| // Copyright 2016 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. |
| |
| #ifndef NGConstraintSpace_h |
| #define NGConstraintSpace_h |
| |
| #include "core/CoreExport.h" |
| #include "core/layout/ng/ng_units.h" |
| #include "core/layout/ng/ng_writing_mode.h" |
| #include "platform/heap/Handle.h" |
| #include "wtf/Optional.h" |
| #include "wtf/text/WTFString.h" |
| |
| namespace blink { |
| |
| class LayoutBox; |
| class NGBoxFragment; |
| |
| enum NGFragmentationType { |
| kFragmentNone, |
| kFragmentPage, |
| kFragmentColumn, |
| kFragmentRegion |
| }; |
| |
| // The NGConstraintSpace represents a set of constraints and available space |
| // which a layout algorithm may produce a NGFragment within. |
| class CORE_EXPORT NGConstraintSpace final |
| : public GarbageCollectedFinalized<NGConstraintSpace> { |
| public: |
| // This should live on NGBlockNode or another layout bridge and probably take |
| // a root NGConstraintSpace. |
| static NGConstraintSpace* CreateFromLayoutObject(const LayoutBox&); |
| |
| const std::shared_ptr<NGExclusions>& Exclusions() const { |
| return exclusions_; |
| } |
| |
| TextDirection Direction() const { |
| return static_cast<TextDirection>(direction_); |
| } |
| |
| NGWritingMode WritingMode() const { |
| return static_cast<NGWritingMode>(writing_mode_); |
| } |
| |
| void AddExclusion(const NGExclusion& exclusion); |
| |
| // The size to use for percentage resolution. |
| // See: https://drafts.csswg.org/css-sizing/#percentage-sizing |
| NGLogicalSize PercentageResolutionSize() const { |
| return percentage_resolution_size_; |
| } |
| |
| // The available space size. |
| // See: https://drafts.csswg.org/css-sizing/#available |
| NGLogicalSize AvailableSize() const { return available_size_; } |
| |
| // Return the block-direction space available in the current fragmentainer. |
| LayoutUnit FragmentainerSpaceAvailable() const { |
| DCHECK(HasBlockFragmentation()); |
| return fragmentainer_space_available_; |
| } |
| |
| // Whether the current constraint space is for the newly established |
| // Formatting Context. |
| bool IsNewFormattingContext() const { return is_new_fc_; } |
| |
| // Whether exceeding the AvailableSize() triggers the presence of a scrollbar |
| // for the indicated direction. |
| // If exceeded the current layout should be aborted and invoked again with a |
| // constraint space modified to reserve space for a scrollbar. |
| bool IsInlineDirectionTriggersScrollbar() const { |
| return is_inline_direction_triggers_scrollbar_; |
| } |
| |
| bool IsBlockDirectionTriggersScrollbar() const { |
| return is_block_direction_triggers_scrollbar_; |
| } |
| |
| // Some layout modes “stretch” their children to a fixed size (e.g. flex, |
| // grid). These flags represented whether a layout needs to produce a |
| // fragment that satisfies a fixed constraint in the inline and block |
| // direction respectively. |
| // If these flags are true, the AvailableSize() is interpreted as the fixed |
| // border-box size of this box in the resepective dimension. |
| bool IsFixedSizeInline() const { return is_fixed_size_inline_; } |
| |
| bool IsFixedSizeBlock() const { return is_fixed_size_block_; } |
| |
| // Whether an auto inline-size should be interpreted as shrink-to-fit |
| // (ie. fit-content). This is used for inline-block, floats, etc. |
| bool IsShrinkToFit() const { return is_shrink_to_fit_; } |
| |
| // If specified a layout should produce a Fragment which fragments at the |
| // blockSize if possible. |
| NGFragmentationType BlockFragmentationType() const; |
| |
| // Return true if this contraint space participates in a fragmentation |
| // context. |
| bool HasBlockFragmentation() const { |
| return BlockFragmentationType() != kFragmentNone; |
| } |
| |
| // Modifies constraint space to account for a placed fragment. Depending on |
| // the shape of the fragment this will either modify the inline or block |
| // size, or add an exclusion. |
| void Subtract(const NGBoxFragment*); |
| |
| NGMarginStrut MarginStrut() const { return margin_strut_; } |
| |
| NGLogicalOffset BfcOffset() const { return bfc_offset_; } |
| |
| DEFINE_INLINE_VIRTUAL_TRACE() {} |
| |
| String ToString() const; |
| |
| private: |
| friend class NGConstraintSpaceBuilder; |
| // Default constructor. |
| NGConstraintSpace(NGWritingMode, |
| TextDirection, |
| NGLogicalSize available_size, |
| NGLogicalSize percentage_resolution_size, |
| LayoutUnit fragmentainer_space_available, |
| bool is_fixed_size_inline, |
| bool is_fixed_size_block, |
| bool is_shrink_to_fit, |
| bool is_inline_direction_triggers_scrollbar, |
| bool is_block_direction_triggers_scrollbar, |
| NGFragmentationType block_direction_fragmentation_type, |
| bool is_new_fc, |
| const NGMarginStrut& margin_strut, |
| const NGLogicalOffset& bfc_offset, |
| const std::shared_ptr<NGExclusions>& exclusions); |
| |
| NGLogicalSize available_size_; |
| NGLogicalSize percentage_resolution_size_; |
| |
| LayoutUnit fragmentainer_space_available_; |
| |
| unsigned is_fixed_size_inline_ : 1; |
| unsigned is_fixed_size_block_ : 1; |
| |
| unsigned is_shrink_to_fit_ : 1; |
| |
| unsigned is_inline_direction_triggers_scrollbar_ : 1; |
| unsigned is_block_direction_triggers_scrollbar_ : 1; |
| |
| unsigned block_direction_fragmentation_type_ : 2; |
| |
| // Whether the current constraint space is for the newly established |
| // formatting Context |
| unsigned is_new_fc_ : 1; |
| |
| unsigned writing_mode_ : 3; |
| unsigned direction_ : 1; |
| |
| NGMarginStrut margin_strut_; |
| NGLogicalOffset bfc_offset_; |
| const std::shared_ptr<NGExclusions> exclusions_; |
| }; |
| |
| inline std::ostream& operator<<(std::ostream& stream, |
| const NGConstraintSpace& value) { |
| return stream << value.ToString(); |
| } |
| |
| } // namespace blink |
| |
| #endif // NGConstraintSpace_h |