libpng处理png图片（二）

 1 void PngOper::run()
 2 {
 3     cout << "你好" << endl;
 4     char * filePath = "C:\\Users\\Administrator\\Desktop\\切图 - 副本\\map_1001.png";
 5     int width = 0;
 6     int height = 0;
 7     
 8     readPngInfo(filePath, &width, &height);
 9     cout << "读取信息:" << width << "*" << height << endl;
10 
11     
12     //小块儿图片的宽,高
13     int cfg_width = 192;
14     int cfg_height = 180;
15 
16     //计算分割的小图片的行,列数目
17     int gW = width / cfg_width;
18     int exceedWidth = width % cfg_width;
19     int gH = height / cfg_height;
20     int exceedHeight = height % cfg_height;
21 
22     int h = exceedHeight > 0 ? (gH + 1) : gH;
23     int w = exceedWidth > 0 ? (gW + 1) : gW;
24 
25     //读取大图片数据域
26     RGBA_data *buff = (RGBA_data *)malloc(width*height*sizeof(RGBA_data));
27     load_png_image(filePath, &width, &height, buff);
28 
29     //分配小块儿地图的数据域
30     RGBA_data *png_buff = (RGBA_data *)malloc(cfg_width * cfg_height * sizeof(RGBA_data));
31     for (int i = 0; i < h; i++)
32     {
33         for (int j = 0; j < w; j++)
34         {
35             //1.获取png_buff数据域
36             buffCopy(buff, width, height, png_buff, cfg_width, cfg_height, j*cfg_width, i*cfg_height);
37             //2.写图片
38             int idx = i*w + j + 1;
39             string fileName = "C:\\Users\\Administrator\\Desktop\\切图 - 副本\\" + to_string(idx) + ".png";
40             write_RGBA_Image(fileName.c_str(), cfg_width, cfg_height, "test", png_buff);
41         }
42     }
43 
44     if (buff != nullptr)
45     {
46         free(buff);
47         buff = nullptr;
48     }
49     if (png_buff != nullptr)
50     {
51         free(png_buff);
52         png_buff = nullptr;
53     }
54 }