First commit >:]

gradient.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"image"
+	"image/color"
+)
+
+func HexToRGBA(hexcolor int) color.RGBA {
+	return color.RGBA{
+		R: uint8(hexcolor >> 0x10 & 0xff),
+		G: uint8(hexcolor >> 0x08 & 0xff),
+		B: uint8(hexcolor >> 0x00 & 0xff),
+		A: 0xff,
+	}
+}
+
+// performs linear gradient fill on target image for the background from top to bottom colors
+func FillGradient(target *image.RGBA, width int, height int, top, bottom color.RGBA) {
+
+	for y := 0; y < height; y++ {
+
+		//the percent of our transition informs our blending
+		percentIn := float64(y) / float64(height)
+
+		//compute top and bottom blend values as factor of percentage
+		pTopR := float64(top.R) * (1 - percentIn)
+		pTopG := float64(top.G) * (1 - percentIn)
+		pTopB := float64(top.B) * (1 - percentIn)
+
+		pBottomR := float64(bottom.R) * (percentIn)
+		pBottomG := float64(bottom.G) * (percentIn)
+		pBottomB := float64(bottom.B) * (percentIn)
+
+		//perform blending on per pixel row basis
+		for x := 0; x < width; x++ {
+			pixelIndex := 4 * (width*y + x)
+			target.Pix[pixelIndex] = uint8(pTopR + pBottomR)
+			target.Pix[pixelIndex+1] = uint8(pTopG + pBottomG)
+			target.Pix[pixelIndex+2] = uint8(pTopB + pBottomB)
+			target.Pix[pixelIndex+3] = 0xff
+		}
+	}
+}