OpenEuphoria

Re: scrolling a window?

• Posted by Derek Parnell <ddparnell at bigpond.com> Jun 02, 2006
• 559 views

Chris S wrote:
> I am trying to figure out how to use the scrollbars on the window to scroll
> the background image that I have displayed on a window that I created.
>  It's driving me nuts.  Will someone please show me a small snippet
> of code that accomplishes this?  I would greatly appreciate it.

Assuming the latest win32lib, here is a program that will give you some clues.

-- scrollbg.exw

include win32lib.ew
integer v_Vscroller
integer v_Hscroller
integer v_SimpleWindow
atom vScrollLines
atom BackGroundBMP
integer vxMax
integer vyMax
integer vx
integer vy

global procedure Scroll_VerticalScroll (integer self, integer event, sequence
parms)
    -- Calculate bitmap offset
    vy = vyMax - parms[1]
    repaintWindow(v_SimpleWindow)
end procedure

global procedure Scroll_HorizontalScroll (integer self, integer event, sequence
parms)
    -- Calculate bitmap offset
    vx = vxMax - parms[1]
    repaintWindow(v_SimpleWindow)
end procedure

procedure WheelScroll(integer pDir)
    integer lPos
    integer lScroller

    if getKeyState( VK_SHIFT ) then
        -- If shift key is down, use horizontal scroller
        lScroller = v_Hscroller
    else
        lScroller = v_Vscroller
    end if

    -- Find out where the current position is, then adjust it by the
    -- direction of the wheel movement.
    lPos = getIndex(lScroller)
    lPos -= (pDir * vScrollLines)

    -- Set the new position and indicate that the scroll thumb is being moved.
    setIndex(lScroller, {lPos, SB_THUMBTRACK})

end procedure

global procedure Mouse_SimpleWindow (integer self, integer event, sequence
parms)
    if parms[1] != WheelMove then
        return
    end if
    WheelScroll(parms[5])
end procedure

global procedure Mouse_VerticalScroll (integer self, integer event, sequence
parms)
    if parms[1] != WheelMove then
        return
    end if
    WheelScroll(parms[5])
end procedure

global procedure Mouse_HorizontalScroll (integer self, integer event, sequence
parms)
    if parms[1] != WheelMove then
        return
    end if
    WheelScroll(parms[5])
end procedure

global procedure Resize_SimpleWindow (integer self, integer event, sequence
parms)
    -- Grow/Shrink the scrollers on the window as it resizes.
    setRect(v_Vscroller, 0, 0, 20, 0.75, 1)
    setRect(v_Hscroller, 21, 0, 0.75, 20, 1)
end procedure

global procedure Paint_SimpleWindow (integer self, integer event, sequence
parms)
   -- Copy the bitmap image to the window's background.
   bitBlt(self,  0, 0,           -- Dest
          BackGroundBMP, vx, vy,   -- Source
          vxMax, vyMax,     -- width, height
          SRCCOPY )                 -- style
end procedure


global function main(sequence pArgs)
    sequence lSize

    vScrollLines = getWheelScrollLines()
    BackGroundBMP = loadBitmapFromFile("..\\demoresources\\landscape.bmp")
    lSize = getCtlSize(BackGroundBMP)
    vxMax = lSize[1]
    vyMax = lSize[2]
    vx = 0
    vy = 0
    createForm({
"Window, Simple Window, at=(0, 0), size=(200, 200),
        bar=status,event=mouse",
"VScroll, Vertical Scroll,at=( 0, 0), size=(20, 0.75), range=(1,100,5),
        delta=(1,8),position=1, event=mouse",
"HScroll, Horizontal Scroll,at=( 21, 0), size=(20, 0.75),
        range=(1,100,5), delta=(1,8),position=1, event=mouse"
        })
    v_Vscroller = getNameId("Vertical Scroll")
    v_Hscroller = getNameId("Horizontal Scroll")
    v_SimpleWindow = getNameId("Simple Window")

    setScrollRange(v_Vscroller, 0, vyMax)
    setScrollPos(v_Vscroller, vyMax)
    setScrollRange(v_Hscroller, 0, vxMax)
    setScrollPos(v_Hscroller, vxMax)
registerRoutine("Scroll_VerticalScroll",
    routine_id("Scroll_VerticalScroll"))
    registerRoutine("Mouse_VerticalScroll", routine_id("Mouse_VerticalScroll"))

registerRoutine("Scroll_HorizontalScroll",
    routine_id("Scroll_HorizontalScroll"))
registerRoutine("Mouse_HorizontalScroll",
    routine_id("Mouse_HorizontalScroll"))

    registerRoutine("Mouse_SimpleWindow", routine_id("Mouse_SimpleWindow"))
    registerRoutine("Resize_SimpleWindow", routine_id("Resize_SimpleWindow"))
    registerRoutine("Paint_SimpleWindow", routine_id("Paint_SimpleWindow"))

    return 0
end function

include w32start.ew

-- 
Derek Parnell
Melbourne, Australia
Skype name: derek.j.parnell