早上，在微博发现一条信息，关于MaxRects算法的，@杜增强DzQ 移植的关于AS3版本的MaxRects算法，具体地址是：http://www.duzengqiang.com/blog/post/971.html
代码如下：
/* Based on the Public Domain MaxRectanglesBinPack.cpp source by Jukka Jylänki https://github.com/juj/RectangleBinPack/Based on C# port by Sven Magnus http://unifycommunity.com/wiki/index.php?title=MaxRectanglesBinPackPorted to ActionScript3 by DUZENGQIANG http://www.duzengqiang.com/blog/post/971.html This version is also public domain - do whatever you want with it. */package {import flash.geom.Rectangle;/*** MaxRectanglesBinPack* @author DUZENGQIANG* @date Jun 7, 2012* @version 1.0*SinaMicroBlog: http://weibo.com/duzengqiang
*blog: http://www.duzengqiang.com
*/public class MaxRectsBinPack{ public var binWidth:int = 0;public var binHeight:int = 0;public var allowRotations:Boolean = false;public var usedRectangles:Vector.= new Vector. ();public var freeRectangles:Vector. = new Vector. ();private var score1:int = 0; // Unused in this function. We don't need to know the score after finding the position.private var score2:int = 0;private var bestShortSideFit:int;private var bestLongSideFit:int;public function MaxRectsBinPack( width:int, height:int, rotations:Boolean = true) {init(width, height, rotations);}private function init(width:int, height:int, rotations:Boolean = true):void{if( count(width) % 1 != 0 ||count(height) % 1 != 0)throw new Error("Must be 2,4,8,16,32,...512,1024,...");binWidth = width;binHeight = height;allowRotations = rotations;var n:Rectangle = new Rectangle();n.x = 0;n.y = 0;n.width = width;n.height = height;usedRectangles.length = 0;freeRectangles.length = 0;freeRectangles.push( n );}private function count(n:Number):Number{if( n >= 2 )return count(n / 2);return n;}/*** Insert a new Rectangle * @param width* @param height* @param method* @return * */ public function insert(width:int, height:int, method:int):Rectangle {var newNode:Rectangle = new Rectangle();score1 = 0;score2 = 0;switch(method) {case FreeRectangleChoiceHeuristic.BestShortSideFit: newNode = findPositionForNewNodeBestShortSideFit(width, height); break;case FreeRectangleChoiceHeuristic.BottomLeftRule: newNode = findPositionForNewNodeBottomLeft(width, height, score1, score2); break;case FreeRectangleChoiceHeuristic.ContactPointRule: newNode = findPositionForNewNodeContactPoint(width, height, score1); break;case FreeRectangleChoiceHeuristic.BestLongSideFit: newNode = findPositionForNewNodeBestLongSideFit(width, height, score2, score1); break;case FreeRectangleChoiceHeuristic.BestAreaFit: newNode = findPositionForNewNodeBestAreaFit(width, height, score1, score2); break;}if (newNode.height == 0)return newNode;placeRectangle(newNode);trace(newNode);return newNode;}public function insert2( Rectangles:Vector. , dst:Vector. , method:int):void {dst.length = 0;while(Rectangles.length > 0) {var bestScore1:int = int.MAX_VALUE;var bestScore2:int = int.MAX_VALUE;var bestRectangleIndex:int = -1;var bestNode:Rectangle = new Rectangle();for(var i:int = 0; i < Rectangles.length; ++i) {var score1:int = 0;var score2:int = 0;var newNode:Rectangle = scoreRectangle(Rectangles[i].width, Rectangles[i].height, method, score1, score2);if (score1 < bestScore1 || (score1 == bestScore1 && score2 < bestScore2)) {bestScore1 = score1;bestScore2 = score2;bestNode = newNode;bestRectangleIndex = i;}}if (bestRectangleIndex == -1)return;placeRectangle(bestNode);Rectangles.splice(bestRectangleIndex,1);}}private function placeRectangle(node:Rectangle):void {var numRectanglesToProcess:int = freeRectangles.length;for(var i:int = 0; i < numRectanglesToProcess; i++) {if (splitFreeNode(freeRectangles[i], node)) {freeRectangles.splice(i,1);--i;--numRectanglesToProcess;}}pruneFreeList();usedRectangles.push(node);}private function scoreRectangle( width:int, height:int, method:int, score1:int, score2:int):Rectangle {var newNode:Rectangle = new Rectangle();score1 = int.MAX_VALUE;score2 = int.MAX_VALUE;switch(method) {case FreeRectangleChoiceHeuristic.BestShortSideFit: newNode = findPositionForNewNodeBestShortSideFit(width, height); break;case FreeRectangleChoiceHeuristic.BottomLeftRule: newNode = findPositionForNewNodeBottomLeft(width, height, score1,score2); break;case FreeRectangleChoiceHeuristic.ContactPointRule: newNode = findPositionForNewNodeContactPoint(width, height, score1); // todo: reversescore1 = -score1; // Reverse since we are minimizing, but for contact point score bigger is better.break;case FreeRectangleChoiceHeuristic.BestLongSideFit: newNode = findPositionForNewNodeBestLongSideFit(width, height, score2, score1); break;case FreeRectangleChoiceHeuristic.BestAreaFit: newNode = findPositionForNewNodeBestAreaFit(width, height, score1, score2); break;}// Cannot fit the current Rectangle.if (newNode.height == 0) {score1 = int.MAX_VALUE;score2 = int.MAX_VALUE;}return newNode;}/// Computes the ratio of used surface area.private function occupancy():Number {var usedSurfaceArea:Number = 0;for(var i:int = 0; i < usedRectangles.length; i++)usedSurfaceArea += usedRectangles[i].width * usedRectangles[i].height;return usedSurfaceArea / (binWidth * binHeight);}private function findPositionForNewNodeBottomLeft(width:int, height:int, bestY:int, bestX:int):Rectangle {var bestNode:Rectangle = new Rectangle();//memset(bestNode, 0, sizeof(Rectangle)); bestY = int.MAX_VALUE;var rect:Rectangle;var topSideY:int;for(var i:int = 0; i < freeRectangles.length; i++) {rect = freeRectangles[i];// Try to place the Rectangle in upright (non-flipped) orientation.if (rect.width >= width && rect.height >= height) {topSideY = rect.y + height;if (topSideY < bestY || (topSideY == bestY && rect.x < bestX)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = width;bestNode.height = height;bestY = topSideY;bestX = rect.x;}}if (allowRotations && rect.width >= height && rect.height >= width) {topSideY = rect.y + width;if (topSideY < bestY || (topSideY == bestY && rect.x < bestX)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = height;bestNode.height = width;bestY = topSideY;bestX = rect.x;}}}return bestNode;}private function findPositionForNewNodeBestShortSideFit(width:int, height:int):Rectangle {var bestNode:Rectangle = new Rectangle();//memset(&bestNode, 0, sizeof(Rectangle)); bestShortSideFit = int.MAX_VALUE;bestLongSideFit = score2;var rect:Rectangle;var leftoverHoriz:int;var leftoverVert:int;var shortSideFit:int;var longSideFit:int;for(var i:int = 0; i < freeRectangles.length; i++) {rect = freeRectangles[i];// Try to place the Rectangle in upright (non-flipped) orientation.if (rect.width >= width && rect.height >= height) {leftoverHoriz = Math.abs(rect.width - width);leftoverVert = Math.abs(rect.height - height);shortSideFit = Math.min(leftoverHoriz, leftoverVert);longSideFit = Math.max(leftoverHoriz, leftoverVert);if (shortSideFit < bestShortSideFit || (shortSideFit == bestShortSideFit && longSideFit < bestLongSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = width;bestNode.height = height;bestShortSideFit = shortSideFit;bestLongSideFit = longSideFit;}}var flippedLeftoverHoriz:Number;var flippedLeftoverVert:Number;var flippedShortSideFit:Number;var flippedLongSideFit:Number;if (allowRotations && rect.width >= height && rect.height >= width) {flippedLeftoverHoriz = Math.abs(rect.width - height);flippedLeftoverVert = Math.abs(rect.height - width);flippedShortSideFit = Math.min(flippedLeftoverHoriz, flippedLeftoverVert);flippedLongSideFit = Math.max(flippedLeftoverHoriz, flippedLeftoverVert);if (flippedShortSideFit < bestShortSideFit || (flippedShortSideFit == bestShortSideFit && flippedLongSideFit < bestLongSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = height;bestNode.height = width;bestShortSideFit = flippedShortSideFit;bestLongSideFit = flippedLongSideFit;}}}return bestNode;}private function findPositionForNewNodeBestLongSideFit(width:int, height:int, bestShortSideFit:int, bestLongSideFit:int):Rectangle {var bestNode:Rectangle = new Rectangle();//memset(&bestNode, 0, sizeof(Rectangle));bestLongSideFit = int.MAX_VALUE;var rect:Rectangle;var leftoverHoriz:int;var leftoverVert:int;var shortSideFit:int;var longSideFit:int;for(var i:int = 0; i < freeRectangles.length; i++) {rect = freeRectangles[i];// Try to place the Rectangle in upright (non-flipped) orientation.if (rect.width >= width && rect.height >= height) {leftoverHoriz = Math.abs(rect.width - width);leftoverVert = Math.abs(rect.height - height);shortSideFit = Math.min(leftoverHoriz, leftoverVert);longSideFit = Math.max(leftoverHoriz, leftoverVert);if (longSideFit < bestLongSideFit || (longSideFit == bestLongSideFit && shortSideFit < bestShortSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = width;bestNode.height = height;bestShortSideFit = shortSideFit;bestLongSideFit = longSideFit;}}if (allowRotations && rect.width >= height && rect.height >= width) {leftoverHoriz = Math.abs(rect.width - height);leftoverVert = Math.abs(rect.height - width);shortSideFit = Math.min(leftoverHoriz, leftoverVert);longSideFit = Math.max(leftoverHoriz, leftoverVert);if (longSideFit < bestLongSideFit || (longSideFit == bestLongSideFit && shortSideFit < bestShortSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = height;bestNode.height = width;bestShortSideFit = shortSideFit;bestLongSideFit = longSideFit;}}}trace(bestNode);return bestNode;}private function findPositionForNewNodeBestAreaFit(width:int, height:int, bestAreaFit:int, bestShortSideFit:int):Rectangle {var bestNode:Rectangle = new Rectangle();//memset(&bestNode, 0, sizeof(Rectangle)); bestAreaFit = int.MAX_VALUE;var rect:Rectangle;var leftoverHoriz:int;var leftoverVert:int;var shortSideFit:int;var areaFit:int;for(var i:int = 0; i < freeRectangles.length; i++) {rect = freeRectangles[i];areaFit = rect.width * rect.height - width * height;// Try to place the Rectangle in upright (non-flipped) orientation.if (rect.width >= width && rect.height >= height) {leftoverHoriz = Math.abs(rect.width - width);leftoverVert = Math.abs(rect.height - height);shortSideFit = Math.min(leftoverHoriz, leftoverVert);if (areaFit < bestAreaFit || (areaFit == bestAreaFit && shortSideFit < bestShortSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = width;bestNode.height = height;bestShortSideFit = shortSideFit;bestAreaFit = areaFit;}}if (allowRotations && rect.width >= height && rect.height >= width) {leftoverHoriz = Math.abs(rect.width - height);leftoverVert = Math.abs(rect.height - width);shortSideFit = Math.min(leftoverHoriz, leftoverVert);if (areaFit < bestAreaFit || (areaFit == bestAreaFit && shortSideFit < bestShortSideFit)) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = height;bestNode.height = width;bestShortSideFit = shortSideFit;bestAreaFit = areaFit;}}}return bestNode;}/// Returns 0 if the two intervals i1 and i2 are disjoint, or the length of their overlap otherwise.private function commonIntervalLength(i1start:int, i1end:int, i2start:int, i2end:int):int {if (i1end < i2start || i2end < i1start)return 0;return Math.min(i1end, i2end) - Math.max(i1start, i2start);}private function contactPointScoreNode(x:int, y:int, width:int, height:int):int {var score:int = 0;if (x == 0 || x + width == binWidth)score += height;if (y == 0 || y + height == binHeight)score += width;var rect:Rectangle;for(var i:int = 0; i < usedRectangles.length; i++) {rect = usedRectangles[i];if (rect.x == x + width || rect.x + rect.width == x)score += commonIntervalLength(rect.y, rect.y + rect.height, y, y + height);if (rect.y == y + height || rect.y + rect.height == y)score += commonIntervalLength(rect.x, rect.x + rect.width, x, x + width);}return score;}private function findPositionForNewNodeContactPoint(width:int, height:int, bestContactScore:int):Rectangle {var bestNode:Rectangle = new Rectangle();//memset(&bestNode, 0, sizeof(Rectangle)); bestContactScore = -1;var rect:Rectangle;var score:int;for(var i:int = 0; i < freeRectangles.length; i++) {rect = freeRectangles[i];// Try to place the Rectangle in upright (non-flipped) orientation.if (rect.width >= width && rect.height >= height) {score = contactPointScoreNode(rect.x, rect.y, width, height);if (score > bestContactScore) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = width;bestNode.height = height;bestContactScore = score;}}if (allowRotations && rect.width >= height && rect.height >= width) {score = contactPointScoreNode(rect.x, rect.y, height, width);if (score > bestContactScore) {bestNode.x = rect.x;bestNode.y = rect.y;bestNode.width = height;bestNode.height = width;bestContactScore = score;}}}return bestNode;}private function splitFreeNode(freeNode:Rectangle, usedNode:Rectangle):Boolean {// Test with SAT if the Rectangles even intersect.if (usedNode.x >= freeNode.x + freeNode.width || usedNode.x + usedNode.width <= freeNode.x ||usedNode.y >= freeNode.y + freeNode.height || usedNode.y + usedNode.height <= freeNode.y)return false;var newNode:Rectangle;if (usedNode.x < freeNode.x + freeNode.width && usedNode.x + usedNode.width > freeNode.x) {// New node at the top side of the used node.if (usedNode.y > freeNode.y && usedNode.y < freeNode.y + freeNode.height) {newNode = freeNode.clone();newNode.height = usedNode.y - newNode.y;freeRectangles.push(newNode);}// New node at the bottom side of the used node.if (usedNode.y + usedNode.height < freeNode.y + freeNode.height) {newNode = freeNode.clone();newNode.y = usedNode.y + usedNode.height;newNode.height = freeNode.y + freeNode.height - (usedNode.y + usedNode.height);freeRectangles.push(newNode);}}if (usedNode.y < freeNode.y + freeNode.height && usedNode.y + usedNode.height > freeNode.y) {// New node at the left side of the used node.if (usedNode.x > freeNode.x && usedNode.x < freeNode.x + freeNode.width) {newNode = freeNode.clone();newNode.width = usedNode.x - newNode.x;freeRectangles.push(newNode);}// New node at the right side of the used node.if (usedNode.x + usedNode.width < freeNode.x + freeNode.width) {newNode = freeNode.clone();newNode.x = usedNode.x + usedNode.width;newNode.width = freeNode.x + freeNode.width - (usedNode.x + usedNode.width);freeRectangles.push(newNode);}}return true;}private function pruneFreeList():void {for(var i:int = 0; i < freeRectangles.length; i++)for(var j:int = i+1; j < freeRectangles.length; j++) {if (isContainedIn(freeRectangles[i], freeRectangles[j])) {freeRectangles.splice(i,1);break;}if (isContainedIn(freeRectangles[j], freeRectangles[i])) {freeRectangles.splice(j,1);}}}private function isContainedIn(a:Rectangle, b:Rectangle):Boolean {return a.x >= b.x && a.y >= b.y && a.x+a.width <= b.x+b.width && a.y+a.height <= b.y+b.height;}}}
package {public class FreeRectangleChoiceHeuristic {public static const BestShortSideFit:int = 0; ///< -BSSF: Positions the Rectangle against the short side of a free Rectangle into which it fits the best.public static const BestLongSideFit:int = 1; ///< -BLSF: Positions the Rectangle against the long side of a free Rectangle into which it fits the best.public static const BestAreaFit:int = 2; ///< -BAF: Positions the Rectangle into the smallest free Rectangle into which it fits.public static const BottomLeftRule:int = 3; ///< -BL: Does the Tetris placement.public static const ContactPointRule:int = 4; ///< -CP: Choosest the placement where the Rectangle touches other Rectangles as much as possible. } }
好奇，做了个测试，代码如下：
package {import flash.display.Bitmap;import flash.display.BitmapData;import flash.display.Sprite;import flash.geom.Point;import flash.geom.Rectangle;[SWF(width="800", height="600", frameRate="30")]public class Demo extends Sprite{[Embed(source="assets/1.png")]private var defence:Class;public function Demo(){var bitmap:Bitmap = Bitmap(new defence());trace(bitmap.width, bitmap.height);//Create new MaxRectsBinPack instancevar maxRect:MaxRectsBinPack = new MaxRectsBinPack(bitmap.width,bitmap.height,false);// insert new rectangle//maxRect.insert(bitmap.width/2, bitmap.height/2, FreeRectangleChoiceHeuristic.BestLongSideFit);// insert new rectangle//maxRect.insert(bitmap.width/2, bitmap.height/2, FreeRectangleChoiceHeuristic.BestLongSideFit);// insert new rectangle//maxRect.insert(bitmap.width/2, bitmap.height/2, FreeRectangleChoiceHeuristic.BestLongSideFit);// insert new rectangle//maxRect.insert(bitmap.width/2, bitmap.height/2, FreeRectangleChoiceHeuristic.BestLongSideFit);var rects:Vector.= new Vector. ();rects.push(new Rectangle(0,0,bitmap.width/2, bitmap.height/2));rects.push(new Rectangle(0,0,bitmap.width/2, bitmap.height/2));rects.push(new Rectangle(0,0,bitmap.width/2, bitmap.height/2));rects.push(new Rectangle(0,0,bitmap.width/2, bitmap.height/2));maxRect.insert2(rects, new Vector. (), FreeRectangleChoiceHeuristic.BestLongSideFit);for(var i:int = 0; i < maxRect.usedRectangles.length; i++) {var rect:Rectangle = maxRect.usedRectangles[i];trace(rect);var bitmapData:BitmapData = new BitmapData(rect.width, rect.height, true, 0);bitmapData.copyPixels(bitmap.bitmapData, rect, new Point());var newBitmap:Bitmap = new Bitmap(bitmapData);newBitmap.x = rect.x;newBitmap.y = rect.y;this.addChild(newBitmap);}}} }
图片用的我们游戏里的，正面2帧，背面2帧，嘿嘿
有几个疑问：
首先，图片要求是2的次幂，如果有的图片，做成影片剪辑时，是3帧，如果能满足 2的次幂的结果是3的倍数呢？这里，我认为有一种方案，可以通过每一帧的偏移量来做，而不是非要3的倍数，不知道这样理解对不对？
其次，这个图片的空白区域，不知道用@杜增强DzQ提供的工具类里，是否带透明部分的自动裁剪。
最后，我试了下面几种方法，但是没感觉到有什么区别，不知道能不能帮忙解答下，非常感谢。
public class FreeRectangleChoiceHeuristic {public static const BestShortSideFit:int = 0; ///< -BSSF: Positions the Rectangle against the short side of a free Rectangle into which it fits the best.public static const BestLongSideFit:int = 1; ///< -BLSF: Positions the Rectangle against the long side of a free Rectangle into which it fits the best.public static const BestAreaFit:int = 2; ///< -BAF: Positions the Rectangle into the smallest free Rectangle into which it fits.public static const BottomLeftRule:int = 3; ///< -BL: Does the Tetris placement.public static const ContactPointRule:int = 4; ///< -CP: Choosest the placement where the Rectangle touches other Rectangles as much as possible.}