chromium/src/third_party/blink/renderer/core/paint/ng/ng_inline_box_fragment_painter.cc

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/core/paint/ng/ng_inline_box_fragment_painter.h"

#include "third_party/blink/renderer/core/layout/background_bleed_avoidance.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_cursor.h"
#include "third_party/blink/renderer/core/layout/ng/ng_fragment.h"
#include "third_party/blink/renderer/core/paint/background_image_geometry.h"
#include "third_party/blink/renderer/core/paint/paint_info.h"
#include "third_party/blink/renderer/core/paint/paint_layer.h"
#include "third_party/blink/renderer/core/paint/paint_phase.h"
#include "third_party/blink/renderer/core/style/nine_piece_image.h"
#include "third_party/blink/renderer/platform/graphics/graphics_context_state_saver.h"
#include "third_party/blink/renderer/platform/graphics/paint/drawing_recorder.h"
#include "third_party/blink/renderer/platform/graphics/paint/scoped_display_item_fragment.h"

namespace blink {

namespace {

template <class Items>
bool HasMultipleItems(const Items items) {
  auto iter = items.begin();
  DCHECK(iter != items.end());
  return iter != items.end() && ++iter != items.end();
}

inline bool MayHaveMultipleFragmentItems(const NGFragmentItem& item,
                                         const LayoutObject& layout_object) {
  return !item.IsFirstForNode() || !item.IsLastForNode() ||
         // TODO(crbug.com/1061423): NGInlineCursor is currently unable to deal
         // with objects split into multiple fragmentainers (e.g. columns). Just
         // return true if it's possible that this object participates in a
         // fragmentation context. This will give false positives, but that
         // should be harmless, given the way the return value is used by the
         // caller.
         UNLIKELY(layout_object.IsInsideFlowThread());
}

}  // namespace

PhysicalBoxSides NGInlineBoxFragmentPainter::SidesToInclude() const {
  return PhysicalFragment().SidesToInclude();
}

void NGInlineBoxFragmentPainter::Paint(const PaintInfo& paint_info,
                                       const PhysicalOffset& paint_offset) {
  ScopedDisplayItemFragment display_item_fragment(
      paint_info.context, inline_box_item_.FragmentId());

  const PhysicalOffset adjusted_paint_offset =
      paint_offset + inline_box_item_.OffsetInContainerFragment();
  if (paint_info.phase == PaintPhase::kForeground)
    PaintBackgroundBorderShadow(paint_info, adjusted_paint_offset);

  const bool suppress_box_decoration_background = true;
  DCHECK(inline_box_cursor_);
  NGBoxFragmentPainter box_painter(*inline_box_cursor_, inline_box_item_,
                                   PhysicalFragment());
  box_painter.PaintObject(paint_info, adjusted_paint_offset,
                          suppress_box_decoration_background);
}

void NGInlineBoxFragmentPainterBase::PaintBackgroundBorderShadow(
    const PaintInfo& paint_info,
    const PhysicalOffset& paint_offset) {
  DCHECK(paint_info.phase == PaintPhase::kForeground);
  if (inline_box_fragment_.Style().Visibility() != EVisibility::kVisible)
    return;

  // You can use p::first-line to specify a background. If so, the direct child
  // inline boxes of line boxes may actually have to paint a background.
  // TODO(layout-dev): Cache HasBoxDecorationBackground on the fragment like
  // we do for LayoutObject. Querying Style each time is too costly.
  bool should_paint_box_decoration_background =
      inline_box_fragment_.GetLayoutObject()->HasBoxDecorationBackground() ||
      inline_box_fragment_.UsesFirstLineStyle();

  if (!should_paint_box_decoration_background)
    return;

  const DisplayItemClient& display_item_client = GetDisplayItemClient();
  if (DrawingRecorder::UseCachedDrawingIfPossible(
          paint_info.context, display_item_client,
          DisplayItem::kBoxDecorationBackground))
    return;

  PhysicalRect frame_rect = inline_box_fragment_.LocalRect();
  PhysicalRect adjusted_frame_rect(paint_offset, frame_rect.size);

  DrawingRecorder recorder(paint_info.context, display_item_client,
                           DisplayItem::kBoxDecorationBackground,
                           VisualRect(paint_offset));

  DCHECK(inline_box_fragment_.GetLayoutObject());
  const LayoutObject& layout_object = *inline_box_fragment_.GetLayoutObject();
  bool object_may_have_multiple_boxes =
      MayHaveMultipleFragmentItems(inline_box_item_, layout_object);

  // TODO(eae): Switch to LayoutNG version of BackgroundImageGeometry.
  BackgroundImageGeometry geometry(*static_cast<const LayoutBoxModelObject*>(
      inline_box_fragment_.GetLayoutObject()));
  DCHECK(inline_box_cursor_);
  NGBoxFragmentPainter box_painter(
      *inline_box_cursor_, inline_box_item_,
      To<NGPhysicalBoxFragment>(inline_box_fragment_));
  PaintBoxDecorationBackground(
      box_painter, paint_info, paint_offset, adjusted_frame_rect, geometry,
      object_may_have_multiple_boxes, SidesToInclude());
}

IntRect NGInlineBoxFragmentPainterBase::VisualRect(
    const PhysicalOffset& paint_offset) {
  PhysicalRect overflow_rect = inline_box_item_.SelfInkOverflow();
  overflow_rect.Move(paint_offset);
  return EnclosingIntRect(overflow_rect);
}

void NGLineBoxFragmentPainter::PaintBackgroundBorderShadow(
    const PaintInfo& paint_info,
    const PhysicalOffset& paint_offset) {
  DCHECK_EQ(paint_info.phase, PaintPhase::kForeground);
  DCHECK_EQ(inline_box_fragment_.Type(), NGPhysicalFragment::kFragmentLineBox);
  DCHECK(NeedsPaint(inline_box_fragment_));
  // |NGFragmentItem| uses the fragment id when painting the background of
  // line boxes. Please see |NGFragmentItem::kInitialLineFragmentId|.
  DCHECK_NE(paint_info.context.GetPaintController().CurrentFragment(), 0u);

  if (line_style_ == style_ ||
      line_style_.Visibility() != EVisibility::kVisible)
    return;

  const DisplayItemClient& display_item_client = GetDisplayItemClient();
  if (DrawingRecorder::UseCachedDrawingIfPossible(
          paint_info.context, display_item_client,
          DisplayItem::kBoxDecorationBackground))
    return;

  // Compute the content box for the `::first-line` box. It's different from
  // fragment size because the height of line box includes `line-height` while
  // the height of inline box does not. The box "behaves similar to that of an
  // inline-level element".
  // https://drafts.csswg.org/css-pseudo-4/#first-line-styling
  const NGPhysicalLineBoxFragment& line_box = PhysicalFragment();
  const FontHeight line_metrics = line_box.Metrics();
  const FontHeight text_metrics = line_style_.GetFontHeight();
  const WritingMode writing_mode = line_style_.GetWritingMode();
  PhysicalRect rect;
  if (IsHorizontalWritingMode(writing_mode)) {
    rect.offset.top = line_metrics.ascent - text_metrics.ascent;
    rect.size = {line_box.Size().width, text_metrics.LineHeight()};
  } else {
    rect.offset.left =
        line_box.Size().width - line_metrics.ascent - text_metrics.descent;
    rect.size = {text_metrics.LineHeight(), line_box.Size().height};
  }
  rect.offset += paint_offset;

  DrawingRecorder recorder(paint_info.context, display_item_client,
                           DisplayItem::kBoxDecorationBackground,
                           VisualRect(paint_offset));

  const LayoutBlockFlow& layout_block_flow =
      *To<LayoutBlockFlow>(block_fragment_.GetLayoutObject());
  BackgroundImageGeometry geometry(layout_block_flow);
  NGBoxFragmentPainter box_painter(block_fragment_);
  PaintBoxDecorationBackground(
      box_painter, paint_info, paint_offset, rect, geometry,
      /*object_has_multiple_boxes*/ false, PhysicalBoxSides());
}

void NGInlineBoxFragmentPainterBase::ComputeFragmentOffsetOnLine(
    TextDirection direction,
    LayoutUnit* offset_on_line,
    LayoutUnit* total_width) const {
  WritingDirectionMode writing_direction =
      inline_box_fragment_.Style().GetWritingDirection();
  NGInlineCursor cursor;
  DCHECK(inline_box_fragment_.GetLayoutObject());
  cursor.MoveTo(*inline_box_fragment_.GetLayoutObject());

  LayoutUnit before;
  LayoutUnit after;
  bool before_self = true;
  for (; cursor; cursor.MoveToNextForSameLayoutObject()) {
    DCHECK(cursor.CurrentItem());
    if (cursor.CurrentItem() == &inline_box_item_) {
      before_self = false;
      continue;
    }
    const NGPhysicalBoxFragment* box_fragment = cursor.Current().BoxFragment();
    DCHECK(box_fragment);
    if (before_self)
      before += NGFragment(writing_direction, *box_fragment).InlineSize();
    else
      after += NGFragment(writing_direction, *box_fragment).InlineSize();
  }

  *total_width =
      before + after +
      NGFragment(writing_direction, inline_box_fragment_).InlineSize();

  // We're iterating over the fragments in physical order before so we need to
  // swap before and after for RTL.
  *offset_on_line = direction == TextDirection::kLtr ? before : after;
}

PhysicalRect NGInlineBoxFragmentPainterBase::PaintRectForImageStrip(
    const PhysicalRect& paint_rect,
    TextDirection direction) const {
  // We have a fill/border/mask image that spans multiple lines.
  // We need to adjust the offset by the width of all previous lines.
  // Think of background painting on inlines as though you had one long line, a
  // single continuous strip. Even though that strip has been broken up across
  // multiple lines, you still paint it as though you had one single line. This
  // means each line has to pick up the background where the previous line left
  // off.
  LayoutUnit offset_on_line;
  LayoutUnit total_width;
  ComputeFragmentOffsetOnLine(direction, &offset_on_line, &total_width);

  if (inline_box_fragment_.Style().IsHorizontalWritingMode()) {
    return PhysicalRect(paint_rect.X() - offset_on_line, paint_rect.Y(),
                        total_width, paint_rect.Height());
  }
  return PhysicalRect(paint_rect.X(), paint_rect.Y() - offset_on_line,
                      paint_rect.Width(), total_width);
}

InlineBoxPainterBase::BorderPaintingType
NGInlineBoxFragmentPainterBase::GetBorderPaintType(
    const PhysicalRect& adjusted_frame_rect,
    IntRect& adjusted_clip_rect,
    bool object_has_multiple_boxes) const {
  const ComputedStyle& style = inline_box_fragment_.Style();
  if (!style.HasBorderDecoration())
    return kDontPaintBorders;

  const NinePieceImage& border_image = style.BorderImage();
  StyleImage* border_image_source = border_image.GetImage();
  bool has_border_image =
      border_image_source && border_image_source->CanRender();
  if (has_border_image && !border_image_source->IsLoaded())
    return kDontPaintBorders;

  // The simple case is where we either have no border image or we are the
  // only box for this object.  In those cases only a single call to draw is
  // required.
  if (!has_border_image || !object_has_multiple_boxes) {
    adjusted_clip_rect = PixelSnappedIntRect(adjusted_frame_rect);
    return kPaintBordersWithoutClip;
  }

  // We have a border image that spans multiple lines.
  adjusted_clip_rect = PixelSnappedIntRect(ClipRectForNinePieceImageStrip(
      style, SidesToInclude(), border_image, adjusted_frame_rect));
  return kPaintBordersWithClip;
}

void NGInlineBoxFragmentPainterBase::PaintNormalBoxShadow(
    const PaintInfo& info,
    const ComputedStyle& s,
    const PhysicalRect& paint_rect) {
  BoxPainterBase::PaintNormalBoxShadow(info, paint_rect, s, SidesToInclude());
}

void NGInlineBoxFragmentPainterBase::PaintInsetBoxShadow(
    const PaintInfo& info,
    const ComputedStyle& s,
    const PhysicalRect& paint_rect) {
  BoxPainterBase::PaintInsetBoxShadowWithBorderRect(info, paint_rect, s,
                                                    SidesToInclude());
}

// Paint all fragments for the |layout_inline|. This function is used only for
// self-painting |LayoutInline|.
void NGInlineBoxFragmentPainter::PaintAllFragments(
    const LayoutInline& layout_inline,
    const PaintInfo& paint_info,
    const PhysicalOffset& paint_offset) {
  // TODO(kojii): If the block flow is dirty, children of these fragments
  // maybe already deleted. crbug.com/963103
  const LayoutBlockFlow* block_flow = layout_inline.ContainingNGBlockFlow();
  if (UNLIKELY(block_flow->NeedsLayout()))
    return;

  NGInlineCursor cursor(*block_flow);
  cursor.MoveTo(layout_inline);
  if (!cursor)
    return;
  // Convert from inline fragment index to container fragment index, as the
  // inline may not start in the first fragment generated for the inline
  // formatting context.
  wtf_size_t target_fragment_idx =
      cursor.ContainerFragmentIndex() +
      paint_info.context.GetPaintController().CurrentFragment();
  for (; cursor; cursor.MoveToNextForSameLayoutObject()) {
    if (target_fragment_idx != cursor.ContainerFragmentIndex())
      continue;
    const NGFragmentItem* item = cursor.CurrentItem();
    DCHECK(item);
    const NGPhysicalBoxFragment* box_fragment = item->BoxFragment();
    DCHECK(box_fragment);
    NGInlineBoxFragmentPainter(cursor, *item, *box_fragment)
        .Paint(paint_info, paint_offset);
  }
}

#if DCHECK_IS_ON()
void NGInlineBoxFragmentPainter::CheckValid() const {
  DCHECK(inline_box_cursor_);
  DCHECK_EQ(inline_box_cursor_->Current().Item(), &inline_box_item_);

  DCHECK_EQ(inline_box_fragment_.Type(),
            NGPhysicalFragment::NGFragmentType::kFragmentBox);
  DCHECK_EQ(inline_box_fragment_.BoxType(),
            NGPhysicalFragment::NGBoxType::kInlineBox);
}
#endif

}  // namespace blink