Changeset 11649 for ImageMagick/trunk

Timestamp:

07/17/08 06:48:49 (6 weeks ago)

Author:

anthony

Message:

Adding Shepards Method as a method of Distortion

Location:

ImageMagick/trunk

Files:

• ChangeLog (modified) (2 diffs)
• magick/distort.c (modified) (17 diffs)
• magick/distort.h (modified) (1 diff)
• magick/option.c (modified) (1 diff)

ImageMagick/trunk/ChangeLog

@@ +1 @@
+2008-07-17  6.4.2-4 Anthony <anthony@griffith...>
+  * New distortions  Shepards which provide semi-localized distorts of single
+    points within an image.  Almost like taffy pulling!
+
 2008-07-12  6.4.2-2 Anthony <anthony@griffith...>
   * Separate coefficient calculation from DistortImages (future development)
@@ -5 +9 @@
   * Affine Distortion now handles 2 point pairs (SRT of a single line)
     and a simple translation if only a single point pair is provided.
+  * Added 'verbose' output of some of the distortion equations generated
+  * Initial addition of polynomal distortion (incomplete - not working yet)
 
 2008-06-29  6.4.2-2 Cristy  <quetzlzacatenango@image...>

ImageMagick/trunk/magick/distort.c

@@ -86 +86 @@
 %  account in the mapping.
 %
+%  If the '-verbose' control option has been set print to standard error the
+%  equicelent '-fx' formula with coefficients for the function, if practical.
+%
 %
 %  The format of the DistortImage() method is:
@@ -197 +200 @@
 }
 
-#if 0  
+
+
+#if 0
    For some reason compiler errors on % in this!
 static inline double MagickFraction(double x)
@@ -340 +345 @@
 static double *DistortCoefficents(Image *image, DistortImageMethod *method,
      const unsigned long number_arguments, const double *arguments,
-     MagickBooleanType bestfit, ExceptionInfo *exception)
+     ExceptionInfo *exception)
 {
   /* Determine correct coefficients for the given input arguments.
@@ -388 +393 @@
       break;
     case PolynomialDistortion:
+      /* number of coefficents depend on the given polynomal 'order' */
       if ( number_arguments < 5 && (number_arguments-1)%4 != 0)
       {
@@ -415 +421 @@
       number_coefficients=5;
       break;
+    case ShepardsDistortion:
+      number_coefficients=1; /* not actually used, but keep things happy */
+      break;
     case UndefinedDistortion:
     default:
@@ -420 +429 @@
       break;
   }
+  if ( number_coefficients == 0 )
+    return((double *) NULL);
 
   /* allocate the array of coefficients needed */
@@ -430 +441 @@
     return((double *) NULL);
   }
+
   /* zero out coeffiecents array */
   for (i=0; i < (long)number_coefficients; i++)
@@ -909 +921 @@
          And convert to affine mapping coefficients
       */
-      x = nx = (double)image->columns/2.0;
-      y = ny = (double)image->rows/2.0;
-      if ( bestfit ) {
-        x = nx += (double)image->page.x;
-        y = ny += (double)image->page.y;
-      }
+      x = nx = (double)image->columns/2.0 + image->page.x;
+      y = ny = (double)image->rows/2.0    + image->page.x;
       sx = sy = 1.0;
       switch ( number_arguments ) {
@@ -1078 +1086 @@
       }
       coefficients[4] = (1.0*image->columns-1.0)/2.0;
+#if 0
+Not working yet --
       if ( GetImageArtifact(image,"verbose") != (const char *) NULL ) {
         fprintf(stderr, "Arc Reverse Map\n");
-#if 0
-  Not working yet
         fprintf(stderr, "c0=%-8lg  # angle for center line in source image\n",
              coefficients[0]);
@@ -1114 +1122 @@
             coefficients[2], ((double)image->rows)/coefficients[3] );
         fprintf(stderr, "       v.p{xx,yy}'\n");
+      }
 #endif
+      return(coefficients);
+    }
+    case ShepardsDistortion:
+    {
+      /* Shepards Distortion  input arguments are the coefficents!
+         Args:  power  u1,v1, x1,y1, ...
+      */
+      if ( number_arguments < 4 && (number_arguments-1)%4 != 0)
+      {
+        (void) ThrowMagickException(exception,GetMagickModule(),OptionError,
+                     "InvalidArgument","%s : '%s'","distort Shepards",
+                     "Invalid number of coord-pairs: [sX,sY,dX,dY]*");
+        return((double *) arguments);
       }
       return(coefficients);
@@ -1175 +1197 @@
     So these no longer need to be considered below.
   */
-  coefficients = DistortCoefficents(image, &method, number_arguments,
-       arguments, bestfit, exception);
-  if ( coefficients == (double *) NULL )
-    return((Image *) NULL);
+  if ( method == ShepardsDistortion )
+    /* these methods do not require coefficents */
+    coefficients = (double *)NULL;
+  else {
+    /* determine the coefficents needed for distortion from input */
+    coefficients = DistortCoefficents(image, &method, number_arguments,
+        arguments, exception);
+    if ( coefficients == (double *) NULL )
+      return((Image *) NULL);
+  }
 
   /*
@@ -1312 +1340 @@
         break;
       }
+      case ShepardsDistortion:
       case BilinearDistortion:
       case PolynomialDistortion:
@@ -1524 +1553 @@
           if ( point.y > MagickEpsilon )
             ScaleResampleFilter( resample_filter[id],
-                coefficients[1]/(2*MagickPI*point.y),0,0,coefficients[3] ); 
+                coefficients[1]/(2*MagickPI*point.y),0,0,coefficients[3] );
           else
             ScaleResampleFilter( resample_filter[id],
@@ -1532 +1561 @@
           point.x = point.x*coefficients[1] + coefficients[4];
           point.y = (coefficients[2] - point.y) * coefficients[3];
+          break;
+        }
+        case ShepardsDistortion:
+        { /* Shepards Method, or Inverse Weighted Distance for
+             displacement around the destination image control points
+             Its coefficents, is the input arguments
+          */
+          unsigned long
+            i;
+          double
+            denominator;
+
+          denominator = point.x = point.y = 0;
+          for(i=0; i<number_arguments; i+=4) {
+            double weight =
+                ((double)x-arguments[i+2])*((double)x-arguments[i+2])
+              + ((double)y-arguments[i+3])*((double)y-arguments[i+3]);
+            if ( weight != 0 )
+              weight = 1/weight;
+            else
+              weight = 1;
+
+            point.x += (arguments[ i ]-arguments[i+2])*weight;
+            point.y += (arguments[i+1]-arguments[i+3])*weight;
+            denominator += weight;
+          }
+          point.x /= denominator;
+          point.y /= denominator;
+          point.x += x; point.y += y;
+
+          /* we can not determine slope using shepards method - interpolate */
           break;
         }
@@ -1539 +1599 @@
             Noop distortion (failsafe) should not happen!
           */
-          point.x=(double) i;
-          point.y=(double) j;
+          point.x=(double) x;
+          point.y=(double) y;
           break;
         }
@@ -1577 +1637 @@
   resample_filter=DestroyResampleFilterThreadSet(resample_filter);
 
+
   /* Arc does not return an offset unless 'bestfit' is in effect
      And the user has not provided an overriding 'viewport'.
@@ -1586 +1647 @@
   if (status == MagickFalse)
     distort_image=DestroyImage(distort_image);
+
+  coefficients = RelinquishMagickMemory(coefficients);
   return(distort_image);
 }

ImageMagick/trunk/magick/distort.h

@@ -35 +35 @@
   PerspectiveProjectionDistortion,
   PolynomialDistortion,
-  ScaleRotateTranslateDistortion
+  ScaleRotateTranslateDistortion,
+  ShepardsDistortion,
 } DistortImageMethod;
 

ImageMagick/trunk/magick/option.c

@@ -787 +787 @@
     { "SRT", (long) ScaleRotateTranslateDistortion },
     { "Arc", (long) ArcDistortion },
+    { "Shepards", (long) ShepardsDistortion },
     { (char *) NULL, (long) UndefinedDistortion }
   },