From 670058fa3c1afb9afababec32afad204dbb7216f Mon Sep 17 00:00:00 2001
From: Randy Heit <rheit@users.noreply.github.com>
Date: Sun, 10 Jan 2016 21:54:28 -0600
Subject: [PATCH] Switch to the bottom-left picker for the Skyline Bin Packer

---
 src/SkylineBinPack.cpp | 69 +++++++++++++++++++++++++++++++++++++++++-
 src/SkylineBinPack.h   |  3 ++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/src/SkylineBinPack.cpp b/src/SkylineBinPack.cpp
index 33f862043..4e9de153e 100644
--- a/src/SkylineBinPack.cpp
+++ b/src/SkylineBinPack.cpp
@@ -119,7 +119,7 @@ Rect SkylineBinPack::Insert(int width, int height)
 		return newNode;
 	}
 	
-	return InsertMinWaste(width, height);
+	return InsertBottomLeft(width, height);
 }
 
 bool SkylineBinPack::RectangleFits(int skylineNodeIndex, int width, int height, int &y) const
@@ -254,6 +254,73 @@ void SkylineBinPack::MergeSkylines()
 		}
 }
 
+Rect SkylineBinPack::InsertBottomLeft(int width, int height)
+{
+	int bestHeight;
+	int bestWidth;
+	int bestIndex;
+	Rect newNode = FindPositionForNewNodeBottomLeft(width, height, bestHeight, bestWidth, bestIndex);
+
+	if (bestIndex != -1)
+	{
+		assert(disjointRects.Disjoint(newNode));
+		// Perform the actual packing.
+		AddSkylineLevel(bestIndex, newNode);
+
+		usedSurfaceArea += width * height;
+#ifdef _DEBUG
+		disjointRects.Add(newNode);
+#endif
+	}
+	else
+		memset(&newNode, 0, sizeof(Rect));
+
+	return newNode;
+}
+
+Rect SkylineBinPack::FindPositionForNewNodeBottomLeft(int width, int height, int &bestHeight, int &bestWidth, int &bestIndex) const
+{
+	bestHeight = INT_MAX;
+	bestIndex = -1;
+	// Used to break ties if there are nodes at the same level. Then pick the narrowest one.
+	bestWidth = INT_MAX;
+	Rect newNode = { 0, 0, 0, 0 };
+	for(unsigned i = 0; i < skyLine.Size(); ++i)
+	{
+		int y;
+		if (RectangleFits(i, width, height, y))
+		{
+			if (y + height < bestHeight || (y + height == bestHeight && skyLine[i].width < bestWidth))
+			{
+				bestHeight = y + height;
+				bestIndex = i;
+				bestWidth = skyLine[i].width;
+				newNode.x = skyLine[i].x;
+				newNode.y = y;
+				newNode.width = width;
+				newNode.height = height;
+				assert(disjointRects.Disjoint(newNode));
+			}
+		}
+/*		if (RectangleFits(i, height, width, y))
+		{
+			if (y + width < bestHeight || (y + width == bestHeight && skyLine[i].width < bestWidth))
+			{
+				bestHeight = y + width;
+				bestIndex = i;
+				bestWidth = skyLine[i].width;
+				newNode.x = skyLine[i].x;
+				newNode.y = y;
+				newNode.width = height;
+				newNode.height = width;
+				assert(disjointRects.Disjoint(newNode));
+			}
+		}
+*/	}
+
+	return newNode;
+}
+
 Rect SkylineBinPack::InsertMinWaste(int width, int height)
 {
 	int bestHeight;
diff --git a/src/SkylineBinPack.h b/src/SkylineBinPack.h
index f93ddd29d..937c88de6 100644
--- a/src/SkylineBinPack.h
+++ b/src/SkylineBinPack.h
@@ -72,7 +72,10 @@ private:
 	bool useWasteMap;
 	GuillotineBinPack wasteMap;
 
+	Rect InsertBottomLeft(int width, int height);
 	Rect InsertMinWaste(int width, int height);
+
+	Rect FindPositionForNewNodeBottomLeft(int width, int height, int &bestHeight, int &bestWidth, int &bestIndex) const;
 	Rect FindPositionForNewNodeMinWaste(int width, int height, int &bestHeight, int &bestWastedArea, int &bestIndex) const;
 
 	bool RectangleFits(int skylineNodeIndex, int width, int height, int &y) const;