TControlScrollBar

type TControlScrollBar = class(TPersistent)

protected

  FControl: TWinControl;

FControl - local variable to hold the Window Control to which the scroll bar belongs

  function ControlHandle; virtual;

ControlHandle - the operating system handle for this control

  function GetAutoScroll; virtual;

  function GetIncrement; virtual;

GetIncrement - returns the size of the increment for each slick in the scroll bar

  function GetPage; virtual;

GetPage - returns the size of the Page-Down (or -Up) Increment for the scroll bar

  function GetPosition; virtual;

GetPosition returns the position of the slider in the scroll bar

  function GetRange; virtual;

GetRange - returns the valid range of values for the scroll bar movement

  function GetSize; virtual;

GetSize - returns the size of the scroll bar

  function GetSmooth; virtual;

GetSmooth - returns True if smooth scrolling is to be used

  function HandleAllocated; virtual;

HandleAllocated - returns True if a handle has been allocated

  function IsRangeStored; virtual;

  procedure AutoCalcRange; virtual;

AutoCalcRange - method for automatically calculating the range of values for the scroll bar

  procedure ControlUpdateScrollBars; virtual;

ControlUpdateScrollBars - method to be used by the owner control for updating its scrollbars

  procedure InternalSetRange(); virtual;

  procedure ScrollHandler();

ScrollHandler - message handler to control scrolling

  procedure SetAutoScroll(); virtual;

  procedure SetIncrement(); virtual;

SetIncrement - specifies the scrolling increment

  procedure SetPage(); virtual;

SetPage - specifies the page scrolling increment

  procedure SetPosition(); virtual;

SetPosition - specifies the position of the slider in the scroll bar

  procedure SetRange(); virtual;

SetRange - specifies the range of values for the scroll bar

  procedure SetSize(); virtual;

SetSize - specifies the size of the scroll bar

  procedure SetSmooth(); virtual;

SetSmooth - specifies whether smooth scrolling is to be used

  procedure SetTracking();

  procedure SetVisible(); virtual;

SetVisible - specifies whether the scroll bar is to be visible

  procedure UpdateScrollBar; virtual;

UpdateScrollBar - method to update the scroll bar (position etc)

  procedure InvalidateScrollInfo;

InvalidateScrollInfo - method to render scroll information non-valid

  function GetHorzScrollBar; virtual;

GetHorzScrollBar - find the position and properties of the horizontal scroll bar

  function GetVertScrollBar; virtual;

GetVertScrollBar - find the position and properties of the vertical scroll bar

  function ScrollBarShouldBeVisible; virtual;

public

  constructor Create();

Create - constructor for TControlScrollBar: performs inherited Create then initialises local flags for page, increment, position etc

  procedure Assign(); override;

Assign - if Source is a TControlScrollBar, copies properties to itself, else performs inherited Assign

  function IsScrollBarVisible; virtual;

Visibility of scroll bar

  function ScrollPos; virtual;

Position of the indicator cursor on the scroll bar

  property Kind: TScrollBarKind; [r]

Finds which kind of scroll bar this is: horizontal or vertical

  function GetOtherScrollBar;

Finds out details of the other scroll bar

  property Size: Integer; [rws]

Determine the size of the scroll bar

  function ClientSize;

  function ClientSizeWithBar;

  function ClientSizeWithoutBar;

published

  property Increment: TScrollBarInc; [rw]

The size of the scrolling increment

  property Page: TScrollBarInc; [rw]

The size of the paging increment for scrolling

  property Smooth: Boolean; [rw]

Determine whether smooth scrolling is to be implemented

  property Position: Integer; [rw]

Position of the scroll bar

  property Range: Integer; [rws]

The range (extent) of the scroll bar

  property Tracking: Boolean; [rw]

  property Visible: Boolean; [rw]

Can the scroll bar be made visible?

end;

TControlScrollBar

TControlScrollBar - base class for defining scroll bars on Forms and windows

TPersistent

TObject