TScrollPanelEx

Fonte: source/classes/scrollex.prg

Inherits from: TPanel

TScrollPanelEx is an enhanced scrollable panel that supports horizontal scrolling of child controls with keyboard, mouse wheel, scroll bar, and gesture (touch/pan) input. It tracks the leftmost and rightmost child controls to compute the scroll range and provides automatic scrollbar management. The panel is commonly used for toolbars, ribbon-style layouts, and overflow containers.

Key DATA Members

DATA	Type	Description
`hStep`	Numeric	Horizontal scroll step in pixels (default 20)
`nScrollRange`	Numeric	Computed scroll range based on child control positions
`oCtrlLeft`	Object	Leftmost child control (used for scroll boundary)
`oCtrlRight`	Object	Rightmost child control
`nRightMargin`	Numeric	Right margin for auto-resize
`nBottomMargin`	Numeric	Bottom margin for auto-resize
`aPages`	Array	Named page positions for GoToPage navigation
`lScrollDrag`	Logical	Drag-to-scroll mode flag

Methods

Method	Description
`New( nTop, nLeft, nBottom, nRight, oWnd, lNoBorder )`	Create a scrollable panel. Pass `lNoBorder := .T.` to omit the border
`Redefine( nId, oWnd, lNoBorder )`	Redefine from a dialog resource
`SetRange()`	Scan child controls and set the scroll range
`ScrollBy( nPix )`	Scroll content horizontally by the given pixel offset
`GoLeft() / GoRight()`	Scroll to the extreme left or right
`GoLeftPix( nPix ) / GoRightPix( nPix )`	Scroll by a specific pixel amount
`PageLeft() / PageRight()`	Scroll by two step sizes (page-style)
`GoToPos( nPos )`	Scroll to an absolute scrollbar position
`GoToPage( cPage )`	Scroll to a named page (registered via SetPage)
`SetPage( cPage, nCol )`	Register a named page at a given column position
`ControlIntoView( oControl )`	Scroll to ensure a specific control is visible
`hScroll( nWParam, nLParam )`	Handle horizontal scroll bar messages
`MouseWheel( nKeys, nDelta, nXPos, nYPos )`	Handle mouse wheel for horizontal scrolling
`HandleGesture( nGesture, nLParam )`	Handle touch pan gestures (kinetic scrolling)

Example: Smooth Scroll Panel with Child Controls

#include "FiveWin.ch"

function Main()

   local oWnd, oPanel, oBtn

   DEFINE WINDOW oWnd TITLE "TScrollPanelEx Demo" SIZE 600, 150

   @ 20, 20 SCROLLPANEX oPanel SIZE 560, 60 OF oWnd

   for n := 1 to 15
      @ 10, ( n - 1 ) * 90 BUTTON "Btn " + Str( n ) ;
         SIZE 80, 30 OF oPanel PIXEL
   next

   oPanel:SetRange()

   ACTIVATE WINDOW oWnd CENTERED

return nil

Notes

Call SetRange() after adding all child controls to compute the scroll boundaries and attach focus-tracking for auto-scroll into view.
Use SetPage( cName, nCol ) with GoToPage( cName ) for named-section navigation.
Drag scrolling is enabled by holding the left mouse button and dragging horizontally on the panel background.
Touch gestures (pan) are supported on devices with touch input via the HandleGesture method (GID_PAN).

TScrollPanelEx

Key DATA Members

Methods

Example: Smooth Scroll Panel with Child Controls

Notes

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