阅读更改和打印PPM图像

1 回答

• -1

  以下代码干净地编译 .

  它是硬编码的文件乌克兰.ppm

  您可以轻松修改文件以使用文件全局字符数组

  主要设置输入文件

  您可以轻松修改文件以使用文件全局字符数组

  主要设置为输出文件

  #include <stdio.h>
  #include <stdlib.h>
  
  struct PPMPixel
  {
      char red;
      char blue;
      char green;
  };
  
  struct PPMImage
  {
       unsigned x, y;
       struct PPMPixel *data;
  };
  
  #define CREATOR "RPFELGUEIRAS"
  #define RGB_COMPONENT_COLOR (255)
  
  static struct PPMImage *readPPM()
  {
       char buff[16];
       struct PPMImage *img;
  
       FILE *fp;
  
       int c;
       int rgb_comp_color;
  
       //open PPM file for reading
       fp = fopen("ukraine.ppm", "rb");
       if (!fp)
       {
           perror( "fopen for ukraine.ppm failed" );
           // fprintf(stderr, "Unable to open file '%s'\n", filename);
            exit(1);
       }
  
       // implied els,e fopen successful
  
       //read image format // get first 15 bytes of image file
       if (!fgets(buff, sizeof(buff), fp))
       {
            perror("ukraine.ppm");
            exit(1);
       }
  
       // implied else, fgets successful
  
      //check the image format
      if (buff[0] != 'P' || buff[1] != '6') {
           fprintf(stderr, "Invalid image format (must be 'P6')\n");
           exit(1);
      }
  
      // implied else, image file file has correct format indicators
  
      //alloc memory for image
      img = malloc(sizeof(struct PPMImage));
      if (!img)
      {
          perror( "malloc for PPMImage failed" );
          //fprintf(stderr, "Unable to allocate memory\n");
           exit(1);
      }
  
      // implied else, malloc successful
  
      //check for comments
      c = getc(fp);
      while (c == '#')
      {
          while( (c = getc(fp)) != '\n') ;
      }
  
      //read image size information
      if (fscanf(fp, "%u %u", &img->x, &img->y) != 2)
      {
          perror( "fscanf for ukraine.ppm image size parameters failed" );
           exit(1);
      }
  
      // implied else, fscanf successful
  
      //read rgb component
      if (fscanf(fp, "%d", &rgb_comp_color) != 1)
      {
          perror( "fscanf for rgb_comp_color in ukraine.ppm failed" );
           //fprintf(stderr, "Invalid rgb component (error loading '%s')\n",      filename);
           exit(1);
      }
  
      // implied else, fscanf successful
  
      //check rgb component depth
      if (rgb_comp_color!= RGB_COMPONENT_COLOR)
      {
           fprintf(stderr, "'ukraine.ppm' does not have 8-bits components\n");
           exit(1);
      }
  
      // implied else, rgb component depth correct
  
      // consume rest of line
      while (fgetc(fp) != '\n') ;
  
      //memory allocation for pixel data
      img->data = malloc(img->x * img->y * sizeof( struct PPMPixel));
  
      if ( !img->data ) //< corrected element being checked
      {
          perror( "malloc for pixel data failed" );
          //fprintf(stderr, "Unable to allocate memory\n");
           exit(1);
      }
  
      // implied else, malloc successful
  
      //read pixel data from file
      if (fread(img->data, 3 * img->x, img->y, fp) != img->y)
      {
          perror( "fread for pixel data failed" );
          // fprintf(stderr, "Error loading image '%s'\n", filename);
           exit(1);
      }
  
      // implied else, fread successful
  
      fclose(fp);
      return img;
  } // end function: readPPM
  
  
  void writePPM(struct PPMImage *img)
  {
      FILE *fp;
      //open file for output
      fp = fopen("ukraine.ppm", "wb");
      if (!fp)
      {
          perror( "fopen for ukraine.ppm for write failed" );
          // fprintf(stderr, "Unable to open file '%s'\n",filename);
           exit(1);
      }
  
      // implied else, fopen successful
  
      //write the header file
      //image format
      fprintf(fp, "P6\n");
  
      //comments
      fprintf(fp, "# Created by %s\n",CREATOR);
  
      //image size
      fprintf(fp, "%d %d\n",img->x,img->y);
  
      // rgb component depth
      fprintf(fp, "%d\n",RGB_COMPONENT_COLOR);
  
      // pixel data
      fwrite(img->data, 3 * img->x, img->y, fp);
      fclose(fp);
  } // end function: writePPM
  
  
  void changeColorPPM(struct PPMImage *img)
  {
      unsigned i;
      if(img)
      {
  
           for(i=0;i<img->x*img->y;i++)
           {
                img->data[i].red=RGB_COMPONENT_COLOR-img->data[i].red;
                img->data[i].green=RGB_COMPONENT_COLOR-img->data[i].green;
                img->data[i].blue=RGB_COMPONENT_COLOR-img->data[i].blue;
           }
      }
  } // end function: changeColorPPM
  
  
  int main()
  {
      struct PPMImage *image;
      image = readPPM();
      changeColorPPM(image);
      writePPM(image);
      printf("Press any key...");
      getchar();
  
      return(0);
  } // end function: main
  

  回复于 2024-05-15T12:18:00+08:00