New "Cygon" Packer is working and promptly achieved a new space efficiency record

git-svn-id: file:///srv/devel/repo-conversion/nusu@22 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/Packing/CygonRectanglePacker.cs

@@ -103,76 +103,95 @@ namespace Nuclex.Support.Packing {
     /// <param name="rectangleHeight">Height of the rectangle to find a position for</param>
     /// <returns>The best position for a rectangle with the specified width</returns>
     private int findBestPosition(int rectangleWidth, int rectangleHeight) {
+
+      // Index and score of the best slice we could find for the rectangle
+      int bestSliceIndex = -1;
+      int bestScore = MaxPackingAreaWidth * MaxPackingAreaHeight; // lower == better!
+
+      // This is the counter for the currently checked position. The search works by
+      // skipping from slice to slice, determining the suitability of the location for the
+      // placement of the rectangle.
       int leftSliceIndex = 0;
+
+      // Determine the slice in which the right end of the rectangle is located
       int rightSliceIndex = this.heightSlices.BinarySearch(
         new Point(rectangleWidth, 0), SliceStartComparer.Default
       );
       if(rightSliceIndex < 0)
         rightSliceIndex = ~rightSliceIndex;
 
-      int leastWastedSliceIndex = -1;
-      int leastWastedArea = MaxPackingAreaWidth * MaxPackingAreaHeight;
-
       while(rightSliceIndex <= this.heightSlices.Count) {
-        // final time (this is the special case where the rectangle is attempted
-        // to be placed at the rightmost end of the packing area)
-      
-        /*
-                // Determine the highest slice at this position. We cannot put the rectangle
-                // any lower than this without colliding into other rectangles
-                int highest = this.heightSlices[leftSliceIndex].Y;
-                for(int index = leftSliceIndex + 1; index < rightSliceIndex; ++index)
-                  highest = Math.Max(highest, this.heightSlices[index].Y);
 
-                // Calculate the amount of space that would go to waste if the rectangle
+        // Determine the highest slice within the slices covered by the rectangle at
-                // would be placed at this location
+        // its current placement. We cannot put the rectangle any lower than this without
-                int wastedArea = 0;
+        // overlapping the other rectangles.
-                for(int index = leftSliceIndex; index < rightSliceIndex - 1; ++index) {
+        int highest = this.heightSlices[leftSliceIndex].Y;
-                  int sliceWidth = this.heightSlices[index + 1].X - this.heightSlices[index].X;
+        for(int index = leftSliceIndex + 1; index < rightSliceIndex; ++index)
-                  wastedArea += (highest - this.heightSlices[index].Y) * sliceWidth;
+          if(this.heightSlices[index].Y > highest)
-                }
+            highest = this.heightSlices[index].Y;
-                wastedArea +=
-                  (highest - this.heightSlices[rightSliceIndex - 1].Y) *
-                  (
-                    (this.heightSlices[leftSliceIndex].X + rectangleWidth) -
-                    this.heightSlices[rightSliceIndex - 1].X
-                  );
 
-                // If this beats the current record for the least wasted area, remember this as
+        if((highest + rectangleHeight < MaxPackingAreaHeight)) {
-                // being the best position found so far
+          int score = highest;
-                if(
-                  (wastedArea < leastWastedArea) &&
-                  (this.heightSlices[leftSliceIndex].Y + rectangleHeight < MaxPackingAreaHeight)
-                ) {
-                  leastWastedArea = wastedArea;
-                  leastWastedSliceIndex = leftSliceIndex;
 
-                  // No sense looking any further if we found the perfect place!
+          // TESTING --------------------------------------------------
-                  if(leastWastedArea == 0)
+          /*
-                    break;
+          // Calculate the amount of space that would go to waste if the rectangle
-                }
+          // would be placed at this location
-        */
+          int wastedArea = 0;
+          for(int index = leftSliceIndex; index < rightSliceIndex - 1; ++index) {
+            int sliceWidth = this.heightSlices[index + 1].X - this.heightSlices[index].X;
+            wastedArea += (highest - this.heightSlices[index].Y) * sliceWidth;
+          }
+          wastedArea +=
+            (highest - this.heightSlices[rightSliceIndex - 1].Y) *
+            (
+              (this.heightSlices[leftSliceIndex].X + rectangleWidth) -
+              this.heightSlices[rightSliceIndex - 1].X
+            );
 
+          //score += Math.Sign(wastedArea);
+          //score += (int)Math.Sqrt((double)wastedArea);
+          //score = wastedArea;
+          */
+          // TESTING --------------------------------------------------
 
-        // If this already was the loop after the final slice, terminate it now!
+          if(score < bestScore) {
-        if(rightSliceIndex == this.heightSlices.Count)
+            bestSliceIndex = leftSliceIndex;
-          break;
+            bestScore = score;
+          }
+        }
 
         // Advance the starting slice to the next slice start
         ++leftSliceIndex;
-        int rightEnd = this.heightSlices[leftSliceIndex].X + rectangleWidth;
+        if(leftSliceIndex >= this.heightSlices.Count)
+          break;
 
-        // Advance the ending slice to where the rectangle ends now
+        // Advance the ending slice until we're on the right slice again, given the new
-        while(rightEnd > this.heightSlices[rightSliceIndex].X) {
+        // starting position of the rectangle.
-          ++rightSliceIndex;
+        int rightRectangleEnd = this.heightSlices[leftSliceIndex].X + rectangleWidth;
-
+        for(; rightSliceIndex <= this.heightSlices.Count; ++rightSliceIndex) {
-          // If the end is reached, stop shifting and make the outer loop run one final time
+          int rightSliceStart;
           if(rightSliceIndex == this.heightSlices.Count)
+            rightSliceStart = MaxPackingAreaWidth;
+          else
+            rightSliceStart = this.heightSlices[rightSliceIndex].X;
+
+          // Is this the slice we're looking for?
+          if(rightSliceStart > rightRectangleEnd)
             break;
         }
+
+        // If we crossed the end of the slice array, the rectangle's right end has left
+        // the packing area, and thus, our search ends.
+        if(rightSliceIndex > this.heightSlices.Count)
+          break;
+
       }
 
-      return leastWastedSliceIndex;
+      // Return the index of the best slice we found for this rectangle. If the rectangle
+      // didn't fit, this variable will still have its initialization value of -1.
+      return bestSliceIndex;
+
     }
 
     /// <summary>Integrates a new rectangle into the height slice table</summary>
@@ -213,8 +232,8 @@ namespace Nuclex.Support.Packing {
       if(startSlice >= this.heightSlices.Count) {
 
         // If the slice ends within the last slice (usual case, unless it has the
-        // exact same with the packing area has), add another slice to return to the
+        // exact same width the packing area has), add another slice to return to
-        // original height at the end of the rectangle.
+        // the original height at the end of the rectangle.
         if(right < MaxPackingAreaWidth)
           this.heightSlices.Add(new Point(right, firstSliceOriginalHeight));
 
@@ -242,9 +261,8 @@ namespace Nuclex.Support.Packing {
           else
             returnHeight = this.heightSlices[endSlice - 1].Y;
 
-          // Remove all slices covered by the rectangle and began a new slice at
+          // Remove all slices covered by the rectangle and begin a new slice at its end
-          // its end to return to the height the slice in which the rectangle ends
+          // to return back to the height of the slice on which the rectangle ends.
-          // has had.
           this.heightSlices.RemoveRange(startSlice, endSlice - startSlice);
           if(right < MaxPackingAreaWidth)
             this.heightSlices.Insert(startSlice, new Point(right, returnHeight));

Source/Packing/RectanglePacker.Test.cs

@@ -54,8 +54,6 @@ namespace Nuclex.Support.Packing {
       return (float)areaCovered / 4900.0f;
     }
 
-
-
   }
 
 } // namespace Nuclex.Support.Packing