Linear 2x Scaler written by [md5]

gistfile1.cpp

// Taken from SCI
void scale2x(const byte *src, byte *dst, int16 srcWidth, int16 srcHeight, byte bytesPerPixel) {
    assert(bytesPerPixel == 1 || bytesPerPixel == 2);
    const int newWidth = srcWidth * 2;
    const int pitch = newWidth * bytesPerPixel;
    const byte *srcPtr = src;

    if (bytesPerPixel == 1) {
        for (int y = 0; y < srcHeight; y++) {
            for (int x = 0; x < srcWidth; x++) {
                const byte color = *srcPtr++;
                dst[0] = color;
                dst[1] = color;
                dst[newWidth] = color;
                dst[newWidth + 1] = color;
                dst += 2;
            }
            dst += newWidth;
        }
    } else if (bytesPerPixel == 2) {
        for (int y = 0; y < srcHeight; y++) {
            for (int x = 0; x < srcWidth; x++) {
                const byte color = *srcPtr++;
                const byte color2 = *srcPtr++;
                dst[0] = color;
                dst[1] = color2;
                dst[2] = color;
                dst[3] = color2;
                dst[pitch] = color;
                dst[pitch + 1] = color2;
                dst[pitch + 2] = color;
                dst[pitch + 3] = color2;
                dst += 4;
            }
            dst += pitch;
        }
    }
}