aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/SkDeviceLooper.cpp
blob: 9346465dfc9f28f102bcdb1903819f8bf25b4578 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkDeviceLooper.h"

SkDeviceLooper::SkDeviceLooper(const SkBitmap& base,
                               const SkRasterClip& rc,
                               const SkIRect& bounds, bool aa)
: fBaseBitmap(base)
, fBaseRC(rc)
, fDelta(aa ? kAA_Delta : kBW_Delta)
{
    // sentinels that next() has not yet been called, and so our mapper functions
    // should not be called either.
    fCurrBitmap = NULL;
    fCurrRC = NULL;

    if (!rc.isEmpty()) {
        // clip must be contained by the bitmap
        SkASSERT(SkIRect::MakeWH(base.width(), base.height()).contains(rc.getBounds()));
    }

    if (rc.isEmpty() || !fClippedBounds.intersect(bounds, rc.getBounds())) {
        fState = kDone_State;
    } else if (this->fitsInDelta(fClippedBounds)) {
        fState = kSimple_State;
    } else {
        // back up by 1 DX, so that next() will put us in a correct starting
        // position.
        fCurrOffset.set(fClippedBounds.left() - fDelta,
                        fClippedBounds.top());
        fState = kComplex_State;
    }
}

SkDeviceLooper::~SkDeviceLooper() {
}

void SkDeviceLooper::mapRect(SkRect* dst, const SkRect& src) const {
    SkASSERT(kDone_State != fState);
    SkASSERT(fCurrBitmap);
    SkASSERT(fCurrRC);

    *dst = src;
    dst->offset(SkIntToScalar(-fCurrOffset.fX),
                SkIntToScalar(-fCurrOffset.fY));
}

void SkDeviceLooper::mapMatrix(SkMatrix* dst, const SkMatrix& src) const {
    SkASSERT(kDone_State != fState);
    SkASSERT(fCurrBitmap);
    SkASSERT(fCurrRC);

    *dst = src;
    dst->postTranslate(SkIntToScalar(-fCurrOffset.fX),
                       SkIntToScalar(-fCurrOffset.fY));
}

bool SkDeviceLooper::computeCurrBitmapAndClip() {
    SkASSERT(kComplex_State == fState);

    SkIRect r = SkIRect::MakeXYWH(fCurrOffset.x(), fCurrOffset.y(),
                                  fDelta, fDelta);
    if (!fBaseBitmap.extractSubset(&fSubsetBitmap, r)) {
        fSubsetRC.setEmpty();
    } else {
        fSubsetBitmap.lockPixels();
        fBaseRC.translate(-r.left(), -r.top(), &fSubsetRC);
        (void)fSubsetRC.op(SkIRect::MakeWH(fDelta, fDelta),
                           SkRegion::kIntersect_Op);
    }

    fCurrBitmap = &fSubsetBitmap;
    fCurrRC = &fSubsetRC;
    return !fCurrRC->isEmpty();
}

static bool next_tile(const SkIRect& boundary, int delta, SkIPoint* offset) {
    // can we move to the right?
    if (offset->x() + delta < boundary.right()) {
        offset->fX += delta;
        return true;
    }

    // reset to the left, but move down a row
    offset->fX = boundary.left();
    if (offset->y() + delta < boundary.bottom()) {
        offset->fY += delta;
        return true;
    }

    // offset is now outside of boundary, so we're done
    return false;
}

bool SkDeviceLooper::next() {
    switch (fState) {
        case kDone_State:
            // in theory, we should not get called here, since we must have
            // previously returned false, but we check anyway.
            break;

        case kSimple_State:
            // first time for simple
            if (NULL == fCurrBitmap) {
                fCurrBitmap = &fBaseBitmap;
                fCurrRC = &fBaseRC;
                fCurrOffset.set(0, 0);
                return true;
            }
            // 2nd time for simple, we are done
            break;

        case kComplex_State:
            // need to propogate fCurrOffset through clippedbounds
            // left to right, until we wrap around and move down

            while (next_tile(fClippedBounds, fDelta, &fCurrOffset)) {
                if (this->computeCurrBitmapAndClip()) {
                    return true;
                }
            }
            break;
    }
    fState = kDone_State;
    return false;
}