diff options
Diffstat (limited to 'Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/interp/bilinear.go')
-rw-r--r-- | Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/interp/bilinear.go | 206 |
1 files changed, 0 insertions, 206 deletions
diff --git a/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/interp/bilinear.go b/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/interp/bilinear.go deleted file mode 100644 index e18321a15..000000000 --- a/Godeps/_workspace/src/code.google.com/p/graphics-go/graphics/interp/bilinear.go +++ /dev/null @@ -1,206 +0,0 @@ -// Copyright 2012 The Graphics-Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package interp - -import ( - "image" - "image/color" - "math" -) - -// Bilinear implements bilinear interpolation. -var Bilinear Interp = bilinear{} - -type bilinear struct{} - -func (i bilinear) Interp(src image.Image, x, y float64) color.Color { - if src, ok := src.(*image.RGBA); ok { - return i.RGBA(src, x, y) - } - return bilinearGeneral(src, x, y) -} - -func bilinearGeneral(src image.Image, x, y float64) color.Color { - p := findLinearSrc(src.Bounds(), x, y) - var fr, fg, fb, fa float64 - var r, g, b, a uint32 - - r, g, b, a = src.At(p.low.X, p.low.Y).RGBA() - fr += float64(r) * p.frac00 - fg += float64(g) * p.frac00 - fb += float64(b) * p.frac00 - fa += float64(a) * p.frac00 - - r, g, b, a = src.At(p.high.X, p.low.Y).RGBA() - fr += float64(r) * p.frac01 - fg += float64(g) * p.frac01 - fb += float64(b) * p.frac01 - fa += float64(a) * p.frac01 - - r, g, b, a = src.At(p.low.X, p.high.Y).RGBA() - fr += float64(r) * p.frac10 - fg += float64(g) * p.frac10 - fb += float64(b) * p.frac10 - fa += float64(a) * p.frac10 - - r, g, b, a = src.At(p.high.X, p.high.Y).RGBA() - fr += float64(r) * p.frac11 - fg += float64(g) * p.frac11 - fb += float64(b) * p.frac11 - fa += float64(a) * p.frac11 - - var c color.RGBA64 - c.R = uint16(fr + 0.5) - c.G = uint16(fg + 0.5) - c.B = uint16(fb + 0.5) - c.A = uint16(fa + 0.5) - return c -} - -func (bilinear) RGBA(src *image.RGBA, x, y float64) color.RGBA { - p := findLinearSrc(src.Bounds(), x, y) - - // Array offsets for the surrounding pixels. - off00 := offRGBA(src, p.low.X, p.low.Y) - off01 := offRGBA(src, p.high.X, p.low.Y) - off10 := offRGBA(src, p.low.X, p.high.Y) - off11 := offRGBA(src, p.high.X, p.high.Y) - - var fr, fg, fb, fa float64 - - fr += float64(src.Pix[off00+0]) * p.frac00 - fg += float64(src.Pix[off00+1]) * p.frac00 - fb += float64(src.Pix[off00+2]) * p.frac00 - fa += float64(src.Pix[off00+3]) * p.frac00 - - fr += float64(src.Pix[off01+0]) * p.frac01 - fg += float64(src.Pix[off01+1]) * p.frac01 - fb += float64(src.Pix[off01+2]) * p.frac01 - fa += float64(src.Pix[off01+3]) * p.frac01 - - fr += float64(src.Pix[off10+0]) * p.frac10 - fg += float64(src.Pix[off10+1]) * p.frac10 - fb += float64(src.Pix[off10+2]) * p.frac10 - fa += float64(src.Pix[off10+3]) * p.frac10 - - fr += float64(src.Pix[off11+0]) * p.frac11 - fg += float64(src.Pix[off11+1]) * p.frac11 - fb += float64(src.Pix[off11+2]) * p.frac11 - fa += float64(src.Pix[off11+3]) * p.frac11 - - var c color.RGBA - c.R = uint8(fr + 0.5) - c.G = uint8(fg + 0.5) - c.B = uint8(fb + 0.5) - c.A = uint8(fa + 0.5) - return c -} - -func (bilinear) Gray(src *image.Gray, x, y float64) color.Gray { - p := findLinearSrc(src.Bounds(), x, y) - - // Array offsets for the surrounding pixels. - off00 := offGray(src, p.low.X, p.low.Y) - off01 := offGray(src, p.high.X, p.low.Y) - off10 := offGray(src, p.low.X, p.high.Y) - off11 := offGray(src, p.high.X, p.high.Y) - - var fc float64 - fc += float64(src.Pix[off00]) * p.frac00 - fc += float64(src.Pix[off01]) * p.frac01 - fc += float64(src.Pix[off10]) * p.frac10 - fc += float64(src.Pix[off11]) * p.frac11 - - var c color.Gray - c.Y = uint8(fc + 0.5) - return c -} - -type bilinearSrc struct { - // Top-left and bottom-right interpolation sources - low, high image.Point - // Fraction of each pixel to take. The 0 suffix indicates - // top/left, and the 1 suffix indicates bottom/right. - frac00, frac01, frac10, frac11 float64 -} - -func findLinearSrc(b image.Rectangle, sx, sy float64) bilinearSrc { - maxX := float64(b.Max.X) - maxY := float64(b.Max.Y) - minX := float64(b.Min.X) - minY := float64(b.Min.Y) - lowX := math.Floor(sx - 0.5) - lowY := math.Floor(sy - 0.5) - if lowX < minX { - lowX = minX - } - if lowY < minY { - lowY = minY - } - - highX := math.Ceil(sx - 0.5) - highY := math.Ceil(sy - 0.5) - if highX >= maxX { - highX = maxX - 1 - } - if highY >= maxY { - highY = maxY - 1 - } - - // In the variables below, the 0 suffix indicates top/left, and the - // 1 suffix indicates bottom/right. - - // Center of each surrounding pixel. - x00 := lowX + 0.5 - y00 := lowY + 0.5 - x01 := highX + 0.5 - y01 := lowY + 0.5 - x10 := lowX + 0.5 - y10 := highY + 0.5 - x11 := highX + 0.5 - y11 := highY + 0.5 - - p := bilinearSrc{ - low: image.Pt(int(lowX), int(lowY)), - high: image.Pt(int(highX), int(highY)), - } - - // Literally, edge cases. If we are close enough to the edge of - // the image, curtail the interpolation sources. - if lowX == highX && lowY == highY { - p.frac00 = 1.0 - } else if sy-minY <= 0.5 && sx-minX <= 0.5 { - p.frac00 = 1.0 - } else if maxY-sy <= 0.5 && maxX-sx <= 0.5 { - p.frac11 = 1.0 - } else if sy-minY <= 0.5 || lowY == highY { - p.frac00 = x01 - sx - p.frac01 = sx - x00 - } else if sx-minX <= 0.5 || lowX == highX { - p.frac00 = y10 - sy - p.frac10 = sy - y00 - } else if maxY-sy <= 0.5 { - p.frac10 = x11 - sx - p.frac11 = sx - x10 - } else if maxX-sx <= 0.5 { - p.frac01 = y11 - sy - p.frac11 = sy - y01 - } else { - p.frac00 = (x01 - sx) * (y10 - sy) - p.frac01 = (sx - x00) * (y11 - sy) - p.frac10 = (x11 - sx) * (sy - y00) - p.frac11 = (sx - x10) * (sy - y01) - } - - return p -} - -// TODO(crawshaw): When we have inlining, consider func (p *RGBA) Off(x, y) int -func offRGBA(src *image.RGBA, x, y int) int { - return (y-src.Rect.Min.Y)*src.Stride + (x-src.Rect.Min.X)*4 -} -func offGray(src *image.Gray, x, y int) int { - return (y-src.Rect.Min.Y)*src.Stride + (x - src.Rect.Min.X) -} |