faster edge re-sort, drop trailing edges

src/core/SkLineClipper.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkLineClipper.h"
 
 template <typename T> T pin_unsorted(T value, T limit0, T limit1) {
@@ skipping 155 matching lines @@
     const SkPoint pts[] = {
         { -540000,    -720000 },
         { -9.10000017e-05f, 9.99999996e-13f }
     };
     float x = sect_with_horizontal(pts, 0);
     SkASSERT(is_between_unsorted(x, pts[0].fX, pts[1].fX));
 }
 #endif
 
 int SkLineClipper::ClipLine(const SkPoint pts[], const SkRect& clip,
-                            SkPoint lines[]) {
+                            SkPoint lines[], bool canClipToTheRight) {
 #ifdef SK_DEBUG
     {
         static bool gOnce;
         if (!gOnce) {
             sect_with_horizontal_test_for_pin_results();
             gOnce = true;
         }
     }
 #endif
 
@@ skipping 47 matching lines @@
         index0 = 1;
         index1 = 0;
         reverse = true;
     }
 
     if (tmp[index1].fX <= clip.fLeft) {  // wholly to the left
         tmp[0].fX = tmp[1].fX = clip.fLeft;
         result = tmp;
         reverse = false;
     } else if (tmp[index0].fX >= clip.fRight) {    // wholly to the right
+        if (canClipToTheRight) {
+            return 0;
+        }
         tmp[0].fX = tmp[1].fX = clip.fRight;
         result = tmp;
         reverse = false;
     } else {
         result = resultStorage;
         SkPoint* r = result;
 
         if (tmp[index0].fX < clip.fLeft) {
             r->set(clip.fLeft, tmp[index0].fY);
             r += 1;
@@ skipping 20 matching lines @@
     if (reverse) {
         // copy the pts in reverse order to maintain winding order
         for (int i = 0; i <= lineCount; i++) {
             lines[lineCount - i] = result[i];
         }
     } else {
         memcpy(lines, result, (lineCount + 1) * sizeof(SkPoint));
     }
     return lineCount;
 }