Rotate Channels or Surfaces in Cinder

SurfaceChannelRotate.cpp

void SurfaceChannelRotateApp::rotateChannel( const ci::Channel &channel, ci::Channel &destChannel )
{
	const int32_t height = channel.getHeight();
	const int32_t width = channel.getWidth();
	
	// 90 deg
	/*
	for( int32_t y = 0; y < height; ++y ) {
		auto ogPtr = channel.getData( ivec2( 0, y ) );
		auto newPtr = destChannel.getData( ivec2( height - y - 1, 0 ) );
		for( int32_t x = 0; x < width; ++x ) {
				int rotRow = height * x;
				auto v = ogPtr[x];
				newPtr[rotRow] = v;
		}
	}*/
	
	// -90 deg
	for( int32_t y = 0; y < height; ++y ) {
		auto ogPtr = channel.getData( ivec2( 0, y ) );
		auto newPtr = destChannel.getData( ivec2( y, 0 ) );
		for( int32_t x = 0; x < width; ++x ) {
			int rotRow = height*x;
			auto v = ogPtr[width - x - 1];
			newPtr[rotRow] = v;
		}
	}
}

void SurfaceChannelRotateApp::rotateSurface( const ci::Surface8u &surface, ci::Surface8u &destSurface )
{
	const int32_t height = surface.getHeight();
	const int32_t width = surface.getWidth();
	const size_t inc = surface.getPixelInc();
	
	for( int32_t y = 0; y < height; ++y ) {
		auto ogPtr = surface.getData( ivec2( 0, y ) );
		auto newPtr = destSurface.getData( ivec2( height - y - 1, 0 ) );
		for( int32_t x = 0; x < width; ++x ) {
			for( int c = 0; c < inc; ++c ) {
				int rotRow = height*(x*inc)+c;
				auto v = ogPtr[x*inc + c];
				newPtr[rotRow] = v;
			}
		}
	}
}