1 /*
2  * Copyright 2015 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 
8 #include "GrStrokeInfo.h"
9 #include "GrResourceKey.h"
10 #include "SkDashPathPriv.h"
11 
all_dash_intervals_zero(const SkScalar * intervals,int count)12 bool all_dash_intervals_zero(const SkScalar* intervals, int count) {
13     for (int i = 0 ; i < count; ++i) {
14         if (intervals[i] != 0) {
15             return false;
16         }
17     }
18     return true;
19 }
20 
applyDashToPath(SkPath * dst,GrStrokeInfo * dstStrokeInfo,const SkPath & src) const21 bool GrStrokeInfo::applyDashToPath(SkPath* dst, GrStrokeInfo* dstStrokeInfo,
22                                    const SkPath& src) const {
23     if (this->isDashed()) {
24         SkPathEffect::DashInfo info;
25         info.fIntervals = fIntervals.get();
26         info.fCount = fIntervals.count();
27         info.fPhase = fDashPhase;
28         GrStrokeInfo filteredStroke(*this, false);
29         // Handle the case where all intervals are 0 and we simply drop the dash effect
30         if (all_dash_intervals_zero(fIntervals.get(), fIntervals.count())) {
31             *dstStrokeInfo = filteredStroke;
32             *dst = src;
33             return true;
34         }
35         // See if we can filter the dash into a path on cpu
36         if (SkDashPath::FilterDashPath(dst, src, &filteredStroke, nullptr, info)) {
37             *dstStrokeInfo = filteredStroke;
38             return true;
39         }
40     }
41     return false;
42 }
43 
asUniqueKeyFragment(uint32_t * data) const44 void GrStrokeInfo::asUniqueKeyFragment(uint32_t* data) const {
45     const int kSkScalarData32Cnt = sizeof(SkScalar) / sizeof(uint32_t);
46     enum {
47         kStyleBits = 2,
48         kJoinBits = 2,
49         kCapBits = 32 - kStyleBits - kJoinBits,
50 
51         kJoinShift = kStyleBits,
52         kCapShift = kJoinShift + kJoinBits,
53     };
54 
55     static_assert(SkStrokeRec::kStyleCount <= (1 << kStyleBits), "style_shift_will_be_wrong");
56     static_assert(SkPaint::kJoinCount <= (1 << kJoinBits), "cap_shift_will_be_wrong");
57     static_assert(SkPaint::kCapCount <= (1 << kCapBits), "cap_does_not_fit");
58     uint32_t styleKey = this->getStyle();
59     if (this->needToApply()) {
60         styleKey |= this->getJoin() << kJoinShift;
61         styleKey |= this->getCap() << kCapShift;
62     }
63     int i = 0;
64     data[i++] = styleKey;
65 
66     // Memcpy the scalar fields. Does not "reinterpret_cast<SkScalar&>(data[i]) = ..." due to
67     // scalars having more strict alignment requirements than what data can guarantee. The
68     // compiler should optimize memcpys to assignments.
69     SkScalar scalar;
70     scalar = this->getMiter();
71     memcpy(&data[i], &scalar, sizeof(scalar));
72     i += kSkScalarData32Cnt;
73 
74     scalar = this->getWidth();
75     memcpy(&data[i], &scalar, sizeof(scalar));
76     i += kSkScalarData32Cnt;
77 
78     if (this->isDashed()) {
79         SkScalar phase = this->getDashPhase();
80         memcpy(&data[i], &phase, sizeof(phase));
81         i += kSkScalarData32Cnt;
82 
83         int32_t count = this->getDashCount() & static_cast<int32_t>(~1);
84         SkASSERT(count == this->getDashCount());
85         const SkScalar* intervals = this->getDashIntervals();
86         int intervalByteCnt = count * sizeof(SkScalar);
87         memcpy(&data[i], intervals, intervalByteCnt);
88         // Enable the line below if fields are added after dashing.
89         SkDEBUGCODE(i += kSkScalarData32Cnt * count);
90     }
91 
92     SkASSERT(this->computeUniqueKeyFragmentData32Cnt() == i);
93 }
94 
95