void RawImage::downsampleInPlace(unsigned int downsampleX, unsigned int downsampleY)
{
RawImage* tmp = downsample(this, downsampleX, downsampleY);
deletePixels();
_type = tmp->getType();
_bytesPerPixel = tmp->getBytesPerPixel();
_width = tmp->getWidth();
_height = tmp->getHeight();
_pixels = tmp->takePixels();
delete tmp;
}
RawImage* downsample(RawImage* src, unsigned int downsampleX, unsigned int downsampleY)
{
RawImage* result = new RawImage(src->getType(), src->getBytesPerPixel(),
src->getWidth() / downsampleX, src->getHeight() / downsampleY);
size_t bpp = result->getBytesPerPixel();
size_t xStride = (downsampleX - 1) * bpp;
for (size_t y = 0; y < result->getHeight(); ++y) {
size_t from = y * downsampleY * src->getWidth() * bpp;
size_t to = y * result->getWidth() * bpp;
for (size_t x = 0; x < result->getWidth(); ++x) {
for (size_t b = 0; b < bpp; ++b) {
result->getPixels()[to] = src->getPixels()[from];
++to;
++from;
}
from += xStride;
}
}
return result;
}