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      1 /*
      2  * Copyright 2014 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 #include "SkOpEdgeBuilder.h"
      8 #include "SkPathOpsCommon.h"
      9 
     10 bool TightBounds(const SkPath& path, SkRect* result) {
     11     SkPath::RawIter iter(path);
     12     SkRect moveBounds = { SK_ScalarMax, SK_ScalarMax, SK_ScalarMin, SK_ScalarMin };
     13     bool wellBehaved = true;
     14     SkPath::Verb verb;
     15     do {
     16         SkPoint pts[4];
     17         verb = iter.next(pts);
     18         switch (verb) {
     19             case SkPath::kMove_Verb:
     20                 moveBounds.fLeft = SkTMin(moveBounds.fLeft, pts[0].fX);
     21                 moveBounds.fTop = SkTMin(moveBounds.fTop, pts[0].fY);
     22                 moveBounds.fRight = SkTMax(moveBounds.fRight, pts[0].fX);
     23                 moveBounds.fBottom = SkTMax(moveBounds.fBottom, pts[0].fY);
     24                 break;
     25             case SkPath::kQuad_Verb:
     26             case SkPath::kConic_Verb:
     27                 if (!wellBehaved) {
     28                     break;
     29                 }
     30                 wellBehaved &= between(pts[0].fX, pts[1].fX, pts[2].fX);
     31                 wellBehaved &= between(pts[0].fY, pts[1].fY, pts[2].fY);
     32                 break;
     33             case SkPath::kCubic_Verb:
     34                 if (!wellBehaved) {
     35                     break;
     36                 }
     37                 wellBehaved &= between(pts[0].fX, pts[1].fX, pts[3].fX);
     38                 wellBehaved &= between(pts[0].fY, pts[1].fY, pts[3].fY);
     39                 wellBehaved &= between(pts[0].fX, pts[2].fX, pts[3].fX);
     40                 wellBehaved &= between(pts[0].fY, pts[2].fY, pts[3].fY);
     41                 break;
     42             default:
     43                 break;
     44         }
     45     } while (verb != SkPath::kDone_Verb);
     46     if (wellBehaved) {
     47         *result = path.getBounds();
     48         return true;
     49     }
     50     char storage[4096];
     51     SkArenaAlloc allocator(storage);  // FIXME: constant-ize, tune
     52     SkOpContour contour;
     53     SkOpContourHead* contourList = static_cast<SkOpContourHead*>(&contour);
     54     SkOpGlobalState globalState(contourList, &allocator  SkDEBUGPARAMS(false)
     55             SkDEBUGPARAMS(nullptr));
     56     // turn path into list of segments
     57     SkScalar scaleFactor = ScaleFactor(path);
     58     SkPath scaledPath;
     59     const SkPath* workingPath;
     60     if (scaleFactor > SK_Scalar1) {
     61         ScalePath(path, 1.f / scaleFactor, &scaledPath);
     62         workingPath = &scaledPath;
     63     } else {
     64         workingPath = &path;
     65     }
     66     SkOpEdgeBuilder builder(*workingPath, contourList, &globalState);
     67     if (!builder.finish()) {
     68         return false;
     69     }
     70     if (!SortContourList(&contourList, false, false)) {
     71         *result = moveBounds;
     72         return true;
     73     }
     74     SkOpContour* current = contourList;
     75     SkPathOpsBounds bounds = current->bounds();
     76     while ((current = current->next())) {
     77         bounds.add(current->bounds());
     78     }
     79     if (scaleFactor > SK_Scalar1) {
     80         bounds.set(bounds.left() * scaleFactor, bounds.top() * scaleFactor,
     81                    bounds.right() * scaleFactor, bounds.bottom() * scaleFactor);
     82     }
     83     *result = bounds;
     84     if (!moveBounds.isEmpty()) {
     85         result->join(moveBounds);
     86     }
     87     return true;
     88 }
     89