vendor: add all of our dependencies

vendor/github.com/disintegration/imaging/tools.go

@@ -0,0 +1,182 @@
+package imaging
+
+import (
+	"image"
+	"math"
+)
+
+// Anchor is the anchor point for image alignment.
+type Anchor int
+
+const (
+	Center Anchor = iota
+	TopLeft
+	Top
+	TopRight
+	Left
+	Right
+	BottomLeft
+	Bottom
+	BottomRight
+)
+
+func anchorPt(b image.Rectangle, w, h int, anchor Anchor) image.Point {
+	var x, y int
+	switch anchor {
+	case TopLeft:
+		x = b.Min.X
+		y = b.Min.Y
+	case Top:
+		x = b.Min.X + (b.Dx()-w)/2
+		y = b.Min.Y
+	case TopRight:
+		x = b.Max.X - w
+		y = b.Min.Y
+	case Left:
+		x = b.Min.X
+		y = b.Min.Y + (b.Dy()-h)/2
+	case Right:
+		x = b.Max.X - w
+		y = b.Min.Y + (b.Dy()-h)/2
+	case BottomLeft:
+		x = b.Min.X
+		y = b.Max.Y - h
+	case Bottom:
+		x = b.Min.X + (b.Dx()-w)/2
+		y = b.Max.Y - h
+	case BottomRight:
+		x = b.Max.X - w
+		y = b.Max.Y - h
+	default:
+		x = b.Min.X + (b.Dx()-w)/2
+		y = b.Min.Y + (b.Dy()-h)/2
+	}
+	return image.Pt(x, y)
+}
+
+// Crop cuts out a rectangular region with the specified bounds
+// from the image and returns the cropped image.
+func Crop(img image.Image, rect image.Rectangle) *image.NRGBA {
+	src := toNRGBA(img)
+	srcRect := rect.Sub(img.Bounds().Min)
+	sub := src.SubImage(srcRect)
+	return Clone(sub) // New image Bounds().Min point will be (0, 0)
+}
+
+// CropAnchor cuts out a rectangular region with the specified size
+// from the image using the specified anchor point and returns the cropped image.
+func CropAnchor(img image.Image, width, height int, anchor Anchor) *image.NRGBA {
+	srcBounds := img.Bounds()
+	pt := anchorPt(srcBounds, width, height, anchor)
+	r := image.Rect(0, 0, width, height).Add(pt)
+	b := srcBounds.Intersect(r)
+	return Crop(img, b)
+}
+
+// CropCenter cuts out a rectangular region with the specified size
+// from the center of the image and returns the cropped image.
+func CropCenter(img image.Image, width, height int) *image.NRGBA {
+	return CropAnchor(img, width, height, Center)
+}
+
+// Paste pastes the img image to the background image at the specified position and returns the combined image.
+func Paste(background, img image.Image, pos image.Point) *image.NRGBA {
+	src := toNRGBA(img)
+	dst := Clone(background)                    // cloned image bounds start at (0, 0)
+	startPt := pos.Sub(background.Bounds().Min) // so we should translate start point
+	endPt := startPt.Add(src.Bounds().Size())
+	pasteBounds := image.Rectangle{startPt, endPt}
+
+	if dst.Bounds().Overlaps(pasteBounds) {
+		intersectBounds := dst.Bounds().Intersect(pasteBounds)
+
+		rowSize := intersectBounds.Dx() * 4
+		numRows := intersectBounds.Dy()
+
+		srcStartX := intersectBounds.Min.X - pasteBounds.Min.X
+		srcStartY := intersectBounds.Min.Y - pasteBounds.Min.Y
+
+		i0 := dst.PixOffset(intersectBounds.Min.X, intersectBounds.Min.Y)
+		j0 := src.PixOffset(srcStartX, srcStartY)
+
+		di := dst.Stride
+		dj := src.Stride
+
+		for row := 0; row < numRows; row++ {
+			copy(dst.Pix[i0:i0+rowSize], src.Pix[j0:j0+rowSize])
+			i0 += di
+			j0 += dj
+		}
+	}
+
+	return dst
+}
+
+// PasteCenter pastes the img image to the center of the background image and returns the combined image.
+func PasteCenter(background, img image.Image) *image.NRGBA {
+	bgBounds := background.Bounds()
+	bgW := bgBounds.Dx()
+	bgH := bgBounds.Dy()
+	bgMinX := bgBounds.Min.X
+	bgMinY := bgBounds.Min.Y
+
+	centerX := bgMinX + bgW/2
+	centerY := bgMinY + bgH/2
+
+	x0 := centerX - img.Bounds().Dx()/2
+	y0 := centerY - img.Bounds().Dy()/2
+
+	return Paste(background, img, image.Pt(x0, y0))
+}
+
+// Overlay draws the img image over the background image at given position
+// and returns the combined image. Opacity parameter is the opacity of the img
+// image layer, used to compose the images, it must be from 0.0 to 1.0.
+//
+// Usage examples:
+//
+//		// draw the sprite over the background at position (50, 50)
+//		dstImage := imaging.Overlay(backgroundImage, spriteImage, image.Pt(50, 50), 1.0)
+//
+//		// blend two opaque images of the same size
+//		dstImage := imaging.Overlay(imageOne, imageTwo, image.Pt(0, 0), 0.5)
+//
+func Overlay(background, img image.Image, pos image.Point, opacity float64) *image.NRGBA {
+	opacity = math.Min(math.Max(opacity, 0.0), 1.0) // check: 0.0 <= opacity <= 1.0
+
+	src := toNRGBA(img)
+	dst := Clone(background)                    // cloned image bounds start at (0, 0)
+	startPt := pos.Sub(background.Bounds().Min) // so we should translate start point
+	endPt := startPt.Add(src.Bounds().Size())
+	pasteBounds := image.Rectangle{startPt, endPt}
+
+	if dst.Bounds().Overlaps(pasteBounds) {
+		intersectBounds := dst.Bounds().Intersect(pasteBounds)
+
+		for y := intersectBounds.Min.Y; y < intersectBounds.Max.Y; y++ {
+			for x := intersectBounds.Min.X; x < intersectBounds.Max.X; x++ {
+				i := y*dst.Stride + x*4
+
+				srcX := x - pasteBounds.Min.X
+				srcY := y - pasteBounds.Min.Y
+				j := srcY*src.Stride + srcX*4
+
+				a1 := float64(dst.Pix[i+3])
+				a2 := float64(src.Pix[j+3])
+
+				coef2 := opacity * a2 / 255.0
+				coef1 := (1 - coef2) * a1 / 255.0
+				coefSum := coef1 + coef2
+				coef1 /= coefSum
+				coef2 /= coefSum
+
+				dst.Pix[i+0] = uint8(float64(dst.Pix[i+0])*coef1 + float64(src.Pix[j+0])*coef2)
+				dst.Pix[i+1] = uint8(float64(dst.Pix[i+1])*coef1 + float64(src.Pix[j+1])*coef2)
+				dst.Pix[i+2] = uint8(float64(dst.Pix[i+2])*coef1 + float64(src.Pix[j+2])*coef2)
+				dst.Pix[i+3] = uint8(math.Min(a1+a2*opacity*(255.0-a1)/255.0, 255.0))
+			}
+		}
+	}
+
+	return dst
+}