C++ PaintInfo::context方法代码示例

void RenderWidget::paintContents(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    IntPoint contentPaintOffset = roundedIntPoint(paintOffset + location() + contentBoxRect().location());
    // Tell the widget to paint now. This is the only time the widget is allowed
    // to paint itself. That way it will composite properly with z-indexed layers.
    LayoutRect paintRect = paintInfo.rect;

    IntPoint widgetLocation = m_widget->frameRect().location();
    IntSize widgetPaintOffset = contentPaintOffset - widgetLocation;
    // When painting widgets into compositing layers, tx and ty are relative to the enclosing compositing layer,
    // not the root. In this case, shift the CTM and adjust the paintRect to be root-relative to fix plug-in drawing.
    if (!widgetPaintOffset.isZero()) {
        paintInfo.context().translate(widgetPaintOffset);
        paintRect.move(-widgetPaintOffset);
    }
    // FIXME: Remove repaintrect encolsing/integral snapping when RenderWidget becomes device pixel snapped.
    m_widget->paint(paintInfo.context(), snappedIntRect(paintRect));

    if (!widgetPaintOffset.isZero())
        paintInfo.context().translate(-widgetPaintOffset);

    if (is<FrameView>(*m_widget)) {
        FrameView& frameView = downcast<FrameView>(*m_widget);
        bool runOverlapTests = !frameView.useSlowRepaintsIfNotOverlapped();
        if (paintInfo.overlapTestRequests && runOverlapTests) {
            ASSERT(!paintInfo.overlapTestRequests->contains(this));
            paintInfo.overlapTestRequests->set(this, m_widget->frameRect());
        }
    }
}

void SVGInlineTextBox::paintSelectionBackground(PaintInfo& paintInfo)
{
    ASSERT(paintInfo.shouldPaintWithinRoot(renderer()));
    ASSERT(paintInfo.phase == PaintPhaseForeground || paintInfo.phase == PaintPhaseSelection);
    ASSERT(truncation() == cNoTruncation);

    if (renderer().style().visibility() != VISIBLE)
        return;

    auto& parentRenderer = parent()->renderer();
    ASSERT(!parentRenderer.document().printing());

    // Determine whether or not we're selected.
    bool paintSelectedTextOnly = paintInfo.phase == PaintPhaseSelection;
    bool hasSelection = selectionState() != RenderObject::SelectionNone;
    if (!hasSelection || paintSelectedTextOnly)
        return;

    Color backgroundColor = renderer().selectionBackgroundColor();
    if (!backgroundColor.isValid() || !backgroundColor.alpha())
        return;

    if (!textShouldBePainted(renderer()))
        return;

    RenderStyle& style = parentRenderer.style();

    int startPosition;
    int endPosition;
    std::tie(startPosition, endPosition) = selectionStartEnd();

    int fragmentStartPosition = 0;
    int fragmentEndPosition = 0;
    AffineTransform fragmentTransform;
    unsigned textFragmentsSize = m_textFragments.size();
    for (unsigned i = 0; i < textFragmentsSize; ++i) {
        SVGTextFragment& fragment = m_textFragments.at(i);
        ASSERT(!m_paintingResource);

        fragmentStartPosition = startPosition;
        fragmentEndPosition = endPosition;
        if (!mapStartEndPositionsIntoFragmentCoordinates(fragment, fragmentStartPosition, fragmentEndPosition))
            continue;

        GraphicsContextStateSaver stateSaver(paintInfo.context());
        fragment.buildFragmentTransform(fragmentTransform);
        if (!fragmentTransform.isIdentity())
            paintInfo.context().concatCTM(fragmentTransform);

        paintInfo.context().setFillColor(backgroundColor);
        paintInfo.context().fillRect(selectionRectForTextFragment(fragment, fragmentStartPosition, fragmentEndPosition, &style), backgroundColor);

        m_paintingResourceMode = ApplyToDefaultMode;
    }

    ASSERT(!m_paintingResource);
}

void paintFlow(const RenderBlockFlow& flow, const Layout& layout, PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    if (paintInfo.phase != PaintPhaseForeground)
        return;

    RenderStyle& style = flow.style();
    if (style.visibility() != VISIBLE)
        return;

    bool debugBordersEnabled = flow.frame().settings().simpleLineLayoutDebugBordersEnabled();

    TextPainter textPainter(paintInfo.context());
    textPainter.setFont(style.fontCascade());
    textPainter.setTextPaintStyle(computeTextPaintStyle(flow.frame(), style, paintInfo));

    Optional<TextDecorationPainter> textDecorationPainter;
    if (style.textDecorationsInEffect() != TextDecorationNone) {
        const RenderText* textRenderer = childrenOfType<RenderText>(flow).first();
        if (textRenderer) {
            textDecorationPainter = TextDecorationPainter(paintInfo.context(), style.textDecorationsInEffect(), *textRenderer, false);
            textDecorationPainter->setFont(style.fontCascade());
            textDecorationPainter->setBaseline(style.fontMetrics().ascent());
        }
    }

    LayoutRect paintRect = paintInfo.rect;
    paintRect.moveBy(-paintOffset);

    auto resolver = runResolver(flow, layout);
    float strokeOverflow = std::ceil(flow.style().textStrokeWidth());
    float deviceScaleFactor = flow.document().deviceScaleFactor();
    for (auto run : resolver.rangeForRect(paintRect)) {
        if (run.start() == run.end())
            continue;

        FloatRect rect = run.rect();
        FloatRect visualOverflowRect = rect;
        visualOverflowRect.inflate(strokeOverflow);
        if (paintRect.y() > visualOverflowRect.maxY() || paintRect.maxY() < visualOverflowRect.y())
            continue;

        TextRun textRun(run.text());
        textRun.setTabSize(!style.collapseWhiteSpace(), style.tabSize());
        // x position indicates the line offset from the rootbox. It's always 0 in case of simple line layout.
        textRun.setXPos(0);
        FloatPoint textOrigin = FloatPoint(rect.x() + paintOffset.x(), roundToDevicePixel(run.baselinePosition() + paintOffset.y(), deviceScaleFactor));
        textPainter.paintText(textRun, textRun.length(), rect, textOrigin);
        if (textDecorationPainter) {
            textDecorationPainter->setWidth(rect.width());
            textDecorationPainter->paintTextDecoration(textRun, textOrigin, rect.location() + paintOffset);
        }
        if (debugBordersEnabled)
            paintDebugBorders(paintInfo.context(), LayoutRect(run.rect()), paintOffset);
    }
}

// Utility to scale when the UI part are not scaled by wkDrawMediaUIPart
static FloatRect getUnzoomedRectAndAdjustCurrentContext(const RenderObject& o, const PaintInfo& paintInfo, const IntRect &originalRect)
{
    float zoomLevel = o.style().effectiveZoom();
    FloatRect unzoomedRect(originalRect);
    if (zoomLevel != 1.0f) {
        unzoomedRect.setWidth(unzoomedRect.width() / zoomLevel);
        unzoomedRect.setHeight(unzoomedRect.height() / zoomLevel);
        paintInfo.context().translate(unzoomedRect.x(), unzoomedRect.y());
        paintInfo.context().scale(FloatSize(zoomLevel, zoomLevel));
        paintInfo.context().translate(-unzoomedRect.x(), -unzoomedRect.y());
    }
    return unzoomedRect;
}

void RenderWidget::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    if (!shouldPaint(paintInfo, paintOffset))
        return;

    LayoutPoint adjustedPaintOffset = paintOffset + location();

    if (hasBoxDecorations() && (paintInfo.phase == PaintPhaseForeground || paintInfo.phase == PaintPhaseSelection))
        paintBoxDecorations(paintInfo, adjustedPaintOffset);

    if (paintInfo.phase == PaintPhaseMask) {
        paintMask(paintInfo, adjustedPaintOffset);
        return;
    }

    if ((paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseSelfOutline) && hasOutline())
        paintOutline(paintInfo, LayoutRect(adjustedPaintOffset, size()));

    if (paintInfo.phase != PaintPhaseForeground)
        return;

    if (style().hasBorderRadius()) {
        LayoutRect borderRect = LayoutRect(adjustedPaintOffset, size());

        if (borderRect.isEmpty())
            return;

        // Push a clip if we have a border radius, since we want to round the foreground content that gets painted.
        paintInfo.context().save();
        FloatRoundedRect roundedInnerRect = FloatRoundedRect(style().getRoundedInnerBorderFor(borderRect,
            paddingTop() + borderTop(), paddingBottom() + borderBottom(), paddingLeft() + borderLeft(), paddingRight() + borderRight(), true, true));
        clipRoundedInnerRect(paintInfo.context(), borderRect, roundedInnerRect);
    }

    if (m_widget)
        paintContents(paintInfo, paintOffset);

    if (style().hasBorderRadius())
        paintInfo.context().restore();

    // Paint a partially transparent wash over selected widgets.
    if (isSelected() && !document().printing()) {
        // FIXME: selectionRect() is in absolute, not painting coordinates.
        paintInfo.context().fillRect(snappedIntRect(selectionRect()), selectionBackgroundColor(), style().colorSpace());
    }

    if (hasLayer() && layer()->canResize())
        layer()->paintResizer(paintInfo.context(), roundedIntPoint(adjustedPaintOffset), paintInfo.rect);
}

// GraphicsContext::drawLine does not seem appropriate to draw menclose lines.
// To avoid unexpected behaviors and inconsistency with other notations, we just use strokePath.
static void drawLine(PaintInfo& info, const LayoutUnit& xStart, const LayoutUnit& yStart, const LayoutUnit& xEnd, const LayoutUnit& yEnd)
{
    Path line;
    line.moveTo(LayoutPoint(xStart, yStart));
    line.addLineTo(LayoutPoint(xEnd, yEnd));
    info.context().strokePath(line);
}

void RenderSVGShape::paint(PaintInfo& paintInfo, const LayoutPoint&)
{
    if (paintInfo.context().paintingDisabled() || paintInfo.phase != PaintPhaseForeground
        || style().visibility() == HIDDEN || isEmpty())
        return;
    FloatRect boundingBox = repaintRectInLocalCoordinates();
    if (!SVGRenderSupport::paintInfoIntersectsRepaintRect(boundingBox, m_localTransform, paintInfo))
        return;

    PaintInfo childPaintInfo(paintInfo);
    GraphicsContextStateSaver stateSaver(childPaintInfo.context());
    childPaintInfo.applyTransform(m_localTransform);

    if (childPaintInfo.phase == PaintPhaseForeground) {
        SVGRenderingContext renderingContext(*this, childPaintInfo);

        if (renderingContext.isRenderingPrepared()) {
            const SVGRenderStyle& svgStyle = style().svgStyle();
            if (svgStyle.shapeRendering() == SR_CRISPEDGES)
                childPaintInfo.context().setShouldAntialias(false);

            fillStrokeMarkers(childPaintInfo);
        }
    }

    if (style().outlineWidth())
        paintOutline(childPaintInfo, IntRect(boundingBox));
}

void RenderSnapshottedPlugIn::paintSnapshot(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    Image* image = m_snapshotResource->image().get();
    if (!image || image->isNull())
        return;

    LayoutUnit cWidth = contentWidth();
    LayoutUnit cHeight = contentHeight();
    if (!cWidth || !cHeight)
        return;

    GraphicsContext& context = paintInfo.context();

    LayoutSize contentSize(cWidth, cHeight);
    LayoutPoint contentLocation = location() + paintOffset;
    contentLocation.move(borderLeft() + paddingLeft(), borderTop() + paddingTop());

    LayoutRect rect(contentLocation, contentSize);
    IntRect alignedRect = snappedIntRect(rect);
    if (alignedRect.width() <= 0 || alignedRect.height() <= 0)
        return;

    InterpolationQuality interpolation = chooseInterpolationQuality(context, *image, image, alignedRect.size());
    ImageOrientationDescription orientationDescription(shouldRespectImageOrientation(), style().imageOrientation());
    context.drawImage(*image, alignedRect, ImagePaintingOptions(orientationDescription, interpolation));
}

void RenderSnapshottedPlugIn::paintSnapshot(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    Image* image = m_snapshotResource->image().get();
    if (!image || image->isNull())
        return;

    LayoutUnit cWidth = contentWidth();
    LayoutUnit cHeight = contentHeight();
    if (!cWidth || !cHeight)
        return;

    GraphicsContext& context = paintInfo.context();

    LayoutSize contentSize(cWidth, cHeight);
    LayoutPoint contentLocation = location() + paintOffset;
    contentLocation.move(borderLeft() + paddingLeft(), borderTop() + paddingTop());

    LayoutRect rect(contentLocation, contentSize);
    IntRect alignedRect = snappedIntRect(rect);
    if (alignedRect.width() <= 0 || alignedRect.height() <= 0)
        return;

    bool useLowQualityScaling = shouldPaintAtLowQuality(context, *image, image, alignedRect.size());

    ImageOrientationDescription orientationDescription(shouldRespectImageOrientation());
#if ENABLE(CSS_IMAGE_ORIENTATION)
    orientationDescription.setImageOrientationEnum(style().imageOrientation());
#endif
    context.drawImage(*image, alignedRect, ImagePaintingOptions(orientationDescription, useLowQualityScaling));
}

bool RenderTheme::paintDecorations(const RenderBox& box, const PaintInfo& paintInfo, const LayoutRect& rect)
{
    if (paintInfo.context().paintingDisabled())
        return false;

    IntRect integralSnappedRect = snappedIntRect(rect);
    FloatRect devicePixelSnappedRect = snapRectToDevicePixels(rect, box.document().deviceScaleFactor());

    // Call the appropriate paint method based off the appearance value.
    switch (box.style().appearance()) {
    case MenulistButtonPart:
        return paintMenuListButtonDecorations(box, paintInfo, devicePixelSnappedRect);
    case TextFieldPart:
        return paintTextFieldDecorations(box, paintInfo, devicePixelSnappedRect);
    case TextAreaPart:
        return paintTextAreaDecorations(box, paintInfo, devicePixelSnappedRect);
    case CheckboxPart:
        return paintCheckboxDecorations(box, paintInfo, integralSnappedRect);
    case RadioPart:
        return paintRadioDecorations(box, paintInfo, integralSnappedRect);
    case PushButtonPart:
        return paintPushButtonDecorations(box, paintInfo, integralSnappedRect);
    case SquareButtonPart:
        return paintSquareButtonDecorations(box, paintInfo, integralSnappedRect);
    case ButtonPart:
        return paintButtonDecorations(box, paintInfo, integralSnappedRect);
    case MenulistPart:
        return paintMenuListDecorations(box, paintInfo, integralSnappedRect);
    case SliderThumbHorizontalPart:
    case SliderThumbVerticalPart:
        return paintSliderThumbDecorations(box, paintInfo, integralSnappedRect);
    case SearchFieldPart:
        return paintSearchFieldDecorations(box, paintInfo, integralSnappedRect);
#if ENABLE(METER_ELEMENT)
    case MeterPart:
    case RelevancyLevelIndicatorPart:
    case ContinuousCapacityLevelIndicatorPart:
    case DiscreteCapacityLevelIndicatorPart:
    case RatingLevelIndicatorPart:
#endif
    case ProgressBarPart:
    case SliderHorizontalPart:
    case SliderVerticalPart:
    case ListboxPart:
    case DefaultButtonPart:
    case SearchFieldCancelButtonPart:
    case SearchFieldDecorationPart:
    case SearchFieldResultsDecorationPart:
    case SearchFieldResultsButtonPart:
#if ENABLE(SERVICE_CONTROLS)
    case ImageControlsButtonPart:
#endif
    default:
        break;
    }

    return false;
}

void RenderEmbeddedObject::paintReplaced(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    if (!showsUnavailablePluginIndicator())
        return;

    if (paintInfo.phase == PaintPhaseSelection)
        return;

    GraphicsContext& context = paintInfo.context();
    if (context.paintingDisabled())
        return;

    FloatRect contentRect;
    FloatRect indicatorRect;
    FloatRect replacementTextRect;
    FloatRect arrowRect;
    FontCascade font;
    TextRun run(emptyString());
    float textWidth;
    if (!getReplacementTextGeometry(paintOffset, contentRect, indicatorRect, replacementTextRect, arrowRect, font, run, textWidth))
        return;

    Path background;
    background.addRoundedRect(indicatorRect, FloatSize(replacementTextRoundedRectRadius, replacementTextRoundedRectRadius));

    GraphicsContextStateSaver stateSaver(context);
    context.clip(contentRect);
    context.setFillColor(m_unavailablePluginIndicatorIsPressed ? replacementTextRoundedRectPressedColor() : replacementTextRoundedRectColor());
    context.fillPath(background);

    Path strokePath;
    FloatRect strokeRect(indicatorRect);
    strokeRect.inflate(1);
    strokePath.addRoundedRect(strokeRect, FloatSize(replacementTextRoundedRectRadius + 1, replacementTextRoundedRectRadius + 1));

    context.setStrokeColor(unavailablePluginBorderColor());
    context.setStrokeThickness(2);
    context.strokePath(strokePath);

    const FontMetrics& fontMetrics = font.fontMetrics();
    float labelX = roundf(replacementTextRect.location().x() + replacementTextRoundedRectLeftTextMargin);
    float labelY = roundf(replacementTextRect.location().y() + (replacementTextRect.size().height() - fontMetrics.height()) / 2 + fontMetrics.ascent() + replacementTextRoundedRectTopTextMargin);
    context.setFillColor(replacementTextColor());
    context.drawBidiText(font, run, FloatPoint(labelX, labelY));

    if (shouldUnavailablePluginMessageBeButton(document(), m_pluginUnavailabilityReason)) {
        arrowRect.inflate(-replacementArrowCirclePadding);

        context.beginTransparencyLayer(1.0);
        context.setFillColor(replacementTextColor());
        context.fillEllipse(arrowRect);

        context.setCompositeOperation(CompositeClear);
        drawReplacementArrow(context, arrowRect);
        context.endTransparencyLayer();
    }
}

void RenderSVGShape::fillStrokeMarkers(PaintInfo& childPaintInfo)
{
    auto paintOrder = style().svgStyle().paintTypesForPaintOrder();
    for (unsigned i = 0; i < paintOrder.size(); ++i) {
        switch (paintOrder.at(i)) {
        case PaintTypeFill:
            fillShape(style(), childPaintInfo.context());
            break;
        case PaintTypeStroke:
            strokeShape(childPaintInfo.context());
            break;
        case PaintTypeMarkers:
            if (!m_markerPositions.isEmpty())
                drawMarkers(childPaintInfo);
            break;
        }
    }
}

void RenderFieldset::paintBoxDecorations(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    if (!paintInfo.shouldPaintWithinRoot(*this))
        return;

    LayoutRect paintRect(paintOffset, size());
    RenderBox* legend = findLegend();
    if (!legend)
        return RenderBlockFlow::paintBoxDecorations(paintInfo, paintOffset);

    // FIXME: We need to work with "rl" and "bt" block flow directions.  In those
    // cases the legend is embedded in the right and bottom borders respectively.
    // https://bugs.webkit.org/show_bug.cgi?id=47236
    if (style().isHorizontalWritingMode()) {
        LayoutUnit yOff = (legend->y() > 0) ? LayoutUnit() : (legend->height() - borderTop()) / 2;
        paintRect.setHeight(paintRect.height() - yOff);
        paintRect.setY(paintRect.y() + yOff);
    } else {
        LayoutUnit xOff = (legend->x() > 0) ? LayoutUnit() : (legend->width() - borderLeft()) / 2;
        paintRect.setWidth(paintRect.width() - xOff);
        paintRect.setX(paintRect.x() + xOff);
    }

    if (!boxShadowShouldBeAppliedToBackground(paintRect.location(), determineBackgroundBleedAvoidance(paintInfo.context())))
        paintBoxShadow(paintInfo, paintRect, style(), Normal);
    paintFillLayers(paintInfo, style().visitedDependentColor(CSSPropertyBackgroundColor), style().backgroundLayers(), paintRect);
    paintBoxShadow(paintInfo, paintRect, style(), Inset);

    if (!style().hasBorder())
        return;
    
    // Create a clipping region around the legend and paint the border as normal
    GraphicsContext& graphicsContext = paintInfo.context();
    GraphicsContextStateSaver stateSaver(graphicsContext);

    // FIXME: We need to work with "rl" and "bt" block flow directions.  In those
    // cases the legend is embedded in the right and bottom borders respectively.
    // https://bugs.webkit.org/show_bug.cgi?id=47236
    LayoutRect clipRect;
    if (style().isHorizontalWritingMode()) {
        clipRect.setX(paintRect.x() + legend->x());
        clipRect.setY(paintRect.y());
        clipRect.setWidth(legend->width());
        clipRect.setHeight(std::max<LayoutUnit>(style().borderTopWidth(), legend->height() - ((legend->height() - borderTop()) / 2)));
    } else {
        clipRect.setX(paintRect.x());
        clipRect.setY(paintRect.y() + legend->y());
        clipRect.setWidth(std::max<LayoutUnit>(style().borderLeftWidth(), legend->width()));
        clipRect.setHeight(legend->height());
    }
    graphicsContext.clipOut(snapRectToDevicePixels(clipRect, document().deviceScaleFactor()));

    paintBorder(paintInfo, paintRect, style());
}

void RenderMathMLToken::paint(PaintInfo& info, const LayoutPoint& paintOffset)
{
    RenderMathMLBlock::paint(info, paintOffset);

    // FIXME: Instead of using DrawGlyph, we may consider using the more general TextPainter so that we can apply mathvariant to strings with an arbitrary number of characters and preserve advanced CSS effects (text-shadow, etc).
    if (info.context().paintingDisabled() || info.phase != PaintPhaseForeground || style().visibility() != VISIBLE || !m_mathVariantCodePoint)
        return;

    auto mathVariantGlyph = style().fontCascade().glyphDataForCharacter(m_mathVariantCodePoint.value(), m_mathVariantIsMirrored);
    if (!mathVariantGlyph.font)
        return;

    GraphicsContextStateSaver stateSaver(info.context());
    info.context().setFillColor(style().visitedDependentColor(CSSPropertyColor));

    GlyphBuffer buffer;
    buffer.add(mathVariantGlyph.glyph, mathVariantGlyph.font, mathVariantGlyph.font->widthForGlyph(mathVariantGlyph.glyph));
    LayoutUnit glyphAscent = static_cast<int>(lroundf(-mathVariantGlyph.font->boundsForGlyph(mathVariantGlyph.glyph).y()));
    info.context().drawGlyphs(style().fontCascade(), *mathVariantGlyph.font, buffer, 0, 1, paintOffset + location() + LayoutPoint(0, glyphAscent));
}

void RenderMathMLRoot::paint(PaintInfo& info, const LayoutPoint& paintOffset)
{
    RenderMathMLRow::paint(info, paintOffset);

    if (!firstChild() || info.context().paintingDisabled() || style().visibility() != VISIBLE || !isValid())
        return;

    // We draw the radical operator.
    LayoutPoint radicalOperatorTopLeft = paintOffset + location();
    LayoutUnit horizontalOffset = 0;
    if (m_kind == RootWithIndex)
        horizontalOffset = m_kernBeforeDegree + getIndex().logicalWidth() + m_kernAfterDegree;
    radicalOperatorTopLeft.move(mirrorIfNeeded(horizontalOffset, m_radicalOperator.width()), m_radicalOperatorTop);
    m_radicalOperator.paint(style(), info, radicalOperatorTopLeft);

    // We draw the radical line.
    if (!m_ruleThickness)
        return;
    GraphicsContextStateSaver stateSaver(info.context());

    info.context().setStrokeThickness(m_ruleThickness);
    info.context().setStrokeStyle(SolidStroke);
    info.context().setStrokeColor(style().visitedDependentColor(CSSPropertyColor));
    LayoutPoint ruleOffsetFrom = paintOffset + location() + LayoutPoint(0, m_radicalOperatorTop + m_ruleThickness / 2);
    LayoutPoint ruleOffsetTo = ruleOffsetFrom;
    horizontalOffset += m_radicalOperator.width();
    ruleOffsetFrom.move(mirrorIfNeeded(horizontalOffset), 0);
    horizontalOffset += m_baseWidth;
    ruleOffsetTo.move(mirrorIfNeeded(horizontalOffset), 0);
    info.context().drawLine(ruleOffsetFrom, ruleOffsetTo);
}