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/*
* Copyright (C) 2024 Apple Inc. All rights reserved.
* Copyright (C) 2024 Igalia S.L.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
namespace WebCore {
// The axis that the span specifies.
enum class PositionAreaAxis : uint8_t {
// Physical axes. Implies self is PositionAreaSelf::No, as physical axes
// do not depend on writing mode of any elements.
Horizontal,
Vertical,
// Logical axes.
X,
Y,
Block,
Inline,
};
// Specifies which tile(s) on the axis that the position-area span occupies.
enum class PositionAreaTrack : uint8_t {
// First tile.
Start,
// First and center tiles.
SpanStart,
// Last tile.
End,
// Center and last tiles.
SpanEnd,
// Center tile.
Center,
// All tiles on the axis.
SpanAll,
};
// When the span refers to a logical axis that needs to be resolved to physical
// axis, this determines whether to use the writing mode of the element's
// containing block or the element itself.
enum class PositionAreaSelf : bool {
// Use the writing mode of the element's containing block.
No,
// Use the writing mode of the element itself.
Yes
};
// A span in the position-area. position-area requires two spans of opposite
// axis to determine the containing block area.
//
// A span is uniquely determined by three properties:
// * the axis the span is on
// * which track it occupies
// * "self" - whether to use the writing mode of the element itself or
// its containing block to resolve logical axes.
//
// How a CSS position-area keyword fits into this model:
// * Every keyword (except start, center, end, span-all) selects a physical
// or logical axis in PositionAreaAxis. For example, left/right/top/bottom
// select the physical Horizontal/Vertical axis, x-*/y-*/block-*/inline-*
// keywords select the logical X/Y/Block/Inline axis.
// * Every keyword also selects the "track", or the tiles on the axis it occupies,
// in PositionAxisTrack. For example:
// * left/top selects the Start track.
// * *-start/*-end keywords selects the Start/End track.
// * Span keywords select the SpanStart/SpanEnd track.
// * center/span-all select the Center/SpanAll track.
// * start, center, end, span-all are "axis ambiguous" - its axis depends on the
// axis of the other keyword in position-area. PositionAreaSpan does not support
// this; Style::BuilderConverter is responsible for resolving to a concrete axis
// before creating a PositionAreaSpan.
class PositionAreaSpan {
public:
PositionAreaSpan(PositionAreaAxis, PositionAreaTrack, PositionAreaSelf);
PositionAreaAxis axis() const { return static_cast<PositionAreaAxis>(m_axis); }
PositionAreaTrack track() const { return static_cast<PositionAreaTrack>(m_track); }
PositionAreaSelf self() const { return static_cast<PositionAreaSelf>(m_self); }
friend bool operator==(PositionAreaSpan, PositionAreaSpan) = default;
private:
uint8_t m_axis : 3;
uint8_t m_track : 3;
uint8_t m_self : 1;
};
WTF::TextStream& operator<<(WTF::TextStream&, const PositionAreaSpan&);
// A position-area is formed by two spans of opposite axes, that uniquely determine
// the area of the containing block.
class PositionArea {
public:
PositionArea(PositionAreaSpan blockOrXAxis, PositionAreaSpan inlineOrYAxis);
PositionAreaSpan blockOrXAxis() const { return m_blockOrXAxis; }
PositionAreaSpan inlineOrYAxis() const { return m_inlineOrYAxis; }
bool operator==(const PositionArea&) const = default;
private:
PositionAreaSpan m_blockOrXAxis;
PositionAreaSpan m_inlineOrYAxis;
};
WTF::TextStream& operator<<(WTF::TextStream&, const PositionArea&);
} // namespace WebCore
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