ScrollBar Class Reference

A scrollbar component. More...

#include <juce_ScrollBar.h>

Inheritance diagram for ScrollBar:

Classes
class	Listener
	A class for receiving events from a ScrollBar. More...
struct	LookAndFeelMethods
	This abstract base class is implemented by LookAndFeel classes to provide scrollbar-drawing functionality. More...

Public Types
enum	ColourIds { backgroundColourId = 0x1000300 , thumbColourId = 0x1000400 , trackColourId = 0x1000401 }
	A set of colour IDs to use to change the colour of various aspects of the component. More...
Public Types inherited from Component
enum class	WindowControlKind {   client , caption , minimise , maximise ,   close , sizeTop , sizeLeft , sizeRight ,   sizeBottom , sizeTopLeft , sizeTopRight , sizeBottomLeft ,   sizeBottomRight }
	Types of control that are commonly found in windows, especially title-bars. More...
enum class	FocusContainerType { none , focusContainer , keyboardFocusContainer }
	A focus container type that can be passed to setFocusContainerType(). More...
enum	FocusChangeType { focusChangedByMouseClick , focusChangedByTabKey , focusChangedDirectly }
	Enumeration used by the focusGained() and focusLost() methods. More...
enum class	FocusChangeDirection { unknown , forward , backward }
	Enumeration used by the focusGainedWithDirection() method. More...

Public Member Functions
	ScrollBar (bool isVertical)
	Creates a Scrollbar.
	~ScrollBar () override
	Destructor.
bool	isVertical () const noexcept
	Returns true if the scrollbar is vertical, false if it's horizontal.
void	setOrientation (bool shouldBeVertical)
	Changes the scrollbar's direction.
void	setAutoHide (bool shouldHideWhenFullRange)
	Tells the scrollbar whether to make itself invisible when not needed.
bool	autoHides () const noexcept
	Returns true if this scrollbar is set to auto-hide when its thumb is as big as its maximum range.
void	setRangeLimits (Range< double > newRangeLimit, NotificationType notification=sendNotificationAsync)
	Sets the minimum and maximum values that the bar will move between.
void	setRangeLimits (double minimum, double maximum, NotificationType notification=sendNotificationAsync)
	Sets the minimum and maximum values that the bar will move between.
Range< double >	getRangeLimit () const noexcept
	Returns the current limits on the thumb position.
double	getMinimumRangeLimit () const noexcept
	Returns the lower value that the thumb can be set to.
double	getMaximumRangeLimit () const noexcept
	Returns the upper value that the thumb can be set to.
bool	setCurrentRange (Range< double > newRange, NotificationType notification=sendNotificationAsync)
	Changes the position of the scrollbar's 'thumb'.
void	setCurrentRange (double newStart, double newSize, NotificationType notification=sendNotificationAsync)
	Changes the position of the scrollbar's 'thumb'.
void	setCurrentRangeStart (double newStart, NotificationType notification=sendNotificationAsync)
	Moves the bar's thumb position.
Range< double >	getCurrentRange () const noexcept
	Returns the current thumb range.
double	getCurrentRangeStart () const noexcept
	Returns the position of the top of the thumb.
double	getCurrentRangeSize () const noexcept
	Returns the current size of the thumb.
void	setSingleStepSize (double newSingleStepSize) noexcept
	Sets the amount by which the up and down buttons will move the bar.
double	getSingleStepSize () const noexcept
	Returns the current step size.
bool	moveScrollbarInSteps (int howManySteps, NotificationType notification=sendNotificationAsync)
	Moves the scrollbar by a number of single-steps.
bool	moveScrollbarInPages (int howManyPages, NotificationType notification=sendNotificationAsync)
	Moves the scroll bar up or down in pages.
bool	scrollToTop (NotificationType notification=sendNotificationAsync)
	Scrolls to the top (or left).
bool	scrollToBottom (NotificationType notification=sendNotificationAsync)
	Scrolls to the bottom (or right).
void	setButtonRepeatSpeed (int initialDelayInMillisecs, int repeatDelayInMillisecs, int minimumDelayInMillisecs=-1)
	Changes the delay before the up and down buttons autorepeat when they are held down.
void	addListener (Listener *listener)
	Registers a listener that will be called when the scrollbar is moved.
void	removeListener (Listener *listener)
	Deregisters a previously-registered listener.
bool	keyPressed (const KeyPress &) override
	Called when a key is pressed.
void	mouseWheelMove (const MouseEvent &, const MouseWheelDetails &) override
	Called when the mouse-wheel is moved.
void	lookAndFeelChanged () override
	Called to let the component react to a change in the look-and-feel setting.
void	mouseDown (const MouseEvent &) override
	Called when a mouse button is pressed.
void	mouseDrag (const MouseEvent &) override
	Called when the mouse is moved while a button is held down.
void	mouseUp (const MouseEvent &) override
	Called when a mouse button is released.
void	paint (Graphics &) override
	Components can override this method to draw their content.
void	resized () override
	Called when this component's size has been changed.
void	parentHierarchyChanged () override
	Called to indicate that the component's parents have changed.
void	setVisible (bool) override
	Makes the component visible or invisible.
std::unique_ptr< AccessibilityHandler >	createAccessibilityHandler () override
	Override this method to return a custom AccessibilityHandler for this component.
Public Member Functions inherited from Component
	Component () noexcept
	Creates a component.
	~Component () override
	Destructor.
	Component (const String &componentName) noexcept
	Creates a component, setting its name at the same time.
String	getName () const noexcept
	Returns the name of this component.
virtual void	setName (const String &newName)
	Sets the name of this component.
String	getComponentID () const noexcept
	Returns the ID string that was set by setComponentID().
void	setComponentID (const String &newID)
	Sets the component's ID string.
bool	isVisible () const noexcept
	Tests whether the component is visible or not.
virtual void	visibilityChanged ()
	Called when this component's visibility changes.
bool	isShowing () const
	Tests whether this component and all its parents are visible.
virtual void	addToDesktop (int windowStyleFlags, void *nativeWindowToAttachTo=nullptr)
	Makes this component appear as a window on the desktop.
void	removeFromDesktop ()
	If the component is currently showing on the desktop, this will hide it.
bool	isOnDesktop () const noexcept
	Returns true if this component is currently showing on the desktop.
ComponentPeer *	getPeer () const
	Returns the heavyweight window that contains this component.
virtual void	userTriedToCloseWindow ()
	For components on the desktop, this is called if the system wants to close the window.
virtual void	minimisationStateChanged (bool isNowMinimised)
	Called for a desktop component which has just been minimised or un-minimised.
virtual float	getDesktopScaleFactor () const
	Returns the default scale factor to use for this component when it is placed on the desktop.
void	toFront (bool shouldAlsoGainKeyboardFocus)
	Brings the component to the front of its siblings.
void	toBack ()
	Changes this component's z-order to be at the back of all its siblings.
void	toBehind (Component *other)
	Changes this component's z-order so that it's just behind another component.
void	setAlwaysOnTop (bool shouldStayOnTop)
	Sets whether the component should always be kept at the front of its siblings.
bool	isAlwaysOnTop () const noexcept
	Returns true if this component is set to always stay in front of its siblings.
int	getX () const noexcept
	Returns the x coordinate of the component's left edge.
int	getY () const noexcept
	Returns the y coordinate of the top of this component.
int	getWidth () const noexcept
	Returns the component's width in pixels.
int	getHeight () const noexcept
	Returns the component's height in pixels.
int	getRight () const noexcept
	Returns the x coordinate of the component's right-hand edge.
Point< int >	getPosition () const noexcept
	Returns the component's top-left position as a Point.
int	getBottom () const noexcept
	Returns the y coordinate of the bottom edge of this component.
Rectangle< int >	getBounds () const noexcept
	Returns this component's bounding box.
Rectangle< int >	getLocalBounds () const noexcept
	Returns the component's bounds, relative to its own origin.
Rectangle< int >	getBoundsInParent () const noexcept
	Returns the area of this component's parent which this component covers.
int	getScreenX () const
	Returns this component's x coordinate relative the screen's top-left origin.
int	getScreenY () const
	Returns this component's y coordinate relative the screen's top-left origin.
Point< int >	getScreenPosition () const
	Returns the position of this component's top-left corner relative to the screen's top-left.
Rectangle< int >	getScreenBounds () const
	Returns the bounds of this component, relative to the screen's top-left.
Point< int >	getLocalPoint (const Component *sourceComponent, Point< int > pointRelativeToSourceComponent) const
	Converts a point to be relative to this component's coordinate space.
Point< float >	getLocalPoint (const Component *sourceComponent, Point< float > pointRelativeToSourceComponent) const
	Converts a point to be relative to this component's coordinate space.
Rectangle< int >	getLocalArea (const Component *sourceComponent, Rectangle< int > areaRelativeToSourceComponent) const
	Converts a rectangle to be relative to this component's coordinate space.
Rectangle< float >	getLocalArea (const Component *sourceComponent, Rectangle< float > areaRelativeToSourceComponent) const
	Converts a rectangle to be relative to this component's coordinate space.
Point< int >	localPointToGlobal (Point< int > localPoint) const
	Converts a point relative to this component's top-left into a screen coordinate.
Point< float >	localPointToGlobal (Point< float > localPoint) const
	Converts a point relative to this component's top-left into a screen coordinate.
Rectangle< int >	localAreaToGlobal (Rectangle< int > localArea) const
	Converts a rectangle from this component's coordinate space to a screen coordinate.
Rectangle< float >	localAreaToGlobal (Rectangle< float > localArea) const
	Converts a rectangle from this component's coordinate space to a screen coordinate.
void	setTopLeftPosition (int x, int y)
	Moves the component to a new position.
void	setTopLeftPosition (Point< int > newTopLeftPosition)
	Moves the component to a new position.
void	setTopRightPosition (int x, int y)
	Moves the component to a new position.
void	setSize (int newWidth, int newHeight)
	Changes the size of the component.
void	setBounds (int x, int y, int width, int height)
	Changes the component's position and size.
void	setBounds (Rectangle< int > newBounds)
	Changes the component's position and size.
void	setBoundsRelative (float proportionalX, float proportionalY, float proportionalWidth, float proportionalHeight)
	Changes the component's position and size in terms of fractions of its parent's size.
void	setBoundsRelative (Rectangle< float > proportionalArea)
	Changes the component's position and size in terms of fractions of its parent's size.
void	setBoundsInset (BorderSize< int > borders)
	Changes the component's position and size based on the amount of space to leave around it.
void	setBoundsToFit (Rectangle< int > targetArea, Justification justification, bool onlyReduceInSize)
	Positions the component within a given rectangle, keeping its proportions unchanged.
void	setCentrePosition (int x, int y)
	Changes the position of the component's centre.
void	setCentrePosition (Point< int > newCentrePosition)
	Changes the position of the component's centre.
void	setCentreRelative (float x, float y)
	Changes the position of the component's centre.
void	centreWithSize (int width, int height)
	Changes the component's size and centres it within its parent.
void	setTransform (const AffineTransform &transform)
	Sets a transform matrix to be applied to this component.
AffineTransform	getTransform () const
	Returns the transform that is currently being applied to this component.
bool	isTransformed () const noexcept
	Returns true if a non-identity transform is being applied to this component.
int	proportionOfWidth (float proportion) const noexcept
	Returns a proportion of the component's width.
int	proportionOfHeight (float proportion) const noexcept
	Returns a proportion of the component's height.
int	getParentWidth () const noexcept
	Returns the width of the component's parent.
int	getParentHeight () const noexcept
	Returns the height of the component's parent.
Rectangle< int >	getParentMonitorArea () const
	Returns the screen coordinates of the monitor that contains this component.
int	getNumChildComponents () const noexcept
	Returns the number of child components that this component contains.
Component *	getChildComponent (int index) const noexcept
	Returns one of this component's child components, by it index.
int	getIndexOfChildComponent (const Component *child) const noexcept
	Returns the index of this component in the list of child components.
const Array< Component * > &	getChildren () const noexcept
	Provides access to the underlying array of child components.
Component *	findChildWithID (StringRef componentID) const noexcept
	Looks for a child component with the specified ID.
void	addChildComponent (Component *child, int zOrder=-1)
	Adds a child component to this one.
void	addChildComponent (Component &child, int zOrder=-1)
	Adds a child component to this one.
void	addAndMakeVisible (Component *child, int zOrder=-1)
	Adds a child component to this one, and also makes the child visible if it isn't already.
void	addAndMakeVisible (Component &child, int zOrder=-1)
	Adds a child component to this one, and also makes the child visible if it isn't already.
void	addChildAndSetID (Component *child, const String &componentID)
	Adds a child component to this one, makes it visible, and sets its component ID.
void	removeChildComponent (Component *childToRemove)
	Removes one of this component's child-components.
Component *	removeChildComponent (int childIndexToRemove)
	Removes one of this component's child-components by index.
void	removeAllChildren ()
	Removes all this component's children.
void	deleteAllChildren ()
	Removes and deletes all of this component's children.
Component *	getParentComponent () const noexcept
	Returns the component which this component is inside.
template<class TargetClass >
TargetClass *	findParentComponentOfClass () const
	Searches the parent components for a component of a specified class.
Component *	getTopLevelComponent () const noexcept
	Returns the highest-level component which contains this one or its parents.
bool	isParentOf (const Component *possibleChild) const noexcept
	Checks whether a component is anywhere inside this component or its children.
virtual void	childrenChanged ()
	Subclasses can use this callback to be told when children are added or removed, or when their z-order changes.
virtual bool	hitTest (int x, int y)
	Tests whether a given point is inside the component.
virtual WindowControlKind	findControlAtPoint (Point< float >) const
	For components that are added to the desktop, this may be called to determine what kind of control is at particular locations in the window.
virtual void	windowControlClickedClose ()
	For components that are added to the desktop, this may be called to indicate that the mouse was clicked inside the area of the "close" control.
virtual void	windowControlClickedMinimise ()
	For components that are added to the desktop, this may be called to indicate that the mouse was clicked inside the area of the "minimise" control.
virtual void	windowControlClickedMaximise ()
	For components that are added to the desktop, this may be called to indicate that the mouse was clicked inside the area of the "maximise" control.
void	setInterceptsMouseClicks (bool allowClicksOnThisComponent, bool allowClicksOnChildComponents) noexcept
	Changes the default return value for the hitTest() method.
void	getInterceptsMouseClicks (bool &allowsClicksOnThisComponent, bool &allowsClicksOnChildComponents) const noexcept
	Retrieves the current state of the mouse-click interception flags.
bool	contains (Point< int > localPoint)
	Returns true if a given point lies within this component or one of its children.
bool	contains (Point< float > localPoint)
	Returns true if a given point lies within this component or one of its children.
bool	reallyContains (Point< int > localPoint, bool returnTrueIfWithinAChild)
	Returns true if a given point lies in this component, taking any overlapping siblings into account.
bool	reallyContains (Point< float > localPoint, bool returnTrueIfWithinAChild)
	Returns true if a given point lies in this component, taking any overlapping siblings into account.
Component *	getComponentAt (int x, int y)
	Returns the component at a certain point within this one.
Component *	getComponentAt (Point< int > position)
	Returns the component at a certain point within this one.
Component *	getComponentAt (Point< float > position)
	Returns the component at a certain point within this one.
void	repaint ()
	Marks the whole component as needing to be redrawn.
void	repaint (int x, int y, int width, int height)
	Marks a subsection of this component as needing to be redrawn.
void	repaint (Rectangle< int > area)
	Marks a subsection of this component as needing to be redrawn.
void	setBufferedToImage (bool shouldBeBuffered)
	Makes the component use an internal buffer to optimise its redrawing.
Image	createComponentSnapshot (Rectangle< int > areaToGrab, bool clipImageToComponentBounds=true, float scaleFactor=1.0f)
	Generates a snapshot of part of this component.
void	paintEntireComponent (Graphics &context, bool ignoreAlphaLevel)
	Draws this component and all its subcomponents onto the specified graphics context.
void	setPaintingIsUnclipped (bool shouldPaintWithoutClipping) noexcept
	This allows you to indicate that this component doesn't require its graphics context to be clipped when it is being painted.
bool	isPaintingUnclipped () const noexcept
	Returns true if this component doesn't require its graphics context to be clipped when it is being painted.
void	setComponentEffect (ImageEffectFilter *newEffect)
	Adds an effect filter to alter the component's appearance.
ImageEffectFilter *	getComponentEffect () const noexcept
	Returns the current component effect.
LookAndFeel &	getLookAndFeel () const noexcept
	Finds the appropriate look-and-feel to use for this component.
void	setLookAndFeel (LookAndFeel *newLookAndFeel)
	Sets the look and feel to use for this component.
FontOptions	withDefaultMetrics (FontOptions opt) const
	Returns a copy of the FontOptions with the default metrics kind from the component's LookAndFeel.
void	sendLookAndFeelChange ()
	Calls the methods repaint(), lookAndFeelChanged(), and colourChanged() in this component and all its children recursively.
void	setOpaque (bool shouldBeOpaque)
	Indicates whether any parts of the component might be transparent.
bool	isOpaque () const noexcept
	Returns true if no parts of this component are transparent.
void	setBroughtToFrontOnMouseClick (bool shouldBeBroughtToFront) noexcept
	Indicates whether the component should be brought to the front when clicked.
bool	isBroughtToFrontOnMouseClick () const noexcept
	Indicates whether the component should be brought to the front when clicked-on.
void	setExplicitFocusOrder (int newFocusOrderIndex)
	Sets the focus order of this component.
int	getExplicitFocusOrder () const
	Returns the focus order of this component, if one has been specified.
void	setFocusContainerType (FocusContainerType containerType) noexcept
	Sets whether this component is a container for components that can have their focus traversed, and the type of focus traversal that it supports.
bool	isFocusContainer () const noexcept
	Returns true if this component has been marked as a focus container.
bool	isKeyboardFocusContainer () const noexcept
	Returns true if this component has been marked as a keyboard focus container.
Component *	findFocusContainer () const
	Returns the focus container for this component.
Component *	findKeyboardFocusContainer () const
	Returns the keyboard focus container for this component.
void	setWantsKeyboardFocus (bool wantsFocus) noexcept
	Sets a flag to indicate whether this component wants keyboard focus or not.
bool	getWantsKeyboardFocus () const noexcept
	Returns true if the component is interested in getting keyboard focus.
void	setMouseClickGrabsKeyboardFocus (bool shouldGrabFocus)
	Chooses whether a click on this component automatically grabs the focus.
bool	getMouseClickGrabsKeyboardFocus () const noexcept
	Returns the last value set with setMouseClickGrabsKeyboardFocus().
void	grabKeyboardFocus ()
	Tries to give keyboard focus to this component.
void	giveAwayKeyboardFocus ()
	If this component or any of its children currently have the keyboard focus, this will defocus it, send a focus change notification, and try to pass the focus to the next component.
bool	hasKeyboardFocus (bool trueIfChildIsFocused) const
	Returns true if this component currently has the keyboard focus.
void	moveKeyboardFocusToSibling (bool moveToNext)
	Tries to move the keyboard focus to one of this component's siblings.
virtual std::unique_ptr< ComponentTraverser >	createFocusTraverser ()
	Creates a ComponentTraverser object to determine the logic by which focus should be passed from this component.
virtual std::unique_ptr< ComponentTraverser >	createKeyboardFocusTraverser ()
	Creates a ComponentTraverser object to use to determine the logic by which keyboard focus should be passed from this component.
void	setHasFocusOutline (bool hasFocusOutline) noexcept
	Use this to indicate that the component should have an outline drawn around it when it has keyboard focus.
bool	hasFocusOutline () const noexcept
	Returns true if this component should have a focus outline.
bool	isEnabled () const noexcept
	Returns true if the component (and all its parents) are enabled.
void	setEnabled (bool shouldBeEnabled)
	Enables or disables this component.
virtual void	enablementChanged ()
	Callback to indicate that this component has been enabled or disabled.
float	getAlpha () const noexcept
	Returns the component's current transparency level.
void	setAlpha (float newAlpha)
	Changes the transparency of this component.
virtual void	alphaChanged ()
	Called when setAlpha() is used to change the alpha value of this component.
void	setMouseCursor (const MouseCursor &cursorType)
	Changes the mouse cursor shape to use when the mouse is over this component.
virtual MouseCursor	getMouseCursor ()
	Returns the mouse cursor shape to use when the mouse is over this component.
void	updateMouseCursor () const
	Forces the current mouse cursor to be updated.
virtual void	paintOverChildren (Graphics &g)
	Components can override this method to draw over the top of their children.
void	mouseMove (const MouseEvent &event) override
	Called when the mouse moves inside a component.
void	mouseEnter (const MouseEvent &event) override
	Called when the mouse first enters a component.
void	mouseExit (const MouseEvent &event) override
	Called when the mouse moves out of a component.
void	mouseDoubleClick (const MouseEvent &event) override
	Called when a mouse button has been double-clicked on a component.
void	mouseMagnify (const MouseEvent &event, float scaleFactor) override
	Called when a pinch-to-zoom mouse-gesture is used.
void	setRepaintsOnMouseActivity (bool shouldRepaint) noexcept
	Causes automatic repaints when the mouse enters or exits this component.
void	addMouseListener (MouseListener *newListener, bool wantsEventsForAllNestedChildComponents)
	Registers a listener to be told when mouse events occur in this component.
void	removeMouseListener (MouseListener *listenerToRemove)
	Deregisters a mouse listener.
void	addKeyListener (KeyListener *newListener)
	Adds a listener that wants to hear about keypresses that this component receives.
void	removeKeyListener (KeyListener *listenerToRemove)
	Removes a previously-registered key listener.
virtual bool	keyStateChanged (bool isKeyDown)
	Called when a key is pressed or released.
virtual void	modifierKeysChanged (const ModifierKeys &modifiers)
	Called when a modifier key is pressed or released.
virtual void	focusGained (FocusChangeType cause)
	Called to indicate that this component has just acquired the keyboard focus.
virtual void	focusGainedWithDirection (FocusChangeType cause, FocusChangeDirection direction)
	Called to indicate that this component has just acquired the keyboard focus.
virtual void	focusLost (FocusChangeType cause)
	Called to indicate that this component has just lost the keyboard focus.
virtual void	focusOfChildComponentChanged (FocusChangeType cause)
	Called to indicate a change in whether or not this component is the parent of the currently-focused component.
bool	isMouseOver (bool includeChildren=false) const
	Returns true if the mouse is currently over this component.
bool	isMouseButtonDown (bool includeChildren=false) const
	Returns true if the mouse button is currently held down in this component.
bool	isMouseOverOrDragging (bool includeChildren=false) const
	True if the mouse is over this component, or if it's being dragged in this component.
Point< int >	getMouseXYRelative () const
	Returns the mouse's current position, relative to this component.
virtual void	moved ()
	Called when this component's position has been changed.
virtual void	childBoundsChanged (Component *child)
	Called when one of this component's children is moved or resized.
virtual void	parentSizeChanged ()
	Called when this component's immediate parent has been resized.
virtual void	broughtToFront ()
	Called when this component has been moved to the front of its siblings.
void	addComponentListener (ComponentListener *newListener)
	Adds a listener to be told about changes to the component hierarchy or position.
void	removeComponentListener (ComponentListener *listenerToRemove)
	Removes a component listener.
void	postCommandMessage (int commandId)
	Dispatches a numbered message to this component.
virtual void	handleCommandMessage (int commandId)
	Called to handle a command that was sent by postCommandMessage().
int	runModalLoop ()
	Runs a component modally, waiting until the loop terminates.
void	enterModalState (bool takeKeyboardFocus=true, ModalComponentManager::Callback *callback=nullptr, bool deleteWhenDismissed=false)
	Puts the component into a modal state.
void	exitModalState (int returnValue=0)
	Ends a component's modal state.
bool	isCurrentlyModal (bool onlyConsiderForemostModalComponent=true) const noexcept
	Returns true if this component is the modal one.
bool	isCurrentlyBlockedByAnotherModalComponent () const
	Checks whether there's a modal component somewhere that's stopping this one from receiving messages.
virtual bool	canModalEventBeSentToComponent (const Component *targetComponent)
	When a component is modal, this callback allows it to choose which other components can still receive events.
virtual void	inputAttemptWhenModal ()
	Called when the user tries to click on a component that is blocked by another modal component.
NamedValueSet &	getProperties () noexcept
	Returns the set of properties that belong to this component.
const NamedValueSet &	getProperties () const noexcept
	Returns the set of properties that belong to this component.
Colour	findColour (int colourID, bool inheritFromParent=false) const
	Looks for a colour that has been registered with the given colour ID number.
void	setColour (int colourID, Colour newColour)
	Registers a colour to be used for a particular purpose.
void	removeColour (int colourID)
	If a colour has been set with setColour(), this will remove it.
bool	isColourSpecified (int colourID) const
	Returns true if the specified colour ID has been explicitly set for this component using the setColour() method.
void	copyAllExplicitColoursTo (Component &target) const
	This looks for any colours that have been specified for this component, and copies them to the specified target component.
virtual void	colourChanged ()
	This method is called when a colour is changed by the setColour() method, or when the look-and-feel is changed by the setLookAndFeel() or sendLookAndFeelChanged() methods.
void *	getWindowHandle () const
	Returns the underlying native window handle for this component.
Positioner *	getPositioner () const noexcept
	Returns the Positioner object that has been set for this component.
void	setPositioner (Positioner *newPositioner)
	Sets a new Positioner object for this component.
void	setCachedComponentImage (CachedComponentImage *newCachedImage)
	Gives the component a CachedComponentImage that should be used to buffer its painting.
CachedComponentImage *	getCachedComponentImage () const noexcept
	Returns the object that was set by setCachedComponentImage().
void	setViewportIgnoreDragFlag (bool ignoreDrag) noexcept
	Sets a flag to indicate whether mouse drag events on this Component should be ignored when it is inside a Viewport with drag-to-scroll functionality enabled.
bool	getViewportIgnoreDragFlag () const noexcept
	Retrieves the current state of the Viewport drag-to-scroll functionality flag.
String	getTitle () const noexcept
	Returns the title text for this component.
void	setTitle (const String &newTitle)
	Sets the title for this component.
String	getDescription () const noexcept
	Returns the description for this component.
void	setDescription (const String &newDescription)
	Sets the description for this component.
String	getHelpText () const noexcept
	Returns the help text for this component.
void	setHelpText (const String &newHelpText)
	Sets the help text for this component.
void	setAccessible (bool shouldBeAccessible)
	Sets whether this component and its children are visible to accessibility clients.
bool	isAccessible () const noexcept
	Returns true if this component and its children are visible to accessibility clients.
AccessibilityHandler *	getAccessibilityHandler ()
	Returns the accessibility handler for this component, or nullptr if this component is not accessible.
void	invalidateAccessibilityHandler ()
	Invalidates the AccessibilityHandler that is currently being used for this component.
Public Member Functions inherited from MouseListener
virtual	~MouseListener ()=default
	Destructor.
Public Member Functions inherited from AsyncUpdater
	AsyncUpdater ()
	Creates an AsyncUpdater object.
virtual	~AsyncUpdater ()
	Destructor.
void	triggerAsyncUpdate ()
	Causes the callback to be triggered at a later time.
void	cancelPendingUpdate () noexcept
	This will stop any pending updates from happening.
void	handleUpdateNowIfNeeded ()
	If an update has been triggered and is pending, this will invoke it synchronously.
bool	isUpdatePending () const noexcept
	Returns true if there's an update callback in the pipeline.

Additional Inherited Members
Static Public Member Functions inherited from Component
static float JUCE_CALLTYPE	getApproximateScaleFactorForComponent (const Component *targetComponent)
	Returns the approximate scale factor for a given component by traversing its parent hierarchy and applying each transform and finally scaling this by the global scale factor.
static Component *JUCE_CALLTYPE	getCurrentlyFocusedComponent () noexcept
	Returns the component that currently has the keyboard focus.
static void JUCE_CALLTYPE	unfocusAllComponents ()
	If any component has keyboard focus, this will defocus it.
static void JUCE_CALLTYPE	beginDragAutoRepeat (int millisecondsBetweenCallbacks)
	Ensures that a non-stop stream of mouse-drag events will be sent during the current mouse-drag operation.
static bool JUCE_CALLTYPE	isMouseButtonDownAnywhere () noexcept
	Returns true if a mouse button is currently down.
static int JUCE_CALLTYPE	getNumCurrentlyModalComponents () noexcept
	Returns the number of components that are currently in a modal state.
static Component *JUCE_CALLTYPE	getCurrentlyModalComponent (int index=0) noexcept
	Returns one of the components that are currently modal.

Detailed Description

A scrollbar component.

To use a scrollbar, set up its total range using the setRangeLimits() method - this sets the range of values it can represent. Then you can use setCurrentRange() to change the position and size of the scrollbar's 'thumb'.

Registering a ScrollBar::Listener with the scrollbar will allow you to find out when the user moves it, and you can use the getCurrentRangeStart() to find out where they moved it to.

The scrollbar will adjust its own visibility according to whether its thumb size allows it to actually be scrolled.

For most purposes, it's probably easier to use a Viewport or ListBox instead of handling a scrollbar directly.

See also

ScrollBar::Listener

Member Enumeration Documentation

ColourIds

enum ScrollBar::ColourIds

A set of colour IDs to use to change the colour of various aspects of the component.

These constants can be used either via the Component::setColour(), or LookAndFeel::setColour() methods.

See also

Component::setColour, Component::findColour, LookAndFeel::setColour, LookAndFeel::findColour

Enumerator
backgroundColourId	The background colour of the scrollbar.
thumbColourId	A base colour to use for the thumb. The look and feel will probably use variations on this colour.
trackColourId	A base colour to use for the slot area of the bar. The look and feel will probably use variations on this colour.

Constructor & Destructor Documentation

ScrollBar()

ScrollBar::ScrollBar

(

bool

isVertical

)

Creates a Scrollbar.

Parameters

isVertical

specifies whether the bar should be a vertical or horizontal

~ScrollBar()

ScrollBar::~ScrollBar ( )

override

Destructor.

Member Function Documentation

isVertical()

bool ScrollBar::isVertical ( ) const

noexcept

Returns true if the scrollbar is vertical, false if it's horizontal.

setOrientation()

void ScrollBar::setOrientation

(

bool

shouldBeVertical

)

Changes the scrollbar's direction.

You'll also need to resize the bar appropriately - this just changes its internal layout.

Parameters

shouldBeVertical

true makes it vertical; false makes it horizontal.

setAutoHide()

void ScrollBar::setAutoHide

(

bool

shouldHideWhenFullRange

)

Tells the scrollbar whether to make itself invisible when not needed.

The default behaviour is for a scrollbar to become invisible when the thumb fills the whole of its range (i.e. when it can't be moved). Setting this value to false forces the bar to always be visible.

See also

autoHides()

autoHides()

bool ScrollBar::autoHides ( ) const

noexcept

Returns true if this scrollbar is set to auto-hide when its thumb is as big as its maximum range.

See also

setAutoHide

setRangeLimits() [1/2]

void ScrollBar::setRangeLimits	(	Range< double >	newRangeLimit,
		NotificationType	notification = sendNotificationAsync )

Sets the minimum and maximum values that the bar will move between.

The bar's thumb will always be constrained so that the entire thumb lies within this range.

Parameters

newRangeLimit	the new range.
notification	whether to send a notification of the change to listeners. A notification will only be sent if the range has changed.

See also

setCurrentRange

setRangeLimits() [2/2]

void ScrollBar::setRangeLimits	(	double	minimum,
		double	maximum,
		NotificationType	notification = sendNotificationAsync )

Sets the minimum and maximum values that the bar will move between.

The bar's thumb will always be constrained so that the entire thumb lies within this range.

Parameters

minimum	the new range minimum.
maximum	the new range maximum.
notification	whether to send a notification of the change to listeners. A notification will only be sent if the range has changed.

See also

setCurrentRange

getRangeLimit()

Range< double > ScrollBar::getRangeLimit ( ) const

noexcept

Returns the current limits on the thumb position.

See also

setRangeLimits

getMinimumRangeLimit()

double ScrollBar::getMinimumRangeLimit ( ) const

noexcept

Returns the lower value that the thumb can be set to.

This is the value set by setRangeLimits().

getMaximumRangeLimit()

double ScrollBar::getMaximumRangeLimit ( ) const

noexcept

Returns the upper value that the thumb can be set to.

This is the value set by setRangeLimits().

setCurrentRange() [1/2]

bool ScrollBar::setCurrentRange	(	Range< double >	newRange,
		NotificationType	notification = sendNotificationAsync )

Changes the position of the scrollbar's 'thumb'.

This sets both the position and size of the thumb - to just set the position without changing the size, you can use setCurrentRangeStart().

If this method call actually changes the scrollbar's position, it will trigger an asynchronous call to ScrollBar::Listener::scrollBarMoved() for all the listeners that are registered.

The notification parameter can be used to optionally send or inhibit a callback to any scrollbar listeners.

Returns

true if the range was changed, or false if nothing was changed.

See also

getCurrentRange. setCurrentRangeStart

setCurrentRange() [2/2]

void ScrollBar::setCurrentRange	(	double	newStart,
		double	newSize,
		NotificationType	notification = sendNotificationAsync )

Changes the position of the scrollbar's 'thumb'.

This sets both the position and size of the thumb - to just set the position without changing the size, you can use setCurrentRangeStart().

Parameters

newStart	the top (or left) of the thumb, in the range getMinimumRangeLimit() <= newStart <= getMaximumRangeLimit(). If the value is beyond these limits, it will be clipped.
newSize	the size of the thumb, such that getMinimumRangeLimit() <= newStart + newSize <= getMaximumRangeLimit(). If the size is beyond these limits, it will be clipped.
notification	specifies if and how a callback should be made to any listeners if the range actually changes

See also

setCurrentRangeStart, getCurrentRangeStart, getCurrentRangeSize

setCurrentRangeStart()

void ScrollBar::setCurrentRangeStart	(	double	newStart,
		NotificationType	notification = sendNotificationAsync )

Moves the bar's thumb position.

This will move the thumb position without changing the thumb size. Note that the maximum thumb start position is (getMaximumRangeLimit() - getCurrentRangeSize()).

If this method call actually changes the scrollbar's position, it will trigger an asynchronous call to ScrollBar::Listener::scrollBarMoved() for all the listeners that are registered.

See also

setCurrentRange

getCurrentRange()

Range< double > ScrollBar::getCurrentRange ( ) const

noexcept

Returns the current thumb range.

See also

getCurrentRange, setCurrentRange

getCurrentRangeStart()

double ScrollBar::getCurrentRangeStart ( ) const

noexcept

Returns the position of the top of the thumb.

See also

getCurrentRange, setCurrentRangeStart

getCurrentRangeSize()

double ScrollBar::getCurrentRangeSize ( ) const

noexcept

Returns the current size of the thumb.

See also

getCurrentRange, setCurrentRange

setSingleStepSize()

void ScrollBar::setSingleStepSize ( double newSingleStepSize )

noexcept

Sets the amount by which the up and down buttons will move the bar.

The value here is in terms of the total range, and is added or subtracted from the thumb position when the user clicks an up/down (or left/right) button.

getSingleStepSize()

double ScrollBar::getSingleStepSize ( ) const

noexcept

Returns the current step size.

See also

setSingleStepSize

moveScrollbarInSteps()

bool ScrollBar::moveScrollbarInSteps	(	int	howManySteps,
		NotificationType	notification = sendNotificationAsync )

Moves the scrollbar by a number of single-steps.

This will move the bar by a multiple of its single-step interval (as specified using the setSingleStepSize() method).

A positive value here will move the bar down or to the right, a negative value moves it up or to the left.

Parameters

howManySteps	the number of steps to move the scrollbar
notification	whether to send a notification of the change to listeners. A notification will only be sent if the position has changed.

Returns

true if the scrollbar's position actually changed.

moveScrollbarInPages()

bool ScrollBar::moveScrollbarInPages	(	int	howManyPages,
		NotificationType	notification = sendNotificationAsync )

Moves the scroll bar up or down in pages.

This will move the bar by a multiple of its current thumb size, effectively doing a page-up or down.

A positive value here will move the bar down or to the right, a negative value moves it up or to the left.

Parameters

howManyPages	the number of pages to move the scrollbar
notification	whether to send a notification of the change to listeners. A notification will only be sent if the position has changed.

Returns

true if the scrollbar's position actually changed.

scrollToTop()

bool ScrollBar::scrollToTop

(

NotificationType

notification = sendNotificationAsync

)

Scrolls to the top (or left).

This is the same as calling setCurrentRangeStart (getMinimumRangeLimit());

Parameters

notification

whether to send a notification of the change to listeners. A notification will only be sent if the position has changed.

Returns

true if the scrollbar's position actually changed.

scrollToBottom()

bool ScrollBar::scrollToBottom

(

NotificationType

notification = sendNotificationAsync

)

Scrolls to the bottom (or right).

This is the same as calling setCurrentRangeStart (getMaximumRangeLimit() - getCurrentRangeSize());

Parameters

notification

whether to send a notification of the change to listeners. A notification will only be sent if the position has changed.

Returns

true if the scrollbar's position actually changed.

setButtonRepeatSpeed()

void ScrollBar::setButtonRepeatSpeed	(	int	initialDelayInMillisecs,
		int	repeatDelayInMillisecs,
		int	minimumDelayInMillisecs = -1 )

Changes the delay before the up and down buttons autorepeat when they are held down.

For an explanation of what the parameters are for, see Button::setRepeatSpeed().

See also

Button::setRepeatSpeed

addListener()

void ScrollBar::addListener

(

Listener *

listener

)

Registers a listener that will be called when the scrollbar is moved.

removeListener()

void ScrollBar::removeListener

(

Listener *

listener

)

Deregisters a previously-registered listener.

keyPressed()

bool ScrollBar::keyPressed ( const KeyPress & key )

overridevirtual

Called when a key is pressed.

When a key is pressed, the component that has the keyboard focus will have this method called. Remember that a component will only be given the focus if its setWantsKeyboardFocus() method has been used to enable this.

If your implementation returns true, the event will be consumed and not passed on to any other listeners. If it returns false, the key will be passed to any KeyListeners that have been registered with this component. As soon as one of these returns true, the process will stop, but if they all return false, the event will be passed upwards to this component's parent, and so on.

The default implementation of this method does nothing and returns false.

See also

keyStateChanged, getCurrentlyFocusedComponent, addKeyListener

Reimplemented from Component.

mouseWheelMove()

void ScrollBar::mouseWheelMove ( const MouseEvent & event, const MouseWheelDetails & wheel )

overridevirtual

Called when the mouse-wheel is moved.

This callback is sent to the component that the mouse is over when the wheel is moved.

If not overridden, a component will forward this message to its parent, so that parent components can collect mouse-wheel messages that happen to child components which aren't interested in them. (Bear in mind that if you attach a component as a mouse-listener to other components, then those wheel moves will also end up calling this method and being passed up to the parents, which may not be what you intended to happen).

Parameters

event	details about the mouse event
wheel	details about the mouse wheel movement

Reimplemented from Component.

lookAndFeelChanged()

void ScrollBar::lookAndFeelChanged ( )

overridevirtual

Called to let the component react to a change in the look-and-feel setting.

When the look-and-feel is changed for a component, this method, repaint(), and colourChanged() are called on the original component and all its children recursively.

It can also be triggered manually by the sendLookAndFeelChange() method, in case an application uses a LookAndFeel class that might have changed internally.

See also

sendLookAndFeelChange, getLookAndFeel

Reimplemented from Component.

mouseDown()

void ScrollBar::mouseDown ( const MouseEvent & event )

overridevirtual

Called when a mouse button is pressed.

The MouseEvent object passed in contains lots of methods for finding out which button was pressed, as well as which modifier keys (e.g. shift, ctrl) were held down at the time.

Once a button is held down, the mouseDrag method will be called when the mouse moves, until the button is released.

Parameters

event

details about the position and status of the mouse event, including the source component in which it occurred

See also

mouseUp, mouseDrag, mouseDoubleClick, contains

Reimplemented from Component.

mouseDrag()

void ScrollBar::mouseDrag ( const MouseEvent & event )

overridevirtual

Called when the mouse is moved while a button is held down.

When a mouse button is pressed inside a component, that component receives mouseDrag callbacks each time the mouse moves, even if the mouse strays outside the component's bounds.

Parameters

event

details about the position and status of the mouse event, including the source component in which it occurred

See also

mouseDown, mouseUp, mouseMove, contains, setDragRepeatInterval

Reimplemented from Component.

mouseUp()

void ScrollBar::mouseUp ( const MouseEvent & event )

overridevirtual

Called when a mouse button is released.

A mouseUp callback is sent to the component in which a button was pressed even if the mouse is actually over a different component when the button is released.

The MouseEvent object passed in contains lots of methods for finding out which buttons were down just before they were released.

Parameters

event

details about the position and status of the mouse event, including the source component in which it occurred

See also

mouseDown, mouseDrag, mouseDoubleClick, contains

Reimplemented from Component.

paint()

void ScrollBar::paint ( Graphics & g )

overridevirtual

Components can override this method to draw their content.

The paint() method gets called when a region of a component needs redrawing, either because the component's repaint() method has been called, or because something has happened on the screen that means a section of a window needs to be redrawn.

Any child components will draw themselves over whatever this method draws. If you need to paint over the top of your child components, you can also implement the paintOverChildren() method to do this.

If you want to cause a component to redraw itself, this is done asynchronously - calling the repaint() method marks a region of the component as "dirty", and the paint() method will automatically be called sometime later, by the message thread, to paint any bits that need refreshing. In JUCE (and almost all modern UI frameworks), you never redraw something synchronously.

You should never need to call this method directly - to take a snapshot of the component you could use createComponentSnapshot() or paintEntireComponent().

Parameters

g	the graphics context that must be used to do the drawing operations.

See also

repaint, paintOverChildren, Graphics

Reimplemented from Component.

resized()

void ScrollBar::resized ( )

overridevirtual

Called when this component's size has been changed.

A component can implement this method to do things such as laying out its child components when its width or height changes.

The method is called synchronously as a result of the setBounds or setSize methods, so repeatedly changing a components size will repeatedly call its resized method (unlike things like repainting, where multiple calls to repaint are coalesced together).

If the component is a top-level window on the desktop, its size could also be changed by operating-system factors beyond the application's control.

See also

moved, setSize

Reimplemented from Component.

parentHierarchyChanged()

void ScrollBar::parentHierarchyChanged ( )

overridevirtual

Called to indicate that the component's parents have changed.

When a component is added or removed from its parent, this method will be called on all of its children (recursively - so all children of its children will also be called as well).

Subclasses can override this if they need to react to this in some way.

See also

getParentComponent, isShowing, ComponentListener::componentParentHierarchyChanged

Reimplemented from Component.

setVisible()

void ScrollBar::setVisible ( bool shouldBeVisible )

overridevirtual

Makes the component visible or invisible.

This method will show or hide the component. Note that components default to being non-visible when first created. Also note that visible components won't be seen unless all their parent components are also visible.

This method will call visibilityChanged() and also componentVisibilityChanged() for any component listeners that are interested in this component.

Parameters

shouldBeVisible

whether to show or hide the component

See also

isVisible, isShowing, visibilityChanged, ComponentListener::componentVisibilityChanged

Reimplemented from Component.

createAccessibilityHandler()

std::unique_ptr< AccessibilityHandler > ScrollBar::createAccessibilityHandler ( )

overridevirtual

Override this method to return a custom AccessibilityHandler for this component.

The default implementation creates and returns a AccessibilityHandler object with an unspecified role, meaning that it will be visible to accessibility clients but without a specific role, action callbacks or interfaces. To control how accessibility clients see and interact with your component subclass AccessibilityHandler, implement the desired behaviours, and return an instance of it from this method in your component subclass.

The accessibility handler you return here is guaranteed to be destroyed before its Component, so it's safe to store and use a reference back to the Component inside the AccessibilityHandler if necessary.

This function should rarely be called directly. If you need to query a component's accessibility handler, it's normally better to call getAccessibilityHandler(). The exception to this rule is derived implementations of createAccessibilityHandler(), which may find it useful to call the base class implementation, and then wrap or modify the result.

See also

getAccessibilityHandler

Reimplemented from Component.

Referenced by Viewport::createScrollBarComponent().

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The documentation for this class was generated from the following file:

• juce_ScrollBar.h