This commit is contained in:
Laurent Le Goff 2011-04-14 15:03:17 +02:00
parent d84ea36159
commit 45159ffd27
2 changed files with 144 additions and 136 deletions

View file

@ -1,37 +1,37 @@
package draw2d
import (
"exp/draw"
"image"
"math"
)
type ImageFilter int
const (
LinearFilter ImageFilter = iota
BilinearFilter
BicubicFilter
)
package draw2d
import (
"exp/draw"
"image"
"math"
)
type ImageFilter int
const (
LinearFilter ImageFilter = iota
BilinearFilter
BicubicFilter
)
//see http://pippin.gimp.org/image_processing/chap_resampling.html
func getColorLinear(img image.Image, x, y float64) image.Color {
return img.At(int(x), int(y))
}
func getColorBilinear(img image.Image, x, y float64) image.Color {
x0 := math.Floor(x)
y0 := math.Floor(y)
dx := x - x0
dy := y - y0
color0 := img.At(int(x0), int(y0))
color1 := img.At(int(x0+1), int(y0))
color2 := img.At(int(x0+1), int(y0+1))
color3 := img.At(int(x0), int(y0+1))
return lerp(lerp(color0, color1, dx), lerp(color3, color2, dx), dy)
}
func getColorLinear(img image.Image, x, y float64) image.Color {
return img.At(int(x), int(y))
}
func getColorBilinear(img image.Image, x, y float64) image.Color {
x0 := math.Floor(x)
y0 := math.Floor(y)
dx := x - x0
dy := y - y0
color0 := img.At(int(x0), int(y0))
color1 := img.At(int(x0+1), int(y0))
color2 := img.At(int(x0+1), int(y0+1))
color3 := img.At(int(x0), int(y0+1))
return lerp(lerp(color0, color1, dx), lerp(color3, color2, dx), dy)
}
/**
-- LERP
-- /lerp/, vi.,n.
@ -39,102 +39,110 @@ func getColorBilinear(img image.Image, x, y float64) image.Color {
-- Quasi-acronym for Linear Interpolation, used as a verb or noun for
-- the operation. "Bresenham's algorithm lerps incrementally between the
-- two endpoints of the line." (From Jargon File (4.4.4, 14 Aug 2003)
*/
func lerp(c1, c2 image.Color, ratio float64) image.Color {
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
r := int(float64(r1)*(1-ratio) + float64(r2)*ratio)
g := int(float64(g1)*(1-ratio) + float64(g2)*ratio)
b := int(float64(b1)*(1-ratio) + float64(b2)*ratio)
a := int(float64(a1)*(1-ratio) + float64(a2)*ratio)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func getColorCubicRow(img image.Image, x, y, offset float64) image.Color {
c0 := img.At(int(x), int(y))
c1 := img.At(int(x+1), int(y))
c2 := img.At(int(x+2), int(y))
c3 := img.At(int(x+3), int(y))
rt, gt, bt, at := c0.RGBA(); r0, g0, b0, a0 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c1.RGBA(); r1, g1, b1, a1 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c2.RGBA(); r2, g2, b2, a2 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c3.RGBA(); r3, g3, b3, a3 := float64(rt), float64(gt), float64(bt), float64(at)
r, g, b, a := cubic(offset, r0, r1, r2, r3), cubic(offset, g0, g1, g2, g3), cubic(offset, b0, b1, b2, b3), cubic(offset, a0, a1, a2, a3)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func getColorBicubic(img image.Image, x, y float64) image.Color {
x0 := math.Floor(x)
y0 := math.Floor(y)
dx := x - x0
dy := y - y0
c0 := getColorCubicRow(img, x0-1, y0-1, dx)
c1 := getColorCubicRow(img, x0-1, y0, dx)
c2 := getColorCubicRow(img, x0-1, y0+1, dx)
c3 := getColorCubicRow(img, x0-1, y0+2, dx)
rt, gt, bt, at := c0.RGBA(); r0, g0, b0, a0 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c1.RGBA(); r1, g1, b1, a1 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c2.RGBA(); r2, g2, b2, a2 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c3.RGBA(); r3, g3, b3, a3 := float64(rt), float64(gt), float64(bt), float64(at)
r, g, b, a := cubic(dy, r0, r1, r2, r3), cubic(dy, g0, g1, g2, g3), cubic(dy, b0, b1, b2, b3), cubic(dy, a0, a1, a2, a3)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func cubic(offset, v0, v1, v2, v3 float64) uint32 {
*/
func lerp(c1, c2 image.Color, ratio float64) image.Color {
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
r := int(float64(r1)*(1-ratio) + float64(r2)*ratio)
g := int(float64(g1)*(1-ratio) + float64(g2)*ratio)
b := int(float64(b1)*(1-ratio) + float64(b2)*ratio)
a := int(float64(a1)*(1-ratio) + float64(a2)*ratio)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func getColorCubicRow(img image.Image, x, y, offset float64) image.Color {
c0 := img.At(int(x), int(y))
c1 := img.At(int(x+1), int(y))
c2 := img.At(int(x+2), int(y))
c3 := img.At(int(x+3), int(y))
rt, gt, bt, at := c0.RGBA()
r0, g0, b0, a0 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c1.RGBA()
r1, g1, b1, a1 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c2.RGBA()
r2, g2, b2, a2 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c3.RGBA()
r3, g3, b3, a3 := float64(rt), float64(gt), float64(bt), float64(at)
r, g, b, a := cubic(offset, r0, r1, r2, r3), cubic(offset, g0, g1, g2, g3), cubic(offset, b0, b1, b2, b3), cubic(offset, a0, a1, a2, a3)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func getColorBicubic(img image.Image, x, y float64) image.Color {
x0 := math.Floor(x)
y0 := math.Floor(y)
dx := x - x0
dy := y - y0
c0 := getColorCubicRow(img, x0-1, y0-1, dx)
c1 := getColorCubicRow(img, x0-1, y0, dx)
c2 := getColorCubicRow(img, x0-1, y0+1, dx)
c3 := getColorCubicRow(img, x0-1, y0+2, dx)
rt, gt, bt, at := c0.RGBA()
r0, g0, b0, a0 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c1.RGBA()
r1, g1, b1, a1 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c2.RGBA()
r2, g2, b2, a2 := float64(rt), float64(gt), float64(bt), float64(at)
rt, gt, bt, at = c3.RGBA()
r3, g3, b3, a3 := float64(rt), float64(gt), float64(bt), float64(at)
r, g, b, a := cubic(dy, r0, r1, r2, r3), cubic(dy, g0, g1, g2, g3), cubic(dy, b0, b1, b2, b3), cubic(dy, a0, a1, a2, a3)
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func cubic(offset, v0, v1, v2, v3 float64) uint32 {
// offset is the offset of the sampled value between v1 and v2
return uint32(((((-7*v0+21*v1-21*v2+7*v3)*offset+
(15*v0-36*v1+27*v2-6*v3))*offset+
(-9*v0+9*v2))*offset + (v0 + 16*v1 + v2)) / 18.0)
}
func compose(c1, c2 image.Color) image.Color {
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
ia := M - a2
r := ((r1 * ia) / M) + r2
g := ((g1 * ia) / M) + g2
b := ((b1 * ia) / M) + b2
a := ((a1 * ia) / M) + a2
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func DrawImage(src image.Image, dest draw.Image, tr MatrixTransform, op draw.Op, filter ImageFilter) {
b := src.Bounds()
x0, y0, x1, y1 := float64(b.Min.X), float64(b.Min.Y), float64(b.Max.X), float64(b.Max.Y)
tr.TransformRectangle(&x0, &y0, &x1, &y1)
var x, y, u, v float64
for x = x0; x < x1; x++ {
for y = y0; y < y1; y++ {
u = x
v = y
tr.InverseTransform(&u, &v)
c1 := dest.At(int(x), int(y))
var c2 image.Color
switch filter {
case LinearFilter:
c2 = src.At(int(u), int(v))
case BilinearFilter:
c2 = getColorBilinear(src, u, v)
case BicubicFilter:
c2 = getColorBicubic(src, u, v)
}
var cr image.Color
switch op {
case draw.Over:
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
ia := M - a2
r := ((r1 * ia) / M) + r2
g := ((g1 * ia) / M) + g2
b := ((b1 * ia) / M) + b2
a := ((a1 * ia) / M) + a2
cr = image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
default:
cr = c2
}
dest.Set(int(x), int(y), cr)
}
}
}
return uint32(((((-7*v0+21*v1-21*v2+7*v3)*offset+
(15*v0-36*v1+27*v2-6*v3))*offset+
(-9*v0+9*v2))*offset + (v0 + 16*v1 + v2)) / 18.0)
}
func compose(c1, c2 image.Color) image.Color {
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
ia := M - a2
r := ((r1 * ia) / M) + r2
g := ((g1 * ia) / M) + g2
b := ((b1 * ia) / M) + b2
a := ((a1 * ia) / M) + a2
return image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
}
func DrawImage(src image.Image, dest draw.Image, tr MatrixTransform, op draw.Op, filter ImageFilter) {
b := src.Bounds()
x0, y0, x1, y1 := float64(b.Min.X), float64(b.Min.Y), float64(b.Max.X), float64(b.Max.Y)
tr.TransformRectangle(&x0, &y0, &x1, &y1)
var x, y, u, v float64
for x = x0; x < x1; x++ {
for y = y0; y < y1; y++ {
u = x
v = y
tr.InverseTransform(&u, &v)
c1 := dest.At(int(x), int(y))
var c2 image.Color
switch filter {
case LinearFilter:
c2 = src.At(int(u), int(v))
case BilinearFilter:
c2 = getColorBilinear(src, u, v)
case BicubicFilter:
c2 = getColorBicubic(src, u, v)
}
var cr image.Color
switch op {
case draw.Over:
r1, g1, b1, a1 := c1.RGBA()
r2, g2, b2, a2 := c2.RGBA()
ia := M - a2
r := ((r1 * ia) / M) + r2
g := ((g1 * ia) / M) + g2
b := ((b1 * ia) / M) + b2
a := ((a1 * ia) / M) + a2
cr = image.RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
default:
cr = c2
}
dest.Set(int(x), int(y), cr)
}
}
}

View file

@ -26,7 +26,7 @@ func (tr MatrixTransform) Transform(points ...*float64) {
}
}
func (tr MatrixTransform) TransformRectangle(x0, y0, x2, y2*float64) {
func (tr MatrixTransform) TransformRectangle(x0, y0, x2, y2 *float64) {
x1 := *x2
y1 := *y0
x3 := *x0
@ -144,10 +144,10 @@ func (tr1 MatrixTransform) Multiply(tr2 MatrixTransform) MatrixTransform {
func (tr *MatrixTransform) Scale(sx, sy float64) *MatrixTransform {
tr[0] = sx*tr[0]
tr[1] = sx*tr[1]
tr[2] = sy*tr[2]
tr[3] = sy*tr[3]
tr[0] = sx * tr[0]
tr[1] = sx * tr[1]
tr[2] = sy * tr[2]
tr[3] = sy * tr[3]
return tr
}