Added text line limits to collapsed and expanded notifications.

ui/message_center/views/bounded_label.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/message_center/views/bounded_label.h"
+
+#include <limits>
+
+#include "base/string_util.h"
+#include "base/utf_string_conversions.h"
+#include "ui/base/text/text_elider.h"
+#include "ui/gfx/canvas.h"
+
+namespace message_center {
+
+BoundedLabel::BoundedLabel(string16 text, size_t max_lines)
+    : views::Label(text, gfx::Font()) {
+  Init(max_lines);
+}
+
+BoundedLabel::BoundedLabel(string16 text, gfx::Font font, size_t max_lines)
+    : views::Label(text, font) {
+  Init(max_lines);
+}
+
+BoundedLabel::~BoundedLabel() {
+}
+
+void BoundedLabel::SetMaxLines(size_t lines) {
+  is_preferred_lines_valid_ = false;
+  is_text_size_valid_ = false;
+  max_lines_ = lines;
+}
+
+size_t BoundedLabel::GetMaxLines() {
+  return max_lines_;
+}
+
+size_t BoundedLabel::GetPreferredLines() {
+  if (!is_preferred_lines_valid_) {
+    int wrap_width = width() - GetInsets().width();
+    int unlimited_lines = std::numeric_limits<size_t>::max();
+    preferred_lines_ = SplitLines(wrap_width, unlimited_lines).size();
+    is_preferred_lines_valid_ = true;
+  }
+  return preferred_lines_;
+}
+
+int BoundedLabel::GetHeightForWidth(int width) const {
+  width = std::max(0, width - GetInsets().width());
+  int height = font().GetHeight();
+  string16 text = JoinString(SplitLines(width, max_lines_), '\n');
+  gfx::Canvas::SizeStringInt(text, font(), &width, &height, GetTextFlags());
+  return height + GetInsets().height();
+}
+
+gfx::Size BoundedLabel::GetTextSize() const {
+  if (!is_text_size_valid_) {
+    text_size_.set_width(width() - GetInsets().width());
+    text_size_.set_height(GetHeightForWidth(width()) - GetInsets().height());
+    is_text_size_valid_ = true;
+  }
+  return text_size_;
+}
+
+void BoundedLabel::OnBoundsChanged(const gfx::Rect& previous_bounds) {
+  is_preferred_lines_valid_ = false;
+  is_text_size_valid_ = false;
+}
+
+void BoundedLabel::PaintText(gfx::Canvas* canvas,
+                             const string16& paint_text,
+                             const gfx::Rect& text_bounds,
+                             int flags) {
+  gfx::Insets insets = GetInsets();
+  gfx::Rect bounds(gfx::Point(insets.left(), insets.top()), GetTextSize());
+  string16 text = JoinString(SplitLines(bounds.width(), max_lines_), '\n');
+  views::Label::PaintText(canvas, text, bounds, GetTextFlags());
+}
+
+void BoundedLabel::Init(size_t max_lines) {
+  SetMultiLine(true);
+  SetAllowCharacterBreak(true);
+  SetElideBehavior(views::Label::ELIDE_AT_END);
+  max_lines_ = max_lines;
+  is_preferred_lines_valid_ = false;
+  is_text_size_valid_ = false;
+}
+
+int BoundedLabel::GetTextFlags() const {
+  int flags = gfx::Canvas::MULTI_LINE | gfx::Canvas::CHARACTER_BREAK;
+
+  // We can't use subpixel rendering if the background is non-opaque.
+  if (SkColorGetA(background_color()) != 0xFF)
+    flags |= gfx::Canvas::NO_SUBPIXEL_RENDERING;
+
+  if (directionality_mode() == AUTO_DETECT_DIRECTIONALITY) {
+    base::i18n::TextDirection direction =
+        base::i18n::GetFirstStrongCharacterDirection(text());
+    if (direction == base::i18n::RIGHT_TO_LEFT)
+      flags |= gfx::Canvas::FORCE_RTL_DIRECTIONALITY;
+    else
+      flags |= gfx::Canvas::FORCE_LTR_DIRECTIONALITY;
+  }
+
+  switch (horizontal_alignment()) {
+    case gfx::ALIGN_LEFT:
+      flags |= gfx::Canvas::TEXT_ALIGN_LEFT;
+      break;
+    case gfx::ALIGN_CENTER:
+      flags |= gfx::Canvas::TEXT_ALIGN_CENTER;
+      break;
+    case gfx::ALIGN_RIGHT:
+      flags |= gfx::Canvas::TEXT_ALIGN_RIGHT;
+      break;
+  }
+
+  return flags;
+}
+
+std::vector<string16> BoundedLabel::SplitLines(int width,
+                                               size_t max_lines) const {
+  // Adjust max_lines so (max_lines + 1) * line_height <= INT_MAX, then use the
+  // adjusted max_lines to get a max_height of (max_lines + 1) * line_height.
+  size_t max_height = std::numeric_limits<int>::max();
+  size_t line_height = std::max(font().GetHeight(), 2);  // At least 2 pixels!
+  max_lines = std::min(max_lines, max_height / line_height - 1);
+  max_height = (max_lines + 1) * line_height;
+
+  // Split. Do not use ui::WRAP_LONG_WORDS instead of ui::IGNORE_LONG_WORDS
+  // below as this may cause ui::ElideRectangleText() to go into an infinite
+  // loop for small width values.
+  std::vector<string16> lines;
+  ui::ElideRectangleText(text(), font(), width, max_height,
+                         ui::IGNORE_LONG_WORDS, &lines);
+
+  // Elide if necessary.
+  if (lines.size() > max_lines) {
+    // Add an ellipsis to the last line. If this ellipsis makes the last line
+    // too wide, that line will be further elided by the ui::ElideText below,
+    // so for example "ABC" could become "ABC..." here and "AB..." below.
+    string16 last = lines[max_lines - 1] + UTF8ToUTF16(ui::kEllipsis);
+    lines.resize(max_lines - 1);
+    lines.push_back((font().GetStringWidth(last) > width) ?
+                    ui::ElideText(last, font(), width, ui::ELIDE_AT_END) :
+                    last);
+  }
+
+  return lines;
+}
+
+}  // namespace message_center