Fleshes out the tooltip implementation for views on Gtk. It doesn't...

views/widget/tooltip_manager.cc

+// Copyright (c) 2009 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 "views/widget/tooltip_manager.h"
+
+#include <vector>
+
+#include "app/gfx/text_elider.h"
+#include "views/screen.h"
+
+namespace views {
+
+// Maximum number of characters we allow in a tooltip.
+static const size_t kMaxTooltipLength = 1024;
+
+// Maximum number of lines we allow in the tooltip.
+static const size_t kMaxLines = 6;
+
+// Breaks |text| along line boundaries, placing each line of text into lines.
+static void SplitTooltipString(const std::wstring& text,
+                               std::vector<std::wstring>* lines) {
+  size_t index = 0;
+  size_t next_index;
+  while ((next_index = text.find(TooltipManager::GetLineSeparator(), index))
+         != std::wstring::npos && lines->size() < kMaxLines) {
+    lines->push_back(text.substr(index, next_index - index));
+    index = next_index + TooltipManager::GetLineSeparator().size();
+  }
+  if (next_index != text.size() && lines->size() < kMaxLines)
+    lines->push_back(text.substr(index, text.size() - index));
+}
+
+// static
+int TooltipManager::GetMaxWidth(int x, int y) {
+  gfx::Rect monitor_bounds =
+      Screen::GetMonitorAreaNearestPoint(gfx::Point(x, y));
+  // We don't want the tooltip to get too big, otherwise it looks wrong.
+  return monitor_bounds.width() == 0 ? 400 : monitor_bounds.width() / 4;
+}
+
+// static
+void TooltipManager::TrimTooltipToFit(std::wstring* text,
+                                      int* max_width,
+                                      int* line_count,
+                                      int x,
+                                      int y) {
+  *max_width = 0;
+  *line_count = 0;
+
+  // Clamp the tooltip length to kMaxTooltipLength so that we don't
+  // accidentally DOS the user with a mega tooltip.
+  if (text->length() > kMaxTooltipLength)
+    *text = text->substr(0, kMaxTooltipLength);
+
+  // Determine the available width for the tooltip.
+  int available_width = GetMaxWidth(x, y);
+
+  // Split the string.
+  std::vector<std::wstring> lines;
+  SplitTooltipString(*text, &lines);
+  *line_count = static_cast<int>(lines.size());
+
+  // Format each line to fit.
+  gfx::Font font = GetDefaultFont();
+  std::wstring result;
+  for (std::vector<std::wstring>::iterator i = lines.begin(); i != lines.end();
+       ++i) {
+    std::wstring elided_text = gfx::ElideText(*i, font, available_width);
+    *max_width = std::max(*max_width, font.GetStringWidth(elided_text));
+    if (i == lines.begin() && i + 1 == lines.end()) {
+      *text = elided_text;
+      return;
+    }
+    if (!result.empty())
+      result.append(GetLineSeparator());
+    result.append(elided_text);
+  }
+  *text = result;
+}
+
+}  // namespace views