OpenEuphoria

2. Re: win32lib mouse question

• Posted by Brian Broker <bkb at CNW.COM> Jul 19, 2000
• 397 views
• Last edited Jul 20, 2000

On Wed, 19 Jul 2000 02:05:10 +0930, Mark Brown wrote:

>Hi all.
>
>I have a win32lib question that I know has been asked before.
>
>Following an "onMouse" event, is there a simple way to receive another
>mouse event (like a second mouse button click) from within the onMouse
>procedure?

Your onMouse routine gets passed 4 variables: event, x, y, and shift.  You
can do different actions for different events (MouseMove, LeftDown,
RightDown, LeftUp, etc. see win32lib.htm for more info) by using if-then
statements.

For Example (warning: untested code):

-- global variables
integer startX, startY, endX, endY

procedure onMouse_Win( integer event, integer x, integer y, integer shift )
  if event = LeftDown then
    -- starting point of line is (x,y)
    startX = x
    startY = y
  elsif event = LeftUp then
    -- ending point of line is new (x,y)
    endX = x
    endY = y
    -- since we actually draw the line here we really don't need
    --   endX nor endY, you could just pass x and y to drawLine...
    -- but you might want the end coordinates for another routine
    drawLine( Win, startX, startY, endX, endY )
  end if
end procedure
onMouse[Win] = routine_id( "onMouse_Win" )

-- end example 1

if you wanted to use separate mouse clicks you could modify like so (again,
this is an untested example):

-- global variables
integer startX, startY, endX, endY, first_click

first_click = True

procedure onMouse_Win( integer event, integer x, integer y, integer shift )
  if event = LeftDown then
    if first_click then
      -- starting point of line is (x,y)
      first_click = False
      startX = x
      startY = y
    else
      -- ending point of line is new (x,y)
      first_click = True
      endX = x
      endY = y
      drawLine( Win, startX, startY, endX, endY )
    end if
  end if
end procedure
onMouse[Win] = routine_id( "onMouse_Win" )

-- end example 2


>Also, my attempts at using getMousePos() results in the x,y being different
>to the actual mouse position. I have a vague memory from the Amiga
>regarding the difference between screen coords and logical coords and
>functions to convert from one to the other. Is this the problem?

getMousePos returns the screen coordinates for the mouse cursor (the
position on your desktop, not the window).  The x and y passed to your
onMouse routine are the coordinates relative to your window...

For a tested example, check out the 'Scribble.exw' demo included with
Win32Lib.  (Scribble is an example used to demonstrate David's IDE.)



-- Brian