ScrollBar Class Reference

A scrollbar component. More...

Inherits Component, AsyncUpdater, and Timer.

List of all members.

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 Member Functions
	ScrollBar (bool isVertical, bool buttonsAreVisible=true)
	Creates a Scrollbar.
	~ScrollBar ()
	Destructor.
bool	isVertical () const throw ()
	Returns true if the scrollbar is vertical, false if it's horizontal.
void	setOrientation (bool shouldBeVertical)
	Changes the scrollbar's direction.
void	setButtonVisibility (bool buttonsAreVisible)
	Shows or hides the scrollbar's buttons.
void	setAutoHide (bool shouldHideWhenFullRange)
	Tells the scrollbar whether to make itself invisible when not needed.
bool	autoHides () const throw ()
	Returns true if this scrollbar is set to auto-hide when its thumb is as big as its maximum range.
void	setRangeLimits (const Range< double > &newRangeLimit)
	Sets the minimum and maximum values that the bar will move between.
void	setRangeLimits (double minimum, double maximum)
	Sets the minimum and maximum values that the bar will move between.
const Range< double >	getRangeLimit () const throw ()
	Returns the current limits on the thumb position.
double	getMinimumRangeLimit () const throw ()
	Returns the lower value that the thumb can be set to.
double	getMaximumRangeLimit () const throw ()
	Returns the upper value that the thumb can be set to.
void	setCurrentRange (const Range< double > &newRange)
	Changes the position of the scrollbar's 'thumb'.
void	setCurrentRange (double newStart, double newSize)
	Changes the position of the scrollbar's 'thumb'.
void	setCurrentRangeStart (double newStart)
	Moves the bar's thumb position.
const Range< double >	getCurrentRange () const throw ()
	Returns the current thumb range.
double	getCurrentRangeStart () const throw ()
	Returns the position of the top of the thumb.
double	getCurrentRangeSize () const throw ()
	Returns the current size of the thumb.
void	setSingleStepSize (double newSingleStepSize)
	Sets the amount by which the up and down buttons will move the bar.
void	moveScrollbarInSteps (int howManySteps)
	Moves the scrollbar by a number of single-steps.
void	moveScrollbarInPages (int howManyPages)
	Moves the scroll bar up or down in pages.
void	scrollToTop ()
	Scrolls to the top (or left).
void	scrollToBottom ()
	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 (ScrollBarListener *listener)
	Registers a listener that will be called when the scrollbar is moved.
void	removeListener (ScrollBarListener *listener)
	Deregisters a previously-registered listener.
bool	keyPressed (const KeyPress &key)
void	mouseWheelMove (const MouseEvent &e, float wheelIncrementX, float wheelIncrementY)
void	lookAndFeelChanged ()
void	handleAsyncUpdate ()
void	mouseDown (const MouseEvent &e)
void	mouseDrag (const MouseEvent &e)
void	mouseUp (const MouseEvent &e)
void	paint (Graphics &g)
void	resized ()

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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 ScrollBarListener 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 ViewportContainer or ListBox instead of handling a scrollbar directly.

See also:

ScrollBarListener

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Member Enumeration Documentation

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.

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Constructor & Destructor Documentation

ScrollBar::ScrollBar	(	bool	isVertical,
		bool	buttonsAreVisible = true
	)

Creates a Scrollbar.

Parameters:

	isVertical	whether it should be a vertical or horizontal bar
	buttonsAreVisible	whether to show the up/down or left/right buttons

ScrollBar::~ScrollBar

(

)

Destructor.

---

Member Function Documentation

bool ScrollBar::isVertical

(

)

const throw ()

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

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.

void ScrollBar::setButtonVisibility

(

bool

buttonsAreVisible

)

Shows or hides the scrollbar's buttons.

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()

bool ScrollBar::autoHides

(

)

const throw ()

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

See also:

setAutoHide

void ScrollBar::setRangeLimits

(

const Range< double > &

newRangeLimit

)

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.

See also:

setCurrentRange

void ScrollBar::setRangeLimits	(	double	minimum,
		double	maximum
	)

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.

See also:

setCurrentRange

const Range<double> ScrollBar::getRangeLimit

(

)

const throw ()

Returns the current limits on the thumb position.

See also:

setRangeLimits

double ScrollBar::getMinimumRangeLimit

(

)

const throw ()

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

This is the value set by setRangeLimits().

double ScrollBar::getMaximumRangeLimit

(

)

const throw ()

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

This is the value set by setRangeLimits().

void ScrollBar::setCurrentRange

(

const Range< double > &

newRange

)

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

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

See also:

getCurrentRange. setCurrentRangeStart

void ScrollBar::setCurrentRange	(	double	newStart,
		double	newSize
	)

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 ScrollBarListener::scrollBarMoved() for all the listeners that are registered.

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.

See also:

setCurrentRangeStart, getCurrentRangeStart, getCurrentRangeSize

void ScrollBar::setCurrentRangeStart

(

double

newStart

)

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 ScrollBarListener::scrollBarMoved() for all the listeners that are registered.

See also:

setCurrentRange

const Range<double> ScrollBar::getCurrentRange

(

)

const throw ()

Returns the current thumb range.

See also:

getCurrentRange, setCurrentRange

double ScrollBar::getCurrentRangeStart

(

)

const throw ()

Returns the position of the top of the thumb.

See also:

getCurrentRange, setCurrentRangeStart

double ScrollBar::getCurrentRangeSize

(

)

const throw ()

Returns the current size of the thumb.

See also:

getCurrentRange, setCurrentRange

void ScrollBar::setSingleStepSize

(

double

newSingleStepSize

)

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.

void ScrollBar::moveScrollbarInSteps

(

int

howManySteps

)

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.

void ScrollBar::moveScrollbarInPages

(

int

howManyPages

)

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.

void ScrollBar::scrollToTop

(

)

Scrolls to the top (or left).

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

void ScrollBar::scrollToBottom

(

)

Scrolls to the bottom (or right).

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

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

void ScrollBar::addListener

(

ScrollBarListener *

listener

)

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

void ScrollBar::removeListener

(

ScrollBarListener *

listener

)

Deregisters a previously-registered listener.

bool ScrollBar::keyPressed

(

const KeyPress &

key

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::mouseWheelMove	(	const MouseEvent &	e,
		float	wheelIncrementX,
		float	wheelIncrementY
	)			[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::lookAndFeelChanged

(

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::handleAsyncUpdate

(

)

[virtual]

For internal use only.

Implements AsyncUpdater.

void ScrollBar::mouseDown

(

const MouseEvent &

e

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::mouseDrag

(

const MouseEvent &

e

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::mouseUp

(

const MouseEvent &

e

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::paint

(

Graphics &

g

)

[virtual]

For internal use only.

Reimplemented from Component.

void ScrollBar::resized

(

)

[virtual]

For internal use only.

Reimplemented from Component.

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

• juce_ScrollBar.h