Changed function signature to include error handling. Filters simplified.
This commit is contained in:
jst
parent
d573c463cb
commit
14d51db8b4
36
filters.go
36
filters.go
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@ -64,10 +64,10 @@ func Bilinear(x, y float32, img image.Image) color.RGBA64 {
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var row [2]RGBA
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var col [2]RGBA
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row = [2]RGBA{toRGBA(img.At(xf, yf)), toRGBA(img.At(xf+1, yf))}
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col[0] = linearInterp(x, &row)
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row = [2]RGBA{toRGBA(img.At(xf, yf+1)), toRGBA(img.At(xf+1, yf+1))}
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col[1] = linearInterp(x, &row)
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for i := 0; i < 2; i++ {
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row = [2]RGBA{toRGBA(img.At(xf, yf+i)), toRGBA(img.At(xf+1, yf+i))}
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col[i] = linearInterp(x, &row)
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}
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c := linearInterp(y, &col)
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return color.RGBA64{c[0], c[1], c[2], c[3]}
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@ -88,14 +88,10 @@ func Bicubic(x, y float32, img image.Image) color.RGBA64 {
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var row [4]RGBA
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var col [4]RGBA
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row = [4]RGBA{toRGBA(img.At(xf-1, yf-1)), toRGBA(img.At(xf, yf-1)), toRGBA(img.At(xf+1, yf-1)), toRGBA(img.At(xf+2, yf-1))}
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col[0] = cubicInterp(x, &row)
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row = [4]RGBA{toRGBA(img.At(xf-1, yf)), toRGBA(img.At(xf, yf)), toRGBA(img.At(xf+1, yf)), toRGBA(img.At(xf+2, yf))}
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col[1] = cubicInterp(x, &row)
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row = [4]RGBA{toRGBA(img.At(xf-1, yf+1)), toRGBA(img.At(xf, yf+1)), toRGBA(img.At(xf+1, yf+1)), toRGBA(img.At(xf+2, yf+1))}
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col[2] = cubicInterp(x, &row)
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row = [4]RGBA{toRGBA(img.At(xf-1, yf+2)), toRGBA(img.At(xf, yf+2)), toRGBA(img.At(xf+1, yf+2)), toRGBA(img.At(xf+2, yf+2))}
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col[3] = cubicInterp(x, &row)
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for i := 0; i < 4; i++ {
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row = [4]RGBA{toRGBA(img.At(xf-1, yf+i-1)), toRGBA(img.At(xf, yf+i-1)), toRGBA(img.At(xf+1, yf+i-1)), toRGBA(img.At(xf+2, yf+i-1))}
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col[i] = cubicInterp(x, &row)
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}
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c := cubicInterp(y, &col)
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return color.RGBA64{c[0], c[1], c[2], c[3]}
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@ -124,18 +120,10 @@ func Lanczos3(x, y float32, img image.Image) color.RGBA64 {
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var row [6]RGBA
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var col [6]RGBA
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row = [6]RGBA{toRGBA(img.At(xf-2, yf-2)), toRGBA(img.At(xf-1, yf-2)), toRGBA(img.At(xf, yf-2)), toRGBA(img.At(xf+1, yf-2)), toRGBA(img.At(xf+2, yf-2)), toRGBA(img.At(xf+3, yf-2))}
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col[0] = lanczos_x(x, &row)
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row = [6]RGBA{toRGBA(img.At(xf-2, yf-1)), toRGBA(img.At(xf-1, yf-1)), toRGBA(img.At(xf, yf-1)), toRGBA(img.At(xf+1, yf-1)), toRGBA(img.At(xf+2, yf-1)), toRGBA(img.At(xf+3, yf-1))}
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col[1] = lanczos_x(x, &row)
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row = [6]RGBA{toRGBA(img.At(xf-2, yf)), toRGBA(img.At(xf-1, yf)), toRGBA(img.At(xf, yf)), toRGBA(img.At(xf+1, yf)), toRGBA(img.At(xf+2, yf)), toRGBA(img.At(xf+3, yf))}
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col[2] = lanczos_x(x, &row)
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row = [6]RGBA{toRGBA(img.At(xf-2, yf+1)), toRGBA(img.At(xf-1, yf+1)), toRGBA(img.At(xf, yf+1)), toRGBA(img.At(xf+1, yf+1)), toRGBA(img.At(xf+2, yf+1)), toRGBA(img.At(xf+3, yf+1))}
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col[3] = lanczos_x(x, &row)
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row = [6]RGBA{toRGBA(img.At(xf-2, yf+2)), toRGBA(img.At(xf-1, yf+2)), toRGBA(img.At(xf, yf+2)), toRGBA(img.At(xf+1, yf+2)), toRGBA(img.At(xf+2, yf+2)), toRGBA(img.At(xf+3, yf+2))}
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col[4] = lanczos_x(x, &row)
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row = [6]RGBA{toRGBA(img.At(xf-2, yf+3)), toRGBA(img.At(xf-1, yf+3)), toRGBA(img.At(xf, yf+3)), toRGBA(img.At(xf+1, yf+3)), toRGBA(img.At(xf+2, yf+3)), toRGBA(img.At(xf+3, yf+3))}
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col[5] = lanczos_x(x, &row)
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for i := 0; i < 6; i++ {
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row = [6]RGBA{toRGBA(img.At(xf-2, yf+i-2)), toRGBA(img.At(xf-1, yf+i-2)), toRGBA(img.At(xf, yf+i-2)), toRGBA(img.At(xf+1, yf+i-2)), toRGBA(img.At(xf+2, yf+i-2)), toRGBA(img.At(xf+3, yf+i-2))}
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col[i] = lanczos_x(x, &row)
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}
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c := lanczos_x(y, &col)
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return color.RGBA64{c[0], c[1], c[2], c[3]}
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51
resize.go
51
resize.go
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@ -25,6 +25,7 @@ THIS SOFTWARE.
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package resize
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import (
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"errors"
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"image"
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"image/color"
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"runtime"
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@ -46,28 +47,21 @@ func (t *Trans2) Eval(x, y float32) (u, v float32) {
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}
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// Calculate scaling factors using old and new image dimensions.
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func calcFactors(w, h int, wo, ho float32) (sx, sy float32) {
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if w <= 0 {
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w = -1
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}
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if h <= 0 {
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h = -1
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}
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if w == -1 {
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if h == -1 {
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sx = 1.0
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sy = 1.0
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func calcFactors(width, height int, oldWidth, oldHeight float32) (scaleX, scaleY float32) {
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if width == -1 {
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if height == -1 {
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scaleX = 1.0
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scaleY = 1.0
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} else {
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sy = ho / float32(h)
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sx = sy
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scaleY = oldHeight / float32(height)
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scaleX = scaleY
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}
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} else {
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sx = wo / float32(w)
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if h == -1 {
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sy = sx
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scaleX = oldWidth / float32(width)
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if height == -1 {
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scaleY = scaleX
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} else {
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sy = ho / float32(h)
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scaleY = oldHeight / float32(height)
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}
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}
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return
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@ -82,15 +76,19 @@ type InterpolationFunction func(float32, float32, image.Image) color.RGBA64
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// If one of the parameters w or h is set to -1, its size will be calculated so that
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// the aspect ratio is that of the originating image.
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// The resizing algorithm uses channels for parallel computation.
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func Resize(w int, h int, img image.Image, interp InterpolationFunction) image.Image {
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b_old := img.Bounds()
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w_old := float32(b_old.Dx())
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h_old := float32(b_old.Dy())
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func Resize(width, height int, img image.Image, interp InterpolationFunction) (out image.Image, err error) {
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if width < -1 || height < -1 {
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err = errors.New("Wrong width/height argument")
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return
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}
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oldBounds := img.Bounds()
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oldWidth := float32(oldBounds.Dx())
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oldHeight := float32(oldBounds.Dy())
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scaleX, scaleY := calcFactors(w, h, w_old, h_old)
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t := Trans2{scaleX, 0, float32(b_old.Min.X), 0, scaleY, float32(b_old.Min.Y)}
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scaleX, scaleY := calcFactors(width, height, oldWidth, oldHeight)
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t := Trans2{scaleX, 0, float32(oldBounds.Min.X), 0, scaleY, float32(oldBounds.Min.Y)}
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m := image.NewRGBA64(image.Rect(0, 0, int(w_old/scaleX), int(h_old/scaleY)))
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m := image.NewRGBA64(image.Rect(0, 0, int(oldWidth/scaleX), int(oldHeight/scaleY)))
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b := m.Bounds()
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c := make(chan int, NCPU)
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@ -110,6 +108,7 @@ func Resize(w int, h int, img image.Image, interp InterpolationFunction) image.I
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for i := 0; i < NCPU; i++ {
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<-c
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}
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out = m
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return m
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return
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}
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@ -11,30 +11,30 @@ var img = image.NewGray16(image.Rect(0, 0, 3, 3))
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func Test_Nearest(t *testing.T) {
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img.Set(1, 1, color.White)
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m := Resize(6, -1, img, NearestNeighbor)
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m, err := Resize(6, -1, img, NearestNeighbor)
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if m.At(2, 2) != m.At(3, 3) {
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if err != nil || m.At(2, 2) != m.At(3, 3) {
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t.Fail()
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}
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}
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func Test_Param1(t *testing.T) {
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m := Resize(-1, -1, img, NearestNeighbor)
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if m.Bounds() != img.Bounds() {
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m, err := Resize(-1, -1, img, NearestNeighbor)
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if err != nil || m.Bounds() != img.Bounds() {
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t.Fail()
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}
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}
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func Test_Param2(t *testing.T) {
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m := Resize(-100, -1, img, NearestNeighbor)
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if m.Bounds() != img.Bounds() {
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_, err := Resize(-100, -1, img, NearestNeighbor)
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if err == nil {
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t.Fail()
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}
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}
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func Test_Param3(t *testing.T) {
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m := Resize(0, -1, img, NearestNeighbor)
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if m.Bounds() != img.Bounds() {
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m, err := Resize(0, -1, img, NearestNeighbor)
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if err != nil || m.Bounds() != image.Rect(0, 0, 0, 0) {
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t.Fail()
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}
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}
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@ -42,8 +42,8 @@ func Test_Param3(t *testing.T) {
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func Test_ZeroImg(t *testing.T) {
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zeroImg := image.NewGray16(image.Rect(0, 0, 0, 0))
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m := Resize(-1, -1, zeroImg, NearestNeighbor)
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if m.Bounds() != zeroImg.Bounds() {
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m, err := Resize(-1, -1, zeroImg, NearestNeighbor)
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if err != nil || m.Bounds() != zeroImg.Bounds() {
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t.Fail()
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}
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}
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