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      1 /*
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      3  *
      4  * Redistribution and use in source and binary forms, with or without
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      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
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     16  * this software without specific prior written permission.
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     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 
     33 #include "platform/graphics/skia/SkiaUtils.h"
     34 
     35 #include "SkColorPriv.h"
     36 #include "SkRegion.h"
     37 #include "platform/graphics/GraphicsContext.h"
     38 #include "platform/graphics/ImageBuffer.h"
     39 
     40 namespace WebCore {
     41 
     42 static const struct CompositOpToXfermodeMode {
     43     uint8_t mCompositOp;
     44     uint8_t m_xfermodeMode;
     45 } gMapCompositOpsToXfermodeModes[] = {
     46     { CompositeClear,           SkXfermode::kClear_Mode },
     47     { CompositeCopy,            SkXfermode::kSrc_Mode },
     48     { CompositeSourceOver,      SkXfermode::kSrcOver_Mode },
     49     { CompositeSourceIn,        SkXfermode::kSrcIn_Mode },
     50     { CompositeSourceOut,       SkXfermode::kSrcOut_Mode },
     51     { CompositeSourceAtop,      SkXfermode::kSrcATop_Mode },
     52     { CompositeDestinationOver, SkXfermode::kDstOver_Mode },
     53     { CompositeDestinationIn,   SkXfermode::kDstIn_Mode },
     54     { CompositeDestinationOut,  SkXfermode::kDstOut_Mode },
     55     { CompositeDestinationAtop, SkXfermode::kDstATop_Mode },
     56     { CompositeXOR,             SkXfermode::kXor_Mode },
     57     { CompositePlusDarker,      SkXfermode::kDarken_Mode },
     58     { CompositePlusLighter,     SkXfermode::kPlus_Mode }
     59 };
     60 
     61 // keep this array in sync with blink::WebBlendMode enum in public/platform/WebBlendMode.h
     62 static const uint8_t gMapBlendOpsToXfermodeModes[] = {
     63     SkXfermode::kClear_Mode, // blink::WebBlendModeNormal
     64     SkXfermode::kMultiply_Mode, // blink::WebBlendModeMultiply
     65     SkXfermode::kScreen_Mode, // blink::WebBlendModeScreen
     66     SkXfermode::kOverlay_Mode, // blink::WebBlendModeOverlay
     67     SkXfermode::kDarken_Mode, // blink::WebBlendModeDarken
     68     SkXfermode::kLighten_Mode, // blink::WebBlendModeLighten
     69     SkXfermode::kColorDodge_Mode, // blink::WebBlendModeColorDodge
     70     SkXfermode::kColorBurn_Mode, // blink::WebBlendModeColorBurn
     71     SkXfermode::kHardLight_Mode, // blink::WebBlendModeHardLight
     72     SkXfermode::kSoftLight_Mode, // blink::WebBlendModeSoftLight
     73     SkXfermode::kDifference_Mode, // blink::WebBlendModeDifference
     74     SkXfermode::kExclusion_Mode, // blink::WebBlendModeExclusion
     75     SkXfermode::kHue_Mode, // blink::WebBlendModeHue
     76     SkXfermode::kSaturation_Mode, // blink::WebBlendModeSaturation
     77     SkXfermode::kColor_Mode, // blink::WebBlendModeColor
     78     SkXfermode::kLuminosity_Mode // blink::WebBlendModeLuminosity
     79 };
     80 
     81 PassRefPtr<SkXfermode> WebCoreCompositeToSkiaComposite(CompositeOperator op, blink::WebBlendMode blendMode)
     82 {
     83     if (blendMode != blink::WebBlendModeNormal) {
     84         if ((uint8_t)blendMode >= SK_ARRAY_COUNT(gMapBlendOpsToXfermodeModes)) {
     85             SkDEBUGF(("GraphicsContext::setPlatformCompositeOperation unknown blink::WebBlendMode %d\n", blendMode));
     86             return adoptRef(SkXfermode::Create(SkXfermode::kSrcOver_Mode));
     87         }
     88         SkXfermode::Mode mode = (SkXfermode::Mode)gMapBlendOpsToXfermodeModes[(uint8_t)blendMode];
     89         return adoptRef(SkXfermode::Create(mode));
     90     }
     91 
     92     const CompositOpToXfermodeMode* table = gMapCompositOpsToXfermodeModes;
     93 
     94     for (unsigned i = 0; i < SK_ARRAY_COUNT(gMapCompositOpsToXfermodeModes); i++) {
     95         if (table[i].mCompositOp == op)
     96             return adoptRef(SkXfermode::Create((SkXfermode::Mode)table[i].m_xfermodeMode));
     97     }
     98 
     99     SkDEBUGF(("GraphicsContext::setPlatformCompositeOperation unknown CompositeOperator %d\n", op));
    100     return adoptRef(SkXfermode::Create(SkXfermode::kSrcOver_Mode)); // fall-back
    101 }
    102 
    103 static U8CPU InvScaleByte(U8CPU component, uint32_t scale)
    104 {
    105     SkASSERT(component == (uint8_t)component);
    106     return (component * scale + 0x8000) >> 16;
    107 }
    108 
    109 SkColor SkPMColorToColor(SkPMColor pm)
    110 {
    111     if (!pm)
    112         return 0;
    113     unsigned a = SkGetPackedA32(pm);
    114     if (!a) {
    115         // A zero alpha value when there are non-zero R, G, or B channels is an
    116         // invalid premultiplied color (since all channels should have been
    117         // multiplied by 0 if a=0).
    118         SkASSERT(false);
    119         // In production, return 0 to protect against division by zero.
    120         return 0;
    121     }
    122 
    123     uint32_t scale = (255 << 16) / a;
    124 
    125     return SkColorSetARGB(a,
    126                           InvScaleByte(SkGetPackedR32(pm), scale),
    127                           InvScaleByte(SkGetPackedG32(pm), scale),
    128                           InvScaleByte(SkGetPackedB32(pm), scale));
    129 }
    130 
    131 void ClipRectToCanvas(const GraphicsContext* context, const SkRect& srcRect, SkRect* destRect)
    132 {
    133     if (!context->getClipBounds(destRect) || !destRect->intersect(srcRect))
    134         destRect->setEmpty();
    135 }
    136 
    137 bool SkPathContainsPoint(const SkPath& originalPath, const FloatPoint& point, SkPath::FillType ft)
    138 {
    139     SkRect bounds = originalPath.getBounds();
    140 
    141     // We can immediately return false if the point is outside the bounding
    142     // rect.  We don't use bounds.contains() here, since it would exclude
    143     // points on the right and bottom edges of the bounding rect, and we want
    144     // to include them.
    145     SkScalar fX = SkFloatToScalar(point.x());
    146     SkScalar fY = SkFloatToScalar(point.y());
    147     if (fX < bounds.fLeft || fX > bounds.fRight || fY < bounds.fTop || fY > bounds.fBottom)
    148         return false;
    149 
    150     // Scale the path to a large size before hit testing for two reasons:
    151     // 1) Skia has trouble with coordinates close to the max signed 16-bit values, so we scale larger paths down.
    152     //    TODO: when Skia is patched to work properly with large values, this will not be necessary.
    153     // 2) Skia does not support analytic hit testing, so we scale paths up to do raster hit testing with subpixel accuracy.
    154     SkScalar biggestCoord = std::max(std::max(std::max(bounds.fRight, bounds.fBottom), -bounds.fLeft), -bounds.fTop);
    155     if (SkScalarNearlyZero(biggestCoord))
    156         return false;
    157     biggestCoord = std::max(std::max(biggestCoord, fX + 1), fY + 1);
    158 
    159     const SkScalar kMaxCoordinate = SkIntToScalar(1 << 15);
    160     SkScalar scale = SkScalarDiv(kMaxCoordinate, biggestCoord);
    161 
    162     SkRegion rgn;
    163     SkRegion clip;
    164     SkMatrix m;
    165     SkPath scaledPath(originalPath);
    166 
    167     scaledPath.setFillType(ft);
    168     m.setScale(scale, scale);
    169     scaledPath.transform(m, 0);
    170 
    171     int x = static_cast<int>(floorf(0.5f + point.x() * scale));
    172     int y = static_cast<int>(floorf(0.5f + point.y() * scale));
    173     clip.setRect(x - 1, y - 1, x + 1, y + 1);
    174 
    175     return rgn.setPath(scaledPath, clip);
    176 }
    177 
    178 SkMatrix affineTransformToSkMatrix(const AffineTransform& source)
    179 {
    180     SkMatrix result;
    181 
    182     result.setScaleX(WebCoreDoubleToSkScalar(source.a()));
    183     result.setSkewX(WebCoreDoubleToSkScalar(source.c()));
    184     result.setTranslateX(WebCoreDoubleToSkScalar(source.e()));
    185 
    186     result.setScaleY(WebCoreDoubleToSkScalar(source.d()));
    187     result.setSkewY(WebCoreDoubleToSkScalar(source.b()));
    188     result.setTranslateY(WebCoreDoubleToSkScalar(source.f()));
    189 
    190     // FIXME: Set perspective properly.
    191     result.setPerspX(0);
    192     result.setPerspY(0);
    193     result.set(SkMatrix::kMPersp2, SK_Scalar1);
    194 
    195     return result;
    196 }
    197 
    198 }  // namespace WebCore
    199