86 lines
1.8 KiB
Go
86 lines
1.8 KiB
Go
package vidio
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import (
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"fmt"
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"image"
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"os"
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"path/filepath"
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"image/color"
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"image/jpeg"
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"image/png"
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)
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// Reads an image from a file. Currently only supports png and jpeg.
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func Read(filename string, buffer ...[]byte) (int, int, []byte, error) {
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f, err := os.Open(filename)
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if err != nil {
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return 0, 0, nil, err
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}
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defer f.Close()
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image, _, err := image.Decode(f)
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if err != nil {
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return 0, 0, nil, err
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}
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bounds := image.Bounds().Max
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size := bounds.X * bounds.Y * 3
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var data []byte
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if len(buffer) > 0 {
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if len(buffer[0]) < size {
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return 0, 0, nil, fmt.Errorf("buffer size (%d) is smaller than image size (%d)", len(buffer[0]), size)
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}
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data = buffer[0]
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} else {
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data = make([]byte, size)
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}
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index := 0
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for h := 0; h < bounds.Y; h++ {
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for w := 0; w < bounds.X; w++ {
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r, g, b, _ := image.At(w, h).RGBA()
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r, g, b = r/256, g/256, b/256
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data[index+0] = byte(r)
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data[index+1] = byte(g)
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data[index+2] = byte(b)
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index += 3
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}
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}
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return bounds.X, bounds.Y, data, nil
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}
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// Writes an image to a file. Currently only supports png and jpeg.
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func Write(filename string, width, height int, buffer []byte) error {
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f, err := os.Create(filename)
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if err != nil {
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return err
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}
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defer f.Close()
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image := image.NewRGBA(image.Rect(0, 0, width, height))
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index := 0
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for h := 0; h < height; h++ {
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for w := 0; w < width; w++ {
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r, g, b := buffer[index], buffer[index+1], buffer[index+2]
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image.Set(w, h, color.RGBA{r, g, b, 255})
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index += 3
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}
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}
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switch filepath.Ext(filename) {
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case ".png":
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if err := png.Encode(f, image); err != nil {
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return err
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}
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case ".jpg", ".jpeg":
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if err := jpeg.Encode(f, image, nil); err != nil {
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return err
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}
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default:
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return fmt.Errorf("unsupported file extension: %s", filepath.Ext(filename))
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}
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return nil
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}
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