1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
/* 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);
/**
* As above, but using the content box.
*/
static nscoord SynthesizeBOffsetFromContentBox(const nsIFrame*, WritingMode,
BaselineSharingGroup);
/**
* As above, but using the padding box.
*/
static nscoord SynthesizeBOffsetFromPaddingBox(const nsIFrame*, WritingMode,
BaselineSharingGroup);
};
} // namespace mozilla
#endif // LAYOUT_BASE_BASELINE_H_
|
