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TScrollBar Class Reference

Implements a scroll bar. More...

#include <views.h>

Inheritance diagram for TScrollBar::

List of all members.

Public Methods
	TScrollBar (const TRect &bounds)
virtual void	draw ()
virtual TPalette&	getPalette () const
virtual void	handleEvent (TEvent &event)
virtual void	scrollDraw ()
virtual int	scrollStep (int part)
void	setParams (int aValue, int aMin, int aMax, int aPgStep, int aArStep)
void	setRange (int aMin, int aMax)
void	setStep (int aPgStep, int aArStep)
void	setValue (int aValue)
void	drawPos (int pos)
int	getPos ()
int	getSize ()
Static Public Methods
TStreamable*	build ()
Public Attributes
int	value
TScrollChars	chars
int	minVal
int	maxVal
int	pgStep
int	arStep
Static Public Attributes
TScrollChars	vChars
TScrollChars	hChars
const char* const	name
Protected Methods
	TScrollBar (StreamableInit)
virtual void	write (opstream &os)
virtual void*	read (ipstream &is)

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Constructor & Destructor Documentation

TScrollBar::TScrollBar ( const TRect & bounds )

Creates and initializes a scroll bar with the given bounds by calling the TView constructor. Sets value, maxVal and minVal to zero. Sets pgStep and arStep to 1. The shapes of the scroll bar parts are set to the defaults in chars data member. If `bounds' produces size.x = 1, scroll bar is vertical; otherwise, it is horizontal. Vertical scroll bars have the growMode data member set to gfGrowLoX | gfGrowHiX | gfGrowHiY; horizontal scroll bars have the growMode data member set to gfGrowLoY | gfGrowHiX | gfGrowHiY.

TScrollBar::TScrollBar ( StreamableInit ) [protected]

Each streamable class needs a "builder" to allocate the correct memory for its objects together with the initialized virtual table pointers. This is achieved by calling this constructor with an argument of type StreamableInit.

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Member Function Documentation

TStreamable * TScrollBar::build ( ) [static]

Called to create an object in certain stream-reading situations. Reimplemented from TView.

void TScrollBar::draw ( ) [virtual]

Draws the scroll bar depending on the current bounds, value, and palette. Reimplemented from TView.

void TScrollBar::drawPos ( int pos )

Undocumented.

TPalette & TScrollBar::getPalette ( ) const [virtual]

Returns the default palette. Reimplemented from TView.

int TScrollBar::getPos ( )

Undocumented.

int TScrollBar::getSize ( )

Undocumented.

void TScrollBar::handleEvent ( TEvent & event ) [virtual]

Handles scroll bar events by calling TView::handleEvent(). Mouse events are broadcast to the scroll bar's owner, which must handle the implications of the scroll bar changes. handleEvent() also determines which scroll bar part has received a mouse click (or equivalent keystroke). Data member value is adjusted according to the current arStep or pgStep values. The scroll bar indicator is redrawn. Reimplemented from TView.

void * TScrollBar::read ( ipstream & is ) [protected, virtual]

Reads from the input stream `is'. Reimplemented from TView.

void TScrollBar::scrollDraw ( ) [virtual]

Is called whenever value data member changes. This virtual member function defaults by sending a cmScrollBarChanged message to the scroll bar's owner: message(owner, evBroadcast, cmScrollBarChanged, this); See also: message

int TScrollBar::scrollStep ( int part ) [virtual]

By default, scrollStep() returns a positive or negative step value, depending on the scroll bar part given by `part', and the current values of arStep and pgStep. Parameter `part' should be one of the following constants: Constant Value Meaning sbLeftArrow 0 Left arrow of horizontal scroll bar sbRightArrow 1 Right arrow of horizontal scroll bar sbPageLeft 2 Left paging area of horizontal scroll bar sbPageRight 3 Right paging area of horizontal scroll bar sbUpArrow 4 Top arrow of vertical scroll bar sbDownArrow 5 Bottom arrow of vertical scroll bar sbPageUp 6 Upper paging area of vertical scroll bar sbPageDown 7 Lower paging area of vertical scroll bar sbIndicator 8 Position indicator on scroll bar These constants define the different areas of a TScrollBar in which the mouse can be clicked. The scrollStep() function converts these constants into actual scroll step values. Although defined, the sbIndicator constant is never passed to scrollStep().

void TScrollBar::setParams ( int aValue, int aMin, int aMax, int aPgStep, int aArStep )

Sets the value, minVal, maxVal, pgStep and arStep with the given argument values. Some adjustments are made if your arguments conflict. The scroll bar is redrawn by calling drawView(). If value is changed, scrollDraw() is also called.

void TScrollBar::setRange ( int aMin, int aMax )

Sets the legal range for value by setting minVal and maxVal to the given arguments `aMin' and `aMax'. Calls setParams(), so drawView() and scrollDraw() will be called if the changes require the scroll bar to be redrawn.

void TScrollBar::setStep ( int aPgStep, int aArStep )

Sets pgStep and arStep to the given arguments `aPgStep' and `aArStep'. Calls setParams() with the other arguments set to their current values.

void TScrollBar::setValue ( int aValue )

Sets value to `aValue' by calling setParams() with the other arguments set to their current values. Note: drawView() and scrollDraw() will be called if this call changes value.

void TScrollBar::write ( opstream & os ) [protected, virtual]

Writes to the output stream `os'. Reimplemented from TView.

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Member Data Documentation

int TScrollBar::arStep

Variable arStep is the amount added or subtracted to the scroll bar's value data member when an arrow area is clicked (sbLeftArrow, sbRightArrow, sbUpArrow, or sbDownArrow) or the equivalent keystroke made. The TScrollBar constructor sets arStep to 1 by default. Definition at line 2281 of file views.h.

TScrollChars TScrollBar::chars

TScrollChars is defined as: typedef char TScrollChars[5]; Variable chars is set with the five basic character patterns used to draw the scroll bar parts. Definition at line 2250 of file views.h.

TScrollChars TScrollBar::hChars [static]

Undocumented. Definition at line 2289 of file views.h.

int TScrollBar::maxVal

Variable maxVal represents the maximum value for the value data member. The TScrollBar constructor sets maxVal to zero by default. Definition at line 2260 of file views.h.

int TScrollBar::minVal

Variable minVal represents the minimum value for the value data member. The TScrollBar constructor sets minVal to zero by default. Definition at line 2255 of file views.h.

const char *const TScrollBar::name [static]

Undocumented. Reimplemented from TView. Definition at line 2320 of file views.h.

int TScrollBar::pgStep

Variable pgStep is the amount added or subtracted to the scroll bar's value data member when a mouse click event occurs in any of the page areas (sbPageLeft, sbPageRight, sbPageUp, or sbPageDown) or an equivalent keystroke is detected (Ctrl-Left, Ctrl-Right, PgUp, or PgDn). The TScrollBar constructor sets pgStep to 1 by default. You can change pgStep using setParams(), setStep() or TScroller::setLimit(). Definition at line 2272 of file views.h.

TScrollChars TScrollBar::vChars [static]

Undocumented. Definition at line 2285 of file views.h.

int TScrollBar::value

This variable represents the current position of the scroll bar indicator. This marker moves along the scroll bar strip to indicate the relative position of the scrollable text being viewed relative to the total text available for scrolling. The TScrollBar constructor sets value to zero by default. Definition at line 2239 of file views.h.

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

• views.h

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