1 // Copyright 2013 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/base/ime/composition_text_util_pango.h" 6 7 #include <pango/pango-attributes.h> 8 9 #include "base/basictypes.h" 10 #include "base/i18n/char_iterator.h" 11 #include "base/strings/string16.h" 12 #include "base/strings/utf_string_conversions.h" 13 #include "ui/base/ime/composition_text.h" 14 15 namespace ui { 16 17 void ExtractCompositionTextFromGtkPreedit(const gchar* utf8_text, 18 PangoAttrList* attrs, 19 int cursor_position, 20 CompositionText* composition) { 21 composition->Clear(); 22 composition->text = UTF8ToUTF16(utf8_text); 23 24 if (composition->text.empty()) 25 return; 26 27 // Gtk/Pango uses character index for cursor position and byte index for 28 // attribute range, but we use char16 offset for them. So we need to do 29 // conversion here. 30 std::vector<size_t> char16_offsets; 31 size_t length = composition->text.length(); 32 base::i18n::UTF16CharIterator char_iterator(&composition->text); 33 do { 34 char16_offsets.push_back(char_iterator.array_pos()); 35 } while (char_iterator.Advance()); 36 37 // The text length in Unicode characters. 38 int char_length = static_cast<int>(char16_offsets.size()); 39 // Make sure we can convert the value of |char_length| as well. 40 char16_offsets.push_back(length); 41 42 size_t cursor_offset = 43 char16_offsets[std::max(0, std::min(char_length, cursor_position))]; 44 45 composition->selection = gfx::Range(cursor_offset); 46 47 if (attrs) { 48 int utf8_length = strlen(utf8_text); 49 PangoAttrIterator* iter = pango_attr_list_get_iterator(attrs); 50 51 // We only care about underline and background attributes and convert 52 // background attribute into selection if possible. 53 do { 54 gint start, end; 55 pango_attr_iterator_range(iter, &start, &end); 56 57 start = std::min(start, utf8_length); 58 end = std::min(end, utf8_length); 59 if (start >= end) 60 continue; 61 62 start = g_utf8_pointer_to_offset(utf8_text, utf8_text + start); 63 end = g_utf8_pointer_to_offset(utf8_text, utf8_text + end); 64 65 // Double check, in case |utf8_text| is not a valid utf-8 string. 66 start = std::min(start, char_length); 67 end = std::min(end, char_length); 68 if (start >= end) 69 continue; 70 71 PangoAttribute* background_attr = 72 pango_attr_iterator_get(iter, PANGO_ATTR_BACKGROUND); 73 PangoAttribute* underline_attr = 74 pango_attr_iterator_get(iter, PANGO_ATTR_UNDERLINE); 75 76 if (background_attr || underline_attr) { 77 // Use a black thin underline by default. 78 CompositionUnderline underline( 79 char16_offsets[start], char16_offsets[end], SK_ColorBLACK, false); 80 81 // Always use thick underline for a range with background color, which 82 // is usually the selection range. 83 if (background_attr) { 84 underline.thick = true; 85 // If the cursor is at start or end of this underline, then we treat 86 // it as the selection range as well, but make sure to set the cursor 87 // position to the selection end. 88 if (underline.start_offset == cursor_offset) { 89 composition->selection.set_start(underline.end_offset); 90 composition->selection.set_end(cursor_offset); 91 } else if (underline.end_offset == cursor_offset) { 92 composition->selection.set_start(underline.start_offset); 93 composition->selection.set_end(cursor_offset); 94 } 95 } 96 if (underline_attr) { 97 int type = reinterpret_cast<PangoAttrInt*>(underline_attr)->value; 98 if (type == PANGO_UNDERLINE_DOUBLE) 99 underline.thick = true; 100 else if (type == PANGO_UNDERLINE_ERROR) 101 underline.color = SK_ColorRED; 102 } 103 composition->underlines.push_back(underline); 104 } 105 } while (pango_attr_iterator_next(iter)); 106 pango_attr_iterator_destroy(iter); 107 } 108 109 // Use a black thin underline by default. 110 if (composition->underlines.empty()) { 111 composition->underlines.push_back( 112 CompositionUnderline(0, length, SK_ColorBLACK, false)); 113 } 114 } 115 116 } // namespace ui 117
