batch merge new edges

src/core/SkScan_Path.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkScanPriv.h"
 #include "SkBlitter.h"
 #include "SkEdge.h"
@@ skipping 43 matching lines @@
     SkEdge* prev = edge->fPrev;
     while (prev->fX > x) {
         prev = prev->fPrev;
     }
     if (prev->fNext != edge) {
         remove_edge(edge);
         insert_edge_after(edge, prev);
     }
 }
 
+#ifndef SK_SUPPORT_LEGACY_INSERT_NEW_EDGES
+// Start from the right side, searching backwards for the point to begin the new edge list
+// insertion, marching forwards from here. The implementation could have started from the left
+// of the prior insertion, and search to the right, or with some additional caching, binary
+// search the starting point. More work could be done to determine optimal new edge insertion.
+static SkEdge* backward_insert_start(SkEdge* prev, SkFixed x) {
+    while (prev->fX > x) {
+        prev = prev->fPrev;
+    }
+    return prev;
+}
+#endif
+
 static void insert_new_edges(SkEdge* newEdge, int curr_y) {
+#ifdef SK_SUPPORT_LEGACY_INSERT_NEW_EDGES
     SkASSERT(newEdge->fFirstY >= curr_y);
 
     while (newEdge->fFirstY == curr_y) {
         SkEdge* next = newEdge->fNext;
         backward_insert_edge_based_on_x(newEdge  SkPARAM(curr_y));
         newEdge = next;
     }
+#else
+    if (newEdge->fFirstY != curr_y) {
+        return;
+    }
+    SkEdge* prev = newEdge->fPrev;
+    if (prev->fX <= newEdge->fX) {
+        return;
+    }
+    // find first x pos to insert
+    SkEdge* start = backward_insert_start(prev, newEdge->fX);
+    // insert the lot, fixing up the links as we go
+    do {
+        SkEdge* next = newEdge->fNext;
+        do {
+            if (start->fNext == newEdge) {
+                goto nextEdge;
+            }
+            SkEdge* after = start->fNext;
+            if (after->fX >= newEdge->fX) {
+                break;
+            }
+            start = after;
+        } while (true);
+        remove_edge(newEdge);
+        insert_edge_after(newEdge, start);
+nextEdge:
+        start = newEdge;
+        newEdge = next;
+    } while (newEdge->fFirstY == curr_y);
+#endif
 }
 
 #ifdef SK_DEBUG
 static void validate_edges_for_y(const SkEdge* edge, int curr_y) {
     while (edge->fFirstY <= curr_y) {
         SkASSERT(edge->fPrev && edge->fNext);
         SkASSERT(edge->fPrev->fNext == edge);
         SkASSERT(edge->fNext->fPrev == edge);
         SkASSERT(edge->fFirstY <= edge->fLastY);
 
@@ skipping 654 matching lines @@
         clipRgn = &wrap.getRgn();
         blitter = wrap.getBlitter();
     }
 
     SkScanClipper clipper(blitter, clipRgn, ir);
     blitter = clipper.getBlitter();
     if (blitter) {
         sk_fill_triangle(pts, clipper.getClipRect(), blitter, ir);
     }
 }