Code to convert images to NRGB

This commit is contained in:
Kovid Goyal 2023-01-02 15:22:41 +05:30
parent 143fd6e4dd
commit d192dcb0d7
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GPG Key ID: 06BC317B515ACE7C
2 changed files with 259 additions and 3 deletions

View File

@ -5,7 +5,6 @@ package icat
import (
"errors"
"fmt"
"image/color"
"os"
"runtime"
"strconv"
@ -19,6 +18,7 @@ import (
"kitty/tools/tui/graphics"
"kitty/tools/tui/loop"
"kitty/tools/utils"
"kitty/tools/utils/images"
"kitty/tools/utils/shm"
"kitty/tools/utils/style"
)
@ -33,7 +33,7 @@ var opts *Options
var lp *loop.Loop
var place *Place
var z_index int32
var remove_alpha *color.NRGBA
var remove_alpha *images.NRGBColor
var flip, flop bool
type transfer_mode int
@ -72,7 +72,7 @@ func parse_background() (err error) {
if err != nil {
return fmt.Errorf("Invalid value for --background: %w", err)
}
remove_alpha = &color.NRGBA{col.Red, col.Green, col.Blue, 255}
remove_alpha = &images.NRGBColor{col.Red, col.Green, col.Blue}
return
}

View File

@ -139,3 +139,259 @@ func (p *NRGB) SubImage(r image.Rectangle) image.Image {
// Opaque scans the entire image and reports whether it is fully opaque.
func (p *NRGB) Opaque() bool { return true }
type scanner_rgb struct {
image image.Image
w, h int
palette []NRGBColor
opaque_base []float64
opaque_base_uint []uint8
}
func blend(dest []uint8, base []float64, r, g, b, a uint8) {
alpha := float64(a) / 255.0
dest[0] = uint8(alpha*float64(r) + (1.0-alpha)*base[0])
dest[1] = uint8(alpha*float64(g) + (1.0-alpha)*base[1])
dest[2] = uint8(alpha*float64(b) + (1.0-alpha)*base[2])
}
func newScannerRGB(img image.Image, opaque_base NRGBColor) *scanner_rgb {
s := &scanner_rgb{
image: img, w: img.Bounds().Dx(), h: img.Bounds().Dy(),
opaque_base: []float64{float64(opaque_base.R), float64(opaque_base.G), float64(opaque_base.B)}[0:3:3],
opaque_base_uint: []uint8{opaque_base.R, opaque_base.G, opaque_base.B}[0:3:3],
}
if img, ok := img.(*image.Paletted); ok {
s.palette = make([]NRGBColor, len(img.Palette))
d := make([]uint8, 3)
for i := 0; i < len(img.Palette); i++ {
r, g, b, a := img.Palette[i].RGBA()
blend(d, s.opaque_base, uint8((r*0xffff/a)>>8), uint8((g*0xffff/a)>>8), uint8((b*0xffff/a)>>8), uint8(a>>8))
s.palette[i] = NRGBColor{d[0], d[1], d[2]}
}
}
return s
}
// scan scans the given rectangular region of the image into dst.
func (s *scanner_rgb) scan(x1, y1, x2, y2 int, dst []uint8) {
switch img := s.image.(type) {
case *image.NRGBA:
j := 0
for y := y1; y < y2; y++ {
i := y*img.Stride + x1*4
for x := x1; x < x2; x++ {
blend(dst[j:j+3:j+3], s.opaque_base, img.Pix[i], img.Pix[i+1], img.Pix[i+2], img.Pix[i+3])
j += 3
i += 4
}
}
case *image.NRGBA64:
j := 0
for y := y1; y < y2; y++ {
i := y*img.Stride + x1*8
for x := x1; x < x2; x++ {
blend(dst[j:j+3:j+3], s.opaque_base, img.Pix[i], img.Pix[i+2], img.Pix[i+4], img.Pix[i+6])
j += 3
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+3 : j+3]
a := img.Pix[i+3]
switch a {
case 0:
d[0] = s.opaque_base_uint[0]
d[1] = s.opaque_base_uint[1]
d[2] = s.opaque_base_uint[2]
case 0xff:
s := img.Pix[i : i+3 : i+3]
d[0] = s[0]
d[1] = s[1]
d[2] = s[2]
default:
r16 := uint16(img.Pix[i])
g16 := uint16(img.Pix[i+1])
b16 := uint16(img.Pix[i+2])
a16 := uint16(a)
blend(d, s.opaque_base, uint8(r16*0xff/a16), uint8(g16*0xff/a16), uint8(b16*0xff/a16), a)
}
j += 3
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++ {
src := img.Pix[i : i+8 : i+8]
d := dst[j : j+3 : j+3]
a := src[6]
switch a {
case 0:
d[0] = s.opaque_base_uint[0]
d[1] = s.opaque_base_uint[1]
d[2] = s.opaque_base_uint[2]
case 0xff:
d[0] = src[0]
d[1] = src[2]
d[2] = src[4]
default:
r32 := uint32(src[0])<<8 | uint32(src[1])
g32 := uint32(src[2])<<8 | uint32(src[3])
b32 := uint32(src[4])<<8 | uint32(src[5])
a32 := uint32(src[6])<<8 | uint32(src[7])
blend(d, s.opaque_base, uint8((r32*0xffff/a32)>>8), uint8((g32*0xffff/a32)>>8), uint8((b32*0xffff/a32)>>8), a)
}
j += 3
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+3 : j+3]
d[0] = c
d[1] = c
d[2] = c
j += 3
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+3 : j+3]
d[0] = c
d[1] = c
d[2] = c
j += 3
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+3 : j+3]
d[0] = uint8(r)
d[1] = uint8(g)
d[2] = uint8(b)
iy++
j += 3
}
}
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+3 : j+3]
d[0] = c.R
d[1] = c.G
d[2] = c.B
j += 3
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+3 : j+3]
switch a16 {
case 0xffff:
d[0] = uint8(r16 >> 8)
d[1] = uint8(g16 >> 8)
d[2] = uint8(b16 >> 8)
case 0:
d[0] = s.opaque_base_uint[0]
d[1] = s.opaque_base_uint[1]
d[2] = s.opaque_base_uint[2]
default:
blend(d, s.opaque_base, uint8(((r16*0xffff)/a16)>>8), uint8(((g16*0xffff)/a16)>>8), uint8(((b16*0xffff)/a16)>>8), uint8(a16>>8))
}
j += 3
}
}
}
}