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1 // Copyright (c) 2011 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 "views/view_text_utils.h" | |
6 | |
7 #include "base/i18n/bidi_line_iterator.h" | |
8 #include "base/i18n/break_iterator.h" | |
9 #include "base/logging.h" | |
10 #include "base/utf_string_conversions.h" | |
11 #include "ui/gfx/canvas_skia.h" | |
12 #include "ui/gfx/font.h" | |
13 #include "ui/gfx/rect.h" | |
14 #include "ui/gfx/size.h" | |
15 #include "ui/views/controls/label.h" | |
16 #include "ui/views/controls/link.h" | |
17 | |
18 namespace view_text_utils { | |
19 | |
20 void DrawTextAndPositionUrl(gfx::Canvas* canvas, | |
21 views::Label* label, | |
22 const string16& text, | |
23 views::Link* link, | |
24 gfx::Rect* rect, | |
25 gfx::Size* position, | |
26 bool text_direction_is_rtl, | |
27 const gfx::Rect& bounds, | |
28 const gfx::Font& font) { | |
29 DCHECK(canvas && position); | |
30 | |
31 // The |text| parameter is potentially a mix of LTR and RTL "runs," where | |
32 // a run is a sequence of words that share the same directionality. We | |
33 // initialize a bidirectional ICU line iterator and split the text into | |
34 // runs that are either strictly LTR or strictly RTL, with no mix. | |
35 base::i18n::BiDiLineIterator bidi_line; | |
36 if (!bidi_line.Open(text, true, false)) | |
37 return; | |
38 | |
39 // Iterate over each run and draw it. | |
40 int run_start = 0; | |
41 int run_end = 0; | |
42 const int runs = bidi_line.CountRuns(); | |
43 for (int run = 0; run < runs; ++run) { | |
44 UBiDiLevel level = 0; | |
45 bidi_line.GetLogicalRun(run_start, &run_end, &level); | |
46 DCHECK(run_end > run_start); | |
47 string16 fragment = text.substr(run_start, run_end - run_start); | |
48 | |
49 // A flag that tells us whether we found LTR text inside RTL text. | |
50 bool ltr_inside_rtl_text = | |
51 ((level & 1) == UBIDI_LTR) && text_direction_is_rtl; | |
52 | |
53 // Draw text chunk contained in |fragment|. |position| is relative to the | |
54 // top left corner of the label we draw inside, even when drawing RTL. | |
55 DrawTextStartingFrom(canvas, label, fragment, position, bounds, font, | |
56 text_direction_is_rtl, ltr_inside_rtl_text); | |
57 | |
58 run_start = run_end; // Advance over what we just drew. | |
59 } | |
60 | |
61 // If the caller is interested in placing a link after this text blurb, we | |
62 // figure out here where to place it. | |
63 if (link && rect) { | |
64 gfx::Size sz = link->GetPreferredSize(); | |
65 gfx::Insets insets = link->GetInsets(); | |
66 WrapIfWordDoesntFit(sz.width(), font.GetHeight(), position, bounds); | |
67 int x = position->width(); | |
68 int y = position->height(); | |
69 | |
70 // Links have a border to allow them to be focused. | |
71 y -= insets.top(); | |
72 | |
73 *rect = gfx::Rect(x, y, sz.width(), sz.height()); | |
74 | |
75 // Go from relative pixel coordinates (within the label we are drawing | |
76 // on) to absolute pixel coordinates (relative to the top left corner of | |
77 // the dialog content). | |
78 rect->Offset(bounds.x(), bounds.y()); | |
79 // And leave some space to draw the link in. | |
80 position->Enlarge(sz.width(), 0); | |
81 } | |
82 } | |
83 | |
84 void DrawTextStartingFrom(gfx::Canvas* canvas, | |
85 views::Label* label, | |
86 const string16& text, | |
87 gfx::Size* position, | |
88 const gfx::Rect& bounds, | |
89 const gfx::Font& font, | |
90 bool text_direction_is_rtl, | |
91 bool ltr_within_rtl) { | |
92 // Iterate through line breaking opportunities (which in English would be | |
93 // spaces and such). This tells us where to wrap. | |
94 string16 text16(text); | |
95 base::i18n::BreakIterator iter(text16, | |
96 base::i18n::BreakIterator::BREAK_SPACE); | |
97 if (!iter.Init()) | |
98 return; | |
99 | |
100 int flags = (text_direction_is_rtl ? gfx::Canvas::TEXT_ALIGN_RIGHT : | |
101 gfx::Canvas::TEXT_ALIGN_LEFT); | |
102 flags |= gfx::Canvas::MULTI_LINE | gfx::Canvas::HIDE_PREFIX; | |
103 | |
104 // Iterate over each word in the text, or put in a more locale-neutral way: | |
105 // iterate to the next line breaking opportunity. | |
106 while (iter.Advance()) { | |
107 // Get the word and figure out the dimensions. | |
108 string16 word; | |
109 if (!ltr_within_rtl) | |
110 word = iter.GetString(); // Get the next word. | |
111 else | |
112 word = text16; // Draw the whole text at once. | |
113 | |
114 int w = font.GetStringWidth(word), h = font.GetHeight(); | |
115 gfx::CanvasSkia::SizeStringInt(word, font, &w, &h, flags); | |
116 | |
117 // If we exceed the boundaries, we need to wrap. | |
118 WrapIfWordDoesntFit(w, font.GetHeight(), position, bounds); | |
119 | |
120 int x = label->GetMirroredXInView(position->width()) + bounds.x(); | |
121 if (text_direction_is_rtl) { | |
122 x -= w; | |
123 // When drawing LTR strings inside RTL text we need to make sure we | |
124 // draw the trailing space (if one exists after the LTR text) to the | |
125 // left of the LTR string. | |
126 if (ltr_within_rtl && word[word.size() - 1] == ' ') { | |
127 int space_w = font.GetStringWidth(ASCIIToUTF16(" ")); | |
128 int space_h = font.GetHeight(); | |
129 gfx::CanvasSkia::SizeStringInt(ASCIIToUTF16(" "), font, &space_w, | |
130 &space_h, flags); | |
131 x += space_w; | |
132 } | |
133 } | |
134 int y = position->height() + bounds.y(); | |
135 | |
136 // Draw the text on the screen (mirrored, if RTL run). | |
137 canvas->DrawStringInt(word, font, label->enabled_color(), x, y, w, | |
138 font.GetHeight(), flags); | |
139 | |
140 if (!word.empty() && word[word.size() - 1] == '\x0a') { | |
141 // When we come across '\n', we move to the beginning of the next line. | |
142 position->set_width(0); | |
143 position->Enlarge(0, font.GetHeight()); | |
144 } else { | |
145 // Otherwise, we advance position to the next word. | |
146 position->Enlarge(w, 0); | |
147 } | |
148 | |
149 if (ltr_within_rtl) | |
150 break; // LTR within RTL is drawn as one unit, so we are done. | |
151 } | |
152 } | |
153 | |
154 void WrapIfWordDoesntFit(int word_width, | |
155 int font_height, | |
156 gfx::Size* position, | |
157 const gfx::Rect& bounds) { | |
158 if (position->width() + word_width > bounds.right()) { | |
159 position->set_width(0); | |
160 position->Enlarge(0, font_height); | |
161 } | |
162 } | |
163 | |
164 } // namespace view_text_utils | |
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