
|
|
// SubsampleRatio is the subsample ratio of the original YCbCr image.
|
|
SubsampleRatio image.YCbCrSubsampleRatio
|
|
}
|
|
|
|
// PixOffset returns the index of the first element of Pix that corresponds to
|
|
// the pixel at (x, y).
|
|
func (p *ycc) PixOffset(x, y int) int {
|
|
return (y-p.Rect.Min.Y)*p.Stride + (x-p.Rect.Min.X)*3
|
|
}
|
|
|
|
func (p *ycc) Bounds() image.Rectangle {
|
|
return p.Rect
|
|
}
|
|
|
|
func (p *ycc) ColorModel() color.Model {
|
|
return color.YCbCrModel
|
|
}
|
|
|
|
func (p *ycc) At(x, y int) color.Color {
|
|
if !(image.Point{x, y}.In(p.Rect)) {
|
|
return color.YCbCr{}
|
|
}
|
|
i := p.PixOffset(x, y)
|
|
return color.YCbCr{
|
|
p.Pix[i+0],
|
|
p.Pix[i+1],
|
|
p.Pix[i+2],
|
|
}
|
|
}
|
|
|
|
func (p *ycc) Opaque() bool {
|
|
return true
|
|
}
|
|
|
|
// SubImage returns an image representing the portion of the image p visible
|
|
// through r. The returned value shares pixels with the original image.
|
|
func (p *ycc) SubImage(r image.Rectangle) image.Image {
|
|
r = r.Intersect(p.Rect)
|
|
if r.Empty() {
|
|
return &ycc{SubsampleRatio: p.SubsampleRatio}
|
|
}
|
|
i := p.PixOffset(r.Min.X, r.Min.Y)
|
|
return &ycc{
|
|
Pix: p.Pix[i:],
|
|
Stride: p.Stride,
|
|
Rect: r,
|
|
SubsampleRatio: p.SubsampleRatio,
|
|
}
|
|
}
|
|
|
|
// newYCC returns a new ycc with the given bounds and subsample ratio.
|
|
func newYCC(r image.Rectangle, s image.YCbCrSubsampleRatio) *ycc {
|
|
w, h := r.Dx(), r.Dy()
|
|
buf := make([]uint8, 3*w*h)
|
|
return &ycc{Pix: buf, Stride: 3 * w, Rect: r, SubsampleRatio: s}
|
|
}
|
|
|
|
// Copy of image.YCbCrSubsampleRatio constants - this allows us to support
|
|
// older versions of Go where these constants are not defined (i.e. Go 1.4)
|
|
const (
|
|
ycbcrSubsampleRatio444 image.YCbCrSubsampleRatio = iota
|
|
ycbcrSubsampleRatio422
|
|
ycbcrSubsampleRatio420
|
|
ycbcrSubsampleRatio440
|
|
ycbcrSubsampleRatio411
|
|
ycbcrSubsampleRatio410
|
|
)
|
|
|
|
// YCbCr converts ycc to a YCbCr image with the same subsample ratio
|
|
// as the YCbCr image that ycc was generated from.
|
|
func (p *ycc) YCbCr() *image.YCbCr {
|
|
ycbcr := image.NewYCbCr(p.Rect, p.SubsampleRatio)
|
|
switch ycbcr.SubsampleRatio {
|
|
case ycbcrSubsampleRatio422:
|
|
return p.ycbcr422(ycbcr)
|
|
case ycbcrSubsampleRatio420:
|
|
return p.ycbcr420(ycbcr)
|
|
case ycbcrSubsampleRatio440:
|
|
return p.ycbcr440(ycbcr)
|
|
case ycbcrSubsampleRatio444:
|
|
return p.ycbcr444(ycbcr)
|
|
case ycbcrSubsampleRatio411:
|
|
return p.ycbcr411(ycbcr)
|
|
case ycbcrSubsampleRatio410:
|
|
return p.ycbcr410(ycbcr)
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
// imageYCbCrToYCC converts a YCbCr image to a ycc image for resizing.
|
|
func imageYCbCrToYCC(in *image.YCbCr) *ycc {
|
|
w, h := in.Rect.Dx(), in.Rect.Dy()
|
|
p := ycc{
|
|
Pix: make([]uint8, 3*w*h),
|
|
Stride: 3 * w,
|
|
Rect: image.Rect(0, 0, w, h),
|
|
SubsampleRatio: in.SubsampleRatio,
|
|
}
|
|
switch in.SubsampleRatio {
|
|
case ycbcrSubsampleRatio422:
|
|
return convertToYCC422(in, &p)
|
|
case ycbcrSubsampleRatio420:
|
|
return convertToYCC420(in, &p)
|
|
case ycbcrSubsampleRatio440:
|
|
return convertToYCC440(in, &p)
|
|
case ycbcrSubsampleRatio444:
|
|
return convertToYCC444(in, &p)
|
|
case ycbcrSubsampleRatio411:
|
|
return convertToYCC411(in, &p)
|
|
case ycbcrSubsampleRatio410:
|
|
return convertToYCC410(in, &p)
|
|
}
|
|
return &p
|
|
}
|
|
|
|
func (p *ycc) ycbcr422(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := y * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x/2
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func (p *ycc) ycbcr420(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := (y / 2) * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x/2
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func (p *ycc) ycbcr440(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := (y / 2) * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func (p *ycc) ycbcr444(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := y * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func (p *ycc) ycbcr411(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := y * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x/4
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func (p *ycc) ycbcr410(ycbcr *image.YCbCr) *image.YCbCr {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := ycbcr.Y
|
|
Cb := ycbcr.Cb
|
|
Cr := ycbcr.Cr
|
|
for y := 0; y < ycbcr.Rect.Max.Y-ycbcr.Rect.Min.Y; y++ {
|
|
yy := y * ycbcr.YStride
|
|
cy := (y / 2) * ycbcr.CStride
|
|
for x := 0; x < ycbcr.Rect.Max.X-ycbcr.Rect.Min.X; x++ {
|
|
ci := cy + x/4
|
|
Y[yy+x] = Pix[off+0]
|
|
Cb[ci] = Pix[off+1]
|
|
Cr[ci] = Pix[off+2]
|
|
off += 3
|
|
}
|
|
}
|
|
return ycbcr
|
|
}
|
|
|
|
func convertToYCC422(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := y * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x/2
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
func convertToYCC420(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := (y / 2) * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x/2
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
func convertToYCC440(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := (y / 2) * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
func convertToYCC444(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := y * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
func convertToYCC411(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := y * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x/4
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|
|
|
|
func convertToYCC410(in *image.YCbCr, p *ycc) *ycc {
|
|
var off int
|
|
Pix := p.Pix
|
|
Y := in.Y
|
|
Cb := in.Cb
|
|
Cr := in.Cr
|
|
for y := 0; y < in.Rect.Max.Y-in.Rect.Min.Y; y++ {
|
|
yy := y * in.YStride
|
|
cy := (y / 2) * in.CStride
|
|
for x := 0; x < in.Rect.Max.X-in.Rect.Min.X; x++ {
|
|
ci := cy + x/4
|
|
Pix[off+0] = Y[yy+x]
|
|
Pix[off+1] = Cb[ci]
|
|
Pix[off+2] = Cr[ci]
|
|
off += 3
|
|
}
|
|
}
|
|
return p
|
|
}
|