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Issue 891013003: Delete RenderTextWin and RenderTextPango. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: gn update Created 5 years, 10 months ago
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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "ui/gfx/render_text_pango.h"
6
7 #include <pango/pangocairo.h>
8 #include <algorithm>
9 #include <string>
10 #include <vector>
11
12 #include "base/i18n/break_iterator.h"
13 #include "base/logging.h"
14 #include "third_party/skia/include/core/SkTypeface.h"
15 #include "ui/gfx/canvas.h"
16 #include "ui/gfx/font.h"
17 #include "ui/gfx/font_list.h"
18 #include "ui/gfx/font_render_params.h"
19 #include "ui/gfx/pango_util.h"
20 #include "ui/gfx/platform_font_pango.h"
21 #include "ui/gfx/utf16_indexing.h"
22
23 namespace gfx {
24
25 namespace {
26
27 // Returns the preceding element in a GSList (O(n)).
28 GSList* GSListPrevious(GSList* head, GSList* item) {
29 GSList* prev = NULL;
30 for (GSList* cur = head; cur != item; cur = cur->next) {
31 DCHECK(cur);
32 prev = cur;
33 }
34 return prev;
35 }
36
37 // Returns true if the given visual cursor |direction| is logically forward
38 // motion in the given Pango |item|.
39 bool IsForwardMotion(VisualCursorDirection direction, const PangoItem* item) {
40 bool rtl = item->analysis.level & 1;
41 return rtl == (direction == CURSOR_LEFT);
42 }
43
44 // Checks whether |range| contains |index|. This is not the same as calling
45 // range.Contains(Range(index)), which returns true if |index| == |range.end()|.
46 bool IndexInRange(const Range& range, size_t index) {
47 return index >= range.start() && index < range.end();
48 }
49
50 // Sets underline metrics on |renderer| according to Pango font |desc|.
51 void SetPangoUnderlineMetrics(PangoFontDescription *desc,
52 internal::SkiaTextRenderer* renderer) {
53 PangoFontMetrics* metrics = GetPangoFontMetrics(desc);
54 int thickness = pango_font_metrics_get_underline_thickness(metrics);
55 // Pango returns the position "above the baseline". Change its sign to convert
56 // it to a vertical offset from the baseline.
57 int position = -pango_font_metrics_get_underline_position(metrics);
58
59 // Note: pango_quantize_line_geometry() guarantees pixel boundaries, so
60 // PANGO_PIXELS() is safe to use.
61 pango_quantize_line_geometry(&thickness, &position);
62 int thickness_pixels = PANGO_PIXELS(thickness);
63 int position_pixels = PANGO_PIXELS(position);
64
65 // Ugly hack: make sure that underlines don't get clipped. See
66 // http://crbug.com/393117.
67 int descent_pixels = PANGO_PIXELS(pango_font_metrics_get_descent(metrics));
68 position_pixels = std::min(position_pixels,
69 descent_pixels - thickness_pixels);
70
71 renderer->SetUnderlineMetrics(thickness_pixels, position_pixels);
72 }
73
74 } // namespace
75
76 // TODO(xji): index saved in upper layer is utf16 index. Pango uses utf8 index.
77 // Since caret_pos is used internally, we could save utf8 index for caret_pos
78 // to avoid conversion.
79
80 RenderTextPango::RenderTextPango()
81 : layout_(NULL),
82 current_line_(NULL),
83 log_attrs_(NULL),
84 num_log_attrs_(0),
85 layout_text_(NULL) {
86 }
87
88 RenderTextPango::~RenderTextPango() {
89 ResetLayout();
90 }
91
92 scoped_ptr<RenderText> RenderTextPango::CreateInstanceOfSameType() const {
93 return scoped_ptr<RenderTextPango>(new RenderTextPango);
94 }
95
96 Size RenderTextPango::GetStringSize() {
97 EnsureLayout();
98 int width = 0, height = 0;
99 pango_layout_get_pixel_size(layout_, &width, &height);
100
101 // Pango returns 0 widths for very long strings (of 0x40000 chars or more).
102 // This is caused by an int overflow in pango_glyph_string_extents_range.
103 // Absurdly long strings may even report non-zero garbage values for width;
104 // while detecting that isn't worthwhile, this handles the 0 width cases.
105 const long kAbsurdLength = 100000;
106 if (width == 0 && g_utf8_strlen(layout_text_, -1) > kAbsurdLength)
107 width = font_list().GetExpectedTextWidth(g_utf8_strlen(layout_text_, -1));
108
109 // Keep a consistent height between this particular string's PangoLayout and
110 // potentially larger text supported by the FontList.
111 // For example, if a text field contains a Japanese character, which is
112 // smaller than Latin ones, and then later a Latin one is inserted, this
113 // ensures that the text baseline does not shift.
114 return Size(width, std::max(height, font_list().GetHeight()));
115 }
116
117 SelectionModel RenderTextPango::FindCursorPosition(const Point& point) {
118 EnsureLayout();
119
120 if (text().empty())
121 return SelectionModel(0, CURSOR_FORWARD);
122
123 Point p(ToTextPoint(point));
124
125 // When the point is outside of text, return HOME/END position.
126 if (p.x() < 0)
127 return EdgeSelectionModel(CURSOR_LEFT);
128 if (p.x() > GetStringSize().width())
129 return EdgeSelectionModel(CURSOR_RIGHT);
130
131 int caret_pos = 0, trailing = 0;
132 pango_layout_xy_to_index(layout_, p.x() * PANGO_SCALE, p.y() * PANGO_SCALE,
133 &caret_pos, &trailing);
134
135 DCHECK_GE(trailing, 0);
136 if (trailing > 0) {
137 caret_pos = g_utf8_offset_to_pointer(layout_text_ + caret_pos,
138 trailing) - layout_text_;
139 DCHECK_LE(static_cast<size_t>(caret_pos), strlen(layout_text_));
140 }
141
142 return SelectionModel(LayoutIndexToTextIndex(caret_pos),
143 (trailing > 0) ? CURSOR_BACKWARD : CURSOR_FORWARD);
144 }
145
146 std::vector<RenderText::FontSpan> RenderTextPango::GetFontSpansForTesting() {
147 EnsureLayout();
148
149 std::vector<RenderText::FontSpan> spans;
150 for (GSList* it = current_line_->runs; it; it = it->next) {
151 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(it->data)->item;
152 const int start = LayoutIndexToTextIndex(item->offset);
153 const int end = LayoutIndexToTextIndex(item->offset + item->length);
154 const Range range(start, end);
155
156 ScopedPangoFontDescription desc(pango_font_describe(item->analysis.font));
157 spans.push_back(RenderText::FontSpan(Font(desc.get()), range));
158 }
159
160 return spans;
161 }
162
163 int RenderTextPango::GetLayoutTextBaseline() {
164 EnsureLayout();
165 return PANGO_PIXELS(pango_layout_get_baseline(layout_));
166 }
167
168 SelectionModel RenderTextPango::AdjacentCharSelectionModel(
169 const SelectionModel& selection,
170 VisualCursorDirection direction) {
171 GSList* run = GetRunContainingCaret(selection);
172 if (!run) {
173 // The cursor is not in any run: we're at the visual and logical edge.
174 SelectionModel edge = EdgeSelectionModel(direction);
175 if (edge.caret_pos() == selection.caret_pos())
176 return edge;
177 else
178 run = (direction == CURSOR_RIGHT) ?
179 current_line_->runs : g_slist_last(current_line_->runs);
180 } else {
181 // If the cursor is moving within the current run, just move it by one
182 // grapheme in the appropriate direction.
183 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
184 size_t caret = selection.caret_pos();
185 if (IsForwardMotion(direction, item)) {
186 if (caret < LayoutIndexToTextIndex(item->offset + item->length)) {
187 caret = IndexOfAdjacentGrapheme(caret, CURSOR_FORWARD);
188 return SelectionModel(caret, CURSOR_BACKWARD);
189 }
190 } else {
191 if (caret > LayoutIndexToTextIndex(item->offset)) {
192 caret = IndexOfAdjacentGrapheme(caret, CURSOR_BACKWARD);
193 return SelectionModel(caret, CURSOR_FORWARD);
194 }
195 }
196 // The cursor is at the edge of a run; move to the visually adjacent run.
197 // TODO(xji): Keep a vector of runs to avoid using a singly-linked list.
198 run = (direction == CURSOR_RIGHT) ?
199 run->next : GSListPrevious(current_line_->runs, run);
200 if (!run)
201 return EdgeSelectionModel(direction);
202 }
203 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
204 return IsForwardMotion(direction, item) ?
205 FirstSelectionModelInsideRun(item) : LastSelectionModelInsideRun(item);
206 }
207
208 SelectionModel RenderTextPango::AdjacentWordSelectionModel(
209 const SelectionModel& selection,
210 VisualCursorDirection direction) {
211 if (obscured())
212 return EdgeSelectionModel(direction);
213
214 base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
215 bool success = iter.Init();
216 DCHECK(success);
217 if (!success)
218 return selection;
219
220 SelectionModel cur(selection);
221 for (;;) {
222 cur = AdjacentCharSelectionModel(cur, direction);
223 GSList* run = GetRunContainingCaret(cur);
224 if (!run)
225 break;
226 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
227 size_t cursor = cur.caret_pos();
228 if (IsForwardMotion(direction, item) ?
229 iter.IsEndOfWord(cursor) : iter.IsStartOfWord(cursor))
230 break;
231 }
232
233 return cur;
234 }
235
236 Range RenderTextPango::GetGlyphBounds(size_t index) {
237 EnsureLayout();
238 PangoRectangle pos;
239 pango_layout_index_to_pos(layout_, TextIndexToLayoutIndex(index), &pos);
240 // TODO(derat): Support fractional ranges for subpixel positioning?
241 return Range(PANGO_PIXELS(pos.x), PANGO_PIXELS(pos.x + pos.width));
242 }
243
244 std::vector<Rect> RenderTextPango::GetSubstringBounds(const Range& range) {
245 DCHECK_LE(range.GetMax(), text().length());
246 if (range.is_empty())
247 return std::vector<Rect>();
248
249 EnsureLayout();
250 int* ranges = NULL;
251 int n_ranges = 0;
252 pango_layout_line_get_x_ranges(current_line_,
253 TextIndexToLayoutIndex(range.GetMin()),
254 TextIndexToLayoutIndex(range.GetMax()),
255 &ranges,
256 &n_ranges);
257
258 const int height = GetStringSize().height();
259
260 std::vector<Rect> bounds;
261 for (int i = 0; i < n_ranges; ++i) {
262 // TODO(derat): Support fractional bounds for subpixel positioning?
263 int x = PANGO_PIXELS(ranges[2 * i]);
264 int width = PANGO_PIXELS(ranges[2 * i + 1]) - x;
265 Rect rect(x, 0, width, height);
266 rect.set_origin(ToViewPoint(rect.origin()));
267 bounds.push_back(rect);
268 }
269 g_free(ranges);
270 return bounds;
271 }
272
273 size_t RenderTextPango::TextIndexToLayoutIndex(size_t index) const {
274 DCHECK(layout_);
275 ptrdiff_t offset = UTF16IndexToOffset(text(), 0, index);
276 // Clamp layout indices to the length of the text actually used for layout.
277 offset = std::min<size_t>(offset, g_utf8_strlen(layout_text_, -1));
278 const char* layout_pointer = g_utf8_offset_to_pointer(layout_text_, offset);
279 return (layout_pointer - layout_text_);
280 }
281
282 size_t RenderTextPango::LayoutIndexToTextIndex(size_t index) const {
283 DCHECK(layout_);
284 const char* layout_pointer = layout_text_ + index;
285 const long offset = g_utf8_pointer_to_offset(layout_text_, layout_pointer);
286 return UTF16OffsetToIndex(text(), 0, offset);
287 }
288
289 bool RenderTextPango::IsValidCursorIndex(size_t index) {
290 if (index == 0 || index == text().length())
291 return true;
292 if (!IsValidLogicalIndex(index))
293 return false;
294
295 EnsureLayout();
296 ptrdiff_t offset = UTF16IndexToOffset(text(), 0, index);
297 // Check that the index is marked as a legitimate cursor position by Pango.
298 return offset < num_log_attrs_ && log_attrs_[offset].is_cursor_position;
299 }
300
301 void RenderTextPango::ResetLayout() {
302 // set_cached_bounds_and_offset_valid(false) is done in RenderText for every
303 // operation that triggers ResetLayout().
304 if (layout_) {
305 // TODO(msw): Keep |layout_| across text changes, etc.; it can be re-used.
306 g_object_unref(layout_);
307 layout_ = NULL;
308 }
309 if (current_line_) {
310 pango_layout_line_unref(current_line_);
311 current_line_ = NULL;
312 }
313 if (log_attrs_) {
314 g_free(log_attrs_);
315 log_attrs_ = NULL;
316 num_log_attrs_ = 0;
317 }
318 layout_text_ = NULL;
319 }
320
321 void RenderTextPango::EnsureLayout() {
322 if (layout_ == NULL) {
323 cairo_surface_t* surface =
324 cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 0, 0);
325 CHECK_EQ(CAIRO_STATUS_SUCCESS, cairo_surface_status(surface));
326 cairo_t* cr = cairo_create(surface);
327 CHECK_EQ(CAIRO_STATUS_SUCCESS, cairo_status(cr));
328
329 layout_ = pango_cairo_create_layout(cr);
330 CHECK_NE(static_cast<PangoLayout*>(NULL), layout_);
331 cairo_destroy(cr);
332 cairo_surface_destroy(surface);
333
334 SetUpPangoLayout(layout_, GetLayoutText(), font_list(), GetTextDirection(),
335 Canvas::DefaultCanvasTextAlignment());
336
337 // No width set so that the x-axis position is relative to the start of the
338 // text. ToViewPoint and ToTextPoint take care of the position conversion
339 // between text space and view spaces.
340 pango_layout_set_width(layout_, -1);
341 // TODO(xji): If RenderText will be used for displaying purpose, such as
342 // label, we will need to remove the single-line-mode setting.
343 pango_layout_set_single_paragraph_mode(layout_, true);
344
345 layout_text_ = pango_layout_get_text(layout_);
346 SetupPangoAttributes(layout_);
347
348 current_line_ = pango_layout_get_line_readonly(layout_, 0);
349 CHECK_NE(static_cast<PangoLayoutLine*>(NULL), current_line_);
350 pango_layout_line_ref(current_line_);
351
352 pango_layout_get_log_attrs(layout_, &log_attrs_, &num_log_attrs_);
353 }
354 }
355
356 void RenderTextPango::SetupPangoAttributes(PangoLayout* layout) {
357 PangoAttrList* attrs = pango_attr_list_new();
358
359 // Splitting text runs to accommodate styling can break Arabic glyph shaping.
360 // Only split text runs as needed for bold and italic font styles changes.
361 BreakList<bool>::const_iterator bold = styles()[BOLD].breaks().begin();
362 BreakList<bool>::const_iterator italic = styles()[ITALIC].breaks().begin();
363 while (bold != styles()[BOLD].breaks().end() &&
364 italic != styles()[ITALIC].breaks().end()) {
365 const int style = (bold->second ? Font::BOLD : 0) |
366 (italic->second ? Font::ITALIC : 0);
367 const size_t bold_end = styles()[BOLD].GetRange(bold).end();
368 const size_t italic_end = styles()[ITALIC].GetRange(italic).end();
369 const size_t style_end = std::min(bold_end, italic_end);
370 if (style != font_list().GetFontStyle()) {
371 // TODO(derat): Don't interpret gfx::FontList font descriptions as Pango
372 // font descriptions: http://crbug.com/393067
373 FontList derived_font_list = font_list().DeriveWithStyle(style);
374 ScopedPangoFontDescription desc(
375 derived_font_list.GetFontDescriptionString());
376
377 PangoAttribute* pango_attr = pango_attr_font_desc_new(desc.get());
378 pango_attr->start_index =
379 TextIndexToLayoutIndex(std::max(bold->first, italic->first));
380 pango_attr->end_index = TextIndexToLayoutIndex(style_end);
381 pango_attr_list_insert(attrs, pango_attr);
382 }
383 bold += bold_end == style_end ? 1 : 0;
384 italic += italic_end == style_end ? 1 : 0;
385 }
386 DCHECK(bold == styles()[BOLD].breaks().end());
387 DCHECK(italic == styles()[ITALIC].breaks().end());
388
389 pango_layout_set_attributes(layout, attrs);
390 pango_attr_list_unref(attrs);
391 }
392
393 void RenderTextPango::DrawVisualText(Canvas* canvas) {
394 DCHECK(layout_);
395
396 // Skia will draw glyphs with respect to the baseline.
397 Vector2d offset(GetLineOffset(0) + Vector2d(0, GetLayoutTextBaseline()));
398
399 SkScalar x = SkIntToScalar(offset.x());
400 SkScalar y = SkIntToScalar(offset.y());
401
402 std::vector<SkPoint> pos;
403 std::vector<uint16> glyphs;
404
405 internal::SkiaTextRenderer renderer(canvas);
406 ApplyFadeEffects(&renderer);
407 ApplyTextShadows(&renderer);
408 renderer.SetFontRenderParams(
409 font_list().GetPrimaryFont().GetFontRenderParams(),
410 background_is_transparent());
411
412 // Temporarily apply composition underlines and selection colors.
413 ApplyCompositionAndSelectionStyles();
414
415 internal::StyleIterator style(colors(), styles());
416 for (GSList* it = current_line_->runs; it; it = it->next) {
417 // Skip painting runs outside the display area.
418 if (SkScalarTruncToInt(x) >= display_rect().right())
419 break;
420
421 PangoLayoutRun* run = reinterpret_cast<PangoLayoutRun*>(it->data);
422 int glyph_count = run->glyphs->num_glyphs;
423 if (glyph_count == 0)
424 continue;
425
426 ScopedPangoFontDescription desc(
427 pango_font_describe(run->item->analysis.font));
428 const std::string family_name =
429 pango_font_description_get_family(desc.get());
430 renderer.SetTextSize(GetPangoFontSizeInPixels(desc.get()));
431
432 glyphs.resize(glyph_count);
433 pos.resize(glyph_count);
434
435 // Track the current glyph and the glyph at the start of its styled range.
436 int glyph_index = 0;
437 int style_start_glyph_index = glyph_index;
438
439 // Track the x-coordinates for each styled range (|x| marks the current).
440 SkScalar style_start_x = x;
441
442 // Track the current style and its text (not layout) index range.
443 style.UpdatePosition(GetGlyphTextIndex(run, style_start_glyph_index));
444 Range style_range = style.GetRange();
445
446 do {
447 const PangoGlyphInfo& glyph = run->glyphs->glyphs[glyph_index];
448 glyphs[glyph_index] = static_cast<uint16>(glyph.glyph);
449 // Use pango_units_to_double() rather than PANGO_PIXELS() here, so units
450 // are not rounded to the pixel grid if subpixel positioning is enabled.
451 pos[glyph_index].set(x + pango_units_to_double(glyph.geometry.x_offset),
452 y + pango_units_to_double(glyph.geometry.y_offset));
453 x += pango_units_to_double(glyph.geometry.width);
454
455 ++glyph_index;
456 // If this is the last glyph of the range or the last glyph inside the
457 // display area (which would cause early termination of the loop), paint
458 // the range.
459 const size_t glyph_text_index = (glyph_index == glyph_count) ?
460 style_range.end() : GetGlyphTextIndex(run, glyph_index);
461 if (!IndexInRange(style_range, glyph_text_index) ||
462 SkScalarTruncToInt(x) >= display_rect().right()) {
463 // TODO(asvitkine): For cases like "fi", where "fi" is a single glyph
464 // but can span multiple styles, Pango splits the
465 // styles evenly over the glyph. We can do this too by
466 // clipping and drawing the glyph several times.
467 renderer.SetForegroundColor(style.color());
468 const int font_style = (style.style(BOLD) ? Font::BOLD : 0) |
469 (style.style(ITALIC) ? Font::ITALIC : 0);
470 renderer.SetFontFamilyWithStyle(family_name, font_style);
471 renderer.DrawPosText(&pos[style_start_glyph_index],
472 &glyphs[style_start_glyph_index],
473 glyph_index - style_start_glyph_index);
474 if (style.style(UNDERLINE))
475 SetPangoUnderlineMetrics(desc.get(), &renderer);
476 renderer.DrawDecorations(style_start_x, y, x - style_start_x,
477 style.style(UNDERLINE), style.style(STRIKE),
478 style.style(DIAGONAL_STRIKE));
479 style.UpdatePosition(glyph_text_index);
480 style_range = style.GetRange();
481 style_start_glyph_index = glyph_index;
482 style_start_x = x;
483 }
484 // Terminates loop when the end of the range has been reached or the next
485 // glyph falls outside the display area.
486 } while (glyph_index < glyph_count &&
487 SkScalarTruncToInt(x) < display_rect().right());
488 }
489
490 renderer.EndDiagonalStrike();
491
492 // Undo the temporarily applied composition underlines and selection colors.
493 UndoCompositionAndSelectionStyles();
494 }
495
496 GSList* RenderTextPango::GetRunContainingCaret(
497 const SelectionModel& caret) const {
498 size_t position = TextIndexToLayoutIndex(caret.caret_pos());
499 LogicalCursorDirection affinity = caret.caret_affinity();
500 GSList* run = current_line_->runs;
501 while (run) {
502 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
503 Range item_range(item->offset, item->offset + item->length);
504 if (RangeContainsCaret(item_range, position, affinity))
505 return run;
506 run = run->next;
507 }
508 return NULL;
509 }
510
511 SelectionModel RenderTextPango::FirstSelectionModelInsideRun(
512 const PangoItem* item) {
513 size_t caret = IndexOfAdjacentGrapheme(
514 LayoutIndexToTextIndex(item->offset), CURSOR_FORWARD);
515 return SelectionModel(caret, CURSOR_BACKWARD);
516 }
517
518 SelectionModel RenderTextPango::LastSelectionModelInsideRun(
519 const PangoItem* item) {
520 size_t caret = IndexOfAdjacentGrapheme(
521 LayoutIndexToTextIndex(item->offset + item->length), CURSOR_BACKWARD);
522 return SelectionModel(caret, CURSOR_FORWARD);
523 }
524
525 size_t RenderTextPango::GetGlyphTextIndex(PangoLayoutRun* run,
526 int glyph_index) const {
527 return LayoutIndexToTextIndex(run->item->offset +
528 run->glyphs->log_clusters[glyph_index]);
529 }
530
531 RenderText* RenderText::CreateNativeInstance() {
532 return new RenderTextPango;
533 }
534
535 } // namespace gfx
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