| // Copyright 2014 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_LAYOUT_BOX_H_ |
| #define COBALT_LAYOUT_BOX_H_ |
| |
| #include <iosfwd> |
| #include <memory> |
| #include <ostream> |
| #include <string> |
| #include <vector> |
| |
| #include "base/memory/ref_counted.h" |
| #include "base/optional.h" |
| #include "cobalt/cssom/css_computed_style_declaration.h" |
| #include "cobalt/cssom/css_style_declaration.h" |
| #include "cobalt/dom/node.h" |
| #include "cobalt/layout/base_direction.h" |
| #include "cobalt/layout/box_intersection_observer_module.h" |
| #include "cobalt/layout/insets_layout_unit.h" |
| #include "cobalt/layout/layout_stat_tracker.h" |
| #include "cobalt/layout/layout_unit.h" |
| #include "cobalt/layout/line_wrapping.h" |
| #include "cobalt/layout/rect_layout_unit.h" |
| #include "cobalt/layout/size_layout_unit.h" |
| #include "cobalt/layout/vector2d_layout_unit.h" |
| #include "cobalt/math/matrix3_f.h" |
| #include "cobalt/math/point_f.h" |
| #include "cobalt/math/rect_f.h" |
| #include "cobalt/math/vector2d.h" |
| #include "cobalt/math/vector2d_f.h" |
| #include "cobalt/render_tree/animations/animate_node.h" |
| #include "cobalt/render_tree/composition_node.h" |
| #include "cobalt/ui_navigation/nav_item.h" |
| #include "cobalt/web_animations/animation_set.h" |
| |
| namespace cobalt { |
| |
| namespace render_tree { |
| struct RoundedCorners; |
| } // namespace render_tree |
| |
| namespace layout { |
| |
| class AnonymousBlockBox; |
| class BlockContainerBox; |
| class ContainerBox; |
| class TextBox; |
| class UsedStyleProvider; |
| |
| struct LayoutParams { |
| LayoutParams() |
| : shrink_to_fit_width_forced(false), |
| freeze_width(false), |
| freeze_height(false), |
| containing_block_direction(kLeftToRightBaseDirection) {} |
| |
| // Normally the used values of "width", "margin-left", and "margin-right" are |
| // calculated by choosing the 1 out of 10 algorithms based on the computed |
| // values of "display", "position", "overflow", and the fact whether the box |
| // is replaced or not, as per: |
| // https://www.w3.org/TR/CSS21/visudet.html#Computing_widths_and_margins |
| // |
| // If this flag is set, block container boxes will follow the algorithm |
| // for inline-level, non-replaced block container boxes, which involves |
| // the calculation of shrink-to-fit width, as per: |
| // https://www.w3.org/TR/CSS21/visudet.html#inlineblock-width |
| // |
| // This override is used during the first pass of layout to calculate |
| // the content size of "inline-block" elements. It's an equivalent of |
| // "trying all possible line breaks", as described by: |
| // https://www.w3.org/TR/CSS21/visudet.html#shrink-to-fit-float |
| bool shrink_to_fit_width_forced; |
| |
| // These overrides are used for flex items when they are sized by the |
| // container. |
| bool freeze_width; |
| bool freeze_height; |
| |
| // Many box positions and sizes are calculated with respect to the edges of |
| // a rectangular box called a containing block. |
| // https://www.w3.org/TR/CSS21/visuren.html#containing-block |
| SizeLayoutUnit containing_block_size; |
| |
| // Margin calculations can depend on the direction property of the containing |
| // block. |
| // https://www.w3.org/TR/CSS21/visudet.html#blockwidth |
| BaseDirection containing_block_direction; |
| |
| bool operator==(const LayoutParams& rhs) const { |
| return shrink_to_fit_width_forced == rhs.shrink_to_fit_width_forced && |
| freeze_width == rhs.freeze_width && |
| freeze_height == rhs.freeze_height && |
| containing_block_size == rhs.containing_block_size && |
| containing_block_direction == rhs.containing_block_direction; |
| } |
| |
| base::Optional<LayoutUnit> maybe_margin_top; |
| base::Optional<LayoutUnit> maybe_margin_bottom; |
| base::Optional<LayoutUnit> maybe_height; |
| }; |
| |
| inline std::ostream& operator<<(std::ostream& stream, |
| const LayoutParams& params) { |
| stream << "{shrink_to_fit_width_forced=" << params.shrink_to_fit_width_forced |
| << " freeze_width=" << params.freeze_width |
| << " freeze_height=" << params.freeze_height |
| << " containing_block_size=" << params.containing_block_size << "}"; |
| return stream; |
| } |
| |
| // A base class for all boxes. |
| // |
| // The CSS box model describes the rectangular boxes that are generated |
| // for elements in the document tree and laid out according to the visual |
| // formatting model. |
| // https://www.w3.org/TR/CSS21/box.html |
| // Boxes are reference counted, because they are referred to by both parent |
| // boxes and LayoutBoxes objects stored with html elements in the DOM tree to |
| // allow incremental box generation. |
| class Box : public base::RefCounted<Box> { |
| public: |
| // Defines the formatting context in which the box should participate. |
| // Do not confuse with the formatting context that the element may establish. |
| enum Level { |
| // The "block" value of the "display" property makes an element block-level. |
| // Block-level boxes participate in a block formatting context. |
| // https://www.w3.org/TR/CSS21/visuren.html#block-boxes |
| kBlockLevel, |
| |
| // The "inline" and "inline-block" values of the "display" property make |
| // an element inline-level. Inline-level boxes that participate in an inline |
| // formatting context. |
| // https://www.w3.org/TR/CSS21/visuren.html#inline-boxes |
| kInlineLevel, |
| }; |
| |
| enum MarginCollapsingStatus { |
| kCollapseMargins, |
| kIgnore, |
| kSeparateAdjoiningMargins, |
| }; |
| |
| enum RelationshipToBox { |
| kIsBoxAncestor, |
| kIsBox, |
| kIsBoxDescendant, |
| }; |
| |
| enum TransformAction { |
| kEnterTransform, |
| kExitTransform, |
| }; |
| |
| // Info tracked on container boxes encountered when a stacking context is |
| // generating its cross references. |
| struct StackingContextContainerBoxInfo { |
| StackingContextContainerBoxInfo(ContainerBox* container_box, |
| bool is_absolute_containing_block, |
| bool has_absolute_position, |
| bool has_overflow_hidden) |
| : container_box(container_box), |
| is_absolute_containing_block(is_absolute_containing_block), |
| is_usable_as_child_container(is_absolute_containing_block), |
| has_absolute_position(has_absolute_position), |
| has_overflow_hidden(has_overflow_hidden) {} |
| |
| ContainerBox* container_box; |
| bool is_absolute_containing_block; |
| bool is_usable_as_child_container; |
| bool has_absolute_position; |
| bool has_overflow_hidden; |
| }; |
| |
| typedef std::vector<StackingContextContainerBoxInfo> |
| StackingContextContainerBoxStack; |
| |
| // List of containing blocks with overflow hidden property. Used by stacking |
| // context children that are added to a stacking context container higher up |
| // the tree than their containing block, so that they can still have the |
| // overflow hidden from those containing blocks applied. |
| typedef std::vector<ContainerBox*> ContainingBlocksWithOverflowHidden; |
| |
| // The RenderSequence of a box is used to compare the relative drawing order |
| // of boxes. It stores a value for the box's drawing order position at each |
| // stacking context up to the root of the render tree. As a result, starting |
| // from the root ancestor, the box for which the render sequence ends first, |
| // or for which the draw order position at a stacking context is lower is |
| // drawn before the other box. |
| typedef std::vector<size_t> RenderSequence; |
| |
| Box(const scoped_refptr<cssom::CSSComputedStyleDeclaration>& |
| css_computed_style_declaration, |
| UsedStyleProvider* used_style_provider, |
| LayoutStatTracker* layout_stat_tracker); |
| virtual ~Box(); |
| |
| // Computed style contains CSS values from the last stage of processing |
| // before the layout. The computed value resolves the specified value as far |
| // as possible without laying out the document or performing other expensive |
| // or hard-to-parallelize operations, such as resolving network requests or |
| // retrieving values other than from the element and its parent. |
| // https://www.w3.org/TR/css-cascade-3/#computed |
| const scoped_refptr<cssom::CSSComputedStyleDeclaration>& |
| css_computed_style_declaration() const { |
| return css_computed_style_declaration_; |
| } |
| |
| const scoped_refptr<const cssom::CSSComputedStyleData>& computed_style() |
| const { |
| return css_computed_style_declaration_->data(); |
| } |
| |
| // The animation set specifies all currently active animations applying |
| // to this box's computed_style() CSS Style Declaration. |
| // https://w3c.github.io/web-animations |
| const web_animations::AnimationSet* animations() const { |
| return css_computed_style_declaration_->animations().get(); |
| } |
| |
| // Specifies the formatting context in which the box should participate. |
| // Do not confuse with the formatting context that the element may establish. |
| virtual Level GetLevel() const = 0; |
| |
| virtual MarginCollapsingStatus GetMarginCollapsingStatus() const { |
| return Box::kCollapseMargins; |
| } |
| |
| // Returns true if the box is positioned (e.g. position is non-static or |
| // transform is not None). Intuitively, this is true if the element does |
| // not follow standard layout flow rules for determining its position. |
| // https://www.w3.org/TR/CSS21/visuren.html#positioned-element. |
| bool IsPositioned() const; |
| |
| // Returns true if the box has a non-"none" value for its transform property. |
| // https://www.w3.org/TR/css3-transforms/#transform-property |
| bool IsTransformed() const; |
| |
| // Absolutely positioned box implies that the element's "position" property |
| // has the value "absolute" or "fixed". |
| // https://www.w3.org/TR/CSS21/visuren.html#absolutely-positioned |
| bool IsAbsolutelyPositioned() const; |
| |
| // Returns true if the box serves as a stacking context for descendant |
| // elements. The core stacking context creation criteria is given here |
| // (https://www.w3.org/TR/CSS21/visuren.html#z-index) however it is extended |
| // by various other specification documents such as those describing opacity |
| // (https://www.w3.org/TR/css3-color/#transparency) and transforms |
| // (https://www.w3.org/TR/css3-transforms/#transform-rendering). |
| virtual bool IsStackingContext() const { return false; } |
| |
| // Updates the size of margin, border, padding, and content boxes. Lays out |
| // in-flow descendants, estimates static positions (but not sizes) of |
| // out-of-flow descendants. Does not update the position of the box. |
| void UpdateSize(const LayoutParams& layout_params); |
| |
| // Returns the offset from root to this box's containing block. |
| Vector2dLayoutUnit GetContainingBlockOffsetFromRoot( |
| bool transform_forms_root) const; |
| |
| // Returns the offset from the containing block (which can be either the |
| // containing block's content box or padding box) to its content box. |
| Vector2dLayoutUnit GetContainingBlockOffsetFromItsContentBox( |
| const ContainerBox* containing_block) const; |
| InsetsLayoutUnit GetContainingBlockInsetFromItsContentBox( |
| const ContainerBox* containing_block) const; |
| |
| // Returns boxes relative to the root or containing block, that take into |
| // account transforms. |
| RectLayoutUnit GetTransformedBoxFromRoot( |
| const RectLayoutUnit& box_from_margin_box) const; |
| RectLayoutUnit GetTransformedBoxFromRootWithScroll( |
| const RectLayoutUnit& box_from_margin_box, |
| bool transform_forms_root = false) const; |
| RectLayoutUnit GetTransformedBoxFromContainingBlock( |
| const ContainerBox* containing_block, |
| const RectLayoutUnit& box_from_margin_box) const; |
| RectLayoutUnit GetTransformedBoxFromContainingBlockContentBox( |
| const ContainerBox* containing_block, |
| const RectLayoutUnit& box_from_margin_box) const; |
| |
| // Used values of "left" and "top" are publicly readable and writable so that |
| // they can be calculated and adjusted by the formatting context of the parent |
| // box. |
| void set_left(LayoutUnit left) { |
| margin_box_offset_from_containing_block_.set_x(left); |
| } |
| LayoutUnit left() const { |
| return margin_box_offset_from_containing_block_.x(); |
| } |
| void set_top(LayoutUnit top) { |
| margin_box_offset_from_containing_block_.set_y(top); |
| } |
| LayoutUnit top() const { |
| return margin_box_offset_from_containing_block_.y(); |
| } |
| |
| // The following static position functions are only used with absolutely |
| // positioned boxes. |
| // https://www.w3.org/TR/CSS21/visuren.html#absolute-positioning |
| |
| // The static position for 'left' is the distance from the left edge of the |
| // containing block to the left margin edge of a hypothetical box that would |
| // have been the first box of the element if its 'position' property had been |
| // 'static' and 'float' had been 'none'. The value is negative if the |
| // hypothetical box is to the left of the containing block. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width |
| void SetStaticPositionLeftFromParent(LayoutUnit left); |
| void SetStaticPositionLeftFromContainingBlockToParent(LayoutUnit left); |
| LayoutUnit GetStaticPositionLeft() const; |
| |
| // The static position for 'right' is the distance from the right edge of the |
| // containing block to the right margin edge of the same hypothetical box as |
| // above. The value is positive if the hypothetical box is to the left of the |
| // containing block's edge. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width |
| void SetStaticPositionRightFromParent(LayoutUnit right); |
| void SetStaticPositionRightFromContainingBlockToParent(LayoutUnit right); |
| LayoutUnit GetStaticPositionRight() const; |
| |
| // For the purposes of this section and the next, the term "static position" |
| // (of an element) refers, roughly, to the position an element would have had |
| // in the normal flow. More precisely, the static position for 'top' is the |
| // distance from the top edge of the containing block to the top margin edge |
| // of a hypothetical box that would have been the first box of the element if |
| // its specified 'position' value had been 'static'. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-height |
| void SetStaticPositionTopFromParent(LayoutUnit top); |
| void SetStaticPositionTopFromContainingBlockToParent(LayoutUnit top); |
| LayoutUnit GetStaticPositionTop() const; |
| |
| // Each box has a content area and optional surrounding padding, border, |
| // and margin areas. |
| // https://www.w3.org/TR/CSS21/box.html#box-dimensions |
| // |
| // Methods below provide read-only access to dimensions and edges of margin, |
| // border, padding, and content boxes. |
| |
| // Margin box. |
| LayoutUnit margin_left() const { return margin_insets_.left(); } |
| LayoutUnit margin_top() const { return margin_insets_.top(); } |
| LayoutUnit margin_right() const { return margin_insets_.right(); } |
| LayoutUnit margin_bottom() const { return margin_insets_.bottom(); } |
| LayoutUnit GetMarginBoxWidth() const; |
| LayoutUnit GetMarginBoxHeight() const; |
| |
| // Used values of "margin" properties are set by overriders |
| // of |UpdateContentSizeAndMargins| method. |
| void set_margin_left(LayoutUnit margin_left) { |
| margin_insets_.set_left(margin_left); |
| } |
| void set_margin_top(LayoutUnit margin_top) { |
| margin_insets_.set_top(margin_top); |
| } |
| void set_margin_right(LayoutUnit margin_right) { |
| margin_insets_.set_right(margin_right); |
| } |
| void set_margin_bottom(LayoutUnit margin_bottom) { |
| margin_insets_.set_bottom(margin_bottom); |
| } |
| |
| math::Matrix3F GetMarginBoxTransformFromContainingBlock( |
| const ContainerBox* containing_block) const; |
| math::Matrix3F GetMarginBoxTransformFromContainingBlockWithScroll( |
| const ContainerBox* containing_block, bool transform_forms_root) const; |
| |
| Vector2dLayoutUnit GetMarginBoxOffsetFromRoot( |
| bool transform_forms_root) const; |
| const Vector2dLayoutUnit& margin_box_offset_from_containing_block() const { |
| return margin_box_offset_from_containing_block_; |
| } |
| LayoutUnit GetMarginBoxRightEdgeOffsetFromContainingBlock() const; |
| LayoutUnit GetMarginBoxBottomEdgeOffsetFromContainingBlock() const; |
| LayoutUnit GetMarginBoxStartEdgeOffsetFromContainingBlock( |
| BaseDirection base_direction) const; |
| LayoutUnit GetMarginBoxEndEdgeOffsetFromContainingBlock( |
| BaseDirection base_direction) const; |
| |
| // Border box. |
| LayoutUnit border_left_width() const { return border_insets_.left(); } |
| LayoutUnit border_top_width() const { return border_insets_.top(); } |
| LayoutUnit border_right_width() const { return border_insets_.right(); } |
| LayoutUnit border_bottom_width() const { return border_insets_.bottom(); } |
| |
| RectLayoutUnit GetBorderBoxFromRoot(bool transform_forms_root) const; |
| |
| LayoutUnit GetBorderBoxWidth() const; |
| LayoutUnit GetBorderBoxHeight() const; |
| SizeLayoutUnit GetClampedBorderBoxSize() const; |
| |
| RectLayoutUnit GetBorderBoxFromMarginBox() const; |
| Vector2dLayoutUnit GetBorderBoxOffsetFromRoot( |
| bool transform_forms_root) const; |
| Vector2dLayoutUnit GetBorderBoxOffsetFromMarginBox() const; |
| |
| void ResetBorderInsets() { border_insets_ = InsetsLayoutUnit(); } |
| |
| // Padding box. |
| LayoutUnit padding_left() const { return padding_insets_.left(); } |
| LayoutUnit padding_top() const { return padding_insets_.top(); } |
| LayoutUnit padding_right() const { return padding_insets_.right(); } |
| LayoutUnit padding_bottom() const { return padding_insets_.bottom(); } |
| LayoutUnit GetPaddingBoxWidth() const; |
| LayoutUnit GetPaddingBoxHeight() const; |
| RectLayoutUnit GetClampedPaddingBox(bool transform_forms_root) const; |
| SizeLayoutUnit GetClampedPaddingBoxSize() const; |
| |
| RectLayoutUnit GetPaddingBoxFromMarginBox() const; |
| Vector2dLayoutUnit GetPaddingBoxOffsetFromRoot( |
| bool transform_forms_root) const; |
| Vector2dLayoutUnit GetPaddingBoxOffsetFromBorderBox() const; |
| LayoutUnit GetPaddingBoxLeftEdgeOffsetFromMarginBox() const; |
| LayoutUnit GetPaddingBoxTopEdgeOffsetFromMarginBox() const; |
| |
| // Set padding insets in InlineContainerBox UpdatePaddings to an empty |
| // LayoutUnit or the computed_style value using is_split_on_*_. |
| void SetPaddingInsets(LayoutUnit left, LayoutUnit top, LayoutUnit right, |
| LayoutUnit bottom); |
| |
| // Content box. |
| LayoutUnit width() const { return content_size_.width(); } |
| LayoutUnit height() const { return content_size_.height(); } |
| const SizeLayoutUnit& content_box_size() const { return content_size_; } |
| |
| RectLayoutUnit GetContentBoxFromMarginBox() const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromRoot( |
| bool transform_forms_root) const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromMarginBox() const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromBorderBox() const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromPaddingBox() const; |
| LayoutUnit GetContentBoxLeftEdgeOffsetFromMarginBox() const; |
| LayoutUnit GetContentBoxTopEdgeOffsetFromMarginBox() const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromContainingBlockContentBox( |
| const ContainerBox* containing_block) const; |
| InsetsLayoutUnit GetContentBoxInsetFromContainingBlockContentBox( |
| const ContainerBox* containing_block) const; |
| Vector2dLayoutUnit GetContentBoxOffsetFromContainingBlock() const; |
| InsetsLayoutUnit GetContentBoxInsetFromContainingBlock( |
| const ContainerBox* containing_block) const; |
| LayoutUnit GetContentBoxLeftEdgeOffsetFromContainingBlock() const; |
| LayoutUnit GetContentBoxTopEdgeOffsetFromContainingBlock() const; |
| LayoutUnit GetContentBoxStartEdgeOffsetFromContainingBlock( |
| BaseDirection base_direction) const; |
| LayoutUnit GetContentBoxEndEdgeOffsetFromContainingBlock( |
| BaseDirection base_direction) const; |
| |
| // Return the size difference between the content and margin box on an axis. |
| LayoutUnit GetContentToMarginHorizontal() const; |
| LayoutUnit GetContentToMarginVertical() const; |
| |
| // The height of each inline-level box in the line box is calculated. For |
| // replaced elements, inline-block elements, and inline-table elements, this |
| // is the height of their margin box; for inline boxes, this is their |
| // 'line-height'. |
| // http://www.w3.org/TR/CSS21/visudet.html#line-height |
| virtual LayoutUnit GetInlineLevelBoxHeight() const; |
| virtual LayoutUnit GetInlineLevelTopMargin() const; |
| |
| // When an element is blockified, that should not affect the static position. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width |
| // https://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo |
| // Return true if the element's outer display type was inline before any |
| // optional blockificiation has occurred. |
| bool is_inline_before_blockification() const { |
| return css_computed_style_declaration_->data() |
| ->is_inline_before_blockification(); |
| } |
| |
| // Attempts to wrap the box based upon the provided wrap policies. |
| // If |is_line_existence_justified| is true, then the line does not require |
| // additional content before wrapping is possible. Otherwise, content |
| // justifying the line must be encountered first. |
| // |available_width| indicates the amount of width remaining on the line |
| // before the boxes overflow it. |
| // If |should_collapse_trailing_white_space| is true, the trailing whitespace |
| // of the box will be collapsed and should not be included in width |
| // calculations. |
| // |
| // Returns the result of the wrap attempt. If the result is |
| // |kWrapResultSplitWrap|, then the box has been split, and the portion of the |
| // box split from the initial box is available via GetSplitSibling(). |
| // |
| // Note that only inline boxes are wrappable. |
| virtual WrapResult TryWrapAt(WrapAtPolicy wrap_at_policy, |
| WrapOpportunityPolicy wrap_opportunity_policy, |
| bool is_line_existence_justified, |
| LayoutUnit available_width, |
| bool should_collapse_trailing_white_space) = 0; |
| |
| // Returns the next box in a linked list of sibling boxes produced from |
| // splits of the original box. |
| // |
| // Note that only inline boxes are splittable. All other box types will return |
| // NULL. |
| virtual Box* GetSplitSibling() const { return NULL; } |
| |
| // Verifies that either an ellipsis can be placed within the box, or that an |
| // ellipsis has already been placed in a previous box in the line, and calls |
| // DoPlaceEllipsisOrProcessPlacedEllipsis() to handle ellipsis placement and |
| // updating of ellipsis-related state within the box. It also sets |
| // |is_placement_requirement_met| to true if the box fulfills the requirement |
| // that the first character or atomic inline-level element must appear on a |
| // line before an ellipsis |
| // (https://www.w3.org/TR/css3-ui/#propdef-text-overflow), regardless of |
| // whether or not the ellipsis can be placed within this specific box. |
| void TryPlaceEllipsisOrProcessPlacedEllipsis( |
| BaseDirection base_direction, LayoutUnit desired_offset, |
| bool* is_placement_requirement_met, bool* is_placed, |
| LayoutUnit* placed_offset); |
| // Whether or not the box fulfills the ellipsis requirement that it not be |
| // be placed until after the "the first character or atomic inline-level |
| // element on a line." |
| // https://www.w3.org/TR/css3-ui/#propdef-text-overflow |
| virtual bool DoesFulfillEllipsisPlacementRequirement() const { return false; } |
| // Do any processing needed prior to ellipsis placement. This involves caching |
| // the old value and resetting the current value so it can be determined |
| // whether or not the ellipsis state within a box changed as a a result of |
| // ellipsis placement. |
| virtual void DoPreEllipsisPlacementProcessing() {} |
| // Do any processing needed following ellipsis placement. This involves |
| // checking the old value against the new value and resetting the cached |
| // render tree node if the ellipsis state changed. |
| virtual void DoPostEllipsisPlacementProcessing() {} |
| // Whether or not the box is fully hidden by an ellipsis. This applies to |
| // atomic inline-level elements that have had an ellipsis placed before them |
| // on a line. https://www.w3.org/TR/css3-ui/#propdef-text-overflow |
| virtual bool IsHiddenByEllipsis() const { return false; } |
| |
| // Initial splitting of boxes between bidi level runs prior to layout, so that |
| // they will not need to occur during layout. |
| virtual void SplitBidiLevelRuns() = 0; |
| |
| // Attempt to split the box at the second level run within it. |
| // Returns true if a split occurs. The second box produced by the split is |
| // retrievable by calling GetSplitSibling(). |
| // NOTE: The splits that occur at the intersection of bidi level runs is |
| // unrelated to line-wrapping and does not introduce wrappable locations. |
| // It is used to facilitate bidi level reordering of the boxes within a |
| // line. |
| virtual bool TrySplitAtSecondBidiLevelRun() = 0; |
| |
| // Retrieve the bidi level for the box, if it has one. |
| virtual base::Optional<int> GetBidiLevel() const = 0; |
| |
| // Sets whether a leading white space in the box or its first non-collapsed |
| // descendant should be collapsed. |
| virtual void SetShouldCollapseLeadingWhiteSpace( |
| bool should_collapse_leading_white_space) = 0; |
| // Sets whether a trailing white space in the box or its last non-collapsed |
| // descendant should be collapsed. |
| virtual void SetShouldCollapseTrailingWhiteSpace( |
| bool should_collapse_trailing_white_space) = 0; |
| // Whether the box or its first non-collapsed descendant starts with a white |
| // space. |
| // |
| // WARNING: undefined, unless the box's size is up-to-date. |
| virtual bool HasLeadingWhiteSpace() const = 0; |
| // Whether the box or its last non-collapsed descendant ends with a white |
| // space. |
| // |
| // WARNING: undefined, unless the box's size is up-to-date. |
| virtual bool HasTrailingWhiteSpace() const = 0; |
| // A box is collapsed if it has no text or white space, nor have its children. |
| // A collapsed box may still have a non-zero width. Atomic inline-level boxes |
| // are never collapsed, even if empty. |
| // |
| // This is used to decide whether two white spaces are following each other in |
| // an inline formatting context. |
| // |
| // WARNING: undefined, unless the box's size is up-to-date. |
| virtual bool IsCollapsed() const = 0; |
| |
| // Line boxes that contain no text, no preserved white space, no inline |
| // elements with non-zero margins, padding, or borders, and no other in-flow |
| // content must be treated as zero-height line boxes for the purposes |
| // of determining the positions of any elements inside of them, and must be |
| // treated as not existing for any other purpose. |
| // https://www.w3.org/TR/CSS21/visuren.html#inline-formatting |
| virtual bool JustifiesLineExistence() const = 0; |
| // Whether or not the box or its last descendant has a trailing line break, |
| // disallowing additional boxes on the same line. |
| virtual bool HasTrailingLineBreak() const { return false; } |
| // Boxes that don't establish a baseline (such as empty blocks or lines) |
| // should not affect the baseline calculation in the block formatting context. |
| virtual bool AffectsBaselineInBlockFormattingContext() const = 0; |
| // Returns the vertical offset of the baseline relatively to the top margin |
| // edge. If the box does not have a baseline, returns the bottom margin edge, |
| // as per https://www.w3.org/TR/CSS21/visudet.html#line-height. |
| virtual LayoutUnit GetBaselineOffsetFromTopMarginEdge() const = 0; |
| |
| // Marks the current set of UpdateSize parameters (which includes the |
| // LayoutParams parameter as well as object member variable state) as valid. |
| // Returns true if previously calculated results from UpdateSize() are still |
| // valid. This is used to avoid redundant recalculations, and is an extremely |
| // important optimization since it applies to all levels of the box hierarchy. |
| // Derived classes may override this method to check if local box state has |
| // changed as well. |
| virtual bool ValidateUpdateSizeInputs(const LayoutParams& params); |
| |
| // Invalidating the sizes causes them to be re-calculated the next time they |
| // are needed. |
| void InvalidateUpdateSizeInputsOfBox(); |
| void InvalidateUpdateSizeInputsOfBoxAndAncestors(); |
| |
| // Invalidating the cross references causes them to be re-calculated the next |
| // time they are needed. |
| virtual void InvalidateCrossReferencesOfBoxAndAncestors(); |
| |
| // Invalidating the render tree nodes causes them to be re-generated the next |
| // time they are needed. |
| void InvalidateRenderTreeNodesOfBoxAndAncestors(); |
| |
| // Converts a layout subtree into a render subtree. |
| // This method defines the overall strategy of the conversion and relies |
| // on the subclasses to provide the actual content. |
| void RenderAndAnimate( |
| render_tree::CompositionNode::Builder* parent_content_node_builder, |
| const math::Vector2dF& offset_from_parent_node, |
| ContainerBox* stacking_context); |
| |
| scoped_refptr<render_tree::Node> RenderAndAnimateOverflow( |
| const scoped_refptr<render_tree::Node>& content_node, |
| const math::Vector2dF& border_offset); |
| |
| // Poor man's reflection. |
| virtual AnonymousBlockBox* AsAnonymousBlockBox(); |
| virtual const AnonymousBlockBox* AsAnonymousBlockBox() const; |
| virtual BlockContainerBox* AsBlockContainerBox(); |
| virtual const BlockContainerBox* AsBlockContainerBox() const; |
| virtual ContainerBox* AsContainerBox(); |
| virtual const ContainerBox* AsContainerBox() const; |
| virtual TextBox* AsTextBox(); |
| virtual const TextBox* AsTextBox() const; |
| |
| #ifdef COBALT_BOX_DUMP_ENABLED |
| // Used by box generator to set a DOM node that produced this box. |
| void SetGeneratingNode(dom::Node* generating_node); |
| // Used by derived classes to dump their children. |
| void DumpWithIndent(std::ostream* stream, int indent) const; |
| #endif // COBALT_BOX_DUMP_ENABLED |
| |
| ContainerBox* parent() { return parent_; } |
| const ContainerBox* parent() const { return parent_; } |
| |
| const ContainerBox* GetAbsoluteContainingBlock() const; |
| ContainerBox* GetAbsoluteContainingBlock() { |
| // Return a mutable ContainerBox. |
| return const_cast<ContainerBox*>( |
| static_cast<const Box*>(this)->GetAbsoluteContainingBlock()); |
| } |
| const ContainerBox* GetFixedContainingBlock() const; |
| ContainerBox* GetFixedContainingBlock() { |
| // Return a mutable ContainerBox. |
| return const_cast<ContainerBox*>( |
| static_cast<const Box*>(this)->GetFixedContainingBlock()); |
| } |
| |
| const ContainerBox* GetContainingBlock() const; |
| ContainerBox* GetContainingBlock() { |
| // Return a mutable ContainerBox. |
| return const_cast<ContainerBox*>( |
| static_cast<const Box*>(this)->GetContainingBlock()); |
| } |
| |
| const ContainerBox* GetStackingContext() const; |
| ContainerBox* GetStackingContext() { |
| // Return a mutable ContainerBox. |
| return const_cast<ContainerBox*>( |
| static_cast<const Box*>(this)->GetStackingContext()); |
| } |
| |
| // Returns the z-index of this box, based on its computed style. |
| int GetZIndex() const; |
| |
| // Returns the order value of this box, based on its computed style. |
| int GetOrder() const; |
| |
| // Invalidates the parent of the box, used in box generation for partial |
| // layout. |
| void InvalidateParent() { parent_ = NULL; } |
| |
| // Returns true if the box is positioned under the passed in coordinate. |
| bool IsUnderCoordinate(const Vector2dLayoutUnit& coordinate) const; |
| |
| // Returns a data structure that can be used by Box::IsRenderedLater(). |
| RenderSequence GetRenderSequence() const; |
| |
| // Returns true if the box for the given render_sequence is rendered after |
| // the box for the other_render_sequence. The boxes must be from the same |
| // layout tree. |
| static bool IsRenderedLater(RenderSequence render_sequence, |
| RenderSequence other_render_sequence); |
| |
| // Applies the specified transform action to the provided coordinates. |
| // Returns false if the transform is not invertible and the action requires |
| // it being inverted. |
| bool ApplyTransformActionToCoordinate(TransformAction action, |
| math::Vector2dF* coordinate) const; |
| bool ApplyTransformActionToCoordinates( |
| TransformAction action, std::vector<math::Vector2dF>* coordinates) const; |
| |
| // Intended to be set to false on the initial containing block, this indicates |
| // that when the background color is rendered, it will be blended with what, |
| // is behind it (only relevant when the color is not opaque). As an example, |
| // if set to false, a background color of transparent will replace any |
| // previous pixel values instead of being a no-op. |
| void set_blend_background_color(bool value) { |
| blend_background_color_ = value; |
| } |
| |
| // Configure the box's UI navigation item with the box's position, size, etc. |
| void UpdateUiNavigationItem(); |
| |
| void SetUiNavItem(const scoped_refptr<ui_navigation::NavItem>& item) { |
| ui_nav_item_ = item; |
| } |
| |
| void AddIntersectionObserverRootsAndTargets( |
| BoxIntersectionObserverModule::IntersectionObserverRootVector&& roots, |
| BoxIntersectionObserverModule::IntersectionObserverTargetVector&& |
| targets); |
| bool ContainsIntersectionObserverRoot( |
| const scoped_refptr<IntersectionObserverRoot>& intersection_observer_root) |
| const; |
| |
| base::Optional<LayoutUnit> collapsed_margin_top_; |
| base::Optional<LayoutUnit> collapsed_margin_bottom_; |
| base::Optional<LayoutUnit> collapsed_empty_margin_; |
| |
| static bool IsBorderStyleNoneOrHidden( |
| const scoped_refptr<cssom::PropertyValue>& border_style); |
| |
| protected: |
| UsedStyleProvider* used_style_provider() const { |
| return used_style_provider_; |
| } |
| |
| LayoutStatTracker* layout_stat_tracker() const { |
| return layout_stat_tracker_; |
| } |
| |
| // Updates used values of "width", "height", and "margin" properties based on |
| // https://www.w3.org/TR/CSS21/visudet.html#Computing_widths_and_margins and |
| // https://www.w3.org/TR/CSS21/visudet.html#Computing_heights_and_margins. |
| // Limits set by "min-width" and "max-width" are honored for non-replaced |
| // boxes, based on https://www.w3.org/TR/CSS21/visudet.html#min-max-widths. |
| virtual void UpdateContentSizeAndMargins( |
| const LayoutParams& layout_params) = 0; |
| |
| // Content box setters. |
| // |
| // Used values of "width" and "height" properties are set by overriders |
| // of |UpdateContentSizeAndMargins| method. |
| void set_width(LayoutUnit width) { content_size_.set_width(width); } |
| void set_height(LayoutUnit height) { content_size_.set_height(height); } |
| |
| // Used to determine whether this box justifies the existence of a line, |
| // as per: |
| // |
| // Line boxes that contain no inline elements with non-zero margins, padding, |
| // or borders must be treated as not existing. |
| // https://www.w3.org/TR/CSS21/visuren.html#phantom-line-box |
| bool HasNonZeroMarginOrBorderOrPadding() const; |
| |
| // Add a box and all of its descendants that are contained within the |
| // specified stacking context to the stacking context's draw order. This is |
| // used when a render tree node that is already cached is encountered to |
| // ensure that it maintains the proper draw order in its stacking context. |
| virtual void AddBoxAndDescendantsToDrawOrderInStackingContext( |
| ContainerBox* stacking_context); |
| |
| // Renders the content of the box. |
| virtual void RenderAndAnimateContent( |
| render_tree::CompositionNode::Builder* border_node_builder, |
| ContainerBox* stacking_context) const = 0; |
| |
| // A transformable element is an element whose layout is governed by the CSS |
| // box model which is either a block-level or atomic inline-level element. |
| // https://www.w3.org/TR/css3-transforms/#transformable-element |
| virtual bool IsTransformable() const = 0; |
| |
| #ifdef COBALT_BOX_DUMP_ENABLED |
| void DumpIndent(std::ostream* stream, int indent) const; |
| virtual void DumpClassName(std::ostream* stream) const = 0; |
| // Overriders must call the base method. |
| virtual void DumpProperties(std::ostream* stream) const; |
| // Overriders must call the base method. |
| virtual void DumpChildrenWithIndent(std::ostream* stream, int indent) const; |
| #endif // COBALT_BOX_DUMP_ENABLED |
| |
| // Updates the source container box's cross references with its descendants in |
| // the box tree that have it as their containing block or stacking context. |
| // This function is called recursively. |
| virtual void UpdateCrossReferencesOfContainerBox( |
| ContainerBox* source_box, RelationshipToBox nearest_containing_block, |
| RelationshipToBox nearest_absolute_containing_block, |
| RelationshipToBox nearest_fixed_containing_block, |
| RelationshipToBox nearest_stacking_context, |
| StackingContextContainerBoxStack* stacking_context_container_box_stack); |
| |
| // Updates the horizontal margins for block level in-flow boxes. This is used |
| // for both non-replaced and replaced elements. See |
| // https://www.w3.org/TR/CSS21/visudet.html#blockwidth and |
| // https://www.w3.org/TR/CSS21/visudet.html#block-replaced-width. |
| void UpdateHorizontalMarginsAssumingBlockLevelInFlowBox( |
| BaseDirection containing_block_direction, |
| LayoutUnit containing_block_width, LayoutUnit border_box_width, |
| const base::Optional<LayoutUnit>& possibly_overconstrained_margin_left, |
| const base::Optional<LayoutUnit>& possibly_overconstrained_margin_right); |
| |
| // Set border insets in InlineContainerBox UpdateBorders to an empty |
| // LayoutUnit or the computed_style value using is_split_on_*_. |
| void SetBorderInsets(LayoutUnit left, LayoutUnit top, LayoutUnit right, |
| LayoutUnit bottom); |
| |
| private: |
| struct CachedRenderTreeNodeInfo { |
| explicit CachedRenderTreeNodeInfo(const math::Vector2dF& offset) |
| : offset_(offset) {} |
| |
| math::Vector2dF offset_; |
| scoped_refptr<render_tree::Node> node_; |
| }; |
| |
| // Updates used values of "border" properties. |
| virtual void UpdateBorders(); |
| // Updates used values of "padding" properties. |
| virtual void UpdatePaddings(const LayoutParams& layout_params); |
| |
| // Computes the normalized "outer" rounded corners (if there are any) from the |
| // border radii. |
| base::Optional<render_tree::RoundedCorners> ComputeRoundedCorners() const; |
| |
| // Computes the corresponding "inner" rounded corners. |
| base::Optional<render_tree::RoundedCorners> ComputePaddingRoundedCorners( |
| const base::Optional<render_tree::RoundedCorners>& rounded_corners) const; |
| |
| // Called after TryPlaceEllipsisOrProcessPlacedEllipsis() determines that the |
| // box is impacted by the ellipsis. This handles both determining the location |
| // of the ellipsis, if it has not already been placed, and updating the |
| // ellipsis-related state of the box, such as whether or not it should be |
| // fully or partially hidden. |
| virtual void DoPlaceEllipsisOrProcessPlacedEllipsis( |
| BaseDirection base_direction, LayoutUnit desired_offset, |
| bool* is_placement_requirement_met, bool* is_placed, |
| LayoutUnit* placed_offset) {} |
| |
| // Get the rectangle for which gives the region that background-color |
| // and background-image would populate. |
| math::RectF GetBackgroundRect(); |
| |
| // Get the transform for this box from the specified containing block (which |
| // may be null to indicate root). |
| math::Matrix3F GetMarginBoxTransformFromContainingBlockInternal( |
| const ContainerBox* containing_block, bool transform_forms_root, |
| bool include_scroll) const; |
| |
| // Some custom CSS transform functions require a UI navigation focus item as |
| // input. This computes the appropriate UI navigation item for this box's |
| // transform. This should only be called if the box IsTransformed(). |
| scoped_refptr<ui_navigation::NavItem> ComputeUiNavFocusForTransform() const; |
| |
| // Returns whether the overflow is animated by a UI navigation item. |
| bool IsOverflowAnimatedByUiNavigation() const { |
| return ui_nav_item_ && ui_nav_item_->IsContainer(); |
| } |
| |
| // Helper methods used by |RenderAndAnimate|. |
| void RenderAndAnimateBorder( |
| const base::Optional<render_tree::RoundedCorners>& rounded_corners, |
| render_tree::CompositionNode::Builder* border_node_builder, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder); |
| void RenderAndAnimateOutline( |
| render_tree::CompositionNode::Builder* border_node_builder, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder); |
| void RenderAndAnimateBackgroundColor( |
| const base::Optional<render_tree::RoundedCorners>& rounded_corners, |
| render_tree::CompositionNode::Builder* border_node_builder, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder); |
| struct RenderAndAnimateBackgroundImageResult { |
| // The node representing the background image (may be a CompositionNode if |
| // there are multiple layers). |
| scoped_refptr<render_tree::Node> node; |
| // Returns whether the background image opaquely fills the entire frame. |
| // If true, then we don't need to even consider rendering the background |
| // color, since it will be occluded by the image. |
| bool is_opaque; |
| }; |
| RenderAndAnimateBackgroundImageResult RenderAndAnimateBackgroundImage( |
| const base::Optional<render_tree::RoundedCorners>& rounded_corners); |
| void RenderAndAnimateBoxShadow( |
| const base::Optional<render_tree::RoundedCorners>& outer_rounded_corners, |
| const base::Optional<render_tree::RoundedCorners>& inner_rounded_corners, |
| render_tree::CompositionNode::Builder* border_node_builder, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder); |
| |
| // If opacity is animated or other than 1, wraps a border node into a filter |
| // node. Otherwise returns the original border node. |
| scoped_refptr<render_tree::Node> RenderAndAnimateOpacity( |
| const scoped_refptr<render_tree::Node>& border_node, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder, |
| float opacity, bool opacity_animated); |
| |
| scoped_refptr<render_tree::Node> RenderAndAnimateOverflow( |
| const base::Optional<render_tree::RoundedCorners>& rounded_corners, |
| const scoped_refptr<render_tree::Node>& content_node, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder, |
| const math::Vector2dF& border_node_offset); |
| |
| // If transform is not "none", wraps a border node in a MatrixTransformNode. |
| // If transform is "none", returns the original border node and leaves |
| // |border_node_transform| intact. |
| scoped_refptr<render_tree::Node> RenderAndAnimateTransform( |
| const scoped_refptr<render_tree::Node>& border_node, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder, |
| const math::Vector2dF& border_node_offset); |
| |
| // This adds an animation to reflect content scrolling by the UI navigation |
| // system. Call this only if IsOverflowAnimatedByUiNavigation(). |
| scoped_refptr<render_tree::Node> RenderAndAnimateUiNavigationContainer( |
| const scoped_refptr<render_tree::Node>& node_to_animate, |
| render_tree::animations::AnimateNode::Builder* animate_node_builder); |
| |
| // The css_computed_style_declaration_ member references the |
| // cssom::CSSComputedStyleDeclaration object owned by the HTML Element from |
| // which this box is derived. |
| const scoped_refptr<cssom::CSSComputedStyleDeclaration> |
| css_computed_style_declaration_; |
| UsedStyleProvider* const used_style_provider_; |
| LayoutStatTracker* const layout_stat_tracker_; |
| |
| #ifdef COBALT_BOX_DUMP_ENABLED |
| std::string generating_html_; |
| #endif // COBALT_BOX_DUMP_ENABLED |
| |
| // The parent of this box is the box that owns this child and is the direct |
| // parent. If DOM element A is a parent of DOM element B, and box A is |
| // derived from DOM element A and box B is derived from DOM element B, then |
| // box A will be the parent of box B. |
| ContainerBox* parent_; |
| |
| // Used values of "left" and "top" properties. |
| Vector2dLayoutUnit margin_box_offset_from_containing_block_; |
| |
| // The following static position variables are only used with absolutely |
| // positioned boxes. |
| // https://www.w3.org/TR/CSS21/visuren.html#absolute-positioning |
| // The static position for 'left' is the distance from the left edge of the |
| // containing block to the left margin edge of a hypothetical box that would |
| // have been the first box of the element if its 'position' property had been |
| // 'static' and 'float' had been 'none'. The value is negative if the |
| // hypothetical box is to the left of the containing block. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width |
| // The static position for 'right' is the distance from the right edge of the |
| // containing block to the right margin edge of the same hypothetical box as |
| // above. The value is positive if the hypothetical box is to the left of the |
| // containing block's edge. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-width |
| // For the purposes of this section and the next, the term "static position" |
| // (of an element) refers, roughly, to the position an element would have had |
| // in the normal flow. More precisely, the static position for 'top' is the |
| // distance from the top edge of the containing block to the top margin edge |
| // of a hypothetical box that would have been the first box of the element if |
| // its specified 'position' value had been 'static'. |
| // https://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-height |
| InsetsLayoutUnit static_position_offset_from_parent_; |
| InsetsLayoutUnit static_position_offset_from_containing_block_to_parent_; |
| |
| // Used values of "margin-left", "margin-top", "margin-right", |
| // and "margin-bottom". |
| InsetsLayoutUnit margin_insets_; |
| // Used values of "border-left-width", "border-top-width", |
| // "border-right-width", and "border-bottom-width". |
| InsetsLayoutUnit border_insets_; |
| // Used values of "padding-left", "padding-top", "padding-right", |
| // and "padding-bottom". |
| InsetsLayoutUnit padding_insets_; |
| // Used values of "width" and "height" properties. |
| SizeLayoutUnit content_size_; |
| |
| // Referenced and updated by ValidateUpdateSizeInputs() to memoize the |
| // parameters we were passed during in last call to UpdateSizes(). |
| base::Optional<LayoutParams> last_update_size_params_; |
| |
| // Render tree node caching is used to prevent the node from needing to be |
| // recalculated during each call to RenderAndAnimateContent. |
| base::Optional<CachedRenderTreeNodeInfo> cached_render_tree_node_info_; |
| |
| // A value that indicates the drawing order relative to other boxes in the |
| // same stacking context. Smaller values indicate boxes that are drawn |
| // earlier. |
| size_t draw_order_position_in_stacking_context_; |
| |
| // Determines whether the background should be rendered as a clear (i.e. with |
| // blending disabled). It is expected that this may only be set on the |
| // initial containing block. |
| bool blend_background_color_ = true; |
| |
| // UI navigation items are used to help animate certain elements. |
| scoped_refptr<ui_navigation::NavItem> ui_nav_item_; |
| |
| std::unique_ptr<BoxIntersectionObserverModule> |
| box_intersection_observer_module_; |
| |
| // For write access to parent/containing_block members. |
| friend class ContainerBox; |
| friend class LayoutBoxes; |
| friend class FlexContainerBox; |
| friend class FlexFormattingContext; |
| friend class FlexLine; |
| friend class MainAxisHorizontalFlexItem; |
| friend class MainAxisVerticalFlexItem; |
| |
| DISALLOW_COPY_AND_ASSIGN(Box); |
| }; |
| |
| #ifdef COBALT_BOX_DUMP_ENABLED |
| |
| // Dumps a box tree recursively to a stream. |
| // Used for layout debugging, not intended for production. |
| inline std::ostream& operator<<(std::ostream& stream, const Box& box) { |
| box.DumpWithIndent(&stream, 0); |
| return stream; |
| } |
| |
| #endif // COBALT_BOX_DUMP_ENABLED |
| |
| typedef std::vector<scoped_refptr<Box> > Boxes; |
| |
| } // namespace layout |
| } // namespace cobalt |
| |
| #endif // COBALT_LAYOUT_BOX_H_ |