Initial commit

process.go

@@ -0,0 +1,111 @@
+package caire
+
+import (
+	"image"
+	"image/color"
+	"image/png"
+	"io"
+	"os"
+	"github.com/fogleman/gg"
+)
+
+// Processor options
+type Processor struct {
+	BlurRadius      int
+	SobelThreshold  int
+}
+
+// Process : Convert image
+func (p *Processor) Process(file io.Reader, output string) (*os.File, error) {
+	src, _, err := image.Decode(file)
+	if err != nil {
+		return nil, err
+	}
+
+	width, height := src.Bounds().Dx(), src.Bounds().Dy()
+	ctx := gg.NewContext(width, height)
+	ctx.DrawRectangle(0, 0, float64(width), float64(height))
+	ctx.SetRGBA(1, 1, 1, 1)
+	ctx.Fill()
+
+	img := toNRGBA(src)
+
+	blur := Stackblur(img, uint32(width), uint32(height), uint32(p.BlurRadius))
+	gray := Grayscale(blur)
+	sobel := SobelFilter(gray, float64(p.SobelThreshold))
+
+	dpTable := &DPTable{width, height, make([]float64, width*height)}
+	dpTable.ComputeSeams(sobel)
+	dpTable.FindLowestEnergySeams()
+
+	fq, err := os.Create(output)
+	if err != nil {
+		return nil, err
+	}
+	defer fq.Close()
+
+	if err = png.Encode(fq, sobel); err != nil {
+		return nil, err
+	}
+
+	return fq, err
+}
+
+// toNRGBA converts any image type to *image.NRGBA with min-point at (0, 0).
+func toNRGBA(img image.Image) *image.NRGBA {
+	srcBounds := img.Bounds()
+	if srcBounds.Min.X == 0 && srcBounds.Min.Y == 0 {
+		if src0, ok := img.(*image.NRGBA); ok {
+			return src0
+		}
+	}
+	srcMinX := srcBounds.Min.X
+	srcMinY := srcBounds.Min.Y
+
+	dstBounds := srcBounds.Sub(srcBounds.Min)
+	dstW := dstBounds.Dx()
+	dstH := dstBounds.Dy()
+	dst := image.NewNRGBA(dstBounds)
+
+	switch src := img.(type) {
+	case *image.NRGBA:
+		rowSize := srcBounds.Dx() * 4
+		for dstY := 0; dstY < dstH; dstY++ {
+			di := dst.PixOffset(0, dstY)
+			si := src.PixOffset(srcMinX, srcMinY+dstY)
+			for dstX := 0; dstX < dstW; dstX++ {
+				copy(dst.Pix[di:di+rowSize], src.Pix[si:si+rowSize])
+			}
+		}
+	case *image.YCbCr:
+		for dstY := 0; dstY < dstH; dstY++ {
+			di := dst.PixOffset(0, dstY)
+			for dstX := 0; dstX < dstW; dstX++ {
+				srcX := srcMinX + dstX
+				srcY := srcMinY + dstY
+				siy := src.YOffset(srcX, srcY)
+				sic := src.COffset(srcX, srcY)
+				r, g, b := color.YCbCrToRGB(src.Y[siy], src.Cb[sic], src.Cr[sic])
+				dst.Pix[di+0] = r
+				dst.Pix[di+1] = g
+				dst.Pix[di+2] = b
+				dst.Pix[di+3] = 0xff
+				di += 4
+			}
+		}
+	default:
+		for dstY := 0; dstY < dstH; dstY++ {
+			di := dst.PixOffset(0, dstY)
+			for dstX := 0; dstX < dstW; dstX++ {
+				c := color.NRGBAModel.Convert(img.At(srcMinX+dstX, srcMinY+dstY)).(color.NRGBA)
+				dst.Pix[di+0] = c.R
+				dst.Pix[di+1] = c.G
+				dst.Pix[di+2] = c.B
+				dst.Pix[di+3] = c.A
+				di += 4
+			}
+		}
+	}
+
+	return dst
+}