SkLayerDrawLooper.cpp revision 3c898186c9082c535e589807752a0a9dc5d28aa0 
1#include "SkCanvas.h"
2#include "SkColor.h"
3#include "SkLayerDrawLooper.h"
4#include "SkPaint.h"
5#include "SkUnPreMultiply.h"
6
7SkLayerDrawLooper::LayerInfo::LayerInfo() {
8    fFlagsMask = 0;                     // ignore our paint flags
9    fPaintBits = 0;                     // ignore our paint fields
10    fColorMode = SkXfermode::kDst_Mode; // ignore our color
11    fOffset.set(0, 0);
12    fPostTranslate = false;
13}
14
15SkLayerDrawLooper::SkLayerDrawLooper()
16        : fRecs(NULL),
17          fCount(0),
18          fCurrRec(NULL) {
19}
20
21SkLayerDrawLooper::~SkLayerDrawLooper() {
22    Rec* rec = fRecs;
23    while (rec) {
24        Rec* next = rec->fNext;
25        SkDELETE(rec);
26        rec = next;
27    }
28}
29
30SkPaint* SkLayerDrawLooper::addLayer(const LayerInfo& info) {
31    fCount += 1;
32
33    Rec* rec = SkNEW(Rec);
34    rec->fNext = fRecs;
35    rec->fInfo = info;
36    fRecs = rec;
37
38    return &rec->fPaint;
39}
40
41void SkLayerDrawLooper::addLayer(SkScalar dx, SkScalar dy) {
42    LayerInfo info;
43
44    info.fOffset.set(dx, dy);
45    (void)this->addLayer(info);
46}
47
48void SkLayerDrawLooper::init(SkCanvas* canvas) {
49    fCurrRec = fRecs;
50    canvas->save(SkCanvas::kMatrix_SaveFlag);
51}
52
53static SkColor xferColor(SkColor src, SkColor dst, SkXfermode::Mode mode) {
54    switch (mode) {
55        case SkXfermode::kSrc_Mode:
56            return src;
57        case SkXfermode::kDst_Mode:
58            return dst;
59        default: {
60            SkPMColor pmS = SkPreMultiplyColor(src);
61            SkPMColor pmD = SkPreMultiplyColor(dst);
62            SkPMColor result = SkXfermode::GetProc(mode)(pmS, pmD);
63            return SkUnPreMultiply::PMColorToColor(result);
64        }
65    }
66}
67
68void SkLayerDrawLooper::ApplyInfo(SkPaint* dst, const SkPaint& src,
69                                  const LayerInfo& info) {
70
71    uint32_t mask = info.fFlagsMask;
72    dst->setFlags((dst->getFlags() & ~mask) | (src.getFlags() & mask));
73
74    dst->setColor(xferColor(src.getColor(), dst->getColor(), info.fColorMode));
75
76    BitFlags bits = info.fPaintBits;
77
78    if (0 == bits) {
79        return;
80    }
81    if (kEntirePaint_Bits == bits) {
82        // we've already computed these, so save it from the assignment
83        uint32_t f = dst->getFlags();
84        SkColor c = dst->getColor();
85        *dst = src;
86        dst->setFlags(f);
87        dst->setColor(c);
88        return;
89    }
90
91    if (bits & kStyle_Bit) {
92        dst->setStyle(src.getStyle());
93        dst->setStrokeWidth(src.getStrokeWidth());
94        dst->setStrokeMiter(src.getStrokeMiter());
95        dst->setStrokeCap(src.getStrokeCap());
96        dst->setStrokeJoin(src.getStrokeJoin());
97    }
98
99    if (bits & kTextSkewX_Bit) {
100        dst->setTextSkewX(src.getTextSkewX());
101    }
102
103    if (bits & kPathEffect_Bit) {
104        dst->setPathEffect(src.getPathEffect());
105    }
106    if (bits & kMaskFilter_Bit) {
107        dst->setMaskFilter(src.getMaskFilter());
108    }
109    if (bits & kShader_Bit) {
110        dst->setShader(src.getShader());
111    }
112    if (bits & kColorFilter_Bit) {
113        dst->setColorFilter(src.getColorFilter());
114    }
115    if (bits & kXfermode_Bit) {
116        dst->setXfermode(src.getXfermode());
117    }
118
119    // we never copy these
120#if 0
121    dst->setFlags(src.getFlags());
122    dst->setTypeface(src.getTypeface());
123    dst->setTextSize(src.getTextSize());
124    dst->setTextScaleX(src.getTextScaleX());
125    dst->setTextSkewX(src.getTextSkewX());
126    dst->setRasterizer(src.getRasterizer());
127    dst->setLooper(src.getLooper());
128    dst->setTextEncoding(src.getTextEncoding());
129    dst->setHinting(src.getHinting());
130#endif
131}
132
133// Should we add this to canvas?
134static void postTranslate(SkCanvas* canvas, SkScalar dx, SkScalar dy) {
135    SkMatrix m = canvas->getTotalMatrix();
136    m.postTranslate(dx, dy);
137    canvas->setMatrix(m);
138}
139
140bool SkLayerDrawLooper::next(SkCanvas* canvas, SkPaint* paint) {
141    canvas->restore();
142    if (NULL == fCurrRec) {
143        return false;
144    }
145
146    ApplyInfo(paint, fCurrRec->fPaint, fCurrRec->fInfo);
147
148    canvas->save(SkCanvas::kMatrix_SaveFlag);
149    if (fCurrRec->fInfo.fPostTranslate) {
150        postTranslate(canvas, fCurrRec->fInfo.fOffset.fX,
151                      fCurrRec->fInfo.fOffset.fY);
152    } else {
153        canvas->translate(fCurrRec->fInfo.fOffset.fX, fCurrRec->fInfo.fOffset.fY);
154    }
155    fCurrRec = fCurrRec->fNext;
156
157    return true;
158}
159
160SkLayerDrawLooper::Rec* SkLayerDrawLooper::Rec::Reverse(Rec* head) {
161    Rec* rec = head;
162    Rec* prev = NULL;
163    while (rec) {
164        Rec* next = rec->fNext;
165        rec->fNext = prev;
166        prev = rec;
167        rec = next;
168    }
169    return prev;
170}
171
172///////////////////////////////////////////////////////////////////////////////
173
174void SkLayerDrawLooper::flatten(SkFlattenableWriteBuffer& buffer) {
175    this->INHERITED::flatten(buffer);
176
177#ifdef SK_DEBUG
178    {
179        Rec* rec = fRecs;
180        int count = 0;
181        while (rec) {
182            rec = rec->fNext;
183            count += 1;
184        }
185        SkASSERT(count == fCount);
186    }
187#endif
188
189    buffer.writeInt(fCount);
190
191    Rec* rec = fRecs;
192    for (int i = 0; i < fCount; i++) {
193        buffer.writeInt(rec->fInfo.fPaintBits);
194        buffer.writeInt(rec->fInfo.fColorMode);
195        buffer.writeScalar(rec->fInfo.fOffset.fX);
196        buffer.writeScalar(rec->fInfo.fOffset.fY);
197        buffer.writeBool(rec->fInfo.fPostTranslate);
198        rec->fPaint.flatten(buffer);
199        rec = rec->fNext;
200    }
201}
202
203SkLayerDrawLooper::SkLayerDrawLooper(SkFlattenableReadBuffer& buffer)
204        : INHERITED(buffer),
205          fRecs(NULL),
206          fCount(0),
207          fCurrRec(NULL) {
208    int count = buffer.readInt();
209
210    for (int i = 0; i < count; i++) {
211        LayerInfo info;
212        info.fPaintBits = buffer.readInt();
213        info.fColorMode = (SkXfermode::Mode)buffer.readInt();
214        info.fOffset.fX = buffer.readScalar();
215        info.fOffset.fY = buffer.readScalar();
216        info.fPostTranslate = buffer.readBool();
217        this->addLayer(info)->unflatten(buffer);
218    }
219    SkASSERT(count == fCount);
220
221    // we're in reverse order, so fix it now
222    fRecs = Rec::Reverse(fRecs);
223
224#ifdef SK_DEBUG
225    {
226        Rec* rec = fRecs;
227        int n = 0;
228        while (rec) {
229            rec = rec->fNext;
230            n += 1;
231        }
232        SkASSERT(count == n);
233    }
234#endif
235}
236
237///////////////////////////////////////////////////////////////////////////////
238
239static SkFlattenable::Registrar gReg("SkLayerDrawLooper",
240                                     SkLayerDrawLooper::CreateProc);
241