gecko-dev/layout/base/AccessibleCaret.h

234 строки
6.9 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef AccessibleCaret_h__
#define AccessibleCaret_h__
#include "mozilla/Attributes.h"
#include "mozilla/dom/AnonymousContent.h"
#include "mozilla/dom/Element.h"
#include "nsCOMPtr.h"
#include "nsIDOMEventListener.h"
#include "nsISupportsBase.h"
#include "nsISupportsImpl.h"
#include "nsRect.h"
#include "mozilla/RefPtr.h"
#include "nsString.h"
class nsIDocument;
class nsIFrame;
class nsIPresShell;
struct nsPoint;
namespace mozilla {
// -----------------------------------------------------------------------------
// Upon the creation of AccessibleCaret, it will insert DOM Element as an
// anonymous content containing the caret image. The caret appearance and
// position can be controlled by SetAppearance() and SetPosition().
//
// All the rect or point are relative to root frame except being specified
// explicitly.
//
// None of the methods in AccessibleCaret will flush layout or style. To ensure
// that SetPosition() works correctly, the caller must make sure the layout is
// up to date.
//
// Please see the wiki page for more information.
// https://wiki.mozilla.org/Copy_n_Paste
class AccessibleCaret
{
public:
explicit AccessibleCaret(nsIPresShell* aPresShell);
virtual ~AccessibleCaret();
// This enumeration representing the visibility and visual style of an
// AccessibleCaret.
//
// Use SetAppearance() to change the appearance, and use GetAppearance() to
// get the current appearance.
enum class Appearance : uint8_t {
// Do not display the caret at all.
None,
// Display the caret in default style.
Normal,
// The caret should be displayed logically but it is kept invisible to the
// user. This enum is the only difference between "logically visible" and
// "visually visible". It can be used for reasons such as:
// 1. Out of scroll port.
// 2. For UX requirement such as hide a caret in an empty text area.
NormalNotShown,
// Display the caret which is tilted to the left.
Left,
// Display the caret which is tilted to the right.
Right
};
friend std::ostream& operator<<(std::ostream& aStream,
const Appearance& aAppearance);
Appearance GetAppearance() const
{
return mAppearance;
}
virtual void SetAppearance(Appearance aAppearance);
// Return true if current appearance is either Normal, NormalNotShown, Left,
// or Right.
bool IsLogicallyVisible() const
{
return mAppearance != Appearance::None;
}
// Return true if current appearance is either Normal, Left, or Right.
bool IsVisuallyVisible() const
{
return (mAppearance != Appearance::None) &&
(mAppearance != Appearance::NormalNotShown);
}
// Set true to enable the "Text Selection Bar" described in "Text Selection
// Visual Spec" in bug 921965.
virtual void SetSelectionBarEnabled(bool aEnabled);
// This enumeration representing the result returned by SetPosition().
enum class PositionChangedResult : uint8_t {
// Position is not changed.
NotChanged,
// Position is changed.
Changed,
// Position is out of scroll port.
Invisible
};
friend std::ostream& operator<<(std::ostream& aStream,
const PositionChangedResult& aResult);
virtual PositionChangedResult SetPosition(nsIFrame* aFrame, int32_t aOffset);
// Does two AccessibleCarets overlap?
bool Intersects(const AccessibleCaret& aCaret) const;
// Is the point within the caret's rect? The point should be relative to root
// frame.
bool Contains(const nsPoint& aPoint) const;
// The geometry center of the imaginary caret (nsCaret) to which this
// AccessibleCaret is attached. It is needed when dragging the caret.
nsPoint LogicalPosition() const
{
return mImaginaryCaretRect.Center();
}
// Element for 'Intersects' test. Container of image and bar elements.
dom::Element* CaretElement() const
{
return mCaretElementHolder->GetContentNode();
}
protected:
// Argument aRect should be relative to CustomContentContainerFrame().
void SetCaretElementStyle(const nsRect& aRect);
void SetSelectionBarElementStyle(const nsRect& aRect);
// Get current zoom level.
float GetZoomLevel();
// Element which contains the caret image for 'Contains' test.
dom::Element* CaretImageElement() const
{
return CaretElement()->GetFirstElementChild();
}
// Element which represents the text selection bar.
dom::Element* SelectionBarElement() const
{
return CaretElement()->GetLastElementChild();
}
nsIFrame* RootFrame() const
{
return mPresShell->GetRootFrame();
}
nsIFrame* CustomContentContainerFrame() const;
// Transform Appearance to CSS class name in ua.css.
static nsString AppearanceString(Appearance aAppearance);
already_AddRefed<dom::Element> CreateCaretElement(nsIDocument* aDocument) const;
// Inject caret element into custom content container.
void InjectCaretElement(nsIDocument* aDocument);
// Remove caret element from custom content container.
void RemoveCaretElement(nsIDocument* aDocument);
// The top-center of the imaginary caret to which this AccessibleCaret is
// attached.
static nsPoint CaretElementPosition(const nsRect& aRect)
{
return aRect.TopLeft() + nsPoint(aRect.width / 2, 0);
}
class DummyTouchListener final : public nsIDOMEventListener
{
public:
NS_DECL_ISUPPORTS
NS_IMETHOD HandleEvent(nsIDOMEvent* aEvent) override
{
return NS_OK;
}
private:
virtual ~DummyTouchListener() {};
};
// Member variables
Appearance mAppearance = Appearance::None;
bool mSelectionBarEnabled = false;
// AccessibleCaretManager owns us. When it's destroyed by
// AccessibleCaretEventHub::Terminate() which is called in
// PresShell::Destroy(), it frees us automatically. No need to worry we
// outlive mPresShell.
nsIPresShell* MOZ_NON_OWNING_REF const mPresShell = nullptr;
RefPtr<dom::AnonymousContent> mCaretElementHolder;
// mImaginaryCaretRect is relative to root frame.
nsRect mImaginaryCaretRect;
// A no-op touch-start listener which prevents APZ from panning when dragging
// the caret.
RefPtr<DummyTouchListener> mDummyTouchListener{new DummyTouchListener()};
// Static class variables
static float sWidth;
static float sHeight;
static float sMarginLeft;
static float sBarWidth;
}; // class AccessibleCaret
std::ostream& operator<<(std::ostream& aStream,
const AccessibleCaret::Appearance& aAppearance);
std::ostream& operator<<(std::ostream& aStream,
const AccessibleCaret::PositionChangedResult& aResult);
} // namespace mozilla
#endif // AccessibleCaret_h__