406 lines
9.0 KiB
Go
406 lines
9.0 KiB
Go
// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
|
|
|
|
package images
|
|
|
|
import (
|
|
"fmt"
|
|
"image"
|
|
"image/color"
|
|
"math"
|
|
)
|
|
|
|
var _ = fmt.Print
|
|
|
|
type scanner struct {
|
|
image image.Image
|
|
w, h int
|
|
palette []color.NRGBA
|
|
}
|
|
|
|
func (s scanner) bytes_per_pixel() int { return 4 }
|
|
func (s scanner) bounds() image.Rectangle { return s.image.Bounds() }
|
|
|
|
func newScanner(img image.Image) *scanner {
|
|
s := &scanner{
|
|
image: img,
|
|
w: img.Bounds().Dx(),
|
|
h: img.Bounds().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
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
type Scanner interface {
|
|
scan(x1, y1, x2, y2 int, dst []uint8)
|
|
bytes_per_pixel() int
|
|
bounds() image.Rectangle
|
|
}
|
|
|
|
func (self *Context) run_paste(src Scanner, background image.Image, pos image.Point, postprocess func([]byte)) {
|
|
pos = pos.Sub(background.Bounds().Min)
|
|
pasteRect := image.Rectangle{Min: pos, Max: pos.Add(src.bounds().Size())}
|
|
interRect := pasteRect.Intersect(background.Bounds())
|
|
if interRect.Empty() {
|
|
return
|
|
}
|
|
bytes_per_pixel := src.bytes_per_pixel()
|
|
var stride int
|
|
var pix []uint8
|
|
switch v := background.(type) {
|
|
case *image.NRGBA:
|
|
i := background.(*image.NRGBA)
|
|
stride = i.Stride
|
|
pix = i.Pix
|
|
case *NRGB:
|
|
i := background.(*NRGB)
|
|
stride = i.Stride
|
|
pix = i.Pix
|
|
default:
|
|
panic(fmt.Sprintf("Unsupported image type: %v", v))
|
|
}
|
|
self.Parallel(interRect.Min.Y, interRect.Max.Y, func(ys <-chan int) {
|
|
for y := range ys {
|
|
x1 := interRect.Min.X - pasteRect.Min.X
|
|
x2 := interRect.Max.X - pasteRect.Min.X
|
|
y1 := y - pasteRect.Min.Y
|
|
y2 := y1 + 1
|
|
i1 := y*stride + interRect.Min.X*bytes_per_pixel
|
|
i2 := i1 + interRect.Dx()*bytes_per_pixel
|
|
dst := pix[i1:i2]
|
|
src.scan(x1, y1, x2, y2, dst)
|
|
postprocess(dst)
|
|
}
|
|
})
|
|
|
|
}
|
|
|
|
func (self *Context) paste_nrgba_onto_opaque(background *image.NRGBA, img image.Image, pos image.Point, bgcol *NRGBColor) {
|
|
src := newScanner(img)
|
|
if bgcol == nil {
|
|
self.run_paste(src, background, pos, func([]byte) {})
|
|
return
|
|
}
|
|
bg := [3]float64{float64(bgcol.R), float64(bgcol.G), float64(bgcol.B)}
|
|
self.run_paste(src, background, pos, func(dst []byte) {
|
|
for len(dst) > 0 {
|
|
a := float64(dst[3]) / 255.0
|
|
for i := range dst[:3] {
|
|
// uint8() automatically converts floats greater than 255 but less than 256 to 255
|
|
dst[i] = uint8(float64(dst[i])*a + bg[i]*(1-a))
|
|
}
|
|
dst[3] = 255
|
|
dst = dst[4:]
|
|
}
|
|
|
|
})
|
|
}
|
|
|
|
// Paste pastes the img image to the background image at the specified position. Optionally composing onto the specified opaque color.
|
|
func (self *Context) Paste(background image.Image, img image.Image, pos image.Point, opaque_bg *NRGBColor) {
|
|
switch background.(type) {
|
|
case *image.NRGBA:
|
|
self.paste_nrgba_onto_opaque(background.(*image.NRGBA), img, pos, opaque_bg)
|
|
case *NRGB:
|
|
self.paste_nrgb_onto_opaque(background.(*NRGB), img, pos, opaque_bg)
|
|
default:
|
|
panic("Unsupported background image type")
|
|
}
|
|
}
|
|
|
|
// PasteCenter pastes the img image to the center of the background image. Optionally composing onto the specified opaque color.
|
|
func (self *Context) PasteCenter(background image.Image, img image.Image, opaque_bg *NRGBColor) {
|
|
bgBounds := background.Bounds()
|
|
bgW := bgBounds.Dx()
|
|
bgH := bgBounds.Dy()
|
|
bgMinX := bgBounds.Min.X
|
|
bgMinY := bgBounds.Min.Y
|
|
|
|
centerX := bgMinX + bgW/2
|
|
centerY := bgMinY + bgH/2
|
|
|
|
x0 := centerX - img.Bounds().Dx()/2
|
|
y0 := centerY - img.Bounds().Dy()/2
|
|
|
|
self.Paste(background, img, image.Pt(x0, y0), opaque_bg)
|
|
}
|
|
|
|
func FitImage(width, height, pwidth, pheight int) (final_width int, final_height int) {
|
|
if height > pheight {
|
|
corrf := float64(pheight) / float64(height)
|
|
width, height = int(math.Floor(corrf*float64(width))), pheight
|
|
}
|
|
if width > pwidth {
|
|
corrf := float64(pwidth) / float64(width)
|
|
width, height = pwidth, int(math.Floor(corrf*float64(height)))
|
|
}
|
|
if height > pheight {
|
|
corrf := float64(pheight) / float64(height)
|
|
width, height = int(math.Floor(corrf*float64(width))), pheight
|
|
}
|
|
|
|
return width, height
|
|
}
|