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                       Using Mouse Pointers and Icons
 
Applications typically use mouse-pointer resources to control the appearance
of the mouse pointer and to draw icons in windows. The following sections
show how to use mouse pointers in applications.
 
Creating or Loading a Mouse Pointer
 
Before an application can use a mouse pointer, it must first receive a
handle to the pointer. Most applications load mouse pointers from the system
or their own resource file. MS OS/2 maintains many predefined mouse pointers
that an application can use by calling the WinQuerySysPointer function.
System mouse pointers include all the standard mouse-pointer shapes and
message-box icons.
 
You can also load mouse pointers that are defined in the resource file for
your application. Typically, you define the mouse-pointer resource using
Icon Editor or a similar program. The resulting mouse pointer or icon can
then be included in your resource file. This is done by pulling the Icon
Editor data file into your resource file using the key word POINTER, a
resource ID number, and a filename for the mouse-pointer data created by the
Icon Editor. When the mouse-pointer resource is included in the resource
file, you can use it by calling the WinLoadPointer function, specifying the
pointer-resource ID and a resource-module handle. Typically, the resource
resides in the executable file of the application, so you can supply NULL
for the module handle to indicate the current application resource file.
 
Finally, you can create mouse pointers at run time by constructing a bitmap
for the pointer and calling the WinCreatePointer function. The bitmap must
be twice as tall as it is wide, with the first half defining the AND mask
and the second half defining the XOR mask. You also must specify the hot
spot when you create a mouse pointer. The handle returned can be used to set
or draw the mouse pointer.
 
Changing the Mouse Pointer
 
Once you create or load a mouse pointer, you can change its shape by calling
the WinSetPointer function. The following are three main situations where an
application typically changes the shape of the mouse pointer:
 
♦  When an application receives a WM_MOUSEMOVE message, there is an
   opportunity to change the mouse pointer based on its location the window.
   If you want the standard arrow pointer, pass this message on to the
   WinDefWindowProc function.
 
♦  When an application is about to start a time-consuming process during
   which it will not accept user input, the application should display the
   "system-wait" mouse pointer. This pointer is shaped like an hourglass,
   indicating that the user must wait. Once this process is complete, the
   application should reset the mouse pointer to its former shape.
 
♦  The following code fragment shows how to save the current mouse pointer,
   set the hourglass pointer, and then restore the original mouse pointer.
   Notice that the hourglass pointer is also saved in a global variable so
   that the application can return it when responding to a WM_MOUSEMOVE
   message during a time-consuming process.
 
   /* Get current pointer. */
 
   hptrOld = WinQueryPointer(HWND_DESKTOP);
 
   /* Get wait mouse pointer. */
 
   hptrWait = WinQuerySysPointer(HWND_DESKTOP, SPTR_WAIT, FALSE);
 
   /* Save wait pointer to use in WM_MOUSEMOVE processing. */
 
   hptrCurrent = hptrWait;
 
   /* Set mouse pointer to wait pointer. */
 
   WinSetPointer(HWND_DESKTOP, hptrWait);
 
   /* Do time-consuming operation; restore original mouse pointer. */
 
   WinSetPointer(HWND_DESKTOP, hptrOld);
 
♦  The mouse pointer can be used to indicate the current operational mode of
   an application. For example, a paint program with a palette of drawing
   tools should change the mouse pointer shape to indicate which drawing
   tool is currently in use.
 
Drawing an Icon
 
You can use mouse-pointer resources to draw icons. The WinDrawPointer
function draws a specified mouse pointer in a specified presentation space.
Many of the predefined system mouse pointers are standard icons displayed in
message boxes.
 
System Bitmaps
 
In addition to mouse pointers and icons defined by the system, you can use
standard system bitmaps by calling the WinGetSysBitmap function. This
function returns a bitmap handle that is passed to the WinDrawBitmap
function or one of the Gpi bitmap calls. The system uses standard bitmaps to
draw portions of control windows such as the system menu, the
minimize/maximize box, and scroll-bar arrows.
 
 
                                      ♦