/**
 * customStructElem.c
 * OpenCV Introduction: Demo 4
 * David Johnston, 2013-01-29
 */

#include <stdio.h>
#include <stdlib.h>
#include "cv.h"
#include "highgui.h"

void display(IplImage* img)
{
	cvShowImage("DEBUG", img);
	cvWaitKey(0);
}

IplConvKernel* createCustomStructElem(IplImage* template)
{
	IplConvKernel* rv = NULL;  // the kernel to be returned
	CvSize size;               // size of 'template'
	int* kernData;             // where the template data is temporarily stored
	int* kernRow;              // points into 'kernData'
	void* templateRow;         // points into 'template->imageData'
	int y;                     // iterates over the rows
	int x;                     // iterates over the columns

	if (template == NULL || cvGetElemType(template) != CV_8UC1) {
		return rv;
	}

	/*
	 * Copy the contents of 'template->imageData' (which is an unsigned char
	 * array) into 'kernData' (which is an int array).
	 *
	 * Both arrays have (size.width * size.height) number of elements.
	 */

	size = cvGetSize(template);
	kernData = (int*) malloc(size.height * size.width * sizeof(int));

	for (y = 0; y < size.height; y++)
	{
		// For both arrays, reinitialize to the 0th element of the y-th row:
		templateRow = template->imageData + (y * template->widthStep);
		kernRow = kernData + (y * size.width);

		// Copy every element on the y-th row:
		for (x = 0; x < size.width; x++) {
			kernRow[x] = ((unsigned char*) templateRow)[x];
		}
	}

	rv = cvCreateStructuringElementEx(
		size.width, size.height,
		size.width / 2, size.height / 2,
		CV_SHAPE_CUSTOM, kernData
	);

	free(kernData);

	return rv;
}


int main(const int argc, const char* argv[])
{

	IplImage* template;
	IplImage* testImage;
	IplConvKernel* rectKernel;
	IplConvKernel* customKernel;

	template = cvLoadImage("inputs/template.png", CV_LOAD_IMAGE_GRAYSCALE);
	testImage = cvLoadImage("inputs/test.png", CV_LOAD_IMAGE_GRAYSCALE);

	cvThreshold( template,  template, 160, 0xFF, CV_THRESH_BINARY_INV);
	cvThreshold(testImage, testImage, 160, 0xFF, CV_THRESH_BINARY_INV);

	rectKernel = cvCreateStructuringElementEx(3, 3, 1, 1, CV_SHAPE_RECT, NULL);

	cvErode(template,   template,  rectKernel, 1);  // decreases white area
	cvDilate(testImage, testImage, rectKernel, 1);  // increases white area

	cvShowImage("Template", template);
	cvShowImage("Test Image", testImage);
	cvWaitKey(0);


	customKernel = createCustomStructElem(template);

	cvErode(testImage, testImage, customKernel, 1);
	cvDilate(testImage, testImage, customKernel, 1);

	cvShowImage("DEBUG", testImage);
	cvWaitKey(0);
}