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Integration of new rectangles into silhouette data structure seems to be working properly

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git-svn-id: file:///srv/devel/repo-conversion/nusu@21 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2007-05-20 20:39:09 +00:00
parent 62d54b5795
commit 5756ed94b3
2 changed files with 143 additions and 50 deletions
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2
Source/Packing/CygonRectanglePacker.Test.cs
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@ -37,7 +37,7 @@ namespace Nuclex.Support.Packing {
public void TestSpaceEfficiency() {
float efficiency = calculateEfficiency(new CygonRectanglePacker(70, 70));
Assert.GreaterOrEqual(efficiency, 0.75, "Packer achieves 75% efficiency");
Assert.GreaterOrEqual(efficiency, 0.75f, "Packer achieves 75% efficiency");
}
}

185
Source/Packing/CygonRectanglePacker.cs
View File

@ -25,6 +25,13 @@ using Microsoft.Xna.Framework;
namespace Nuclex.Support.Packing {
/// <summary>Packer using a custom algorithm by Markus Ewald</summary>
/// <remarks>
/// This algorithms always places as close to the top as possible. So, for any new
/// rectangle, the packer has to determine a X coordinate at which the rectangle
/// can be placed at the highest point. To quickly discover these locations,
/// the packer keeps a dynamically list of "height slices", which store the
/// baseline of the rectangles that have been placed so far.
/// </remarks>
public class CygonRectanglePacker : RectanglePacker {
#region class SliceStartComparer
@ -68,22 +75,111 @@ namespace Nuclex.Support.Packing {
public override bool TryAllocate(
int rectangleWidth, int rectangleHeight, out Point placement
) {
integrateRectangle(0, 1, 5);
integrateRectangle(20, 5, 30);
integrateRectangle(10, 10, 50);
integrateRectangle(10, 15, 25);
integrateRectangle(35, 20, 25);
integrateRectangle(40, 25, 15);
int sliceIndex = findBestPosition(rectangleWidth, rectangleHeight);
// TODO: Rectangle might not even fit there!
if(sliceIndex == -1) {
placement = Point.Zero;
return false;
} else {
placement = this.heightSlices[sliceIndex];
integrateRectangle(
this.heightSlices[sliceIndex].X,
rectangleWidth,
this.heightSlices[sliceIndex].Y + rectangleHeight
);
return true;
}
}
/// <summary>Finds the best position for a rectangle of the given width</summary>
/// <param name="rectangleWidth">Width of the rectangle to find a position for</param>
/// <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) {
int leftSliceIndex = 0;
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
// 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
);
// If this beats the current record for the least wasted area, remember this as
// being the best position found so far
if(
(wastedArea < leastWastedArea) &&
(this.heightSlices[leftSliceIndex].Y + rectangleHeight < MaxPackingAreaHeight)
) {
leastWastedArea = wastedArea;
leastWastedSliceIndex = leftSliceIndex;
// No sense looking any further if we found the perfect place!
if(leastWastedArea == 0)
break;
}
*/
// If this already was the loop after the final slice, terminate it now!
if(rightSliceIndex == this.heightSlices.Count)
break;
// Advance the starting slice to the next slice start
++leftSliceIndex;
int rightEnd = this.heightSlices[leftSliceIndex].X + rectangleWidth;
// Advance the ending slice to where the rectangle ends now
while(rightEnd > this.heightSlices[rightSliceIndex].X) {
++rightSliceIndex;
// If the end is reached, stop shifting and make the outer loop run one final time
if(rightSliceIndex == this.heightSlices.Count)
break;
}
}
return leastWastedSliceIndex;
}
/// <summary>Integrates a new rectangle into the height slice table</summary>
/// <param name="left">Position of the rectangle's left side</param>
/// <param name="bottom">Position of the rectangle's lower side</param>
/// <param name="width">Width of the rectangle</param>
private void integrateRectangle(int left, int bottom, int width) {
/// <param name="bottom">Position of the rectangle's lower side</param>
private void integrateRectangle(int left, int width, int bottom) {
// Find the first slice that is touched by the rectangle
int startSlice = this.heightSlices.BinarySearch(
@ -97,7 +193,6 @@ namespace Nuclex.Support.Packing {
// We scored a direct hit, so we can replace the slice we have hit
firstSliceOriginalHeight = this.heightSlices[startSlice].Y;
this.heightSlices[startSlice] = new Point(left, bottom);
++startSlice;
} else { // No direct hit, slice starts inside another slice
@ -108,58 +203,56 @@ namespace Nuclex.Support.Packing {
}
// Special case, the rectangle was on the last slice, so we cannot
// use the start slice + 1 as start index for the binary search
if(startSlice >= this.heightSlices.Count) {
} else {
int right = left + width;
++startSlice;
// Special case, the rectangle started on the last slice, so we cannot
// use the start slice + 1 for the binary search and the possibly already
// modified start slice height now only remains in our temporary
// firstSliceOriginalHeight variable
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
// original height at the end of the rectangle.
if(right < MaxPackingAreaWidth)
this.heightSlices.Add(new Point(right, firstSliceOriginalHeight));
} else { // The rectangle doesn't start on the last slice
int endSlice = this.heightSlices.BinarySearch(
startSlice, this.heightSlices.Count - startSlice,
new Point(right, 0), SliceStartComparer.Default
);
}
//this.heightSlices.RemoveRange(startSlice, endSlice - startSlice);
/*
int nextSlice = firstSlice + 1;
bool isLastSlice = (nextSlice >= this.heightSlices.Count);
// Another direct hit on the final slice's end?
if(endSlice > 0) {
*/
/*
this.heightSlices.RemoveRange(startSlice, endSlice - startSlice);
} else { // No direct hit, rectangle ends inside another slice
int nextSlice = firstSlice + 1;
bool isLastSlice = (nextSlice >= this.heightSlices.Count);
endSlice = ~endSlice;
//
bool endsInFirstSlice;
if(isLastSlice)
endsInFirstSlice = right < MaxPackingAreaWidth;
// Find out to which height we need to return at the right end of
// the rectangle
int returnHeight;
if(endSlice == startSlice)
returnHeight = firstSliceOriginalHeight;
else
endsInFirstSlice = right < this.heightSlices[nextSlice].X;
returnHeight = this.heightSlices[endSlice - 1].Y;
if(endsInFirstSlice) {
this.heightSlices.Insert(
nextSlice, new Point(right, this.heightSlices[firstSlice].Y)
);
this.heightSlices[firstSlice] = new Point(left, bottom);
return;
} else { // Integrated rect continues beyond the discovered slice
this.heightSlices[firstSlice] = new Point(left, bottom);
}
} else {
firstSlice = ~firstSlice;
//firstSliceOriginalHeight = this.heightSlices[firstSlice].Y;
this.heightSlices.Insert(firstSlice, new Point(left, bottom));
++firstSlice;
// Remove all slices covered by the rectangle and began a new slice at
// its end to return to the height the slice in which the rectangle ends
// has had.
this.heightSlices.RemoveRange(startSlice, endSlice - startSlice);
if(right < MaxPackingAreaWidth)
this.heightSlices.Insert(startSlice, new Point(right, returnHeight));
}
*/
}
}
/// <summary>Stores the height silhouette of the rectangles</summary>