summaryrefslogtreecommitdiffstats
path: root/layout/mathml/nsMathMLFrame.cpp
blob: 9a7d94a992e57831f304bb7bfde744bc39da74ca (plain)
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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */

#include "nsMathMLFrame.h"

#include "gfxContext.h"
#include "gfxUtils.h"
#include "mozilla/gfx/2D.h"
#include "nsCSSValue.h"
#include "nsLayoutUtils.h"
#include "nsNameSpaceManager.h"
#include "nsMathMLChar.h"
#include "nsCSSPseudoElements.h"
#include "mozilla/dom/MathMLElement.h"
#include "gfxMathTable.h"
#include "nsPresContextInlines.h"

// used to map attributes into CSS rules
#include "mozilla/ServoStyleSet.h"
#include "nsDisplayList.h"

using namespace mozilla;
using namespace mozilla::gfx;

eMathMLFrameType nsMathMLFrame::GetMathMLFrameType() {
  // see if it is an embellished operator (mapped to 'Op' in TeX)
  if (mEmbellishData.coreFrame)
    return GetMathMLFrameTypeFor(mEmbellishData.coreFrame);

  // if it has a prescribed base, fetch the type from there
  if (mPresentationData.baseFrame)
    return GetMathMLFrameTypeFor(mPresentationData.baseFrame);

  // everything else is treated as ordinary (mapped to 'Ord' in TeX)
  return eMathMLFrameType_Ordinary;
}

NS_IMETHODIMP
nsMathMLFrame::InheritAutomaticData(nsIFrame* aParent) {
  mEmbellishData.flags = 0;
  mEmbellishData.coreFrame = nullptr;
  mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
  mEmbellishData.leadingSpace = 0;
  mEmbellishData.trailingSpace = 0;

  mPresentationData.flags = 0;
  mPresentationData.baseFrame = nullptr;

  // by default, just inherit the display of our parent
  nsPresentationData parentData;
  GetPresentationDataFrom(aParent, parentData);

#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
  mPresentationData.flags |= NS_MATHML_SHOW_BOUNDING_METRICS;
#endif

  return NS_OK;
}

NS_IMETHODIMP
nsMathMLFrame::UpdatePresentationData(uint32_t aFlagsValues,
                                      uint32_t aWhichFlags) {
  NS_ASSERTION(NS_MATHML_IS_COMPRESSED(aWhichFlags) ||
                   NS_MATHML_IS_DTLS_SET(aWhichFlags),
               "aWhichFlags should only be compression or dtls flag");

  if (NS_MATHML_IS_COMPRESSED(aWhichFlags)) {
    // updating the compression flag is allowed
    if (NS_MATHML_IS_COMPRESSED(aFlagsValues)) {
      // 'compressed' means 'prime' style in App. G, TeXbook
      mPresentationData.flags |= NS_MATHML_COMPRESSED;
    }
    // no else. the flag is sticky. it retains its value once it is set
  }
  // These flags determine whether the dtls font feature settings should
  // be applied.
  if (NS_MATHML_IS_DTLS_SET(aWhichFlags)) {
    if (NS_MATHML_IS_DTLS_SET(aFlagsValues)) {
      mPresentationData.flags |= NS_MATHML_DTLS;
    } else {
      mPresentationData.flags &= ~NS_MATHML_DTLS;
    }
  }
  return NS_OK;
}

/* static */
void nsMathMLFrame::GetEmbellishDataFrom(nsIFrame* aFrame,
                                         nsEmbellishData& aEmbellishData) {
  // initialize OUT params
  aEmbellishData.flags = 0;
  aEmbellishData.coreFrame = nullptr;
  aEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
  aEmbellishData.leadingSpace = 0;
  aEmbellishData.trailingSpace = 0;

  if (aFrame && aFrame->IsFrameOfType(nsIFrame::eMathML)) {
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
    if (mathMLFrame) {
      mathMLFrame->GetEmbellishData(aEmbellishData);
    }
  }
}

// helper to get the presentation data of a frame, by possibly walking up
// the frame hierarchy if we happen to be surrounded by non-MathML frames.
/* static */
void nsMathMLFrame::GetPresentationDataFrom(
    nsIFrame* aFrame, nsPresentationData& aPresentationData, bool aClimbTree) {
  // initialize OUT params
  aPresentationData.flags = 0;
  aPresentationData.baseFrame = nullptr;

  nsIFrame* frame = aFrame;
  while (frame) {
    if (frame->IsFrameOfType(nsIFrame::eMathML)) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(frame);
      if (mathMLFrame) {
        mathMLFrame->GetPresentationData(aPresentationData);
        break;
      }
    }
    // stop if the caller doesn't want to lookup beyond the frame
    if (!aClimbTree) {
      break;
    }
    // stop if we reach the root <math> tag
    nsIContent* content = frame->GetContent();
    NS_ASSERTION(content || !frame->GetParent(),  // no assert for the root
                 "dangling frame without a content node");
    if (!content) break;

    if (content->IsMathMLElement(nsGkAtoms::math)) {
      break;
    }
    frame = frame->GetParent();
  }
  NS_WARNING_ASSERTION(
      frame && frame->GetContent(),
      "bad MathML markup - could not find the top <math> element");
}

/* static */
void nsMathMLFrame::GetRuleThickness(DrawTarget* aDrawTarget,
                                     nsFontMetrics* aFontMetrics,
                                     nscoord& aRuleThickness) {
  nscoord xHeight = aFontMetrics->XHeight();
  char16_t overBar = 0x00AF;
  nsBoundingMetrics bm = nsLayoutUtils::AppUnitBoundsOfString(
      &overBar, 1, *aFontMetrics, aDrawTarget);
  aRuleThickness = bm.ascent + bm.descent;
  if (aRuleThickness <= 0 || aRuleThickness >= xHeight) {
    // fall-back to the other version
    GetRuleThickness(aFontMetrics, aRuleThickness);
  }
}

/* static */
void nsMathMLFrame::GetAxisHeight(DrawTarget* aDrawTarget,
                                  nsFontMetrics* aFontMetrics,
                                  nscoord& aAxisHeight) {
  RefPtr<gfxFont> mathFont =
      aFontMetrics->GetThebesFontGroup()->GetFirstMathFont();
  if (mathFont) {
    aAxisHeight = mathFont->MathTable()->Constant(
        gfxMathTable::AxisHeight, aFontMetrics->AppUnitsPerDevPixel());
    return;
  }

  nscoord xHeight = aFontMetrics->XHeight();
  char16_t minus = 0x2212;  // not '-', but official Unicode minus sign
  nsBoundingMetrics bm = nsLayoutUtils::AppUnitBoundsOfString(
      &minus, 1, *aFontMetrics, aDrawTarget);
  aAxisHeight = bm.ascent - (bm.ascent + bm.descent) / 2;
  if (aAxisHeight <= 0 || aAxisHeight >= xHeight) {
    // fall-back to the other version
    GetAxisHeight(aFontMetrics, aAxisHeight);
  }
}

/* static */
nscoord nsMathMLFrame::CalcLength(nsPresContext* aPresContext,
                                  ComputedStyle* aComputedStyle,
                                  const nsCSSValue& aCSSValue,
                                  float aFontSizeInflation) {
  NS_ASSERTION(aCSSValue.IsLengthUnit(), "not a length unit");

  if (aCSSValue.IsPixelLengthUnit()) {
    return aCSSValue.GetPixelLength();
  }

  nsCSSUnit unit = aCSSValue.GetUnit();

  if (eCSSUnit_EM == unit) {
    const nsStyleFont* font = aComputedStyle->StyleFont();
    return font->mFont.size.ScaledBy(aCSSValue.GetFloatValue()).ToAppUnits();
  }

  if (eCSSUnit_XHeight == unit) {
    RefPtr<nsFontMetrics> fm = nsLayoutUtils::GetFontMetricsForComputedStyle(
        aComputedStyle, aPresContext, aFontSizeInflation);
    nscoord xHeight = fm->XHeight();
    return NSToCoordRound(aCSSValue.GetFloatValue() * (float)xHeight);
  }

  // MathML doesn't specify other CSS units such as rem or ch
  NS_ERROR("Unsupported unit");
  return 0;
}

/* static */
void nsMathMLFrame::GetSubDropFromChild(nsIFrame* aChild, nscoord& aSubDrop,
                                        float aFontSizeInflation) {
  RefPtr<nsFontMetrics> fm =
      nsLayoutUtils::GetFontMetricsForFrame(aChild, aFontSizeInflation);
  GetSubDrop(fm, aSubDrop);
}

/* static */
void nsMathMLFrame::GetSupDropFromChild(nsIFrame* aChild, nscoord& aSupDrop,
                                        float aFontSizeInflation) {
  RefPtr<nsFontMetrics> fm =
      nsLayoutUtils::GetFontMetricsForFrame(aChild, aFontSizeInflation);
  GetSupDrop(fm, aSupDrop);
}

/* static */
void nsMathMLFrame::ParseNumericValue(const nsString& aString,
                                      nscoord* aLengthValue, uint32_t aFlags,
                                      nsPresContext* aPresContext,
                                      ComputedStyle* aComputedStyle,
                                      float aFontSizeInflation) {
  nsCSSValue cssValue;

  if (!dom::MathMLElement::ParseNumericValue(aString, cssValue, aFlags,
                                             aPresContext->Document())) {
    // Invalid attribute value. aLengthValue remains unchanged, so the default
    // length value is used.
    return;
  }

  nsCSSUnit unit = cssValue.GetUnit();

  if (unit == eCSSUnit_Percent || unit == eCSSUnit_Number) {
    // Relative units. A multiple of the default length value is used.
    *aLengthValue = NSToCoordRound(
        *aLengthValue * (unit == eCSSUnit_Percent ? cssValue.GetPercentValue()
                                                  : cssValue.GetFloatValue()));
    return;
  }

  // Absolute units.
  *aLengthValue =
      CalcLength(aPresContext, aComputedStyle, cssValue, aFontSizeInflation);
}

namespace mozilla {
#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
class nsDisplayMathMLBoundingMetrics final : public nsDisplayItem {
 public:
  nsDisplayMathMLBoundingMetrics(nsDisplayListBuilder* aBuilder,
                                 nsIFrame* aFrame, const nsRect& aRect)
      : nsDisplayItem(aBuilder, aFrame), mRect(aRect) {
    MOZ_COUNT_CTOR(nsDisplayMathMLBoundingMetrics);
  }
  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayMathMLBoundingMetrics)

  virtual void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
  NS_DISPLAY_DECL_NAME("MathMLBoundingMetrics", TYPE_MATHML_BOUNDING_METRICS)
 private:
  nsRect mRect;
};

void nsDisplayMathMLBoundingMetrics::Paint(nsDisplayListBuilder* aBuilder,
                                           gfxContext* aCtx) {
  DrawTarget* drawTarget = aCtx->GetDrawTarget();
  Rect r = NSRectToRect(mRect + ToReferenceFrame(),
                        mFrame->PresContext()->AppUnitsPerDevPixel());
  ColorPattern blue(ToDeviceColor(Color(0.f, 0.f, 1.f, 1.f)));
  drawTarget->StrokeRect(r, blue);
}

void nsMathMLFrame::DisplayBoundingMetrics(nsDisplayListBuilder* aBuilder,
                                           nsIFrame* aFrame, const nsPoint& aPt,
                                           const nsBoundingMetrics& aMetrics,
                                           const nsDisplayListSet& aLists) {
  if (!NS_MATHML_PAINT_BOUNDING_METRICS(mPresentationData.flags)) return;

  nscoord x = aPt.x + aMetrics.leftBearing;
  nscoord y = aPt.y - aMetrics.ascent;
  nscoord w = aMetrics.rightBearing - aMetrics.leftBearing;
  nscoord h = aMetrics.ascent + aMetrics.descent;

  aLists.Content()->AppendNewToTop<nsDisplayMathMLBoundingMetrics>(
      aBuilder, aFrame, nsRect(x, y, w, h));
}
#endif

class nsDisplayMathMLBar final : public nsPaintedDisplayItem {
 public:
  nsDisplayMathMLBar(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                     const nsRect& aRect)
      : nsPaintedDisplayItem(aBuilder, aFrame), mRect(aRect) {
    MOZ_COUNT_CTOR(nsDisplayMathMLBar);
  }
  MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayMathMLBar)

  virtual void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
  NS_DISPLAY_DECL_NAME("MathMLBar", TYPE_MATHML_BAR)

 private:
  nsRect mRect;
};

void nsDisplayMathMLBar::Paint(nsDisplayListBuilder* aBuilder,
                               gfxContext* aCtx) {
  // paint the bar with the current text color
  DrawTarget* drawTarget = aCtx->GetDrawTarget();
  Rect rect = NSRectToNonEmptySnappedRect(
      mRect + ToReferenceFrame(), mFrame->PresContext()->AppUnitsPerDevPixel(),
      *drawTarget);
  ColorPattern color(ToDeviceColor(
      mFrame->GetVisitedDependentColor(&nsStyleText::mWebkitTextFillColor)));
  drawTarget->FillRect(rect, color);
}

}  // namespace mozilla

void nsMathMLFrame::DisplayBar(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                               const nsRect& aRect,
                               const nsDisplayListSet& aLists,
                               uint32_t aIndex) {
  if (!aFrame->StyleVisibility()->IsVisible() || aRect.IsEmpty()) return;

  aLists.Content()->AppendNewToTopWithIndex<nsDisplayMathMLBar>(
      aBuilder, aFrame, aIndex, aRect);
}

void nsMathMLFrame::GetRadicalParameters(nsFontMetrics* aFontMetrics,
                                         bool aDisplayStyle,
                                         nscoord& aRadicalRuleThickness,
                                         nscoord& aRadicalExtraAscender,
                                         nscoord& aRadicalVerticalGap) {
  nscoord oneDevPixel = aFontMetrics->AppUnitsPerDevPixel();
  RefPtr<gfxFont> mathFont =
      aFontMetrics->GetThebesFontGroup()->GetFirstMathFont();

  // get the radical rulethickness
  if (mathFont) {
    aRadicalRuleThickness = mathFont->MathTable()->Constant(
        gfxMathTable::RadicalRuleThickness, oneDevPixel);
  } else {
    GetRuleThickness(aFontMetrics, aRadicalRuleThickness);
  }

  // get the leading to be left at the top of the resulting frame
  if (mathFont) {
    aRadicalExtraAscender = mathFont->MathTable()->Constant(
        gfxMathTable::RadicalExtraAscender, oneDevPixel);
  } else {
    // This seems more reliable than using aFontMetrics->GetLeading() on
    // suspicious fonts.
    nscoord em;
    GetEmHeight(aFontMetrics, em);
    aRadicalExtraAscender = nscoord(0.2f * em);
  }

  // get the clearance between rule and content
  if (mathFont) {
    aRadicalVerticalGap = mathFont->MathTable()->Constant(
        aDisplayStyle ? gfxMathTable::RadicalDisplayStyleVerticalGap
                      : gfxMathTable::RadicalVerticalGap,
        oneDevPixel);
  } else {
    // Rule 11, App. G, TeXbook
    aRadicalVerticalGap =
        aRadicalRuleThickness +
        (aDisplayStyle ? aFontMetrics->XHeight() : aRadicalRuleThickness) / 4;
  }
}