Re: Mouse tracking

From: [at]} <frei{>
Date: Thu, 24 May 2001 12:58:45 +0200

Robert,

this was a BlackBox Component Builder 1.4 Beta problem. In the final release
it will be fixed and your procedure will work properly.

Regards,
Marc Frei
Oberon microsystems, Inc.


>
>In the outline procedure below I try to monitor the status of
>the modifier (Ctrl) key while tracking the mouse position
>during a 'drag' operation. The intention is to only allow the
>drag if the Ctrl key is pressed, and to abort the operation if
>it is released.
>
>However I find that modifiers is only updated to reflect the mouse
>buttons, not updated to replect the current state of the modifier key.
>
>The commented out WinApi approach also does not work.
>
>Can anyone tell me how to monitor the Ctrl key during a mouse drag?
>
>
>
>Thanks
>
>
>Robert Campbell
>
>
>(I have only tried this in 1.4 beta.)
>
>
>
>PROCEDURE (v : View) HandleCtrlMsg* (frame : Views.Frame;
> VAR msg : Controllers.Message; VAR focus : Views.View);
> VAR
> x, y : INTEGER;
> modifiers : SET;
> ctlFlg, isDown : BOOLEAN;
> BEGIN
> WITH msg : Controllers.TrackMsg DO
> ctlFlg := Controllers.modify IN msg.modifiers;
> IF ctlFlg THEN
> REPEAT
> frame.Input (x, y, modifiers, isDown);
> ctlFlg := Controllers.modify IN modifiers;
>(*
> ctlFlg := WinApi.GetKeyState (Api.VK_CONTROL) < 0;
>*)
> ... Show status of x, y ...
>
> UNTIL ~(isDown & ctlFlg);
> IF ctlFlg THEN ... Take action with x, y ... END
> END
> END
> END HandleCtrlMsg;
>
>
>
>
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Received on Thu May 24 2001 - 10:58:45 UTC

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