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Issue 26541007: ozone: Allow building for ozone without depending on pango (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: prepare-land Created 7 years, 1 month 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_linux.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_render_params_linux.h"
18 #include "ui/gfx/pango_util.h"
19 #include "ui/gfx/utf16_indexing.h"
20
21 namespace gfx {
22
23 namespace {
24
25 // Returns the preceding element in a GSList (O(n)).
26 GSList* GSListPrevious(GSList* head, GSList* item) {
27 GSList* prev = NULL;
28 for (GSList* cur = head; cur != item; cur = cur->next) {
29 DCHECK(cur);
30 prev = cur;
31 }
32 return prev;
33 }
34
35 // Returns true if the given visual cursor |direction| is logically forward
36 // motion in the given Pango |item|.
37 bool IsForwardMotion(VisualCursorDirection direction, const PangoItem* item) {
38 bool rtl = item->analysis.level & 1;
39 return rtl == (direction == CURSOR_LEFT);
40 }
41
42 // Checks whether |range| contains |index|. This is not the same as calling
43 // |range.Contains(gfx::Range(index))| - as that would return true when
44 // |index| == |range.end()|.
45 bool IndexInRange(const Range& range, size_t index) {
46 return index >= range.start() && index < range.end();
47 }
48
49 // Sets underline metrics on |renderer| according to Pango font |desc|.
50 void SetPangoUnderlineMetrics(PangoFontDescription *desc,
51 internal::SkiaTextRenderer* renderer) {
52 PangoFontMetrics* metrics = GetPangoFontMetrics(desc);
53 int thickness = pango_font_metrics_get_underline_thickness(metrics);
54 // Pango returns the position "above the baseline". Change its sign to convert
55 // it to a vertical offset from the baseline.
56 int position = -pango_font_metrics_get_underline_position(metrics);
57 pango_quantize_line_geometry(&thickness, &position);
58 // Note: pango_quantize_line_geometry() guarantees pixel boundaries, so
59 // PANGO_PIXELS() is safe to use.
60 renderer->SetUnderlineMetrics(PANGO_PIXELS(thickness),
61 PANGO_PIXELS(position));
62 }
63
64 } // namespace
65
66 // TODO(xji): index saved in upper layer is utf16 index. Pango uses utf8 index.
67 // Since caret_pos is used internally, we could save utf8 index for caret_pos
68 // to avoid conversion.
69
70 RenderTextLinux::RenderTextLinux()
71 : layout_(NULL),
72 current_line_(NULL),
73 log_attrs_(NULL),
74 num_log_attrs_(0),
75 layout_text_(NULL) {
76 }
77
78 RenderTextLinux::~RenderTextLinux() {
79 ResetLayout();
80 }
81
82 Size RenderTextLinux::GetStringSize() {
83 EnsureLayout();
84 int width = 0, height = 0;
85 pango_layout_get_pixel_size(layout_, &width, &height);
86 // Keep a consistent height between this particular string's PangoLayout and
87 // potentially larger text supported by the FontList.
88 // For example, if a text field contains a Japanese character, which is
89 // smaller than Latin ones, and then later a Latin one is inserted, this
90 // ensures that the text baseline does not shift.
91 return Size(width, std::max(height, font_list().GetHeight()));
92 }
93
94 SelectionModel RenderTextLinux::FindCursorPosition(const Point& point) {
95 EnsureLayout();
96
97 if (text().empty())
98 return SelectionModel(0, CURSOR_FORWARD);
99
100 Point p(ToTextPoint(point));
101
102 // When the point is outside of text, return HOME/END position.
103 if (p.x() < 0)
104 return EdgeSelectionModel(CURSOR_LEFT);
105 if (p.x() > GetStringSize().width())
106 return EdgeSelectionModel(CURSOR_RIGHT);
107
108 int caret_pos = 0, trailing = 0;
109 pango_layout_xy_to_index(layout_, p.x() * PANGO_SCALE, p.y() * PANGO_SCALE,
110 &caret_pos, &trailing);
111
112 DCHECK_GE(trailing, 0);
113 if (trailing > 0) {
114 caret_pos = g_utf8_offset_to_pointer(layout_text_ + caret_pos,
115 trailing) - layout_text_;
116 DCHECK_LE(static_cast<size_t>(caret_pos), strlen(layout_text_));
117 }
118
119 return SelectionModel(LayoutIndexToTextIndex(caret_pos),
120 (trailing > 0) ? CURSOR_BACKWARD : CURSOR_FORWARD);
121 }
122
123 std::vector<RenderText::FontSpan> RenderTextLinux::GetFontSpansForTesting() {
124 EnsureLayout();
125
126 std::vector<RenderText::FontSpan> spans;
127 for (GSList* it = current_line_->runs; it; it = it->next) {
128 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(it->data)->item;
129 const int start = LayoutIndexToTextIndex(item->offset);
130 const int end = LayoutIndexToTextIndex(item->offset + item->length);
131 const Range range(start, end);
132
133 ScopedPangoFontDescription desc(pango_font_describe(item->analysis.font));
134 spans.push_back(RenderText::FontSpan(Font(desc.get()), range));
135 }
136
137 return spans;
138 }
139
140 int RenderTextLinux::GetLayoutTextBaseline() {
141 EnsureLayout();
142 return PANGO_PIXELS(pango_layout_get_baseline(layout_));
143 }
144
145 SelectionModel RenderTextLinux::AdjacentCharSelectionModel(
146 const SelectionModel& selection,
147 VisualCursorDirection direction) {
148 GSList* run = GetRunContainingCaret(selection);
149 if (!run) {
150 // The cursor is not in any run: we're at the visual and logical edge.
151 SelectionModel edge = EdgeSelectionModel(direction);
152 if (edge.caret_pos() == selection.caret_pos())
153 return edge;
154 else
155 run = (direction == CURSOR_RIGHT) ?
156 current_line_->runs : g_slist_last(current_line_->runs);
157 } else {
158 // If the cursor is moving within the current run, just move it by one
159 // grapheme in the appropriate direction.
160 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
161 size_t caret = selection.caret_pos();
162 if (IsForwardMotion(direction, item)) {
163 if (caret < LayoutIndexToTextIndex(item->offset + item->length)) {
164 caret = IndexOfAdjacentGrapheme(caret, CURSOR_FORWARD);
165 return SelectionModel(caret, CURSOR_BACKWARD);
166 }
167 } else {
168 if (caret > LayoutIndexToTextIndex(item->offset)) {
169 caret = IndexOfAdjacentGrapheme(caret, CURSOR_BACKWARD);
170 return SelectionModel(caret, CURSOR_FORWARD);
171 }
172 }
173 // The cursor is at the edge of a run; move to the visually adjacent run.
174 // TODO(xji): Keep a vector of runs to avoid using a singly-linked list.
175 run = (direction == CURSOR_RIGHT) ?
176 run->next : GSListPrevious(current_line_->runs, run);
177 if (!run)
178 return EdgeSelectionModel(direction);
179 }
180 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
181 return IsForwardMotion(direction, item) ?
182 FirstSelectionModelInsideRun(item) : LastSelectionModelInsideRun(item);
183 }
184
185 SelectionModel RenderTextLinux::AdjacentWordSelectionModel(
186 const SelectionModel& selection,
187 VisualCursorDirection direction) {
188 if (obscured())
189 return EdgeSelectionModel(direction);
190
191 base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
192 bool success = iter.Init();
193 DCHECK(success);
194 if (!success)
195 return selection;
196
197 SelectionModel cur(selection);
198 for (;;) {
199 cur = AdjacentCharSelectionModel(cur, direction);
200 GSList* run = GetRunContainingCaret(cur);
201 if (!run)
202 break;
203 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
204 size_t cursor = cur.caret_pos();
205 if (IsForwardMotion(direction, item) ?
206 iter.IsEndOfWord(cursor) : iter.IsStartOfWord(cursor))
207 break;
208 }
209
210 return cur;
211 }
212
213 Range RenderTextLinux::GetGlyphBounds(size_t index) {
214 PangoRectangle pos;
215 pango_layout_index_to_pos(layout_, TextIndexToLayoutIndex(index), &pos);
216 // TODO(derat): Support fractional ranges for subpixel positioning?
217 return Range(PANGO_PIXELS(pos.x), PANGO_PIXELS(pos.x + pos.width));
218 }
219
220 std::vector<Rect> RenderTextLinux::GetSubstringBounds(const Range& range) {
221 DCHECK_LE(range.GetMax(), text().length());
222 if (range.is_empty())
223 return std::vector<Rect>();
224
225 EnsureLayout();
226 int* ranges = NULL;
227 int n_ranges = 0;
228 pango_layout_line_get_x_ranges(current_line_,
229 TextIndexToLayoutIndex(range.GetMin()),
230 TextIndexToLayoutIndex(range.GetMax()),
231 &ranges,
232 &n_ranges);
233
234 const int height = GetStringSize().height();
235
236 std::vector<Rect> bounds;
237 for (int i = 0; i < n_ranges; ++i) {
238 // TODO(derat): Support fractional bounds for subpixel positioning?
239 int x = PANGO_PIXELS(ranges[2 * i]);
240 int width = PANGO_PIXELS(ranges[2 * i + 1]) - x;
241 Rect rect(x, 0, width, height);
242 rect.set_origin(ToViewPoint(rect.origin()));
243 bounds.push_back(rect);
244 }
245 g_free(ranges);
246 return bounds;
247 }
248
249 size_t RenderTextLinux::TextIndexToLayoutIndex(size_t index) const {
250 DCHECK(layout_);
251 ptrdiff_t offset = gfx::UTF16IndexToOffset(text(), 0, index);
252 // Clamp layout indices to the length of the text actually used for layout.
253 offset = std::min<size_t>(offset, g_utf8_strlen(layout_text_, -1));
254 const char* layout_pointer = g_utf8_offset_to_pointer(layout_text_, offset);
255 return (layout_pointer - layout_text_);
256 }
257
258 size_t RenderTextLinux::LayoutIndexToTextIndex(size_t index) const {
259 DCHECK(layout_);
260 const char* layout_pointer = layout_text_ + index;
261 const long offset = g_utf8_pointer_to_offset(layout_text_, layout_pointer);
262 return gfx::UTF16OffsetToIndex(text(), 0, offset);
263 }
264
265 bool RenderTextLinux::IsCursorablePosition(size_t position) {
266 if (position == 0 && text().empty())
267 return true;
268 if (position >= text().length())
269 return position == text().length();
270 if (!gfx::IsValidCodePointIndex(text(), position))
271 return false;
272
273 EnsureLayout();
274 ptrdiff_t offset = gfx::UTF16IndexToOffset(text(), 0, position);
275 // Check that the index corresponds with a valid text code point, that it is
276 // marked as a legitimate cursor position by Pango, and that it is not
277 // truncated from layout text (its glyph is shown on screen).
278 return (offset < num_log_attrs_ && log_attrs_[offset].is_cursor_position &&
279 offset < g_utf8_strlen(layout_text_, -1));
280 }
281
282 void RenderTextLinux::ResetLayout() {
283 // set_cached_bounds_and_offset_valid(false) is done in RenderText for every
284 // operation that triggers ResetLayout().
285 if (layout_) {
286 // TODO(msw): Keep |layout_| across text changes, etc.; it can be re-used.
287 g_object_unref(layout_);
288 layout_ = NULL;
289 }
290 if (current_line_) {
291 pango_layout_line_unref(current_line_);
292 current_line_ = NULL;
293 }
294 if (log_attrs_) {
295 g_free(log_attrs_);
296 log_attrs_ = NULL;
297 num_log_attrs_ = 0;
298 }
299 layout_text_ = NULL;
300 }
301
302 void RenderTextLinux::EnsureLayout() {
303 if (layout_ == NULL) {
304 cairo_surface_t* surface =
305 cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 0, 0);
306 CHECK_EQ(CAIRO_STATUS_SUCCESS, cairo_surface_status(surface));
307 cairo_t* cr = cairo_create(surface);
308 CHECK_EQ(CAIRO_STATUS_SUCCESS, cairo_status(cr));
309
310 layout_ = pango_cairo_create_layout(cr);
311 CHECK_NE(static_cast<PangoLayout*>(NULL), layout_);
312 cairo_destroy(cr);
313 cairo_surface_destroy(surface);
314
315 SetupPangoLayoutWithFontDescription(layout_,
316 GetLayoutText(),
317 font_list().GetFontDescriptionString(),
318 0,
319 GetTextDirection(),
320 Canvas::DefaultCanvasTextAlignment());
321
322 // No width set so that the x-axis position is relative to the start of the
323 // text. ToViewPoint and ToTextPoint take care of the position conversion
324 // between text space and view spaces.
325 pango_layout_set_width(layout_, -1);
326 // TODO(xji): If RenderText will be used for displaying purpose, such as
327 // label, we will need to remove the single-line-mode setting.
328 pango_layout_set_single_paragraph_mode(layout_, true);
329
330 layout_text_ = pango_layout_get_text(layout_);
331 SetupPangoAttributes(layout_);
332
333 current_line_ = pango_layout_get_line_readonly(layout_, 0);
334 CHECK_NE(static_cast<PangoLayoutLine*>(NULL), current_line_);
335 pango_layout_line_ref(current_line_);
336
337 pango_layout_get_log_attrs(layout_, &log_attrs_, &num_log_attrs_);
338 }
339 }
340
341 void RenderTextLinux::SetupPangoAttributes(PangoLayout* layout) {
342 PangoAttrList* attrs = pango_attr_list_new();
343
344 // Splitting text runs to accommodate styling can break Arabic glyph shaping.
345 // Only split text runs as needed for bold and italic font styles changes.
346 BreakList<bool>::const_iterator bold = styles()[BOLD].breaks().begin();
347 BreakList<bool>::const_iterator italic = styles()[ITALIC].breaks().begin();
348 while (bold != styles()[BOLD].breaks().end() &&
349 italic != styles()[ITALIC].breaks().end()) {
350 const int style = (bold->second ? Font::BOLD : 0) |
351 (italic->second ? Font::ITALIC : 0);
352 const size_t bold_end = styles()[BOLD].GetRange(bold).end();
353 const size_t italic_end = styles()[ITALIC].GetRange(italic).end();
354 const size_t style_end = std::min(bold_end, italic_end);
355 if (style != font_list().GetFontStyle()) {
356 FontList derived_font_list = font_list().DeriveFontList(style);
357 ScopedPangoFontDescription desc(pango_font_description_from_string(
358 derived_font_list.GetFontDescriptionString().c_str()));
359
360 PangoAttribute* pango_attr = pango_attr_font_desc_new(desc.get());
361 pango_attr->start_index =
362 TextIndexToLayoutIndex(std::max(bold->first, italic->first));
363 pango_attr->end_index = TextIndexToLayoutIndex(style_end);
364 pango_attr_list_insert(attrs, pango_attr);
365 }
366 bold += bold_end == style_end ? 1 : 0;
367 italic += italic_end == style_end ? 1 : 0;
368 }
369 DCHECK(bold == styles()[BOLD].breaks().end());
370 DCHECK(italic == styles()[ITALIC].breaks().end());
371
372 pango_layout_set_attributes(layout, attrs);
373 pango_attr_list_unref(attrs);
374 }
375
376 void RenderTextLinux::DrawVisualText(Canvas* canvas) {
377 DCHECK(layout_);
378
379 // Skia will draw glyphs with respect to the baseline.
380 Vector2d offset(GetLineOffset(0) + Vector2d(0, GetLayoutTextBaseline()));
381
382 SkScalar x = SkIntToScalar(offset.x());
383 SkScalar y = SkIntToScalar(offset.y());
384
385 std::vector<SkPoint> pos;
386 std::vector<uint16> glyphs;
387
388 internal::SkiaTextRenderer renderer(canvas);
389 ApplyFadeEffects(&renderer);
390 ApplyTextShadows(&renderer);
391
392 // TODO(derat): Use font-specific params: http://crbug.com/125235
393 const gfx::FontRenderParams& render_params =
394 gfx::GetDefaultFontRenderParams();
395 const bool use_subpixel_rendering =
396 render_params.subpixel_rendering !=
397 gfx::FontRenderParams::SUBPIXEL_RENDERING_NONE;
398 renderer.SetFontSmoothingSettings(
399 render_params.antialiasing,
400 use_subpixel_rendering && !background_is_transparent());
401
402 // Temporarily apply composition underlines and selection colors.
403 ApplyCompositionAndSelectionStyles();
404
405 internal::StyleIterator style(colors(), styles());
406 for (GSList* it = current_line_->runs; it; it = it->next) {
407 PangoLayoutRun* run = reinterpret_cast<PangoLayoutRun*>(it->data);
408 int glyph_count = run->glyphs->num_glyphs;
409 // TODO(msw): Skip painting runs outside the display rect area, like Win.
410 if (glyph_count == 0)
411 continue;
412
413 ScopedPangoFontDescription desc(
414 pango_font_describe(run->item->analysis.font));
415
416 const std::string family_name =
417 pango_font_description_get_family(desc.get());
418 renderer.SetTextSize(GetPangoFontSizeInPixels(desc.get()));
419
420 glyphs.resize(glyph_count);
421 pos.resize(glyph_count);
422
423 // Track the current glyph and the glyph at the start of its styled range.
424 int glyph_index = 0;
425 int style_start_glyph_index = glyph_index;
426
427 // Track the x-coordinates for each styled range (|x| marks the current).
428 SkScalar style_start_x = x;
429
430 // Track the current style and its text (not layout) index range.
431 style.UpdatePosition(GetGlyphTextIndex(run, style_start_glyph_index));
432 Range style_range = style.GetRange();
433
434 do {
435 const PangoGlyphInfo& glyph = run->glyphs->glyphs[glyph_index];
436 glyphs[glyph_index] = static_cast<uint16>(glyph.glyph);
437 // Use pango_units_to_double() rather than PANGO_PIXELS() here, so units
438 // are not rounded to the pixel grid if subpixel positioning is enabled.
439 pos[glyph_index].set(x + pango_units_to_double(glyph.geometry.x_offset),
440 y + pango_units_to_double(glyph.geometry.y_offset));
441 x += pango_units_to_double(glyph.geometry.width);
442
443 ++glyph_index;
444 const size_t glyph_text_index = (glyph_index == glyph_count) ?
445 style_range.end() : GetGlyphTextIndex(run, glyph_index);
446 if (!IndexInRange(style_range, glyph_text_index)) {
447 // TODO(asvitkine): For cases like "fi", where "fi" is a single glyph
448 // but can span multiple styles, Pango splits the
449 // styles evenly over the glyph. We can do this too by
450 // clipping and drawing the glyph several times.
451 renderer.SetForegroundColor(style.color());
452 const int font_style = (style.style(BOLD) ? Font::BOLD : 0) |
453 (style.style(ITALIC) ? Font::ITALIC : 0);
454 renderer.SetFontFamilyWithStyle(family_name, font_style);
455 renderer.DrawPosText(&pos[style_start_glyph_index],
456 &glyphs[style_start_glyph_index],
457 glyph_index - style_start_glyph_index);
458 if (style.style(UNDERLINE))
459 SetPangoUnderlineMetrics(desc.get(), &renderer);
460 renderer.DrawDecorations(style_start_x, y, x - style_start_x,
461 style.style(UNDERLINE), style.style(STRIKE),
462 style.style(DIAGONAL_STRIKE));
463 style.UpdatePosition(glyph_text_index);
464 style_range = style.GetRange();
465 style_start_glyph_index = glyph_index;
466 style_start_x = x;
467 }
468 } while (glyph_index < glyph_count);
469 }
470
471 // Undo the temporarily applied composition underlines and selection colors.
472 UndoCompositionAndSelectionStyles();
473 }
474
475 GSList* RenderTextLinux::GetRunContainingCaret(
476 const SelectionModel& caret) const {
477 size_t position = TextIndexToLayoutIndex(caret.caret_pos());
478 LogicalCursorDirection affinity = caret.caret_affinity();
479 GSList* run = current_line_->runs;
480 while (run) {
481 PangoItem* item = reinterpret_cast<PangoLayoutRun*>(run->data)->item;
482 Range item_range(item->offset, item->offset + item->length);
483 if (RangeContainsCaret(item_range, position, affinity))
484 return run;
485 run = run->next;
486 }
487 return NULL;
488 }
489
490 SelectionModel RenderTextLinux::FirstSelectionModelInsideRun(
491 const PangoItem* item) {
492 size_t caret = IndexOfAdjacentGrapheme(
493 LayoutIndexToTextIndex(item->offset), CURSOR_FORWARD);
494 return SelectionModel(caret, CURSOR_BACKWARD);
495 }
496
497 SelectionModel RenderTextLinux::LastSelectionModelInsideRun(
498 const PangoItem* item) {
499 size_t caret = IndexOfAdjacentGrapheme(
500 LayoutIndexToTextIndex(item->offset + item->length), CURSOR_BACKWARD);
501 return SelectionModel(caret, CURSOR_FORWARD);
502 }
503
504 size_t RenderTextLinux::GetGlyphTextIndex(PangoLayoutRun* run,
505 int glyph_index) const {
506 return LayoutIndexToTextIndex(run->item->offset +
507 run->glyphs->log_clusters[glyph_index]);
508 }
509
510 RenderText* RenderText::CreateInstance() {
511 return new RenderTextLinux;
512 }
513
514 } // namespace gfx
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