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Issue 2989763002: Update charted to 0.4.8 and roll (Closed)
Patch Set: Removed Cutch from list of reviewers Created 3 years, 4 months ago
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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
2 // for details. All rights reserved. Use of this source code is governed by a 2 // for details. All rights reserved. Use of this source code is governed by a
3 // BSD-style license that can be found in the LICENSE file. 3 // BSD-style license that can be found in the LICENSE file.
4 4
5 part of intl; 5 part of intl;
6 6
7 /** 7 /// Bidi stands for Bi-directional text. According to
8 * Bidi stands for Bi-directional text. 8 /// [Wikipedia](http://en.wikipedia.org/wiki/Bi-directional_text):
9 * According to [Wikipedia](http://en.wikipedia.org/wiki/Bi-directional_text): 9 /// Bi-directional text is text containing text in both text directionalities,
10 * Bi-directional text is text containing text in both text directionalities, 10 /// both right-to-left (RTL) and left-to-right (LTR). It generally involves text
11 * both right-to-left (RTL) and left-to-right (LTR). It generally involves text 11 /// containing different types of alphabets, but may also refer to
12 * containing different types of alphabets, but may also refer to boustrophedon, 12 /// boustrophedon, which is changing text directionality in each row.
13 * which is changing text directionality in each row. 13 ///
14 * 14 /// Utility class for formatting display text in a potentially
15 * Utility class for formatting display text in a potentially 15 /// opposite-directionality context without garbling layout issues. Mostly a
16 * opposite-directionality context without garbling layout issues. 16 /// very "slimmed-down" and dart-ified port of the Closure Birectional
17 * Mostly a very "slimmed-down" and dart-ified port of the Closure Birectional 17 /// formatting libary. If there is a utility in the Closure library (or ICU, or
18 * formatting libary. If there is a utility in the Closure library (or ICU, or 18 /// elsewhere) that you would like this formatter to make available, please
19 * elsewhere) that you would like this formatter to make available, please 19 /// contact the Dart team.
20 * contact the Dart team. 20 ///
21 * 21 /// Provides the following functionality:
22 * Provides the following functionality: 22 ///
23 * 23 /// 1. *BiDi Wrapping*
24 * 1. *BiDi Wrapping* 24 /// When text in one language is mixed into a document in another, opposite-
25 * When text in one language is mixed into a document in another, opposite- 25 /// directionality language, e.g. when an English business name is embedded in a
26 * directionality language, e.g. when an English business name is embedded in a 26 /// Hebrew web page, both the inserted string and the text following it may be
27 * Hebrew web page, both the inserted string and the text following it may be 27 /// displayed incorrectly unless the inserted string is explicitly separated
28 * displayed incorrectly unless the inserted string is explicitly separated 28 /// from the surrounding text in a "wrapper" that declares its directionality at
29 * from the surrounding text in a "wrapper" that declares its directionality at 29 /// the start and then resets it back at the end. This wrapping can be done in
30 * the start and then resets it back at the end. This wrapping can be done in 30 /// HTML mark-up (e.g. a 'span dir=rtl' tag) or - only in contexts where mark-up
31 * HTML mark-up (e.g. a 'span dir=rtl' tag) or - only in contexts where mark-up 31 /// can not be used - in Unicode BiDi formatting codes (LRE|RLE and PDF).
32 * can not be used - in Unicode BiDi formatting codes (LRE|RLE and PDF). 32 /// Providing such wrapping services is the basic purpose of the BiDi formatter.
33 * Providing such wrapping services is the basic purpose of the BiDi formatter. 33 ///
34 * 34 /// 2. *Directionality estimation*
35 * 2. *Directionality estimation* 35 /// How does one know whether a string about to be inserted into surrounding
36 * How does one know whether a string about to be inserted into surrounding 36 /// text has the same directionality? Well, in many cases, one knows that this
37 * text has the same directionality? Well, in many cases, one knows that this 37 /// must be the case when writing the code doing the insertion, e.g. when a
38 * must be the case when writing the code doing the insertion, e.g. when a 38 /// localized message is inserted into a localized page. In such cases there is
39 * localized message is inserted into a localized page. In such cases there is 39 /// no need to involve the BiDi formatter at all. In the remaining cases, e.g.
40 * no need to involve the BiDi formatter at all. In the remaining cases, e.g. 40 /// when the string is user-entered or comes from a database, the language of
41 * when the string is user-entered or comes from a database, the language of 41 /// the string (and thus its directionality) is not known a priori, and must be
42 * the string (and thus its directionality) is not known a priori, and must be 42 /// estimated at run-time. The BiDi formatter does this automatically.
43 * estimated at run-time. The BiDi formatter does this automatically. 43 ///
44 * 44 /// 3. *Escaping*
45 * 3. *Escaping* 45 /// When wrapping plain text - i.e. text that is not already HTML or HTML-
46 * When wrapping plain text - i.e. text that is not already HTML or HTML- 46 /// escaped - in HTML mark-up, the text must first be HTML-escaped to prevent
47 * escaped - in HTML mark-up, the text must first be HTML-escaped to prevent XSS 47 /// XSS attacks and other nasty business. This of course is always true, but the
48 * attacks and other nasty business. This of course is always true, but the 48 /// escaping cannot be done after the string has already been wrapped in
49 * escaping cannot be done after the string has already been wrapped in 49 /// mark-up, so the BiDi formatter also serves as a last chance and includes
50 * mark-up, so the BiDi formatter also serves as a last chance and includes 50 /// escaping services.
51 * escaping services. 51 ///
52 * 52 /// Thus, in a single call, the formatter will escape the input string as
53 * Thus, in a single call, the formatter will escape the input string as 53 /// specified, determine its directionality, and wrap it as necessary. It is
54 * specified, determine its directionality, and wrap it as necessary. It is 54 /// then up to the caller to insert the return value in the output.
55 * then up to the caller to insert the return value in the output.
56 */
57 55
58 class BidiFormatter { 56 class BidiFormatter {
59 57
60 /** The direction of the surrounding text (the context). */ 58 /// The direction of the surrounding text (the context).
61 TextDirection contextDirection; 59 TextDirection contextDirection;
62 60
63 /** 61 /// Indicates if we should always wrap the formatted text in a <span<,.
64 * Indicates if we should always wrap the formatted text in a <span<,.
65 */
66 bool _alwaysSpan; 62 bool _alwaysSpan;
67 63
68 /** 64 /// Create a formatting object with a direction. If [alwaysSpan] is true we
69 * Create a formatting object with a direction. If [alwaysSpan] is true we 65 /// should always use a `span` tag, even when the input directionality is
70 * should always use a `span` tag, even when the input directionality is 66 /// neutral or matches the context, so that the DOM structure of the output
71 * neutral or matches the context, so that the DOM structure of the output 67 /// does not depend on the combination of directionalities.
72 * does not depend on the combination of directionalities.
73 */
74 BidiFormatter.LTR([alwaysSpan = false]) 68 BidiFormatter.LTR([alwaysSpan = false])
75 : contextDirection = TextDirection.LTR, 69 : contextDirection = TextDirection.LTR,
76 _alwaysSpan = alwaysSpan; 70 _alwaysSpan = alwaysSpan;
77 BidiFormatter.RTL([alwaysSpan = false]) 71 BidiFormatter.RTL([alwaysSpan = false])
78 : contextDirection = TextDirection.RTL, 72 : contextDirection = TextDirection.RTL,
79 _alwaysSpan = alwaysSpan; 73 _alwaysSpan = alwaysSpan;
80 BidiFormatter.UNKNOWN([alwaysSpan = false]) 74 BidiFormatter.UNKNOWN([alwaysSpan = false])
81 : contextDirection = TextDirection.UNKNOWN, 75 : contextDirection = TextDirection.UNKNOWN,
82 _alwaysSpan = alwaysSpan; 76 _alwaysSpan = alwaysSpan;
83 77
84 /** Is true if the known context direction for this formatter is RTL. */ 78 /// Is true if the known context direction for this formatter is RTL.
85 bool get isRTL => contextDirection == TextDirection.RTL; 79 bool get isRTL => contextDirection == TextDirection.RTL;
86 80
87 /** 81 /// Formats a string of a given (or estimated, if not provided) [direction]
88 * Formats a string of a given (or estimated, if not provided) 82 /// for use in HTML output of the context directionality, so an
89 * [direction] for use in HTML output of the context directionality, so 83 /// opposite-directionality string is neither garbled nor garbles what follows
90 * an opposite-directionality string is neither garbled nor garbles what 84 /// it.
91 * follows it. 85 ///
92 * If the input string's directionality doesn't match the context 86 ///If the input string's directionality doesn't match the context
93 * directionality, we wrap it with a `span` tag and add a `dir` attribute 87 /// directionality, we wrap it with a `span` tag and add a `dir` attribute
94 * (either "dir=rtl" or "dir=ltr"). 88 /// (either "dir=rtl" or "dir=ltr"). If alwaysSpan was true when constructing
95 * If alwaysSpan was true when constructing the formatter, the input is always 89 /// the formatter, the input is always wrapped with `span` tag, skipping the
96 * wrapped with `span` tag, skipping the dir attribute when it's not needed. 90 /// dir attribute when it's not needed.
97 * 91 ///
98 * If [resetDir] is true and the overall directionality or the exit 92 /// If [resetDir] is true and the overall directionality or the exit
99 * directionality of [text] is opposite to the context directionality, 93 /// directionality of [text] is opposite to the context directionality,
100 * a trailing unicode BiDi mark matching the context directionality is 94 /// a trailing unicode BiDi mark matching the context directionality is
101 * appended (LRM or RLM). If [isHtml] is false, we HTML-escape the [text]. 95 /// appended (LRM or RLM). If [isHtml] is false, we HTML-escape the [text].
102 */
103 String wrapWithSpan(String text, 96 String wrapWithSpan(String text,
104 {bool isHtml: false, bool resetDir: true, TextDirection direction}) { 97 {bool isHtml: false, bool resetDir: true, TextDirection direction}) {
105 if (direction == null) direction = estimateDirection(text, isHtml: isHtml); 98 if (direction == null) direction = estimateDirection(text, isHtml: isHtml);
106 var result; 99 var result;
107 if (!isHtml) text = HTML_ESCAPE.convert(text); 100 if (!isHtml) text = HTML_ESCAPE.convert(text);
108 var directionChange = contextDirection.isDirectionChange(direction); 101 var directionChange = contextDirection.isDirectionChange(direction);
109 if (_alwaysSpan || directionChange) { 102 if (_alwaysSpan || directionChange) {
110 var spanDirection = ''; 103 var spanDirection = '';
111 if (directionChange) { 104 if (directionChange) {
112 spanDirection = ' dir=${direction.spanText}'; 105 spanDirection = ' dir=${direction.spanText}';
113 } 106 }
114 result = '<span$spanDirection>$text</span>'; 107 result = '<span$spanDirection>$text</span>';
115 } else { 108 } else {
116 result = text; 109 result = text;
117 } 110 }
118 return result + (resetDir ? _resetDir(text, direction, isHtml) : ''); 111 return result + (resetDir ? _resetDir(text, direction, isHtml) : '');
119 } 112 }
120 113
121 /** 114 /// Format [text] of a known (if specified) or estimated [direction] for use
122 * Format [text] of a known (if specified) or estimated [direction] for use 115 /// in *plain-text* output of the context directionality, so an
123 * in *plain-text* output of the context directionality, so an 116 /// opposite-directionality text is neither garbled nor garbles what follows
124 * opposite-directionality text is neither garbled nor garbles what follows 117 /// it. Unlike wrapWithSpan, this makes use of unicode BiDi formatting
125 * it. Unlike wrapWithSpan, this makes use of unicode BiDi formatting 118 /// characters instead of spans for wrapping. The returned string would be
126 * characters instead of spans for wrapping. The returned string would be 119 /// RLE+text+PDF for RTL text, or LRE+text+PDF for LTR text.
127 * RLE+text+PDF for RTL text, or LRE+text+PDF for LTR text. 120 ///
128 * 121 /// If [resetDir] is true, and if the overall directionality or the exit
129 * If [resetDir] is true, and if the overall directionality or the exit 122 /// directionality of text are opposite to the context directionality,
130 * directionality of text are opposite to the context directionality, 123 /// a trailing unicode BiDi mark matching the context directionality is
131 * a trailing unicode BiDi mark matching the context directionality is 124 /// appended (LRM or RLM).
132 * appended (LRM or RLM). 125 ///
133 * 126 /// In HTML, the *only* valid use of this function is inside of elements that
134 * In HTML, the *only* valid use of this function is inside of elements that 127 /// do not allow markup, e.g. an 'option' tag.
135 * do not allow markup, e.g. an 'option' tag. 128 /// This function does *not* do HTML-escaping regardless of the value of
136 * This function does *not* do HTML-escaping regardless of the value of 129 /// [isHtml]. [isHtml] is used to designate if the text contains HTML (escaped
137 * [isHtml]. [isHtml] is used to designate if the text contains HTML (escaped 130 /// or unescaped).
138 * or unescaped).
139 */
140 String wrapWithUnicode(String text, 131 String wrapWithUnicode(String text,
141 {bool isHtml: false, bool resetDir: true, TextDirection direction}) { 132 {bool isHtml: false, bool resetDir: true, TextDirection direction}) {
142 if (direction == null) direction = estimateDirection(text, isHtml: isHtml); 133 if (direction == null) direction = estimateDirection(text, isHtml: isHtml);
143 var result = text; 134 var result = text;
144 if (contextDirection.isDirectionChange(direction)) { 135 if (contextDirection.isDirectionChange(direction)) {
145 var marker = direction == TextDirection.RTL ? Bidi.RLE : Bidi.LRE; 136 var marker = direction == TextDirection.RTL ? Bidi.RLE : Bidi.LRE;
146 result = "${marker}$text${Bidi.PDF}"; 137 result = "${marker}$text${Bidi.PDF}";
147 } 138 }
148 return result + (resetDir ? _resetDir(text, direction, isHtml) : ''); 139 return result + (resetDir ? _resetDir(text, direction, isHtml) : '');
149 } 140 }
150 141
151 /** 142 /// Estimates the directionality of [text] using the best known
152 * Estimates the directionality of [text] using the best known 143 /// general-purpose method (using relative word counts). A
153 * general-purpose method (using relative word counts). A 144 /// TextDirection.UNKNOWN return value indicates completely neutral input.
154 * TextDirection.UNKNOWN return value indicates completely neutral input. 145 /// [isHtml] is true if [text] HTML or HTML-escaped.
155 * [isHtml] is true if [text] HTML or HTML-escaped.
156 */
157 TextDirection estimateDirection(String text, {bool isHtml: false}) { 146 TextDirection estimateDirection(String text, {bool isHtml: false}) {
158 return Bidi.estimateDirectionOfText(text, isHtml: isHtml); //TODO~!!! 147 return Bidi.estimateDirectionOfText(text, isHtml: isHtml); //TODO~!!!
159 } 148 }
160 149
161 /** 150 /// Returns a unicode BiDi mark matching the surrounding context's [direction]
162 * Returns a unicode BiDi mark matching the surrounding context's [direction] 151 /// (not necessarily the direction of [text]). The function returns an LRM or
163 * (not necessarily the direction of [text]). The function returns an LRM or 152 /// RLM if the overall directionality or the exit directionality of [text] is
164 * RLM if the overall directionality or the exit directionality of [text] is 153 /// opposite the context directionality. Otherwise
165 * opposite the context directionality. Otherwise 154 /// return the empty string. [isHtml] is true if [text] is HTML or
166 * return the empty string. [isHtml] is true if [text] is HTML or 155 /// HTML-escaped.
167 * HTML-escaped.
168 */
169 String _resetDir(String text, TextDirection direction, bool isHtml) { 156 String _resetDir(String text, TextDirection direction, bool isHtml) {
170 // endsWithRtl and endsWithLtr are called only if needed (short-circuit). 157 // endsWithRtl and endsWithLtr are called only if needed (short-circuit).
171 if ((contextDirection == TextDirection.LTR && 158 if ((contextDirection == TextDirection.LTR &&
172 (direction == TextDirection.RTL || 159 (direction == TextDirection.RTL ||
173 Bidi.endsWithRtl(text, isHtml))) || 160 Bidi.endsWithRtl(text, isHtml))) ||
174 (contextDirection == TextDirection.RTL && 161 (contextDirection == TextDirection.RTL &&
175 (direction == TextDirection.LTR || 162 (direction == TextDirection.LTR ||
176 Bidi.endsWithLtr(text, isHtml)))) { 163 Bidi.endsWithLtr(text, isHtml)))) {
177 return contextDirection == TextDirection.LTR ? Bidi.LRM : Bidi.RLM; 164 return contextDirection == TextDirection.LTR ? Bidi.LRM : Bidi.RLM;
178 } else { 165 } else {
179 return ''; 166 return '';
180 } 167 }
181 } 168 }
182 } 169 }
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