41 lines
1.0 KiB
Go
41 lines
1.0 KiB
Go
package resize_image
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import (
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"image"
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"image/color"
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)
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func Resize(img image.RGBA, width int, height int) (*image.RGBA, error) {
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originalWidth := img.Bounds().Dx()
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originalHeight := img.Bounds().Dy()
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if width <= 0 && height <= 0 {
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return nil, nil
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} else if width <= 0 {
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width = int(float64(height) * float64(originalWidth) / float64(originalHeight))
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} else if height <= 0 {
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height = int(float64(width) * float64(originalHeight) / float64(originalWidth))
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}
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newImg := image.NewRGBA(image.Rect(0, 0, width, height))
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scaleX := float64(originalWidth) / float64(width)
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scaleY := float64(originalHeight) / float64(height)
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for y := 0; y < height; y++ {
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for x := 0; x < width; x++ {
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srcX := int(float64(x) * scaleX)
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srcY := int(float64(y) * scaleY)
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r, g, b, a := getPixel(img, srcX, srcY)
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newImg.Set(x, y, color.RGBA{r, g, b, a})
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}
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}
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return newImg, nil
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}
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func getPixel(img image.RGBA, x int, y int) (uint8, uint8, uint8, uint8) {
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index := img.PixOffset(x, y)
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return img.Pix[index], img.Pix[index+1], img.Pix[index+2], img.Pix[index+3]
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}
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