13 May 2010


DefMouse is an hold over from previous GFA-BASIC versions, but is still – with a little twist - supported in GFA-BASIC 32. In GFA-BASIC 16 bit DefMouse was used to set the mouse shape for the entire screen. DefMouse changed the mouse globally, for each GB window and control, as well as for the desktop. With GB32 the mouse-cursor shape is set for each OCX object individually, which is much more flexible. Now, the general way of setting a mouse-cursor is by setting the control's MousePointer, MouseCursor, or MouseIcon property, either at design-time or at runtime.

DefMouse 0 is the secret
GFA-BASIC 32 tries to be as compatible as can be with previous versions, so the DefMouse command had to be implemented as well. It works, however the region is now limited to GFA-BASIC windows (and controls) only. An improvement, wouldn't you agree? How does that work? How does GFABASIC prevent corrupting mouse pointers? The solution to the problem is the DefMouse value. When DefMouse == 0 (or basDefault) the individual mouse settings of the Forms and controls are used. However, when DefMouse n (where n <>0) is used to select a new mouse shape the individual OCX mouse settings are ignored. On the plus side, you are guaranteed with the new mouse shape over every(!) OCX control/form. To revert to the individual settings you must invoke DefMouse 0.

A Popup window
A Popup selection menu is a system window executed in the context of the GFA-BASIC 32 application. It isn't an Ocx object (it should have been!) and has no private mouse settings. Especially when a Popup is used from within a TrayIcon Ocx GFA-BASIC 32 has to revert to the DefMouse setting. However when DefMouse = 0 GFA-BASIC does nothing, because it expects to handle the individual Ocx mouse settings. The WM_SETCURSOR message isn't handled properly an a random cursor value is used to tell the system (Windows) which cursor to use. The mouse cursor is drawn incorrectly when showing the popup menu. Consequently, the global mouse must be set to a non-zero value before invoking Popup, for instance DefMouse basArrow. When Popup returns the global mouse setting must revert to zero: DefMouse 0.

Screen Ocx
The Screen Ocx supports the MousePointer, MouseCursor, or MouseIcon properties as well. These operate exactly the same as DefMouse, eg on the global mouse setting. Thus DefMouse can be replaced by Screen.MousePointer = n, where n is a basXX mouse value.
The DefMouse command can also be passed a string containing a bit-pattern to create a custom (monochrome) mouse.
The Screen.MouseCursor on the other hand accepts a MouseCursor object (a real Windows cursor resource in an external file). In addition, Screen.MouseIcon accepts a Picture object. So, there many different options to create a custom – global – mouse shape.

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