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# AFTERImage example 6: Image rotation

demonstrates flipping image in 90 degree increments

libAfterImage/tutorials/ASFlip

- NAME

  ASFlip

- SYNOPSIS

      libAfterImage application for image rotation.

- DESCRIPTION

      New steps described in this tutorial are :
      ASFlip.1. Flip value.
      ASFlip.2. Rotating ASImage.

- SEE ALSO

      Tutorial 1: ASView  - explanation of basic steps needed to use
                            libAfterImage and some other simple things.
      Tutorial 2: ASScale - image scaling basics.
      Tutorial 3: ASTile  - image tiling and tinting.
      Tutorial 4: ASMerge - scaling and blending of arbitrary number of
                            images.
      Tutorial 5: ASGrad  - drawing multipoint linear gradients.

- SOURCE

      #include "../afterbase.h"
      #include "../afterimage.h"
      #include "common.h"

      void usage()
      {
          printf( "Usage: asflip [-h]|[[-f flip]|[-m vertical] "
                  "[-g geom] image]");
          printf( "\nWhere: image - is image filename\n");
          printf( "       flip  - rotation angle in degrees. "
                  "90, 180 and 270 degrees supported\n");
          printf( "       geom  - source image is tiled using this geometry, "
                  "prior to rotation\n");
          printf( "       vertical - 1 - mirror image in vertical direction, "
                  "0 - horizontal\n");
      }

      int main(int argc, char* argv[])
      {
          Display *dpy = NULL;
          ASVisual *asv ;
          int screen = 0 , depth = 0 ;
          char *image_file = "rose512.jpg" ;
          int flip = FLIP_VERTICAL;
          Bool vertical = False, mirror = False ;
          int tile_x, tile_y, geom_flags = 0;
          unsigned int tile_width, tile_height ;
          ASImage *im = NULL;
          ASImage *flipped_im = NULL ;

          /* see ASView.1 : */
          set_application_name( argv[0] );

          if( argc > 1 )
          {
              int i = 1 ;
              if( strcmp( argv[1], "-h" ) == 0 )
              {
                  usage();
                  return 0;
              }
              for( i = 1 ; i < argc ; i++ )
              {
                  if( argv[i][0] == '-' && i < argc-1 )
                  {
                      switch(argv[i][1])
                      {
                          case 'm' :
                              mirror = True;
                              vertical = atoi(argv[i+1]) ;
                              break ;
                          case 'f' :          /* see ASFlip.1 */
                              mirror = False;
                              flip = atoi(argv[i+1])/90 ;
                              break ;
                          case 'g' :          /* see ASTile.2 : */
                              geom_flags = XParseGeometry( argv[i+1],
                                                           &tile_x, &tile_y,
                                                           &tile_width,
                                                           &tile_height );
                              break ;
                      }
                      ++i ;
                  }else
                      image_file = argv[i] ;
              }
          }else
              usage();

      #ifndef X_DISPLAY_MISSING
          dpy = XOpenDisplay(NULL);
          _XA_WM_DELETE_WINDOW = XInternAtom( dpy, "WM_DELETE_WINDOW", False);
          screen = DefaultScreen(dpy);
          depth = DefaultDepth( dpy, screen );
      #endif
          /* see ASView.2 : */
          im = file2ASImage( image_file, 0xFFFFFFFF, SCREEN_GAMMA, 0, getenv("IMAGE_PATH"), NULL );
          if( im == NULL )
              return 1;

          /* Making sure tiling geometry is sane : */
          if( !get_flags(geom_flags, XValue ) )
              tile_x = 0 ;
          if( !get_flags(geom_flags, YValue ) )
              tile_y = 0 ;
          if( !get_flags(geom_flags, WidthValue ) )
          {
              if( !mirror )
                  tile_width = (get_flags(flip,FLIP_VERTICAL))?
                                  im->height:im->width ;
              else
                  tile_width = im->width ;
          }
          if( !get_flags(geom_flags, HeightValue ) )
          {
              if( !mirror )
                  tile_height = (get_flags(flip,FLIP_VERTICAL))?
                                  im->width:im->height;
              else
                  tile_height = im->height ;
          }
          printf( "%s: tiling image \"%s\" to %dx%d%+d%+d and then "
                  "flipping it by %d degrees\n",
                  get_application_name(), image_file,
                  tile_width, tile_height,tile_x, tile_y, flip*90 );

          /* see ASView.3 : */
          asv = create_asvisual( dpy, screen, depth, NULL );

          /* see ASFlip.2 : */
          if( !mirror )
              flipped_im = flip_asimage(  asv, im,
                                          tile_x, tile_y,
                                          tile_width, tile_height,
                                          flip,
                                          ASA_ASImage, 0,
                                          ASIMAGE_QUALITY_DEFAULT );
          else
              flipped_im = mirror_asimage(asv, im,
                                          tile_x, tile_y,
                                          tile_width, tile_height,
                                          vertical,
                                          ASA_ASImage, 0,
                                          ASIMAGE_QUALITY_DEFAULT );
          destroy_asimage( &im );

          if( flipped_im )
          {
      #ifndef X_DISPLAY_MISSING
              /* see ASView.4 : */
              Window w = create_top_level_window( asv, DefaultRootWindow(dpy),
                                                  32, 32,
                                                  tile_width, tile_height,
                                                  1, 0, NULL,
                                                  "ASFlip", image_file );
              if( w != None )
              {
                  Pixmap p ;

                  XMapRaised   (dpy, w);
                  /* see ASView.5 : */
                  p = asimage2pixmap( asv, DefaultRootWindow(dpy), flipped_im,
                                      NULL, True );
                  destroy_asimage( &flipped_im );
                  /* see common.c: set_window_background_and_free() : */
                  p = set_window_background_and_free( w, p );
                  /* see common.c: wait_closedown() : */
              }
              wait_closedown(w);
              dpy = NULL;
      #else
              /* writing result into the file */
              ASImage2file( flipped_im, NULL, "asflip.jpg", ASIT_Jpeg, NULL );
              destroy_asimage( &flipped_im );
      #endif
          }
          return 0 ;
      }

libAfterImage/tutorials/ASFlip.1 [6.1]

- SYNOPSIS

      Step 1. Flip value.

- DESCRIPTION

      libAfterImage provides facility for rotating images in 90 degree
      increments - flipping essentially. Accordingly flip parameter could
      have 4 values - 0, -90, -180, -270 degrees.

- EXAMPLE

          flip = atoi(argv[2])/90;

- SEE ALSO

      flip

libAfterImage/tutorials/ASFlip.2 [6.2]

- SYNOPSIS

      Step 2. Flipping ASImage.

- DESCRIPTION

      Flipping can actually be combined with offset and tiling. Original
      image gets tiled to supplied rectangle, and then gets rotated to
      requested degree.

- EXAMPLE

          flipped_im = flip_asimage(asv, im,
                                        tile_x, tile_y,
                                        tile_width, tile_height,
                                        flip,
                                        ASA_XImage,0,
                                        ASIMAGE_QUALITY_DEFAULT );
              destroy_asimage( &im );

- NOTES

      As far as we need to render rotated image right away - we set to_xim
      parameter to True, so that image will be rotated into XImage. Right
      after rotation is done - we can destroy original image.

- SEE ALSO

      flip_asimage()

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