Aura: Tooltips

ui/aura_shell/shell_tooltip_manager.cc

+// Copyright (c) 2011 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/aura_shell/shell_tooltip_manager.h"
+
+#include <vector>
+
+#include "base/location.h"
+#include "base/string_split.h"
+#include "base/time.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/event.h"
+#include "ui/aura/window.h"
+#include "ui/aura_shell/shell.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/base/text/text_elider.h"
+#include "ui/gfx/font.h"
+#include "ui/gfx/point.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/screen.h"
+#include "ui/views/widget/widget.h"
+#include "views/background.h"
+#include "views/border.h"
+#include "views/controls/label.h"
+
+namespace {
+
+SkColor kTooltipBackground = 0xFFFFFFCC;
+SkColor kTooltipBorder = 0xFF000000;
+int kTooltipBorderWidth = 1;
+int kTooltipTimeoutMs = 500;
+
+// FIXME: get cursor offset from actual cursor size.
+int kCursorOffsetX = 10;
+int kCursorOffsetY = 15;
+
+// Maximum number of characters we allow in a tooltip.
+const size_t kMaxTooltipLength = 1024;
+
+// Maximum number of lines we allow in the tooltip.
+const size_t kMaxLines = 6;
+
+gfx::Font GetDefaultFont() {
+  return ui::ResourceBundle::GetSharedInstance().GetFont(
+      ui::ResourceBundle::BaseFont);
+}
+
+// Returns the maximum width of the tooltip. |x| and |y| give the location
+// the tooltip is to be displayed on in screen coordinates.
+int GetMaxWidth(int x, int y) {
+  gfx::Rect monitor_bounds =
+      gfx::Screen::GetMonitorAreaNearestPoint(gfx::Point(x, y));
+  return (monitor_bounds.width() + 1) / 2;
+}
+
+// Trims the tooltip to fit, setting |text| to the clipped result,
+// |max_width| to the width (in pixels) of the clipped text and |line_count|
+// to the number of lines of text in the tooltip. |x| and |y| give the
+// location of the tooltip in screen coordinates.
+void TrimTooltipToFit(string16* 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 into at most kMaxLines lines.
+  std::vector<string16> lines;
+  base::SplitString(*text, '\n', &lines);
+  if (lines.size() > kMaxLines)
+    lines.resize(kMaxLines);
+  *line_count = static_cast<int>(lines.size());
+
+  // Format each line to fit.
+  gfx::Font font = GetDefaultFont();
+  string16 result;
+  for (std::vector<string16>::iterator i = lines.begin(); i != lines.end();
+       ++i) {
+    string16 elided_text = ui::ElideText(*i, font, available_width, false);
+    *max_width = std::max(*max_width, font.GetStringWidth(elided_text));
+    if (!result.empty())
+      result.push_back('\n');
+    result.append(elided_text);
+  }
+  *text = result;
+}
+
+// Creates a widget of type TYPE_TOOLTIP
+views::Widget* CreateTooltip() {
+  views::Widget* widget = new views::Widget;
+  views::Widget::InitParams params;
+  // For aura, since we set the type to TOOLTIP_TYPE, the widget will get
+  // auto-parented to the MenuAndTooltipsContainer.
+  params.type = views::Widget::InitParams::TYPE_TOOLTIP;
+  params.keep_on_top = true;
+  params.accept_events = false;
+  params.transparent = true;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  widget->Init(params);
+  return widget;
+}
+
+}  // namespace
+
+namespace aura_shell {
+
+// Displays a widget with tooltip using a views::Label.
+class ShellTooltipManager::Tooltip {
+ public:
+  Tooltip() {
+    label_.set_background(
+        views::Background::CreateSolidBackground(kTooltipBackground));
+    label_.set_border(
+        views::Border::CreateSolidBorder(kTooltipBorderWidth, kTooltipBorder));
+    label_.set_parent_owned(false);
+    widget_.reset(CreateTooltip());
+    widget_->SetContentsView(&label_);
+    widget_->Activate();
+  }
+
+  ~Tooltip() {
+    widget_->Close();
+  }
+
+  // Updates the text on the tooltip and resizes to fit.
+  void SetText(string16 tooltip_text, gfx::Point location) {
+    int max_width, line_count;
+    TrimTooltipToFit(&tooltip_text, &max_width, &line_count,
+                     location.x(), location.y());
+    label_.SetText(tooltip_text);
+
+    SetTooltipBounds(location, max_width + 2 * kTooltipBorderWidth,
+                     label_.GetPreferredSize().height());
+  }
+
+  // Shows the tooltip.
+  void Show() {
+    widget_->Show();
+  }
+
+  // Hides the tooltip.
+  void Hide() {
+    widget_->Hide();
+  }
+
+  bool IsVisible() {
+    return widget_->IsVisible();
+  }
+
+ private:
+  views::Label label_;
+  scoped_ptr<views::Widget> widget_;
+
+  // Adjusts the bounds given by the arguments to fit inside the desktop
+  // and applies the adjusted bounds to the label_.
+  void SetTooltipBounds(gfx::Point mouse_pos,
+                        int tooltip_width,
+                        int tooltip_height) {
+    gfx::Rect tooltip_rect(mouse_pos.x(), mouse_pos.y(), tooltip_width,
+                           tooltip_height);
+
+    tooltip_rect.Offset(kCursorOffsetX, kCursorOffsetY);
+    gfx::Rect monitor_bounds =
+        gfx::Screen::GetMonitorAreaNearestPoint(tooltip_rect.origin());
+    widget_->SetBounds(tooltip_rect.AdjustToFit(monitor_bounds));
+  }
+
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// ShellTooltipManager public:
+
+ShellTooltipManager::ShellTooltipManager() : aura::EventFilter(NULL),
+                                             tooltip_window_(NULL),
+                                             tooltip_(new Tooltip) {
+  tooltip_timer_.Start(FROM_HERE,
+      base::TimeDelta::FromMilliseconds(kTooltipTimeoutMs),
+      this, &ShellTooltipManager::TooltipTimerFired);
+}
+
+ShellTooltipManager::~ShellTooltipManager() {
+  if (tooltip_window_)
+    tooltip_window_->RemoveObserver(this);
+}
+
+void ShellTooltipManager::UpdateTooltip(aura::Window* target) {
+  // If tooltip is visible, we may want to hide it. If it is not, we are ok.
+  if (tooltip_window_ == target && tooltip_->IsVisible())
+    UpdateIfRequired();
+}
+
+bool ShellTooltipManager::PreHandleKeyEvent(aura::Window* target,
+                                            aura::KeyEvent* event) {
+  return false;
+}
+
+bool ShellTooltipManager::PreHandleMouseEvent(aura::Window* target,
+                                              aura::MouseEvent* event) {
+  switch (event->type()) {
+    case ui::ET_MOUSE_MOVED:
+      if (tooltip_window_ != target) {
+        if (tooltip_window_)
+          tooltip_window_->RemoveObserver(this);
+        tooltip_window_ = target;
+        tooltip_window_->AddObserver(this);
+      }
+      curr_mouse_loc_ = event->location();
+      if (tooltip_timer_.IsRunning())
+        tooltip_timer_.Reset();
+
+      if (tooltip_->IsVisible())
+        UpdateIfRequired();
+      break;
+    case ui::ET_MOUSE_PRESSED:
+    case ui::ET_MOUSE_RELEASED:
+    case ui::ET_MOUSE_DRAGGED:
+    case ui::ET_MOUSEWHEEL:
+      // Hide the tooltip for click, release, drag, wheel events.
+      if (tooltip_->IsVisible())
+        tooltip_->Hide();
+      break;
+    default:
+      break;
+  }
+  return false;
+}
+
+ui::TouchStatus ShellTooltipManager::PreHandleTouchEvent(
+    aura::Window* target,
+    aura::TouchEvent* event) {
+  return ui::TOUCH_STATUS_UNKNOWN;
+}
+
+void ShellTooltipManager::OnWindowDestroyed(aura::Window* window) {
+  if (tooltip_window_ == window) {
+    tooltip_window_->RemoveObserver(this);
+    tooltip_window_ = NULL;
+  }
+}
+
+void ShellTooltipManager::TooltipTimerFired() {
+  UpdateIfRequired();
+}
+
+void ShellTooltipManager::UpdateIfRequired() {
+  string16 tooltip_text;
+  if (tooltip_window_) {
+    void* property = tooltip_window_->GetProperty(aura::kTooltipTextKey);
+    if (property)
+      tooltip_text = *static_cast<string16*>(property);
+  }
+
+  if (tooltip_text_ != tooltip_text) {
+    tooltip_text_ = tooltip_text;
+    if (tooltip_text_.empty()) {
+      tooltip_->Hide();
+    } else {
+      string16 tooltip_text(tooltip_text_);
+      gfx::Point widget_loc = curr_mouse_loc_;
+      widget_loc = widget_loc.Add(tooltip_window_->GetScreenBounds().origin());
+      tooltip_->SetText(tooltip_text, widget_loc);
+      tooltip_->Show();
+    }
+  }
+}
+
+}  // namespace aura_shell