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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef LAYOUT_BASE_BASELINE_H_
#define LAYOUT_BASE_BASELINE_H_
#include "nsCoord.h"
#include "mozilla/WritingModes.h"
class nsIFrame;
namespace mozilla {
// https://drafts.csswg.org/css-align-3/#baseline-sharing-group
enum class BaselineSharingGroup : uint8_t {
// NOTE Used as an array index so must be 0 and 1.
First = 0,
Last = 1,
};
// Layout context under which the baseline is being exported to.
enum class BaselineExportContext : uint8_t {
LineLayout = 0,
Other = 1,
};
class Baseline {
public:
/**
* Synthesize a first(last) inline-axis baseline in aWM based on aFrame's
* margin-box.
*
* An alphabetical baseline is at the end edge of aFrame's margin-box with
* respect to aWM's block-axis, and a central baseline is halfway between the
* start and end edges. (aWM tells which baseline to use.)
* https://drafts.csswg.org/css-align-3/#synthesize-baseline
*
* @note This works only when aFrame's writing-mode is parallel to aWM.
* @param aWM the writing-mode of the alignment context.
* @return an offset from aFrame's border-box start(end) edge in aWM's
* block-axis for a first(last) baseline, respectively.
*/
static nscoord SynthesizeBOffsetFromMarginBox(const nsIFrame* aFrame,
WritingMode aWM,
BaselineSharingGroup);
/**
* Synthesize a first(last) inline-axis baseline in aWM based on aFrame's
* border-box.
*
* An alphabetical baseline is at the end edge of aFrame's border-box with
* respect to aWM's block-axis, and a central baseline is halfway between the
* start and end edges. (aWM tells which baseline to use.)
* https://drafts.csswg.org/css-align-3/#synthesize-baseline
*
* @param aWM the writing-mode of the alignment context.
* @return an offset from aFrame's border-box start(end) edge in aWM's
* block-axis for a first(last) baseline, respectively.
*/
static nscoord SynthesizeBOffsetFromBorderBox(const nsIFrame* aFrame,
WritingMode aWM,
BaselineSharingGroup);
/**
* Synthesize a first(last) inline-axis baseline in aWM based on aFrame's
* content-box.
*
* An alphabetical baseline is at the end edge of aFrame's content-box with
* respect to aWM's block-axis, and a central baseline is halfway between the
* start and end edges. (aWM tells which baseline to use.)
* https://drafts.csswg.org/css-align-3/#synthesize-baseline
*
* @note This works only when aFrame's writing-mode is parallel to aWM.
* @param aWM the writing-mode of the alignment context.
* @return an offset from aFrame's border-box start(end) edge in aWM's
* block-axis for a first(last) baseline, respectively.
*/
static nscoord SynthesizeBOffsetFromContentBox(const nsIFrame* aFrame,
WritingMode aWM,
BaselineSharingGroup);
};
} // namespace mozilla
#endif // LAYOUT_BASE_BASELINE_H_
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