histogram.cpp

#include <stdio.h>
#include <stdlib.h>
#include "myImageIO.h"


void Histogram(myImageData *img, int binsize){

	int W = img->getWidth();
	int H = img->getHeight();
	
	int nBins = 256/binsize;
	int * histdata = new int [nBins];

	for(int idx = 0; idx < nBins; idx++){
		histdata[idx] = 0;
	}
	
	for(int y = 0; y < H; y++){
		for(int x = 0; x < W; x++){
			
			int value = img->get(x,y);
			int bin = value/binsize;
			histdata[bin]++;
		}
	}

	// print the histogram
	
	for(int idx = 0; idx < nBins; idx++){
		
		printf("[%.03d-%.03d]\t", idx*binsize, (idx+1)*binsize-1);
		
		int num = histdata[idx];
		int denom = 0.1*W*H/nBins;
		for(int cnt = 0; cnt < num/denom; cnt++){
			printf("*");
		}
		
		printf("\n");
	}
	
	delete [] histdata;	
	
	return;
	
}


int main(int argc, char **argv){
	
	// read image data to img1
	
	myImageData * img1 = new myImageData();
	img1->read(argv[1]);

	int W = img1->getWidth();
	int H = img1->getHeight();
	
	Histogram(img1, 8);
	
	delete img1;
	
	return 1; // normal termination
	
}