forked from mozilla/gecko-dev
-
Notifications
You must be signed in to change notification settings - Fork 2
/
nsMathMLmsubFrame.cpp
215 lines (187 loc) · 8.17 KB
/
nsMathMLmsubFrame.cpp
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
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla MathML Project.
*
* The Initial Developer of the Original Code is
* The University Of Queensland.
* Portions created by the Initial Developer are Copyright (C) 1999
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Roger B. Sidje <rbs@maths.uq.edu.au>
* David J. Fiddes <D.J.Fiddes@hw.ac.uk>
* Shyjan Mahamud <mahamud@cs.cmu.edu> (added TeX rendering rules)
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsMathMLmsubFrame.h"
//
// <msub> -- attach a subscript to a base - implementation
//
nsIFrame*
NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
return new (aPresShell) nsMathMLmsubFrame(aContext);
}
NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsubFrame)
nsMathMLmsubFrame::~nsMathMLmsubFrame()
{
}
NS_IMETHODIMP
nsMathMLmsubFrame::TransmitAutomaticData()
{
// if our base is an embellished operator, let its state bubble to us
mPresentationData.baseFrame = mFrames.FirstChild();
GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData);
// 1. The REC says:
// The <msub> element increments scriptlevel by 1, and sets displaystyle to
// "false", within subscript, but leaves both attributes unchanged within base.
// 2. The TeXbook (Ch 17. p.141) says the subscript is compressed
UpdatePresentationDataFromChildAt(1, -1,
~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
return NS_OK;
}
/* virtual */ nsresult
nsMathMLmsubFrame::Place (nsRenderingContext& aRenderingContext,
PRBool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize)
{
// extra spacing after sup/subscript
nscoord scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f); // 0.5pt as in plain TeX
// check if the subscriptshift attribute is there
nscoord subScriptShift = 0;
nsAutoString value;
GetAttribute(mContent, mPresentationData.mstyle,
nsGkAtoms::subscriptshift_, value);
if (!value.IsEmpty()) {
nsCSSValue cssValue;
if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
subScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
}
}
return nsMathMLmsubFrame::PlaceSubScript(PresContext(),
aRenderingContext,
aPlaceOrigin,
aDesiredSize,
this,
subScriptShift,
scriptSpace);
}
// exported routine that both munder and msub share.
// munder uses this when movablelimits is set.
nsresult
nsMathMLmsubFrame::PlaceSubScript (nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
PRBool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize,
nsMathMLContainerFrame* aFrame,
nscoord aUserSubScriptShift,
nscoord aScriptSpace)
{
// force the scriptSpace to be atleast 1 pixel
aScriptSpace = NS_MAX(nsPresContext::CSSPixelsToAppUnits(1), aScriptSpace);
////////////////////////////////////
// Get the children's desired sizes
nsBoundingMetrics bmBase, bmSubScript;
nsHTMLReflowMetrics baseSize;
nsHTMLReflowMetrics subScriptSize;
nsIFrame* baseFrame = aFrame->GetFirstChild(nsnull);
nsIFrame* subScriptFrame = nsnull;
if (baseFrame)
subScriptFrame = baseFrame->GetNextSibling();
if (!baseFrame || !subScriptFrame || subScriptFrame->GetNextSibling()) {
// report an error, encourage people to get their markups in order
return aFrame->ReflowError(aRenderingContext, aDesiredSize);
}
GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript);
// get the subdrop from the subscript font
nscoord subDrop;
GetSubDropFromChild(subScriptFrame, subDrop);
// parameter v, Rule 18a, App. G, TeXbook
nscoord minSubScriptShift = bmBase.descent + subDrop;
//////////////////
// Place Children
// get min subscript shift limit from x-height
// = h(x) - 4/5 * sigma_5, Rule 18b, App. G, TeXbook
nscoord xHeight = 0;
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm));
xHeight = fm->XHeight();
nscoord minShiftFromXHeight = (nscoord)
(bmSubScript.ascent - (4.0f/5.0f) * xHeight);
// subScriptShift
// = minimum amount to shift the subscript down set by user or from the font
// = sub1 in TeX
// = subscriptshift attribute * x-height
nscoord subScriptShift, dummy;
// get subScriptShift default from font
GetSubScriptShifts (fm, subScriptShift, dummy);
subScriptShift =
NS_MAX(subScriptShift, aUserSubScriptShift);
// get actual subscriptshift to be used
// Rule 18b, App. G, TeXbook
nscoord actualSubScriptShift =
NS_MAX(minSubScriptShift,NS_MAX(subScriptShift,minShiftFromXHeight));
// get bounding box for base + subscript
nsBoundingMetrics boundingMetrics;
boundingMetrics.ascent =
NS_MAX(bmBase.ascent, bmSubScript.ascent - actualSubScriptShift);
boundingMetrics.descent =
NS_MAX(bmBase.descent, bmSubScript.descent + actualSubScriptShift);
// add aScriptSpace to the subscript's width
boundingMetrics.width = bmBase.width + bmSubScript.width + aScriptSpace;
boundingMetrics.leftBearing = bmBase.leftBearing;
boundingMetrics.rightBearing = NS_MAX(bmBase.rightBearing, bmBase.width +
NS_MAX(bmSubScript.width + aScriptSpace, bmSubScript.rightBearing));
aFrame->SetBoundingMetrics (boundingMetrics);
// reflow metrics
aDesiredSize.ascent =
NS_MAX(baseSize.ascent, subScriptSize.ascent - actualSubScriptShift);
aDesiredSize.height = aDesiredSize.ascent +
NS_MAX(baseSize.height - baseSize.ascent,
subScriptSize.height - subScriptSize.ascent + actualSubScriptShift);
aDesiredSize.width = boundingMetrics.width;
aDesiredSize.mBoundingMetrics = boundingMetrics;
aFrame->SetReference(nsPoint(0, aDesiredSize.ascent));
if (aPlaceOrigin) {
nscoord dx, dy;
// now place the base ...
dx = 0; dy = aDesiredSize.ascent - baseSize.ascent;
FinishReflowChild (baseFrame, aPresContext, nsnull, baseSize, dx, dy, 0);
// ... and subscript
dx = bmBase.width;
dy = aDesiredSize.ascent - (subScriptSize.ascent - actualSubScriptShift);
FinishReflowChild (subScriptFrame, aPresContext, nsnull, subScriptSize, dx, dy, 0);
}
return NS_OK;
}