MacViews: Implement Tooltips

ui/views/cocoa/tooltip_manager_mac.mm

+// Copyright 2015 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/views/cocoa/tooltip_manager_mac.h"
+
+#include "ui/gfx/font_list.h"
+#import "ui/gfx/mac/coordinate_conversion.h"
+#import "ui/views/cocoa/bridged_content_view.h"
+#import "ui/views/cocoa/bridged_native_widget.h"
+
+// Max visual tooltip width in DIPs. Beyond this, Cocoa will wrap text.
+const int kTooltipMaxWidthPixels = 250;

[Andre, 2015/05/13 19:33:13]

Should be inside unnamed namespace.

[tapted, 2015/05/15 07:59:55]

Done (`const` also imposes internal linkage, but I've always struggled to form
an opinion on this - more often an anonymous namespace comes later anyway when a
function is needed).

+
+namespace views {
+
+TooltipManagerMac::TooltipManagerMac(BridgedNativeWidget* widget)
+    : widget_(widget) {
+}
+
+TooltipManagerMac::~TooltipManagerMac() {
+}
+
+int TooltipManagerMac::GetMaxWidth(const gfx::Point& location,
+                                   gfx::NativeView context) const {
+  return kTooltipMaxWidthPixels;
+}
+
+const gfx::FontList& TooltipManagerMac::GetFontList() const {
+  CR_DEFINE_STATIC_LOCAL(gfx::FontList, font_list,
+                         (gfx::Font([NSFont toolTipsFontOfSize:0])));
+  return font_list;
+}
+
+void TooltipManagerMac::UpdateTooltip() {
+  NSWindow* window = widget_->ns_window();
+  BridgedContentView* view = widget_->ns_view();
+
+  NSPoint nspoint = [window convertScreenToBase:[NSEvent mouseLocation]];

[Andre, 2015/05/13 19:33:13]

Why not [window mouseLocationOutsideOfEventStream]?

[tapted, 2015/05/15 07:59:55]

Hm, it wasn't a conscious decision. I tried it out. Unfortunately
mouseLocationOutsideOfEventStream doesn't get the mouse coordinate from [NSEvent
mouseLocation] so it's a bit harder to test for (swizzling instance methods is
more fiddly). But it still uses convertScreenToBase:. The trace is:

- NativeWidgetMacNSWindow NSWindow mouseLocationOutsideOfEventStream
- NativeWidgetMacNSWindow NSWindow windowNumber
- NSApplication NSApplication contextID
- NativeWidgetMacNSWindow NSWindow convertScreenToBase:

For [NSEvent mouseLocation], it is

+ NSEvent NSEvent mouseLocation
+ NSScreen NSScreen _zeroScreenHeight
(then our own) - NativeWidgetMacNSWindow NSWindow convertScreenToBase:


I could go either way, but I think I'm slightly in favour of mouseLocation since
it's a cross-platform concept (i.e. gfx::Screen::GetCursorScreenPoint(), whereas
there's no Widget::LastMouseLocation), and it's slightly easier to test for.

mouseLocationOutsideOfEventStream could work here with more changes in
event_generator_delegate_mac.mm

+  // Note: flip in the view's frame, which matches the window's contentRect.
+  gfx::Point point(nspoint.x, NSHeight([view frame]) - nspoint.y);
+  [view updateTooltipIfRequiredAt:point];
+}
+
+void TooltipManagerMac::TooltipTextChanged(View* view) {
+  // The intensive part is View::GetTooltipHandlerForPoint(), which will be done
+  // in [BridgedContentView updateTooltipIfRequiredAt:]. Don't do it here as
+  // well.
+  UpdateTooltip();
+}
+
+}  // namespace views