Function ChamferedDistanceTransform

BeefySysLib/img/ImgEffects.cpp:601–655

}

static void ChamferedDistanceTransform(uint32* out, int width, int height)
{
	AutoPerf gPerf("ImgEffects - ChamferedDistanceTransform");

	if ((width < 4) || (height < 4))
	{
		ChamferedDistanceTransformSlow(out, width, height, 0, 0, width, height);
		return;
	}

	// Do 2 pixel border (where we have to clamp)
	ChamferedDistanceTransformSlow(out, width, height, 0, 0, width, 2);
	ChamferedDistanceTransformSlow(out, width, height, 0, height-2, width, 2);
	ChamferedDistanceTransformSlow(out, width, height, 0, 2, 2, height - 2);
	ChamferedDistanceTransformSlow(out, width, height, width - 2, 2, 2, height - 2);

	// Do inner region (no clamping)
	int kernelCountFwd = sizeof(gKernelValsFwd) / sizeof(int);
	int kernelCountRev = sizeof(gKernelValsRev) / sizeof(int);
	
	int aStartX = 2;
	int aStartY = 2;
	int aEndX = width - 2;
	int aEndY = height - 2;

	for (int y = aStartY; y < aEndY; y++)
	{
		for (int x = aStartX; x < aEndX; x++)
		{
			for (int kernIdx = 0; kernIdx < kernelCountFwd; kernIdx++)
			{
				int cx = x + gKernelOfsFwd[kernIdx][0];
				int cy = y + gKernelOfsFwd[kernIdx][1];
				int aVal = out[cx+cy*width] + gKernelValsFwd[kernIdx];
				if (aVal < (int) out[x+y*width])
					out[x+y*width] = aVal;
			}
		}
	}	

	for (int y = aEndY - 1; y >= aStartY; y--)
	{
		for (int x = aEndX - 1; x >= aStartX; x--)
		{
			for (int kernIdx = 0; kernIdx < kernelCountRev; kernIdx++)
			{
				int cx = x + gKernelOfsRev[kernIdx][0];
				int cy = y + gKernelOfsRev[kernIdx][1];
				int aVal = out[cx+cy*width] + gKernelValsRev[kernIdx];
				if (aVal < (int) out[x+y*width])
					out[x+y*width] = aVal;
			}
		}
	}
}

#define IN_PIXEL(xval,yval) in[(xval) + (yval)*width]
#define IN_PIXEL_YX(yval,xval) in[(xval) + (yval)*width]