flutter_flutter/sky/engine/core/rendering/RenderReplaced.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
 * Copyright (C) Research In Motion Limited 2011-2012. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "flutter/sky/engine/core/rendering/RenderReplaced.h"

#include "flutter/sky/engine/core/rendering/RenderBlock.h"
#include "flutter/sky/engine/core/rendering/RenderLayer.h"
#include "flutter/sky/engine/core/rendering/RenderView.h"
#include "flutter/sky/engine/platform/LengthFunctions.h"
#include "flutter/sky/engine/platform/graphics/GraphicsContext.h"

namespace blink {

const int RenderReplaced::defaultWidth = 300;
const int RenderReplaced::defaultHeight = 150;

RenderReplaced::RenderReplaced()
    : m_intrinsicSize(defaultWidth, defaultHeight) {
  setReplaced(true);
}

RenderReplaced::RenderReplaced(const LayoutSize& intrinsicSize)
    : m_intrinsicSize(intrinsicSize) {
  setReplaced(true);
}

RenderReplaced::~RenderReplaced() {}

void RenderReplaced::willBeDestroyed() {
  if (!documentBeingDestroyed() && parent())
    parent()->dirtyLinesFromChangedChild(this);

  RenderBox::willBeDestroyed();
}

void RenderReplaced::layout() {
  ASSERT(needsLayout());

  setHeight(minimumReplacedHeight());

  updateLogicalWidth();
  updateLogicalHeight();

  m_overflow.clear();
  addVisualEffectOverflow();
  updateLayerTransformAfterLayout();

  clearNeedsLayout();
}

void RenderReplaced::intrinsicSizeChanged() {
  m_intrinsicSize = IntSize(defaultWidth, defaultHeight);
  setNeedsLayoutAndPrefWidthsRecalc();
}

void RenderReplaced::paint(PaintInfo& paintInfo,
                           const LayoutPoint& paintOffset,
                           Vector<RenderBox*>& layers) {
  if (!shouldPaint(paintInfo, paintOffset))
    return;

  LayoutPoint adjustedPaintOffset = paintOffset + location();

  if (hasBoxDecorationBackground())
    paintBoxDecorationBackground(paintInfo, adjustedPaintOffset);

  LayoutRect paintRect = LayoutRect(adjustedPaintOffset, size());

  bool completelyClippedOut = false;
  if (style()->hasBorderRadius()) {
    LayoutRect borderRect = LayoutRect(adjustedPaintOffset, size());

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

  if (!completelyClippedOut) {
    paintReplaced(paintInfo, adjustedPaintOffset);
    if (style()->hasBorderRadius())
      paintInfo.context->restore();
  }

  // The selection tint never gets clipped by border-radius rounding, since we
  // want it to run right up to the edges of surrounding content.
  if (selectionState() != SelectionNone) {
    LayoutRect selectionPaintingRect = localSelectionRect();
    selectionPaintingRect.moveBy(adjustedPaintOffset);
    paintInfo.context->fillRect(pixelSnappedIntRect(selectionPaintingRect),
                                selectionBackgroundColor());
  }
}

bool RenderReplaced::shouldPaint(PaintInfo& paintInfo,
                                 const LayoutPoint& paintOffset) {
  LayoutPoint adjustedPaintOffset = paintOffset + location();

  // Early exit if the element touches the edges.
  LayoutUnit top = adjustedPaintOffset.y() + visualOverflowRect().y();
  LayoutUnit bottom = adjustedPaintOffset.y() + visualOverflowRect().maxY();
  if (isSelected() && inlineBoxWrapper()) {
    LayoutUnit selTop =
        paintOffset.y() + inlineBoxWrapper()->root().selectionTop();
    LayoutUnit selBottom =
        paintOffset.y() + selTop + inlineBoxWrapper()->root().selectionHeight();
    top = std::min(selTop, top);
    bottom = std::max(selBottom, bottom);
  }

  if (adjustedPaintOffset.x() + visualOverflowRect().x() >=
          paintInfo.rect.maxX() ||
      adjustedPaintOffset.x() + visualOverflowRect().maxX() <=
          paintInfo.rect.x())
    return false;

  if (top >= paintInfo.rect.maxY() || bottom <= paintInfo.rect.y())
    return false;

  return true;
}

bool RenderReplaced::hasReplacedLogicalHeight() const {
  if (style()->logicalHeight().isAuto())
    return false;

  if (style()->logicalHeight().isSpecified()) {
    if (hasAutoHeightOrContainingBlockWithAutoHeight())
      return false;
    return true;
  }

  if (style()->logicalHeight().isIntrinsic())
    return true;

  return false;
}

bool RenderReplaced::needsPreferredWidthsRecalculation() const {
  // If the height is a percentage and the width is auto, then the
  // containingBlocks's height changing can cause this node to change it's
  // preferred width because it maintains aspect ratio.
  return hasRelativeLogicalHeight() && style()->logicalWidth().isAuto() &&
         !hasAutoHeightOrContainingBlockWithAutoHeight();
}

static inline bool rendererHasAspectRatio(const RenderObject* renderer) {
  ASSERT(renderer);
  return renderer->isImage() || renderer->isCanvas();
}

void RenderReplaced::computeAspectRatioInformationForRenderBox(
    FloatSize& constrainedSize,
    double& intrinsicRatio) const {
  FloatSize intrinsicSize;
  computeIntrinsicRatioInformation(intrinsicSize, intrinsicRatio);
  if (intrinsicRatio && !intrinsicSize.isEmpty())
    m_intrinsicSize = LayoutSize(intrinsicSize);

  // Now constrain the intrinsic size along each axis according to minimum and
  // maximum width/heights along the opposite axis. So for example a maximum
  // width that shrinks our width will result in the height we compute here
  // having to shrink in order to preserve the aspect ratio. Because we compute
  // these values independently along each axis, the final returned size may in
  // fact not preserve the aspect ratio.
  // FIXME: In the long term, it might be better to just return this code more
  // to the way it used to be before this function was added, since all it has
  // done is make the code more unclear.
  constrainedSize = intrinsicSize;
  if (intrinsicRatio && !intrinsicSize.isEmpty() &&
      style()->logicalWidth().isAuto() && style()->logicalHeight().isAuto()) {
    // We can't multiply or divide by 'intrinsicRatio' here, it breaks tests,
    // like fast/images/zoomed-img-size.html, which can only be fixed once
    // subpixel precision is available for things like intrinsicWidth/Height.
    constrainedSize.setWidth(RenderBox::computeReplacedLogicalHeight() *
                             intrinsicSize.width() / intrinsicSize.height());
    constrainedSize.setHeight(RenderBox::computeReplacedLogicalWidth() *
                              intrinsicSize.height() / intrinsicSize.width());
  }
}

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;
}

void RenderReplaced::computeIntrinsicRatioInformation(
    FloatSize& intrinsicSize,
    double& intrinsicRatio) const {
  intrinsicSize = FloatSize(intrinsicLogicalWidth().toFloat(),
                            intrinsicLogicalHeight().toFloat());

  // Figure out if we need to compute an intrinsic ratio.
  if (intrinsicSize.isEmpty() || !rendererHasAspectRatio(this))
    return;

  intrinsicRatio = intrinsicSize.width() / intrinsicSize.height();
}

LayoutUnit RenderReplaced::computeReplacedLogicalWidth(
    ShouldComputePreferred shouldComputePreferred) const {
  if (style()->logicalWidth().isSpecified() ||
      style()->logicalWidth().isIntrinsic())
    return computeReplacedLogicalWidthRespectingMinMaxWidth(
        computeReplacedLogicalWidthUsing(style()->logicalWidth()),
        shouldComputePreferred);

  // 10.3.2 Inline, replaced elements:
  // http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-width
  double intrinsicRatio = 0;
  FloatSize constrainedSize;
  computeAspectRatioInformationForRenderBox(constrainedSize, intrinsicRatio);

  if (style()->logicalWidth().isAuto()) {
    bool computedHeightIsAuto = hasAutoHeightOrContainingBlockWithAutoHeight();
    bool hasIntrinsicWidth = constrainedSize.width() > 0;

    // If 'height' and 'width' both have computed values of 'auto' and the
    // element also has an intrinsic width, then that intrinsic width is the
    // used value of 'width'.
    if (computedHeightIsAuto && hasIntrinsicWidth)
      return computeReplacedLogicalWidthRespectingMinMaxWidth(
          constrainedSize.width(), shouldComputePreferred);

    bool hasIntrinsicHeight = constrainedSize.height() > 0;
    if (intrinsicRatio) {
      // If 'height' and 'width' both have computed values of 'auto' and the
      // element has no intrinsic width, but does have an intrinsic height and
      // intrinsic ratio; or if 'width' has a computed value of 'auto', 'height'
      // has some other computed value, and the element does have an intrinsic
      // ratio; then the used value of 'width' is: (used height) * (intrinsic
      // ratio)
      if (intrinsicRatio &&
          ((computedHeightIsAuto && !hasIntrinsicWidth && hasIntrinsicHeight) ||
           !computedHeightIsAuto)) {
        LayoutUnit logicalHeight = computeReplacedLogicalHeight();
        return computeReplacedLogicalWidthRespectingMinMaxWidth(
            roundToInt(round(logicalHeight * intrinsicRatio)),
            shouldComputePreferred);
      }

      // If 'height' and 'width' both have computed values of 'auto' and the
      // element has an intrinsic ratio but no intrinsic height or width, then
      // the used value of 'width' is undefined in CSS 2.1. However, it is
      // suggested that, if the containing block's width does not itself depend
      // on the replaced element's width, then the used value of 'width' is
      // calculated from the constraint equation used for block-level,
      // non-replaced elements in normal flow.
      if (computedHeightIsAuto && !hasIntrinsicWidth && !hasIntrinsicHeight) {
        if (shouldComputePreferred == ComputePreferred)
          return 0;
        // The aforementioned 'constraint equation' used for block-level,
        // non-replaced elements in normal flow: 'margin-left' +
        // 'border-left-width' + 'padding-left' + 'width' + 'padding-right' +
        // 'border-right-width' + 'margin-right' = width of containing block
        LayoutUnit logicalWidth = containingBlock()->availableLogicalWidth();

        // This solves above equation for 'width' (== logicalWidth).
        LayoutUnit marginStart =
            minimumValueForLength(style()->marginStart(), logicalWidth);
        LayoutUnit marginEnd =
            minimumValueForLength(style()->marginEnd(), logicalWidth);
        logicalWidth = std::max<LayoutUnit>(
            0, logicalWidth -
                   (marginStart + marginEnd + (width() - clientWidth())));
        return computeReplacedLogicalWidthRespectingMinMaxWidth(
            logicalWidth, shouldComputePreferred);
      }
    }

    // Otherwise, if 'width' has a computed value of 'auto', and the element has
    // an intrinsic width, then that intrinsic width is the used value of
    // 'width'.
    if (hasIntrinsicWidth)
      return computeReplacedLogicalWidthRespectingMinMaxWidth(
          constrainedSize.width(), shouldComputePreferred);

    // Otherwise, if 'width' has a computed value of 'auto', but none of the
    // conditions above are met, then the used value of 'width' becomes 300px.
    // If 300px is too wide to fit the device, UAs should use the width of the
    // largest rectangle that has a 2:1 ratio and fits the device instead. Note:
    // We fall through and instead return intrinsicLogicalWidth() here - to
    // preserve existing WebKit behavior, which might or might not be correct,
    // or desired. Changing this to return cDefaultWidth, will affect lots of
    // test results. Eg. some tests assume that a blank <img> tag (which implies
    // width/height=auto) has no intrinsic size, which is wrong per CSS 2.1, but
    // matches our behavior since a long time.
  }

  return computeReplacedLogicalWidthRespectingMinMaxWidth(
      intrinsicLogicalWidth(), shouldComputePreferred);
}

LayoutUnit RenderReplaced::computeReplacedLogicalHeight() const {
  // 10.5 Content height: the 'height' property:
  // http://www.w3.org/TR/CSS21/visudet.html#propdef-height
  if (hasReplacedLogicalHeight())
    return computeReplacedLogicalHeightRespectingMinMaxHeight(
        computeReplacedLogicalHeightUsing(style()->logicalHeight()));

  // 10.6.2 Inline, replaced elements:
  // http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-height
  double intrinsicRatio = 0;
  FloatSize constrainedSize;
  computeAspectRatioInformationForRenderBox(constrainedSize, intrinsicRatio);

  bool widthIsAuto = style()->logicalWidth().isAuto();
  bool hasIntrinsicHeight = constrainedSize.height() > 0;

  // If 'height' and 'width' both have computed values of 'auto' and the element
  // also has an intrinsic height, then that intrinsic height is the used value
  // of 'height'.
  if (widthIsAuto && hasIntrinsicHeight)
    return computeReplacedLogicalHeightRespectingMinMaxHeight(
        constrainedSize.height());

  // Otherwise, if 'height' has a computed value of 'auto', and the element has
  // an intrinsic ratio then the used value of 'height' is: (used width) /
  // (intrinsic ratio)
  if (intrinsicRatio)
    return computeReplacedLogicalHeightRespectingMinMaxHeight(
        roundToInt(round(availableLogicalWidth() / intrinsicRatio)));

  // Otherwise, if 'height' has a computed value of 'auto', and the element has
  // an intrinsic height, then that intrinsic height is the used value of
  // 'height'.
  if (hasIntrinsicHeight)
    return computeReplacedLogicalHeightRespectingMinMaxHeight(
        constrainedSize.height());

  // Otherwise, if 'height' has a computed value of 'auto', but none of the
  // conditions above are met, then the used value of 'height' must be set to
  // the height of the largest rectangle that has a 2:1 ratio, has a height not
  // greater than 150px, and has a width not greater than the device width.
  return computeReplacedLogicalHeightRespectingMinMaxHeight(
      intrinsicLogicalHeight());
}

void RenderReplaced::computeIntrinsicLogicalWidths(
    LayoutUnit& minLogicalWidth,
    LayoutUnit& maxLogicalWidth) const {
  minLogicalWidth = maxLogicalWidth = intrinsicLogicalWidth();
}

void RenderReplaced::computePreferredLogicalWidths() {
  ASSERT(preferredLogicalWidthsDirty());

  // We cannot resolve any percent logical width here as the available logical
  // width may not be set on our containing block.
  if (style()->logicalWidth().isPercent())
    computeIntrinsicLogicalWidths(m_minPreferredLogicalWidth,
                                  m_maxPreferredLogicalWidth);
  else
    m_minPreferredLogicalWidth = m_maxPreferredLogicalWidth =
        computeReplacedLogicalWidth(ComputePreferred);

  RenderStyle* styleToUse = style();
  if (styleToUse->logicalWidth().isPercent() ||
      styleToUse->logicalMaxWidth().isPercent())
    m_minPreferredLogicalWidth = 0;

  if (styleToUse->logicalMinWidth().isFixed() &&
      styleToUse->logicalMinWidth().value() > 0) {
    m_maxPreferredLogicalWidth = std::max(
        m_maxPreferredLogicalWidth, adjustContentBoxLogicalWidthForBoxSizing(
                                        styleToUse->logicalMinWidth().value()));
    m_minPreferredLogicalWidth = std::max(
        m_minPreferredLogicalWidth, adjustContentBoxLogicalWidthForBoxSizing(
                                        styleToUse->logicalMinWidth().value()));
  }

  if (styleToUse->logicalMaxWidth().isFixed()) {
    m_maxPreferredLogicalWidth = std::min(
        m_maxPreferredLogicalWidth, adjustContentBoxLogicalWidthForBoxSizing(
                                        styleToUse->logicalMaxWidth().value()));
    m_minPreferredLogicalWidth = std::min(
        m_minPreferredLogicalWidth, adjustContentBoxLogicalWidthForBoxSizing(
                                        styleToUse->logicalMaxWidth().value()));
  }

  LayoutUnit borderAndPadding = borderAndPaddingLogicalWidth();
  m_minPreferredLogicalWidth += borderAndPadding;
  m_maxPreferredLogicalWidth += borderAndPadding;

  clearPreferredLogicalWidthsDirty();
}

PositionWithAffinity RenderReplaced::positionForPoint(
    const LayoutPoint& point) {
  // FIXME: This code is buggy if the replaced element is relative positioned.
  InlineBox* box = inlineBoxWrapper();
  RootInlineBox* rootBox = box ? &box->root() : 0;

  LayoutUnit top = rootBox ? rootBox->selectionTop() : logicalTop();
  LayoutUnit bottom = rootBox ? rootBox->selectionBottom() : logicalBottom();

  LayoutUnit blockDirectionPosition = point.y() + y();

  if (blockDirectionPosition < top)
    return createPositionWithAffinity(caretMinOffset(),
                                      DOWNSTREAM);  // coordinates are above

  if (blockDirectionPosition >= bottom)
    return createPositionWithAffinity(caretMaxOffset(),
                                      DOWNSTREAM);  // coordinates are below

  return RenderBox::positionForPoint(point);
}

LayoutRect RenderReplaced::localSelectionRect(bool checkWhetherSelected) const {
  if (checkWhetherSelected && !isSelected())
    return LayoutRect();

  if (!inlineBoxWrapper())
    // We're a block-level replaced element.  Just return our own dimensions.
    return LayoutRect(LayoutPoint(), size());

  RootInlineBox& root = inlineBoxWrapper()->root();
  LayoutUnit newLogicalTop =
      root.selectionTop() - inlineBoxWrapper()->logicalTop();
  return LayoutRect(0, newLogicalTop, width(), root.selectionHeight());
}

void RenderReplaced::setSelectionState(SelectionState state) {
  // The selection state for our containing block hierarchy is updated by the
  // base class call.
  RenderBox::setSelectionState(state);

  if (!inlineBoxWrapper())
    return;

  if (canUpdateSelectionOnRootLineBoxes())
    inlineBoxWrapper()->root().setHasSelectedChildren(isSelected());
}

bool RenderReplaced::isSelected() const {
  return false;
}

}  // namespace blink