/**
 * projections.c
 * OpenCV Introduction: Demo 3
 * David Johnston, 2013-01-29
 */


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

void printHistLine(int, int);

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

/**
 * A similar solution could be accomplished more simply via cvReduce().
 */

int main(const int argc, const char* argv[])
{
	int i;
	IplImage* src = cvLoadImage("inputs/test.png", CV_LOAD_IMAGE_GRAYSCALE);
	int numRows = src->height;
	int numCols = src->width;
	CvScalar avg = {0};

	cvThreshold(src, src, 160, 0xFF, CV_THRESH_BINARY_INV);
	cvShowImage("Filtered", src);


	/*
	 * Allocate the CvMat struct. We do not yet initialize its fields, and 
	 * we do not allocate the matrix data.
	 *
	 * This struct will be used as header to point to some sliver of the data in 'src'.
	 */

	CvMat vec;


	/**
	 * Find the average of each row.
	 *
	 * For each row in 'src', call cvGetRow() to make 'vec' to be an
	 * interface to the i-th row of pixels of the 'src' image data.
	 */

	puts("*** ROW AVERAGES ***");
	for (i = 0; i < numRows; i++)
	{
		cvGetRow(src, &vec, i);
		avg = cvAvg(&vec, NULL);
		printHistLine(i, (int) avg.val[0]);
	}


	/**
	 * Find the x-axis bounds of the staff lines using vertical projection.
	 */

	puts("\n*** COLUMN AVERAGES ***");
	for (i = 0; i < numCols; i++)
	{
		cvGetCol(src, &vec, i);
		avg = cvAvg(&vec, NULL);
		printHistLine(i, (int) avg.val[0]);
	}

	cvWaitKey(0);
}



void printHistLine(int lineNum, int val) {
	int numStars = val / 8;
	printf("%3d: ", lineNum);
	for (int i = 0; i < numStars; i++)
		putchar('*');
	putchar('\n');
}