wails/v3/pkg/application/image.go

package application

import (
	"bytes"
	"image"
	"image/draw"
	"image/png"
)

func pngToImage(data []byte) (*image.RGBA, error) {
	img, err := png.Decode(bytes.NewReader(data))
	if err != nil {
		return nil, err
	}

	bounds := img.Bounds()
	rgba := image.NewRGBA(bounds)
	draw.Draw(rgba, bounds, img, bounds.Min, draw.Src)
	return rgba, nil
}

func ToARGB(img *image.RGBA) (int, int, []byte) {
	w, h := img.Bounds().Dx(), img.Bounds().Dy()
	data := make([]byte, w*h*4)
	i := 0
	for y := 0; y < h; y++ {
		for x := 0; x < w; x++ {
			r, g, b, a := img.At(x, y).RGBA()
			data[i] = byte(a)
			data[i+1] = byte(r)
			data[i+2] = byte(g)
			data[i+3] = byte(b)
			i += 4
		}
	}
	return w, h, data
}