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) {
+    string16 last = lines[max_lines - 1] + UTF8ToUTF16(ui::kEllipsis);

[Jun Mukai, 2013/03/14 09:26:47]

what will happen if lines[max_lines - 1] is shorter than the width, but
lines[max_lines - 1] + '...' exceeds the width?  Is that okay?

[dharcourt, 2013/03/14 20:21:57]

If lines[max_lines - 1] + '...' exceeds the width, it will get elided at line
142 below, so for example "ABC" will have become "ABC..." here and will become
"AB..." below to fit within the line width.

I've added a comment to that effect.

+    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