C++ LayoutSize类代码示例

LayoutRect RenderReplaced::replacedContentRect(const LayoutSize* overriddenIntrinsicSize) const
{
    LayoutRect contentRect = contentBoxRect();
    ObjectFit objectFit = style()->objectFit();

    if (objectFit == ObjectFitFill && style()->objectPosition() == RenderStyle::initialObjectPosition())
        objectFit = ObjectFitContain;

    LayoutSize intrinsicSize = overriddenIntrinsicSize ? *overriddenIntrinsicSize : this->intrinsicSize();
    if (!intrinsicSize.width() || !intrinsicSize.height())
        return contentRect;

    LayoutRect finalRect = contentRect;
    switch (objectFit) {
    case ObjectFitContain:
    case ObjectFitScaleDown:
    case ObjectFitCover:
        finalRect.setSize(finalRect.size().fitToAspectRatio(intrinsicSize, objectFit == ObjectFitCover ? AspectRatioFitGrow : AspectRatioFitShrink));
        if (objectFit != ObjectFitScaleDown || finalRect.width() <= intrinsicSize.width())
            break;
        // fall through
    case ObjectFitNone:
        finalRect.setSize(intrinsicSize);
        break;
    case ObjectFitFill:
        break;
    default:
        ASSERT_NOT_REACHED();
    }

    LayoutUnit xOffset = minimumValueForLength(style()->objectPosition().x(), contentRect.width() - finalRect.width());
    LayoutUnit yOffset = minimumValueForLength(style()->objectPosition().y(), contentRect.height() - finalRect.height());
    finalRect.move(xOffset, yOffset);

    return finalRect;
}

LayoutSize RenderVideo::calculateIntrinsicSize()
{
    // Spec text from 4.8.6
    //
    // The intrinsic width of a video element's playback area is the intrinsic width 
    // of the video resource, if that is available; otherwise it is the intrinsic 
    // width of the poster frame, if that is available; otherwise it is 300 CSS pixels.
    //
    // The intrinsic height of a video element's playback area is the intrinsic height 
    // of the video resource, if that is available; otherwise it is the intrinsic 
    // height of the poster frame, if that is available; otherwise it is 150 CSS pixels.
    MediaPlayer* player = videoElement().player();
    if (player && videoElement().readyState() >= HTMLVideoElement::HAVE_METADATA) {
        LayoutSize size = player->naturalSize();
        if (!size.isEmpty())
            return size;
    }

    if (videoElement().shouldDisplayPosterImage() && !m_cachedImageSize.isEmpty() && !imageResource()->errorOccurred())
        return m_cachedImageSize;

    // When the natural size of the video is unavailable, we use the provided
    // width and height attributes of the video element as the intrinsic size until
    // better values become available.
    if (videoElement().hasAttribute(widthAttr) && videoElement().hasAttribute(heightAttr))
        return LayoutSize(videoElement().width(), videoElement().height());

    // <video> in standalone media documents should not use the default 300x150
    // size since they also have audio-only files. By setting the intrinsic
    // size to 300x1 the video will resize itself in these cases, and audio will
    // have the correct height (it needs to be > 0 for controls to render properly).
    if (videoElement().document().isMediaDocument())
        return LayoutSize(defaultSize().width(), 1);

    return defaultSize();
}

void RenderImage::layoutShadowControls(const LayoutSize& oldSize)
{
    auto* controlsRenderer = downcast<RenderBox>(firstChild());
    if (!controlsRenderer)
        return;
    
    bool controlsNeedLayout = controlsRenderer->needsLayout();
    // If the region chain has changed we also need to relayout the controls to update the region box info.
    // FIXME: We can do better once we compute region box info for RenderReplaced, not only for RenderBlock.
    const RenderFlowThread* flowThread = flowThreadContainingBlock();
    if (flowThread && !controlsNeedLayout) {
        if (flowThread->pageLogicalSizeChanged())
            controlsNeedLayout = true;
    }

    LayoutSize newSize = contentBoxRect().size();
    if (newSize == oldSize && !controlsNeedLayout)
        return;

    // When calling layout() on a child node, a parent must either push a LayoutStateMaintainter, or 
    // instantiate LayoutStateDisabler. Since using a LayoutStateMaintainer is slightly more efficient,
    // and this method might be called many times per second during video playback, use a LayoutStateMaintainer:
    LayoutStateMaintainer statePusher(view(), *this, locationOffset(), hasTransform() || hasReflection() || style().isFlippedBlocksWritingMode());

    if (shadowControlsNeedCustomLayoutMetrics()) {
        controlsRenderer->setLocation(LayoutPoint(borderLeft(), borderTop()) + LayoutSize(paddingLeft(), paddingTop()));
        controlsRenderer->style().setHeight(Length(newSize.height(), Fixed));
        controlsRenderer->style().setWidth(Length(newSize.width(), Fixed));
    }

    controlsRenderer->setNeedsLayout(MarkOnlyThis);
    controlsRenderer->layout();
    clearChildNeedsLayout();

    statePusher.pop();
}

void ImageDocument::imageUpdated()
{
    ASSERT(m_imageElement);

    if (m_imageSizeIsKnown)
        return;

    LayoutSize imageSize = this->imageSize();
    if (imageSize.isEmpty())
        return;

    m_imageSizeIsKnown = true;

    if (m_shouldShrinkImage) {
#if PLATFORM(IOS)
        FloatSize screenSize = page()->chrome().screenSize();
        if (imageSize.width() > screenSize.width())
            processViewport(String::format("width=%u", static_cast<unsigned>(imageSize.width().toInt())), ViewportArguments::ImageDocument);
#else
        // Call windowSizeChanged for its side effect of sizing the image.
        windowSizeChanged();
#endif
    }
}

void RenderGeometryMap::push(const RenderObject* renderer, const LayoutSize& offsetFromContainer, bool accumulatingTransform, bool isNonUniform, bool isFixedPosition, bool hasTransform, LayoutSize offsetForFixedPosition)
{
//    fprintf(stderr, "RenderGeometryMap::push %p %d,%d isNonUniform=%d\n", renderer, offsetFromContainer.width().toInt(), offsetFromContainer.height().toInt(), isNonUniform);

    ASSERT(m_insertionPosition != kNotFound);
    ASSERT(!renderer->isRenderView() || !m_insertionPosition || m_mapCoordinatesFlags & TraverseDocumentBoundaries);
    ASSERT(offsetForFixedPosition.isZero() || renderer->isRenderView());

    m_mapping.insert(m_insertionPosition, RenderGeometryMapStep(renderer, accumulatingTransform, isNonUniform, isFixedPosition, hasTransform));

    RenderGeometryMapStep& step = m_mapping[m_insertionPosition];
    step.m_offset = offsetFromContainer;
    step.m_offsetForFixedPosition = offsetForFixedPosition;

    stepInserted(step);
}

void LayoutGeometryMap::push(const LayoutObject* layoutObject, const LayoutSize& offsetFromContainer, GeometryInfoFlags flags, LayoutSize offsetForFixedPosition)
{
    LAYOUT_GEOMETRY_MAP_LOG("LayoutGeometryMap::push %p %d,%d isNonUniform=%d\n", layoutObject, offsetFromContainer.width().toInt(), offsetFromContainer.height().toInt(), isNonUniform);

    ASSERT(m_insertionPosition != kNotFound);
    ASSERT(!layoutObject->isLayoutView() || !m_insertionPosition || m_mapCoordinatesFlags & TraverseDocumentBoundaries);
    ASSERT(offsetForFixedPosition.isZero() || layoutObject->isLayoutView());

    m_mapping.insert(m_insertionPosition, LayoutGeometryMapStep(layoutObject, flags));

    LayoutGeometryMapStep& step = m_mapping[m_insertionPosition];
    step.m_offset = offsetFromContainer;
    step.m_offsetForFixedPosition = offsetForFixedPosition;

    stepInserted(step);
}

void RenderGeometryMap::push(const RenderObject* renderer, const TransformationMatrix& t, bool accumulatingTransform, bool isNonUniform, bool isFixedPosition, bool hasTransform, LayoutSize offsetForFixedPosition)
{
    ASSERT(m_insertionPosition != kNotFound);
    ASSERT(!renderer->isRenderView() || !m_insertionPosition || m_mapCoordinatesFlags & TraverseDocumentBoundaries);
    ASSERT(offsetForFixedPosition.isZero() || renderer->isRenderView());

    m_mapping.insert(m_insertionPosition, RenderGeometryMapStep(renderer, accumulatingTransform, isNonUniform, isFixedPosition, hasTransform));

    RenderGeometryMapStep& step = m_mapping[m_insertionPosition];
    step.m_offsetForFixedPosition = offsetForFixedPosition;

    if (!t.isIntegerTranslation())
        step.m_transform = adoptPtr(new TransformationMatrix(t));
    else
        step.m_offset = LayoutSize(t.e(), t.f());

    stepInserted(step);
}

void CachedImage::setContainerSizeForRenderer(const CachedImageClient* renderer, const LayoutSize& containerSize, float containerZoom)
{
    if (containerSize.isEmpty())
        return;
    ASSERT(renderer);
    ASSERT(containerZoom);
    if (!m_image) {
        m_pendingContainerSizeRequests.set(renderer, SizeAndZoom(containerSize, containerZoom));
        return;
    }

    if (!m_image->isSVGImage()) {
        m_image->setContainerSize(containerSize);
        return;
    }

    m_svgImageCache->setContainerSizeForRenderer(renderer, containerSize, containerZoom);
}

bool ImageDocument::imageFitsInWindow()
{
    if (!m_imageElement)
        return true;

    FrameView* view = this->view();
    if (!view)
        return true;

    LayoutSize imageSize = this->imageSize();
    LayoutSize windowSize = LayoutSize(view->width(), view->height());
    return imageSize.width() <= windowSize.width() && imageSize.height() <= windowSize.height();
}

LayoutRect RenderSnapshottedPlugIn::tryToFitStartLabel(LabelSize size, const LayoutRect& contentBox) const
{
    Image* labelImage = startLabelImage(size);
    if (!labelImage)
        return LayoutRect();

    // Assume that the labelImage has been provided to match our device scale.
    float scaleFactor = 1;
    if (document()->page())
        scaleFactor = document()->page()->deviceScaleFactor();
    IntSize labelImageSize = labelImage->size();
    labelImageSize.scale(1 / (scaleFactor ? scaleFactor : 1));

    LayoutSize labelSize = labelImageSize - LayoutSize(2 * startLabelInset, 2 * startLabelInset);
    LayoutRect candidateRect(contentBox.maxXMinYCorner() + LayoutSize(-startLabelPadding, startLabelPadding) + LayoutSize(-labelSize.width(), 0), labelSize);
    // The minimum allowed content box size is the label image placed in the center of the box, surrounded by startLabelPadding.
    if (candidateRect.x() < startLabelPadding || candidateRect.maxY() > contentBox.height() - startLabelPadding)
        return LayoutRect();
    return candidateRect;
}

void ShapeOutsideInfo::setReferenceBoxLogicalSize(
    LayoutSize newReferenceBoxLogicalSize) {
  bool isHorizontalWritingMode =
      m_layoutBox.containingBlock()->style()->isHorizontalWritingMode();
  switch (referenceBox(*m_layoutBox.style()->shapeOutside())) {
    case MarginBox:
      if (isHorizontalWritingMode)
        newReferenceBoxLogicalSize.expand(m_layoutBox.marginWidth(),
                                          m_layoutBox.marginHeight());
      else
        newReferenceBoxLogicalSize.expand(m_layoutBox.marginHeight(),
                                          m_layoutBox.marginWidth());
      break;
    case BorderBox:
      break;
    case PaddingBox:
      if (isHorizontalWritingMode)
        newReferenceBoxLogicalSize.shrink(m_layoutBox.borderWidth(),
                                          m_layoutBox.borderHeight());
      else
        newReferenceBoxLogicalSize.shrink(m_layoutBox.borderHeight(),
                                          m_layoutBox.borderWidth());
      break;
    case ContentBox:
      if (isHorizontalWritingMode)
        newReferenceBoxLogicalSize.shrink(m_layoutBox.borderAndPaddingWidth(),
                                          m_layoutBox.borderAndPaddingHeight());
      else
        newReferenceBoxLogicalSize.shrink(m_layoutBox.borderAndPaddingHeight(),
                                          m_layoutBox.borderAndPaddingWidth());
      break;
    case BoxMissing:
      ASSERT_NOT_REACHED();
      break;
  }

  newReferenceBoxLogicalSize.clampNegativeToZero();

  if (m_referenceBoxLogicalSize == newReferenceBoxLogicalSize)
    return;
  markShapeAsDirty();
  m_referenceBoxLogicalSize = newReferenceBoxLogicalSize;
}

bool ImageDocument::imageFitsInWindow() const
{
    ASSERT(m_shrinkToFitMode == Desktop);

    if (!m_imageElement || m_imageElement->document() != this)
        return true;

    FrameView* view = frame()->view();
    if (!view)
        return true;

    ASSERT(m_imageElement->cachedImage());
    LayoutSize imageSize = m_imageElement->cachedImage()->imageSizeForLayoutObject(m_imageElement->layoutObject(), pageZoomFactor(this));
    LayoutSize windowSize = LayoutSize(view->width(), view->height());

    return imageSize.width() <= windowSize.width() && imageSize.height() <= windowSize.height();
}

float ImageDocument::scale() const
{
    if (!m_imageElement || m_imageElement->document() != this)
        return 1.0f;

    FrameView* view = frame()->view();
    if (!view)
        return 1;

    ASSERT(m_imageElement->cachedImage());
    LayoutSize imageSize = m_imageElement->cachedImage()->imageSizeForLayoutObject(m_imageElement->layoutObject(), pageZoomFactor(this));
    LayoutSize windowSize = LayoutSize(view->width(), view->height());

    float widthScale = windowSize.width().toFloat() / imageSize.width().toFloat();
    float heightScale = windowSize.height().toFloat() / imageSize.height().toFloat();

    return min(widthScale, heightScale);
}

LayoutSize RenderBoxModelObject::relativePositionOffset() const
{
    LayoutSize offset = accumulateInFlowPositionOffsets(this);

    RenderBlock* containingBlock = this->containingBlock();

    // Objects that shrink to avoid floats normally use available line width when computing containing block width.  However
    // in the case of relative positioning using percentages, we can't do this.  The offset should always be resolved using the
    // available width of the containing block.  Therefore we don't use containingBlockLogicalWidthForContent() here, but instead explicitly
    // call availableWidth on our containing block.
    if (!style()->left().isAuto()) {
        if (!style()->right().isAuto() && !containingBlock->style()->isLeftToRightDirection())
            offset.setWidth(-valueForLength(style()->right(), containingBlock->availableWidth()));
        else
            offset.expand(valueForLength(style()->left(), containingBlock->availableWidth()), 0);
    } else if (!style()->right().isAuto()) {
        offset.expand(-valueForLength(style()->right(), containingBlock->availableWidth()), 0);
    }

    // If the containing block of a relatively positioned element does not
    // specify a height, a percentage top or bottom offset should be resolved as
    // auto. An exception to this is if the containing block has the WinIE quirk
    // where <html> and <body> assume the size of the viewport. In this case,
    // calculate the percent offset based on this height.
    // See <https://bugs.webkit.org/show_bug.cgi?id=26396>.
    if (!style()->top().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->top().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, valueForLength(style()->top(), containingBlock->availableHeight()));

    else if (!style()->bottom().isAuto()
        && (!containingBlock->hasAutoHeightOrContainingBlockWithAutoHeight()
            || !style()->bottom().isPercent()
            || containingBlock->stretchesToViewport()))
        offset.expand(0, -valueForLength(style()->bottom(), containingBlock->availableHeight()));

    return offset;
}

void ShapeOutsideInfo::setReferenceBoxLogicalSize(LayoutSize newReferenceBoxLogicalSize)
{
    bool isHorizontalWritingMode = m_renderer.containingBlock()->style().isHorizontalWritingMode();
    switch (referenceBox(*m_renderer.style().shapeOutside())) {
    case MarginBox:
        if (isHorizontalWritingMode)
            newReferenceBoxLogicalSize.expand(m_renderer.horizontalMarginExtent(), m_renderer.verticalMarginExtent());
        else
            newReferenceBoxLogicalSize.expand(m_renderer.verticalMarginExtent(), m_renderer.horizontalMarginExtent());
        break;
    case BorderBox:
        break;
    case PaddingBox:
        if (isHorizontalWritingMode)
            newReferenceBoxLogicalSize.shrink(m_renderer.horizontalBorderExtent(), m_renderer.verticalBorderExtent());
        else
            newReferenceBoxLogicalSize.shrink(m_renderer.verticalBorderExtent(), m_renderer.horizontalBorderExtent());
        break;
    case ContentBox:
        if (isHorizontalWritingMode)
            newReferenceBoxLogicalSize.shrink(m_renderer.horizontalBorderAndPaddingExtent(), m_renderer.verticalBorderAndPaddingExtent());
        else
            newReferenceBoxLogicalSize.shrink(m_renderer.verticalBorderAndPaddingExtent(), m_renderer.horizontalBorderAndPaddingExtent());
        break;
    case Fill:
    case Stroke:
    case ViewBox:
    case BoxMissing:
        ASSERT_NOT_REACHED();
        break;
    }

    if (m_referenceBoxLogicalSize == newReferenceBoxLogicalSize)
        return;
    markShapeAsDirty();
    m_referenceBoxLogicalSize = newReferenceBoxLogicalSize;
}