Include kernel boundary check
Filter kernels should yield Zero if they are evaluted outside their intended size. Though filterModel.Interpolate doesn't do this by design, it's better to include it anyways.
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3e06045c3f
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dd1c157427
28
filters.go
28
filters.go
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@ -29,6 +29,7 @@ func clampToUint16(x float32) (y uint16) {
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if x < 0 {
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y = 0
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} else if x > float32(0xfffe) {
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// "else if x > float32(0xffff)" will cause overflows!
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y = 0xffff
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}
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return
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@ -150,8 +151,14 @@ func NearestNeighbor(img image.Image, factor [2]float32) Filter {
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// Bilinear interpolation
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func Bilinear(img image.Image, factor [2]float32) Filter {
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return createFilter(img, factor, 2, func(x float32) float32 {
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return 1 - float32(math.Abs(float64(x)))
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return createFilter(img, factor, 2, func(x float32) (y float32) {
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absX := float32(math.Abs(float64(x)))
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if absX <= 1 {
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y = 1 - absX
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} else {
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y = 0
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}
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return
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})
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}
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@ -161,8 +168,10 @@ func Bicubic(img image.Image, factor [2]float32) Filter {
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absX := float32(math.Abs(float64(x)))
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if absX <= 1 {
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y = absX*absX*(1.5*absX-2.5) + 1
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} else {
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} else if absX <= 2 {
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y = absX*(absX*(2.5-0.5*absX)-4) + 2
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} else {
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y = 0
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}
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return
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})
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@ -174,16 +183,23 @@ func MitchellNetravali(img image.Image, factor [2]float32) Filter {
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absX := float32(math.Abs(float64(x)))
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if absX <= 1 {
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y = absX*absX*(7*absX-12) + 16.0/3
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} else {
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} else if absX <= 2 {
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y = -(absX - 2) * (absX - 2) / 3 * (7*absX - 8)
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} else {
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y = 0
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}
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return
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})
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}
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func lanczosKernel(a uint) func(float32) float32 {
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return func(x float32) float32 {
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return float32(Sinc(float64(x))) * float32(Sinc(float64(x/float32(a))))
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return func(x float32) (y float32) {
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if x > -float32(a) && x < float32(a) {
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y = float32(Sinc(float64(x))) * float32(Sinc(float64(x/float32(a))))
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} else {
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y = 0
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}
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return
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}
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}
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13
resize.go
13
resize.go
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@ -21,7 +21,7 @@ THIS SOFTWARE.
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// utilized in the computations.
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//
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// Example:
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// imgResized := resize.Resize(1000, 0, imgOld, Lanczos3)
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// imgResized := resize.Resize(1000, 0, imgOld, resize.MitchellNetravali)
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package resize
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import (
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@ -77,8 +77,8 @@ func Resize(width, height uint, img image.Image, interp InterpolationFunction) i
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for y := b.Min.Y; y < b.Max.Y; y++ {
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for x := b.Min.X; x < b.Max.X; x++ {
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u, v = t.Eval(float32(x), float32(y))
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//resizedImg.SetRGBA64(x, y, filter.Interpolate(u, v))
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color = filter.Interpolate(u, v)
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i := resizedImg.PixOffset(x, y)
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resizedImg.Pix[i+0] = uint8(color.R >> 8)
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resizedImg.Pix[i+1] = uint8(color.R)
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@ -124,12 +124,11 @@ func calcFactors(width, height uint, oldWidth, oldHeight float32) (scaleX, scale
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// Set filter scaling factor to avoid moire patterns.
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// This is only useful in case of downscaling (factor>1).
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func clampFactor(factor float32) (r float32) {
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r = factor
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if r < 1 {
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r = 1
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func clampFactor(factor float32) float32 {
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if factor < 1 {
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factor = 1
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}
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return
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return factor
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}
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// Set number of parallel jobs
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