image composition in go

image_composition.go

package main

import (
	"fmt"
	"image"
	"image/draw"
	"image/jpeg"
	"image/png"
	"os"
)

func main() {

	mm1Fp, _ := os.Open("mm1.png")
	defer mm1Fp.Close()

	mm1Image, _ := png.Decode(mm1Fp)
	mm1ImageB := mm1Image.Bounds()

	mm2Fp, _ := os.Open("mm2.jpg")
	defer mm2Fp.Close()

	mm2Image, _ := jpeg.Decode(mm2Fp)
	mm2ImageB := mm2Image.Bounds()

	mm3Fp, _ := os.Open("mm3.jpg")
	defer mm3Fp.Close()

	mm3Image, _ := jpeg.Decode(mm3Fp)
	mm3ImageB := mm3Image.Bounds()

	dstH := sum(mm1ImageB.Max.Y-mm1ImageB.Min.Y,
		mm2ImageB.Max.Y-mm2ImageB.Min.Y,
		mm3ImageB.Max.Y-mm3ImageB.Min.Y)

	dstW := max(mm1ImageB.Max.X-mm1ImageB.Min.X,
		mm2ImageB.Max.X-mm2ImageB.Min.X,
		mm3ImageB.Max.X-mm3ImageB.Min.X)

	fmt.Println("Dst Image:", dstW, dstH)

	dstX := 0
	dstY := 0

	p1 := image.Point{
		dstX, dstY,
	}

	fmt.Println("B1:", mm1ImageB)
	fmt.Println("P1:", p1)

	dstY += mm1ImageB.Max.Y - mm1ImageB.Min.Y
	p2 := image.Point{
		dstX, dstY,
	}

	fmt.Println("B2:", mm2ImageB)
	fmt.Println("P2:", p2)

	dstY += mm2ImageB.Max.Y - mm2ImageB.Min.Y

	p3 := image.Point{
		dstX, dstY,
	}

	fmt.Println("B3:", mm3ImageB)
	fmt.Println("P3:", p3)

	dstRect := image.Rect(0, 0, dstW, dstH)
	dstImage := image.NewRGBA(dstRect)

	dstRect1 := mm1ImageB.Add(p1)
	dstRect2 := mm2ImageB.Add(p2)
	dstRect3 := mm3ImageB.Add(p3)

	fmt.Println("Dst1:", dstRect1)
	fmt.Println("Dst2:", dstRect2)
	fmt.Println("Dst3:", dstRect3)

	draw.Draw(dstImage, dstRect1, mm1Image, mm1ImageB.Min, draw.Src)
	draw.Draw(dstImage, dstRect2, mm2Image, mm2ImageB.Min, draw.Src)
	draw.Draw(dstImage, dstRect3, mm3Image, mm3ImageB.Min, draw.Src)

	dstFp, _ := os.OpenFile("result.png", os.O_CREATE|os.O_WRONLY, 0666)
	png.Encode(dstFp, dstImage)
}

func sum(nums ...int) int {
	s := 0
	for _, n := range nums {
		s += n
	}
	return s
}

func max(nums ...int) int {
	m := nums[0]
	for _, n := range nums {
		if n > m {
			m = n
		}
	}
	return m
}