www.pudn.com > qrencode-2.0.0.rar > mask.c

/*
 * qrencode - QR Code encoder
 *
 * Masking.
 * Copyright (C) 2006, 2007, 2008 Kentaro Fukuchi 
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include 
#include 
#include "qrencode.h"
#include "qrencode_inner.h"
#include "qrspec.h"
#include "mask.h"

/**
 * Demerit coefficients.
 * See Section 8.8.2, pp.45, JIS X0510:2004.
 */
#define N1 (3)
#define N2 (3)
#define N3 (40)
#define N4 (10)

#define MASKMAKER(__exp__) \
	int x, y;\
	unsigned int b = 0;\
\
	for(y=0; y= 5) {
			demerit += N1 + (runLength[i] - 5);
			//n1 += N1 + (runLength[i] - 5);
		}
		if((i & 1)) {
			if(i >= 3 && i < length-2 && (runLength[i] % 3) == 0) {
				fact = runLength[i] / 3;
				if(runLength[i-2] == fact &&
				   runLength[i-1] == fact &&
				   runLength[i+1] == fact &&
				   runLength[i+2] == fact) {
					if(runLength[i-3] < 0 || runLength[i-3] >= 4 * fact) {
						demerit += N3;
						//n3 += N3;
					} else if(i+3 >= length || runLength[i+3] >= 4 * fact) {
						demerit += N3;
						//n3 += N3;
					}
				}
			}
		}
	}

	return demerit;
}

int Mask_evaluateSymbol(int width, unsigned char *frame)
{
	int x, y;
	unsigned char *p;
	unsigned char b22, w22;
	unsigned int i;
	int head;
	int demerit = 0;

	p = frame;
	i = 0;
	for(y=0; y 0 && y > 0) {
				b22 = p[0] & p[-1] & p[-width] & p [-width-1];
				w22 = p[0] | p[-1] | p[-width] | p [-width-1];
				if((b22 | (w22 ^ 1))&1) {
					demerit += N2;
				}
			}
			if(x == 0 && (p[0] & 1)) {
				runLength[0] = -1;
				head = 1;
				runLength[head] = 1;
			} else if(x > 0) {
				if((p[0] ^ p[-1]) & 1) {
					head++;
					runLength[head] = 1;
				} else {
					runLength[head]++;
				}
			}
			p++;
		}
		demerit += Mask_calcN1N3(head+1, runLength);
	}

	i = 0;
	for(x=0; x 0) {
				if((p[0] ^ p[-width]) & 1) {
					head++;
					runLength[head] = 1;
				} else {
					runLength[head]++;
				}
			}
			p+=width;
		}
		demerit += Mask_calcN1N3(head+1, runLength);
	}

	return demerit;
}

unsigned char *Mask_mask(int width, unsigned char *frame, QRecLevel level)
{
	int i;
	unsigned char *mask, *bestMask;
	int minDemerit = INT_MAX;
	int bestMaskNum = 0;
	int blacks;
	int demerit;

	bestMask = NULL;

	for(i=0; i<8; i++) {
//		n1 = n2 = n3 = n4 = 0;
		demerit = 0;
		mask = (unsigned char *)malloc(width * width);
		blacks = maskMakers[i](width, frame, mask);
		blacks += QRcode_writeFormatInformation(width, mask, i, level);
		blacks = 100 * blacks / (width * width);
		demerit = (abs(blacks - 50) / 5) * N4;
//		n4 = demerit;
		if(demerit > minDemerit) {
			free(mask);
			continue;
		}
		demerit += Mask_evaluateSymbol(width, mask);
//		printf("(%d,%d,%d,%d)=%d\n", n1, n2, n3 ,n4, demerit);
		if(demerit < minDemerit) {
			minDemerit = demerit;
			bestMaskNum = i;
			if(bestMask != NULL) {
				free(bestMask);
			}
			bestMask = mask;
		} else {
			free(mask);
		}
	}

	return bestMask;
}