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// Copyright 2017 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ebiten
import (
"image"
"image/color"
"image/draw"
)
// copyImage copies img to a new RGBA image.
//
// Basically copyImage just calls draw.Draw.
// If img is a paletted image, an optimized copying method is used.
func copyImage(img image.Image) []byte {
size := img.Bounds().Size()
w, h := size.X, size.Y
bs := make([]byte, 4*w*h)
switch img := img.(type) {
case *image.Paletted:
b := img.Bounds()
x0 := b.Min.X
y0 := b.Min.Y
x1 := b.Max.X
y1 := b.Max.Y
palette := make([]uint8, len(img.Palette)*4)
for i, c := range img.Palette {
rgba := color.RGBAModel.Convert(c).(color.RGBA)
palette[4*i] = rgba.R
palette[4*i+1] = rgba.G
palette[4*i+2] = rgba.B
palette[4*i+3] = rgba.A
}
// Even img is a subimage of another image, Pix starts with 0-th index.
idx0 := 0
idx1 := 0
d := img.Stride - (x1 - x0)
for j := 0; j < y1-y0; j++ {
for i := 0; i < x1-x0; i++ {
p := int(img.Pix[idx0])
bs[idx1] = palette[4*p]
bs[idx1+1] = palette[4*p+1]
bs[idx1+2] = palette[4*p+2]
bs[idx1+3] = palette[4*p+3]
idx0++
idx1 += 4
}
idx0 += d
}
default:
dstImg := &image.RGBA{
Pix: bs,
Stride: 4 * w,
Rect: image.Rect(0, 0, w, h),
}
draw.Draw(dstImg, image.Rect(0, 0, w, h), img, img.Bounds().Min, draw.Src)
}
return bs
}
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