diff options
Diffstat (limited to 'sixel.go')
| -rw-r--r-- | sixel.go | 21 |
1 files changed, 7 insertions, 14 deletions
@@ -31,12 +31,6 @@ func (c sixelRGB) RGBA() (r, g, b, a uint32) { return scaleFFFF(c.r), scaleFFFF(c.g), scaleFFFF(c.b), 0xffff } -func lcg(state *uint64) int { - s := *state*6364136223846793005 + 1 - *state = s - return int(s >> 33) -} - func partition[S ~[]E, E any](a S, lo, hi, pivotIndex int, cmp func(E, E) int) (int, int) { pivot := a[pivotIndex] lt := lo @@ -58,13 +52,13 @@ func partition[S ~[]E, E any](a S, lo, hi, pivotIndex int, cmp func(E, E) int) ( return lt, gt } -func quickSelect[S ~[]E, E any](list S, k int, cmp func(E, E) int, randState *uint64) { +func quickSelect[S ~[]E, E any](list S, k int, cmp func(E, E) int) { left, right := 0, len(list)-1 for { if left == right { return } - pivotIndex := left + lcg(randState)%(right-left+1) + pivotIndex := left + rand.IntN(right-left+1) pivotLeft, pivotRight := partition(list, left, right, pivotIndex, cmp) if pivotLeft <= k && k <= pivotRight { return @@ -90,17 +84,17 @@ func bucketRange(colors []color.RGBA) color.RGBA { return color.RGBA{R: maxR - minR, G: maxG - minG, B: maxB - minB} } -func cutOnce(colors []color.RGBA, bucketRange color.RGBA, rand *uint64) [2][]color.RGBA { +func cutOnce(colors []color.RGBA, bucketRange color.RGBA) [2][]color.RGBA { if len(colors) == 0 { return [...][]color.RGBA{colors, colors} } rRange, gRange, bRange := bucketRange.R, bucketRange.G, bucketRange.B if rRange >= gRange && rRange >= bRange { - quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.R) - int(y.R) }, rand) + quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.R) - int(y.R) }) } else if gRange >= rRange && gRange >= bRange { - quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.G) - int(y.G) }, rand) + quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.G) - int(y.G) }) } else { - quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.B) - int(y.B) }, rand) + quickSelect(colors, len(colors)/2, func(x, y color.RGBA) int { return int(x.B) - int(y.B) }) } return [...][]color.RGBA{colors[:len(colors)/2], colors[len(colors)/2:]} } @@ -128,7 +122,6 @@ func medianCut(img image.Image) color.Palette { } buckets := [][]color.RGBA{colors} bucketRanges := []color.RGBA{{}} - randState := rand.Uint64() for { var bestRange uint8 var bestIdx int @@ -139,7 +132,7 @@ func medianCut(img image.Image) color.Palette { bestIdx = i } } - split := cutOnce(buckets[bestIdx], bucketRanges[bestIdx], &randState) + split := cutOnce(buckets[bestIdx], bucketRanges[bestIdx]) buckets = slices.Replace(buckets, bestIdx, bestIdx+1, split[:]...) if len(buckets) == 255 { break |