for (int y = 0; y < yMax && y < (int)h; y++) {
spectrum.setPixel(leftDist + i, topDist + h-y-1, qRgba(225, 182, 255, 255));
}
for (int y = 0; y < yMax && y < (int)h; y++) {
spectrum.setPixel(leftDist + i, topDist + h-y-1, qRgba(225, 182, 255, 255));
}