Esempio n. 1
0
// Returns whether or not the gpu can fast path the dash line effect.
static bool can_fast_path_dash(const SkPoint pts[2], const GrStrokeInfo& strokeInfo,
                               const GrDrawTarget& target, const SkMatrix& viewMatrix) {
    if (target.getDrawState().getRenderTarget()->isMultisampled()) {
        return false;
    }

    // Pts must be either horizontal or vertical in src space
    if (pts[0].fX != pts[1].fX && pts[0].fY != pts[1].fY) {
        return false;
    }

    // May be able to relax this to include skew. As of now cannot do perspective
    // because of the non uniform scaling of bloating a rect
    if (!viewMatrix.preservesRightAngles()) {
        return false;
    }

    if (!strokeInfo.isDashed() || 2 != strokeInfo.dashCount()) {
        return false;
    }

    const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo();
    if (0 == info.fIntervals[0] && 0 == info.fIntervals[1]) {
        return false;
    }

    SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap();
    // Current we do don't handle Round or Square cap dashes
    if (SkPaint::kRound_Cap == cap && info.fIntervals[0] != 0.f) {
        return false;
    }

    return true;
}
Esempio n. 2
0
bool GrDashingEffect::DrawDashLine(const SkPoint pts[2], const GrPaint& paint,
                                   const GrStrokeInfo& strokeInfo, GrGpu* gpu,
                                   GrDrawTarget* target, const SkMatrix& vm) {

    if (!can_fast_path_dash(pts, strokeInfo, *target, vm)) {
        return false;
    }

    const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo();

    SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap();

    SkScalar srcStrokeWidth = strokeInfo.getStrokeRec().getWidth();

    // the phase should be normalized to be [0, sum of all intervals)
    SkASSERT(info.fPhase >= 0 && info.fPhase < info.fIntervals[0] + info.fIntervals[1]);

    SkScalar srcPhase = info.fPhase;

    // Rotate the src pts so they are aligned horizontally with pts[0].fX < pts[1].fX
    SkMatrix srcRotInv;
    SkPoint ptsRot[2];
    if (pts[0].fY != pts[1].fY || pts[0].fX > pts[1].fX) {
        SkMatrix rotMatrix;
        align_to_x_axis(pts, &rotMatrix, ptsRot);
        if(!rotMatrix.invert(&srcRotInv)) {
            GrPrintf("Failed to create invertible rotation matrix!\n");
            return false;
        }
    } else {
        srcRotInv.reset();
        memcpy(ptsRot, pts, 2 * sizeof(SkPoint));
    }

    bool useAA = paint.isAntiAlias();

    // Scale corrections of intervals and stroke from view matrix
    SkScalar parallelScale;
    SkScalar perpScale;
    calc_dash_scaling(&parallelScale, &perpScale, vm, ptsRot);

    bool hasCap = SkPaint::kButt_Cap != cap && 0 != srcStrokeWidth;

    // We always want to at least stroke out half a pixel on each side in device space
    // so 0.5f / perpScale gives us this min in src space
    SkScalar halfSrcStroke = SkMaxScalar(srcStrokeWidth * 0.5f, 0.5f / perpScale);

    SkScalar strokeAdj;
    if (!hasCap) {
        strokeAdj = 0.f;
    } else {
        strokeAdj = halfSrcStroke;
    }

    SkScalar startAdj = 0;

    SkMatrix combinedMatrix = srcRotInv;
    combinedMatrix.postConcat(vm);

    bool lineDone = false;
    SkRect startRect;
    bool hasStartRect = false;
    // If we are using AA, check to see if we are drawing a partial dash at the start. If so
    // draw it separately here and adjust our start point accordingly
    if (useAA) {
        if (srcPhase > 0 && srcPhase < info.fIntervals[0]) {
            SkPoint startPts[2];
            startPts[0] = ptsRot[0];
            startPts[1].fY = startPts[0].fY;
            startPts[1].fX = SkMinScalar(startPts[0].fX + info.fIntervals[0] - srcPhase,
                                         ptsRot[1].fX);
            startRect.set(startPts, 2);
            startRect.outset(strokeAdj, halfSrcStroke);

            hasStartRect = true;
            startAdj = info.fIntervals[0] + info.fIntervals[1] - srcPhase;
        }
    }

    // adjustments for start and end of bounding rect so we only draw dash intervals
    // contained in the original line segment.
    startAdj += calc_start_adjustment(info);
    if (startAdj != 0) {
        ptsRot[0].fX += startAdj;
        srcPhase = 0;
    }
    SkScalar endingInterval = 0;
    SkScalar endAdj = calc_end_adjustment(info, ptsRot, srcPhase, &endingInterval);
    ptsRot[1].fX -= endAdj;
    if (ptsRot[0].fX >= ptsRot[1].fX) {
        lineDone = true;
    }

    SkRect endRect;
    bool hasEndRect = false;
    // If we are using AA, check to see if we are drawing a partial dash at then end. If so
    // draw it separately here and adjust our end point accordingly
    if (useAA && !lineDone) {
        // If we adjusted the end then we will not be drawing a partial dash at the end.
        // If we didn't adjust the end point then we just need to make sure the ending
        // dash isn't a full dash
        if (0 == endAdj && endingInterval != info.fIntervals[0]) {
            SkPoint endPts[2];
            endPts[1] = ptsRot[1];
            endPts[0].fY = endPts[1].fY;
            endPts[0].fX = endPts[1].fX - endingInterval;

            endRect.set(endPts, 2);
            endRect.outset(strokeAdj, halfSrcStroke);

            hasEndRect = true;
            endAdj = endingInterval + info.fIntervals[1];

            ptsRot[1].fX -= endAdj;
            if (ptsRot[0].fX >= ptsRot[1].fX) {
                lineDone = true;
            }
        }
    }

    if (startAdj != 0) {
        srcPhase = 0;
    }

    // Change the dashing info from src space into device space
    SkScalar devIntervals[2];
    devIntervals[0] = info.fIntervals[0] * parallelScale;
    devIntervals[1] = info.fIntervals[1] * parallelScale;
    SkScalar devPhase = srcPhase * parallelScale;
    SkScalar strokeWidth = srcStrokeWidth * perpScale;

    if ((strokeWidth < 1.f && !useAA) || 0.f == strokeWidth) {
        strokeWidth = 1.f;
    }

    SkScalar halfDevStroke = strokeWidth * 0.5f;

    if (SkPaint::kSquare_Cap == cap && 0 != srcStrokeWidth) {
        // add cap to on interveal and remove from off interval
        devIntervals[0] += strokeWidth;
        devIntervals[1] -= strokeWidth;
    }
    SkScalar startOffset = devIntervals[1] * 0.5f + devPhase;

    SkScalar bloatX = useAA ? 0.5f / parallelScale : 0.f;
    SkScalar bloatY = useAA ? 0.5f / perpScale : 0.f;

    SkScalar devBloat = useAA ? 0.5f : 0.f;

    GrDrawState* drawState = target->drawState();
    if (devIntervals[1] <= 0.f && useAA) {
        // Case when we end up drawing a solid AA rect
        // Reset the start rect to draw this single solid rect
        // but it requires to upload a new intervals uniform so we can mimic
        // one giant dash
        ptsRot[0].fX -= hasStartRect ? startAdj : 0;
        ptsRot[1].fX += hasEndRect ? endAdj : 0;
        startRect.set(ptsRot, 2);
        startRect.outset(strokeAdj, halfSrcStroke);
        hasStartRect = true;
        hasEndRect = false;
        lineDone = true;

        SkPoint devicePts[2];
        vm.mapPoints(devicePts, ptsRot, 2);
        SkScalar lineLength = SkPoint::Distance(devicePts[0], devicePts[1]);
        if (hasCap) {
            lineLength += 2.f * halfDevStroke;
        }
        devIntervals[0] = lineLength;
    }
    if (devIntervals[1] > 0.f || useAA) {
        SkPathEffect::DashInfo devInfo;
        devInfo.fPhase = devPhase;
        devInfo.fCount = 2;
        devInfo.fIntervals = devIntervals;
        GrEffectEdgeType edgeType= useAA ? kFillAA_GrEffectEdgeType :
            kFillBW_GrEffectEdgeType;
        bool isRoundCap = SkPaint::kRound_Cap == cap;
        GrDashingEffect::DashCap capType = isRoundCap ? GrDashingEffect::kRound_DashCap :
                                                        GrDashingEffect::kNonRound_DashCap;
        drawState->addCoverageEffect(
            GrDashingEffect::Create(edgeType, devInfo, strokeWidth, capType), 1)->unref();
    }

    // Set up the vertex data for the line and start/end dashes
    drawState->setVertexAttribs<gDashLineVertexAttribs>(SK_ARRAY_COUNT(gDashLineVertexAttribs));

    int totalRectCnt = 0;

    totalRectCnt += !lineDone ? 1 : 0;
    totalRectCnt += hasStartRect ? 1 : 0;
    totalRectCnt += hasEndRect ? 1 : 0;

    GrDrawTarget::AutoReleaseGeometry geo(target, totalRectCnt * 4, 0);
    if (!geo.succeeded()) {
        GrPrintf("Failed to get space for vertices!\n");
        return false;
    }

    DashLineVertex* verts = reinterpret_cast<DashLineVertex*>(geo.vertices());

    int curVIdx = 0;

    if (SkPaint::kRound_Cap == cap && 0 != srcStrokeWidth) {
        // need to adjust this for round caps to correctly set the dashPos attrib on vertices
        startOffset -= halfDevStroke;
    }

    // Draw interior part of dashed line
    if (!lineDone) {
        SkPoint devicePts[2];
        vm.mapPoints(devicePts, ptsRot, 2);
        SkScalar lineLength = SkPoint::Distance(devicePts[0], devicePts[1]);
        if (hasCap) {
            lineLength += 2.f * halfDevStroke;
        }

        SkRect bounds;
        bounds.set(ptsRot[0].fX, ptsRot[0].fY, ptsRot[1].fX, ptsRot[1].fY);
        bounds.outset(bloatX + strokeAdj, bloatY + halfSrcStroke);
        setup_dashed_rect(bounds, verts, curVIdx, combinedMatrix, startOffset, devBloat,
                          lineLength, halfDevStroke);
        curVIdx += 4;
    }

    if (hasStartRect) {
        SkASSERT(useAA);  // so that we know bloatX and bloatY have been set
        startRect.outset(bloatX, bloatY);
        setup_dashed_rect(startRect, verts, curVIdx, combinedMatrix, startOffset, devBloat,
                          devIntervals[0], halfDevStroke);
        curVIdx += 4;
    }

    if (hasEndRect) {
        SkASSERT(useAA);  // so that we know bloatX and bloatY have been set
        endRect.outset(bloatX, bloatY);
        setup_dashed_rect(endRect, verts, curVIdx, combinedMatrix, startOffset, devBloat,
                          devIntervals[0], halfDevStroke);
    }

    target->setIndexSourceToBuffer(gpu->getContext()->getQuadIndexBuffer());
    target->drawIndexedInstances(kTriangles_GrPrimitiveType, totalRectCnt, 4, 6);
    target->resetIndexSource();
    return true;
}