Miscellany

uint8 getValue(IplImage *input,int x, int y) {
	uint8 *iData = (uint8 *)input->imageData;
	uint8 retval;

	if((x < input->width) && (x >= 0) && (y < input->height) && (y >= 0)) { // inside bounds
		retval = iData[(y * input->widthStep) + x];
	}
	else if(x < 0) { 
		if(y < 0) { // diagonal top left
			retval = iData[0];
		}
		else if(y >= input->height) { // diagonal bottom left
			retval = iData[(input->height - 1) * input->widthStep];
		}
		else { // off left
			retval = iData[(y * input->widthStep)];
		}
	}
	else if(x >= input->width) {
		if(y < 0) { // diagonal top right
			retval = iData[input->width - 1];
		}
		else if(y >= input->height) { // diagonal bottom right
			retval = iData[((input->height - 1) * input->widthStep) + (input->width - 1)];
		}
		else { // off right
			retval = iData[(y * input->widthStep) + (input->width - 1)];
		}
	}
	else if(y < 0) { // off top
		retval = iData[x];
	}
	else if(y >= input->height) { // off bottom
		retval = iData[((input->height - 1) * input->widthStep) + x];
	}
	
	return retval;
}