cmd

var RootCmd = &cobra.Command{
	Use:   "rgba-channel-merge <image-filepath> <image-channel-mask> [(<image-filepath> <image-channel-mask>)...] <output-png-file-path>",
	Short: "image channel merge tool",
	Long: `A tool to merge specific color channels of multiple images into one rgba image.

The channel masks for each image should match the regex [rgbax]{4}, with r, g, b, and a representing the red, green, blue and alpha channel, and x meaning that this channel should be ignored. E.g., the channel mask "rbax" would mean that the first (red) channel of the input image will be used as the red channel for the output image, the second (green) will be used as the blue channel, the third (blue) will be used as alpha channel, and the fourth (alpha) will be ignored.`,
	Run: func(cmd *cobra.Command, args []string) {
		imgs, outputPath, err := parseArgs(args)
		if err != nil {
			fmt.Fprintf(os.Stderr, "%s\n", err)
			os.Exit(1)
		}

		maxSize, err := imgs.openImages()
		if err != nil {
			fmt.Fprintf(os.Stderr, "%s\n", err)
			os.Exit(2)
		}

		outImg := image.NewNRGBA(image.Rectangle{Min: image.Point{0, 0}, Max: maxSize})
		draw.Draw(outImg, outImg.Bounds(), &image.Uniform{color.RGBA{0, 0, 0, 255}}, image.ZP, draw.Src)

		imgs.mergeChannels(outImg)

		outFile, err := os.Create(outputPath)
		if err != nil {
			fmt.Fprintf(os.Stderr, "%s\n", err)
			os.Exit(3)
		}
		defer outFile.Close()

		png.Encode(outFile, outImg)
	},
}