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
10bool 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    SkSTArenaAlloc<4096> allocator;  // FIXME: constant-ize, tune
51    SkOpContour contour;
52    SkOpContourHead* contourList = static_cast<SkOpContourHead*>(&contour);
53    SkOpGlobalState globalState(contourList, &allocator  SkDEBUGPARAMS(false)
54            SkDEBUGPARAMS(nullptr));
55    // turn path into list of segments
56    SkScalar scaleFactor = ScaleFactor(path);
57    SkPath scaledPath;
58    const SkPath* workingPath;
59    if (scaleFactor > SK_Scalar1) {
60        ScalePath(path, 1.f / scaleFactor, &scaledPath);
61        workingPath = &scaledPath;
62    } else {
63        workingPath = &path;
64    }
65    SkOpEdgeBuilder builder(*workingPath, contourList, &globalState);
66    if (!builder.finish()) {
67        return false;
68    }
69    if (!SortContourList(&contourList, false, false)) {
70        *result = moveBounds;
71        return true;
72    }
73    SkOpContour* current = contourList;
74    SkPathOpsBounds bounds = current->bounds();
75    while ((current = current->next())) {
76        bounds.add(current->bounds());
77    }
78    if (scaleFactor > SK_Scalar1) {
79        bounds.set(bounds.left() * scaleFactor, bounds.top() * scaleFactor,
80                   bounds.right() * scaleFactor, bounds.bottom() * scaleFactor);
81    }
82    *result = bounds;
83    if (!moveBounds.isEmpty()) {
84        result->join(moveBounds);
85    }
86    return true;
87}
88