51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
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package webcam
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import "testing"
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func TestDecodeBMP_roundtripRGB(t *testing.T) {
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// 2x2 24-bit BI_RGB bottom-up BMP
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row := []byte{
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0, 0, 255, // BGR red
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0, 255, 0, // green
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0, 0, // pad to 4-byte boundary: 6 bytes -> pad 2
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}
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row2 := []byte{
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255, 0, 0, // blue
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255, 255, 255, // white
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0, 0,
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}
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pixelData := append(append([]byte{}, row2...), row...) // bottom row first
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header := make([]byte, 54)
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header[0], header[1] = 'B', 'M'
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binaryPutUint32 := func(b []byte, v uint32) {
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b[0] = byte(v)
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b[1] = byte(v >> 8)
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b[2] = byte(v >> 16)
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b[3] = byte(v >> 24)
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}
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binaryPutUint16 := func(b []byte, v uint16) {
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b[0] = byte(v)
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b[1] = byte(v >> 8)
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}
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fileSize := uint32(54 + len(pixelData))
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binaryPutUint32(header[2:], fileSize)
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binaryPutUint32(header[10:], 54)
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binaryPutUint32(header[14:], 40) // DIB header size
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binaryPutUint32(header[18:], 2) // width
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binaryPutUint32(header[22:], 2) // height (bottom-up)
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binaryPutUint16(header[26:], 1) // planes
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binaryPutUint16(header[28:], 24) // bpp
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img, err := decodeBMP(append(header, pixelData...))
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if err != nil {
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t.Fatal(err)
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}
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if img.Bounds().Dx() != 2 || img.Bounds().Dy() != 2 {
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t.Fatalf("size = %v", img.Bounds())
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}
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r, g, b, _ := img.At(0, 0).RGBA()
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if r>>8 != 255 || g>>8 != 0 || b>>8 != 0 {
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t.Fatalf("pixel 0,0 = %d,%d,%d want red", r>>8, g>>8, b>>8)
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}
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}
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