libpng+VS2012(VS2015)的使用

  1 #include <opencv2\opencv.hpp>
  2 #include <stddef.h>
  3 #include <stdlib.h>
  4 #include <string.h>
  5 #include <stdio.h>
  6 #include <png.h>
  7 #include <zlib.h>
  8 
  9 using namespace cv;
 10 
 11 int write_png_file(char *file_name , Mat srcImg, int imgW, int imgH, int channels)
 12 {
 13      uchar* pImgData=(uchar*)srcImg.data;
 14      int j, i, temp, pos;
 15      png_byte color_type;
 16 
 17      png_structp png_ptr;
 18      png_infop info_ptr; 
 19      png_bytep * row_pointers;
 20      /* create file */
 21      FILE *fp = fopen(file_name, "wb");
 22      if (!fp)
 23      {
 24           printf("[write_png_file] File %s could not be opened for writing", file_name);
 25           return -1;
 26      }
 27 
 28      /* initialize stuff */
 29      png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
 30 
 31      if (!png_ptr)
 32      {
 33          printf("[write_png_file] png_create_write_struct failed");
 34          return -1;
 35      }
 36      info_ptr = png_create_info_struct(png_ptr);
 37      if (!info_ptr)
 38      {
 39         printf("[write_png_file] png_create_info_struct failed");
 40         return -1;
 41      }
 42      if (setjmp(png_jmpbuf(png_ptr)))
 43      {
 44         printf("[write_png_file] Error during init_io");
 45         return -1;
 46      }
 47      png_init_io(png_ptr, fp);
 48 
 49      /* write header */
 50      if (setjmp(png_jmpbuf(png_ptr)))
 51      {
 52          printf("[write_png_file] Error during writing header");
 53          return -1;
 54      }
 55      /* 判断要写入至文件的图片数据是否有透明度，来选择色彩类型 */
 56      if(channels == 4) 
 57      {
 58          color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 59      }
 60      else if(channels==1)
 61      {
 62          color_type = PNG_COLOR_TYPE_GRAY;
 63      }
 64      else
 65      {
 66          color_type = PNG_COLOR_TYPE_RGB;
 67      }
 68      
 69      png_set_IHDR(png_ptr, info_ptr, imgW, imgH,
 70       8, color_type, PNG_INTERLACE_NONE,
 71       PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 72 
 73      png_write_info(png_ptr, info_ptr);
 74 
 75      /* write bytes */
 76      if (setjmp(png_jmpbuf(png_ptr)))
 77      {
 78         printf("[write_png_file] Error during writing bytes");
 79         return -1;
 80      }
 81      if(channels == 4) 
 82      {
 83         temp = (4 * imgW);
 84      }
 85      else if(channels == 1)
 86      {
 87          temp = ( imgW);
 88      }
 89      else
 90      {
 91          temp = ( 3*imgW);
 92      }
 93  
 94      row_pointers = (png_bytep*)malloc(imgH*sizeof(png_bytep));
 95      for(i = 0; i < imgH; i++)
 96      {
 97           row_pointers[i] = (png_bytep)malloc(sizeof(uchar)*temp);
 98           for(j = 0; j < imgW; j += 1)
 99           {
100                if(channels==4) 
101                {
102                    row_pointers[i][j*3+0]  = pImgData[i*imgW*3+ j*3+0]; // blue
103                    row_pointers[i][j*3+1] = pImgData[i*imgW*3+ j*3+1]; // green
104                    row_pointers[i][j*3+2] = pImgData[i*imgW*3+ j*3+2];  // red
105                    row_pointers[i][j*3+3] = pImgData[i*imgW*3+ j*3+3];  // alpha
106                }
107                else if(channels==1)
108                {
109                    row_pointers[i][j]  = pImgData[i*imgW+ j]; // gray
110                }
111                else
112                {
113                    row_pointers[i][j*3+0]  = pImgData[i*imgW*3+ j*3+0]; // blue
114                    row_pointers[i][j*3+1] = pImgData[i*imgW*3+ j*3+1]; // green
115                    row_pointers[i][j*3+2] = pImgData[i*imgW*3+ j*3+2];  // red
116                }
117           }
118      }
119      png_write_image(png_ptr, row_pointers);
120 
121      /* end write */
122      if (setjmp(png_jmpbuf(png_ptr)))
123      {
124       printf("[write_png_file] Error during end of write");
125       return -1;
126      }
127      png_write_end(png_ptr, NULL);
128 
129         /* cleanup heap allocation */
130      for (j=0; j<imgH; j++)
131      {
132         free(row_pointers[j]);
133      }
134      free(row_pointers);
135 
136     fclose(fp);
137     return 0;
138 }
139 
140 void main()
141 {
142     Mat img=imread("lena.jpg", 0);
143     namedWindow("lena");
144     imshow("lena",img);
145     waitKey(0);
146     char imgName[10]="lena.png";
147     int imgWidth=img.cols;
148     int imgHeight=img.rows;
149     int channels=img.channels();
150     write_png_file(imgName , img, imgWidth, imgHeight, channels);
151 
152     getchar();
153 }