From b839f0f6a92db9bcdbf8aa8004f20b0c0000111c Mon Sep 17 00:00:00 2001
From: "rileya@google.com"
 <rileya@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81>
Date: Mon, 10 Sep 2012 17:31:05 +0000
Subject: Add optional aspect ratio parameter to R-Tree, this helps the bulk
 load algorithm create more square tiles. Review URL:
 https://codereview.appspot.com/6489102

git-svn-id: http://skia.googlecode.com/svn/trunk@5466 2bbb7eff-a529-9590-31e7-b0007b416f81
---
 src/core/SkRTree.cpp | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

(limited to 'src/core/SkRTree.cpp')

diff --git a/src/core/SkRTree.cpp b/src/core/SkRTree.cpp
index 18a3f61971..c6f0d60d1c 100644
--- a/src/core/SkRTree.cpp
+++ b/src/core/SkRTree.cpp
@@ -19,20 +19,21 @@ static inline void join_no_empty_check(const SkIRect& joinWith, SkIRect* out);
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
-SkRTree* SkRTree::Create(int minChildren, int maxChildren) {
+SkRTree* SkRTree::Create(int minChildren, int maxChildren, SkScalar aspectRatio) {
     if (minChildren < maxChildren && (maxChildren + 1) / 2 >= minChildren &&
         minChildren > 0 && maxChildren < static_cast<int>(SK_MaxU16)) {
-        return new SkRTree(minChildren, maxChildren);
+        return new SkRTree(minChildren, maxChildren, aspectRatio);
     }
     return NULL;
 }
 
-SkRTree::SkRTree(int minChildren, int maxChildren)
+SkRTree::SkRTree(int minChildren, int maxChildren, SkScalar aspectRatio)
     : fMinChildren(minChildren)
     , fMaxChildren(maxChildren)
     , fNodeSize(sizeof(Node) + sizeof(Branch) * maxChildren)
     , fCount(0)
-    , fNodes(fNodeSize * 256) {
+    , fNodes(fNodeSize * 256)
+    , fAspectRatio(aspectRatio) {
     SkASSERT(minChildren < maxChildren && minChildren > 0 && maxChildren <
              static_cast<int>(SK_MaxU16));
     SkASSERT((maxChildren + 1) / 2 >= minChildren);
@@ -339,13 +340,16 @@ SkRTree::Branch SkRTree::bulkLoad(SkTDArray<Branch>* branches, int level) {
             }
         }
 
-        int numStrips = SkScalarCeil(SkScalarSqrt(SkIntToScalar(numBranches)));
+        int numStrips = SkScalarCeil(SkScalarSqrt(SkIntToScalar(numBranches) *
+                                     SkScalarInvert(fAspectRatio)));
+        int numTiles = SkScalarCeil(SkScalarSqrt(SkIntToScalar(numBranches) /
+                                    SkIntToScalar(numStrips)));
         int currentBranch = 0;
 
         for (int i = 0; i < numStrips; ++i) {
             int begin = currentBranch;
-            int end = currentBranch + numStrips * fMaxChildren - SkMin32(remainder,
-                      (fMaxChildren - fMinChildren) * numStrips);
+            int end = currentBranch + numTiles * fMaxChildren - SkMin32(remainder,
+                      (fMaxChildren - fMinChildren) * numTiles);
             if (end > branches->count()) {
                 end = branches->count();
             }
@@ -354,7 +358,7 @@ SkRTree::Branch SkRTree::bulkLoad(SkTDArray<Branch>* branches, int level) {
             SkQSort<int, Branch>(level, branches->begin() + begin, branches->begin() + end - 1,
                                  &RectLessX);
 
-            for (int j = 0; j < numStrips && currentBranch < branches->count(); ++j) {
+            for (int j = 0; j < numTiles && currentBranch < branches->count(); ++j) {
                 int incrementBy = fMaxChildren;
                 if (remainder != 0) {
                     // if need be, omit some nodes to make up for remainder
-- 
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