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/* -*- 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 */
/* the caret is the text cursor used, e.g., when editing */
#ifndef nsCaret_h__
#define nsCaret_h__
#include "mozilla/MemoryReporting.h"
#include "mozilla/SelectionMovementUtils.h"
#include "nsCoord.h"
#include "nsIFrame.h"
#include "nsISelectionListener.h"
#include "nsPoint.h"
#include "nsRect.h"
class nsFrameSelection;
class nsIContent;
class nsIFrame;
class nsINode;
class nsITimer;
namespace mozilla {
class PresShell;
enum class CaretAssociationHint;
namespace gfx {
class DrawTarget;
} // namespace gfx
} // namespace mozilla
class nsCaret final : public nsISelectionListener {
typedef mozilla::gfx::DrawTarget DrawTarget;
virtual ~nsCaret();
using CaretAssociationHint = mozilla::CaretAssociationHint;
nsresult Init(mozilla::PresShell*);
void Terminate();
void SetSelection(mozilla::dom::Selection*);
mozilla::dom::Selection* GetSelection();
* Sets whether the caret should only be visible in nodes that are not
* user-modify: read-only, or whether it should be visible in all nodes.
* @param aIgnoreUserModify true to have the cursor visible in all nodes,
* false to have it visible in all nodes except
* those with user-modify: read-only
void SetIgnoreUserModify(bool aIgnoreUserModify);
* SetVisible will set the visibility of the caret
* @param aVisible true to show the caret, false to hide it
void SetVisible(bool aVisible);
* IsVisible will get the visibility of the caret.
* It does not take account of blinking or the caret being hidden because
* we're in non-editable/disabled content.
bool IsVisible() const;
* AddForceHide() increases mHideCount and hide the caret even if
* SetVisible(true) has been or will be called. This is useful when the
* caller wants to hide caret temporarily and it needs to cancel later.
* Especially, in the latter case, it's too difficult to decide if the
* caret should be actually visible or not because caret visible state
* is set from a lot of event handlers. So, it's very stateful.
void AddForceHide();
* RemoveForceHide() decreases mHideCount if it's over 0.
* If the value becomes 0, this may show the caret if SetVisible(true)
* has been called.
void RemoveForceHide();
/** SetCaretReadOnly set the appearance of the caret
* @param inMakeReadonly true to show the caret in a 'read only' state,
* false to show the caret in normal, editing state
void SetCaretReadOnly(bool aReadOnly);
* @param aVisibility true if the caret should be visible even when the
* selection is not collapsed.
void SetVisibilityDuringSelection(bool aVisibility);
* Set the caret's position explicitly to the specified node and offset
* instead of tracking its selection.
* Passing null for aNode would set the caret to track its selection again.
void SetCaretPosition(nsINode* aNode, int32_t aOffset);
* Schedule a repaint for the frame where the caret would appear.
* Does not check visibility etc.
void SchedulePaint();
nsIFrame* GetLastPaintedFrame() { return mLastPaintedFrame; }
void SetLastPaintedFrame(nsIFrame* aFrame) { mLastPaintedFrame = aFrame; }
* Returns a frame to paint in, and the bounds of the painted caret
* relative to that frame.
* The rectangle includes bidi decorations.
* Returns null if the caret should not be drawn (including if it's blinked
* off).
nsIFrame* GetPaintGeometry(nsRect* aRect);
* Same as the overload above, but returns the caret and hook rects
* separately, and also computes the color if requested.
nsIFrame* GetPaintGeometry(nsRect* aCaretRect, nsRect* aHookRect,
nscolor* aCaretColor = nullptr);
* A simple wrapper around GetGeometry. Does not take any caret state into
* account other than the current selection.
nsIFrame* GetGeometry(nsRect* aRect) {
return GetGeometry(GetSelection(), aRect);
/** PaintCaret
* Actually paint the caret onto the given rendering context.
void PaintCaret(DrawTarget& aDrawTarget, nsIFrame* aForFrame,
const nsPoint& aOffset);
// nsISelectionListener interface
/** The current caret position. */
struct CaretPosition {
nsCOMPtr<nsINode> mContent;
int32_t mOffset = 0;
CaretAssociationHint mHint{0};
mozilla::intl::BidiEmbeddingLevel mBidiLevel;
bool operator==(const CaretPosition& aOther) const {
return mContent == aOther.mContent && mOffset == aOther.mOffset &&
mHint == aOther.mHint && mBidiLevel == aOther.mBidiLevel;
explicit operator bool() const { return !!mContent; }
static CaretPosition CaretPositionFor(const mozilla::dom::Selection*);
* Gets the position and size of the caret that would be drawn for
* the focus node/offset of aSelection (assuming it would be drawn,
* i.e., disregarding blink status). The geometry is stored in aRect,
* and we return the frame aRect is relative to.
* Only looks at the focus node of aSelection, so you can call it even if
* aSelection is not collapsed.
* This rect does not include any extra decorations for bidi.
* @param aRect must be non-null
static nsIFrame* GetGeometry(const mozilla::dom::Selection* aSelection,
nsRect* aRect);
static nsRect GetGeometryForFrame(nsIFrame* aFrame, int32_t aFrameOffset,
nscoord* aBidiIndicatorSize);
// Get the frame and frame offset based on aPosition.
static mozilla::CaretFrameData GetFrameAndOffset(
const CaretPosition& aPosition);
size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
static void CaretBlinkCallback(nsITimer* aTimer, void* aClosure);
void CheckSelectionLanguageChange();
void CaretVisibilityMaybeChanged();
void ResetBlinking();
void StopBlinking();
struct Metrics {
nscoord mBidiIndicatorSize; // width and height of bidi indicator
nscoord mCaretWidth; // full caret width including bidi indicator
static Metrics ComputeMetrics(nsIFrame* aFrame, int32_t aOffset,
nscoord aCaretHeight);
void ComputeCaretRects(nsIFrame* aFrame, int32_t aFrameOffset,
nsRect* aCaretRect, nsRect* aHookRect);
// If we're tracking the selection, this updates the caret position and
// invalidates paint as needed.
void UpdateCaretPositionFromSelectionIfNeeded();
nsWeakPtr mPresShell;
mozilla::WeakPtr<mozilla::dom::Selection> mDomSelectionWeak;
nsCOMPtr<nsITimer> mBlinkTimer;
CaretPosition mCaretPosition;
// The last frame we painted the caret in.
WeakFrame mLastPaintedFrame;
* mBlinkCount is used to control the number of times to blink the caret
* before stopping the blink. This is reset each time we reset the
* blinking.
int32_t mBlinkCount = -1;
* mBlinkRate is the rate of the caret blinking the last time we read it.
* It is used as a way to optimize whether we need to reset the blinking
* timer. 0 or a negative value means no blinking.
int32_t mBlinkRate = 0;
* mHideCount is not 0, it means that somebody doesn't want the caret
* to be visible. See AddForceHide() and RemoveForceHide().
uint32_t mHideCount = 0;
* mIsBlinkOn is true when we're in a blink cycle where the caret is on.
bool mIsBlinkOn = false;
* mIsVisible is true when SetVisible was last called with 'true'.
bool mVisible = false;
* mReadOnly is true when the caret is set to "read only" mode (i.e.,
* it doesn't blink).
bool mReadOnly = false;
* mShowDuringSelection is true when the caret should be shown even when
* the selection is not collapsed.
bool mShowDuringSelection = false;
* mIgnoreUserModify is true when the caret should be shown even when
* it's in non-user-modifiable content.
bool mIgnoreUserModify = true;
* If the caret position is fixed, it's been overridden externally and it
* will not track the selection.
bool mFixedCaretPosition = false;
* If we're currently hiding the caret due to the selection not being
* collapsed. Can only be true if mShowDuringSelection is false.
bool mHiddenDuringSelection = false;
#endif // nsCaret_h__