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Window Related Events
Volume Number:9
Issue Number:1
Column Tag:Getting Started

Related Info: Event Manager Window Manager

Window Related Events

Handling update, activate and suspend/resume events

By Dave Mark, MacTech Magazine Regular Contributing Author

Note: Source code files accompanying this article are located on MacTech CD-ROM or source code disks.

In last month’s column, we covered the basics of event loop programming, focusing on four specific events: the mouseDown, mouseUp, keyDown, and autoKey events. If you haven’t already, be sure to read through the Event Manager chapters in Inside Macintosh, Volumes I and VI. Pay specific attention to the sections that describe the mouseDown, mouseUp, keyDown, and autoKey events in detail. Finally, go back to last month’s program and flesh it out a little. When a mouseDown occurs, draw a string in the event window that describes where and when the mouseDown occurred. For a keyDown, draw the character and key codes embedded in the EventRecord.

In this month’s column, we’re going to expand our event handling repertoire, focusing on activate, update, and suspend/resume events.

Activate Events

Every time your application creates a window, that window is added to a list maintained by the Window Manager. The windows in this list are in the order that they appear on the screen, from the frontmost to the rearmost. The frontmost window is also known as the active window. In Figure 1, Window #1 starts off as the active window. Notice the difference between the title bars of the active and non-active window.

When the mouse is clicked in the rear window, Window #1 is made inactive, then the rear window, Window #2, is made active. Since the front window is made inactive before another window is brought to the front, there will never be more than one active window at a time!

The Window Manager accomplishes this by sending your application a series of activate events. If a rear window is being brought to the front, your application will receive two activate events. The first tells you that the frontmost window is becoming inactive. This event is also known as a deactivate event. The second event tells your application that a window is becoming active. Both of these events set EventRecord.what to activateEvt.

If a window is created, and there are no currently open windows, the Window Manager only generates a single activate event, indicating that the newly created window is becoming active. In this case, no deactivate event is sent.

Figure 1. A mouse click in Window #2 brings it to the front.

In general, you’ll use activate events if you treat window contents differently for an active window than for an inactive window. For example, your application might highlight selected text in the active window, but not in an inactive window. Activate events are provided for your benefit. Use them as you see fit. You’ll see how we discriminate between an activate and deactivate event when we get to our program later in the column.

Figure 2. When Window #1 is dragged to the left, more of Window #2 is exposed, causing an update event.

Update Events

Next on our list of events is an event that tells your program to update the contents of a window. The updateEvt is generated when a window is created (after the activateEvt is generated) and when a new portion of a window is revealed. Figure two shows a typical sequence that generates an updateEvt. The first picture shows Window #1 partially obscuring Window #2. Next, Window #1 is dragged to the left, revealing a previously hidden section of the Window #2. The Window Manager sends an updateEvt to your application, telling it to update the contents of Window #2. The third picture shows the window, after the program responded to the update event.

Figure 3 shows a slightly different sequence, involving update and activate events. This time, the mouse is clicked in Window #2, bringing it to the front. First, a deactivate event is generated for Window #1. Next, an activate event is generated for Window #2. Finally, an update event is generated, asking the program to update the contents of Window #2.

Once again, you’ll see update and activate events in action in the program later in the column.

Figure 3. When Window #2 is moved to the front, two activate events and an update event are generated.

Suspend/Resume Events

Under MultiFinder (System 6) and under System 7, more than one application is allowed to run at a time. When you click in a window belonging to a background application, the active application receives a suspend event, and the background application receives a resume event and is moved to the foreground.

You might use suspend and resume events to determine the actions taken by your program. For example, in the foreground, you might display a special tool palette, or perhaps run an animation. When your application moves into the background, you’ll receive a suspend event and you might hide the tool palette, or discontinue the animation until you get a resume event.

It’s important to note that your application can continue running, even if it receives a suspend event. It will still continue to receive update (and other appropriate events) while in the background. At the very least, it’s a good idea to treat a suspend event as you would a deactivate event when it comes to the contents of your windows. For example, if you usually deselect any selected text when a window is deactivated, do the same thing for the active window when you receive a suspend event.

At Last! The Program!

As promised, here’s a program that incorporates all the events described in this column. WindowMaster creates a single window and handles all the usual events relating to windows. Figure 4 shows the WindowMaster window in all its glory. Notice that this window sports a close box, a zoom box, a drag region (the title bar), and a grow box. Though this window doesn’t support scroll bars, there is room for them. In most cases, if a window has a grow box, it has room for scroll bars. We’ll get to scroll bars in a later column.

Figure 4. WindowMaster in action.

Creating the WindowMaster Resources

Create a folder in your development folder named WindowMaster. Launch ResEdit, then create a resource file named WindowMaster.Π.rsrc in your WindowMaster folder. You’ll create two resources in this file.

First, create a WIND resource according to the specifications in Figure 5. Next, select Set 'WIND' Characteristics... from the WIND menu and set the window’s title to PICT 128. Next, copy a graphic from your scrapbook into the clipboard. If you don’t have anything interesting in your scrapbook, go draw something. I’ll wait.

Figure 5. Specifications for WindowMaster’s WIND resource.

Once you’ve got a graphic in the clipboard, return to ResEdit and select Paste from the Edit menu. ResEdit will place your picture in a PICT resource. Make sure the PICT resource has a resource ID of 128. Well, that’s it for ResEdit. Quit, making sure you save your changes.

Creating the WindowMaster Project

Once you’re out of ResEdit, launch THINK C and create a new project file named WindowMaster.Π in the WindowMaster folder. Add MacTraps to the project file. Next, select New from the File menu and type this source code into the window that appears.

/* 1 */
#include <Values.h>

#define kBaseResID 128
#define kMoveToFront (WindowPtr)-1L
#define kSleep   MAXLONG

#define kScrollBarAdjust  (16-1)
#define kLeaveWhereItIs   false
#define kNormalUpdates    true

#define kMinWindowHeight  50
#define kMinWindowWidth   80

/*************/
/*  Globals  */
/*************/

Boolean gDone;

/***************/
/*  Functions  */
/***************/

void  ToolBoxInit( void );
void  WindowInit( void );
void  EventLoop( void );
void  DoEvent( EventRecord *eventPtr );
void  HandleMouseDown( EventRecord *eventPtr );
void  DoUpdate( EventRecord *eventPtr );
void  DoPicture( WindowPtr window, PicHandle picture );
void  DoActivate( WindowPtr window, Boolean becomingActive );
void  DoSuspendResume( Boolean resuming );
void  CenterPict( PicHandle picture, Rect *srcRectPtr,
 Rect *destRectPtr );


/******************************** main *********/

void  main( void )
{
 ToolBoxInit();
 WindowInit();
 
 EventLoop();
}

/*********************************** ToolBoxInit */

void  ToolBoxInit( void )
{
 InitGraf( &thePort );
 InitFonts();
 InitWindows();
 InitMenus();
 TEInit();
 InitDialogs( nil );
 InitCursor();
}

/******************************** WindowInit *********/

void  WindowInit( void )
{
 WindowPtrwindow;
 
 window = GetNewWindow( kBaseResID, nil, kMoveToFront );
 
 if ( window == nil )
 {
 SysBeep( 10 );  /*  Couldn't load the WIND resource!!!  */
 ExitToShell();
 }
 
 ShowWindow( window );
 SetPort( window );
}
/******************************** EventLoop *********/

void  EventLoop( void )
{
 EventRecordevent;
 
 gDone = false;
 while ( gDone == false )
 {
 if ( WaitNextEvent( everyEvent, &event, kSleep, nil ) )
 DoEvent( &event );
 }
}

/************************************* DoEvent      */

void  DoEvent( EventRecord *eventPtr )
{
 BooleanbecomingActive, resuming;
 
 switch ( eventPtr->what )
 {
 case mouseDown: 
 HandleMouseDown( eventPtr );
 break;
 case updateEvt:
 DoUpdate( eventPtr );
 break;
 case activateEvt:
 becomingActive = ( (eventPtr->modifiers & activeFlag)
 == activeFlag );
 DoActivate( (WindowPtr)eventPtr->message, 
 becomingActive );
 break;
 case osEvt:
 resuming = ( eventPtr->message & suspendResumeMessage )
 == resumeFlag;
 DoSuspendResume( resuming );
 break;
 }
}

/************************************* HandleMouseDown */

void  HandleMouseDown( EventRecord *eventPtr )
{
 WindowPtrwindow;
 short  thePart;
 GrafPtroldPort;
 long   windSize;
 Rect   growRect;
 
 thePart = FindWindow( eventPtr->where, &window );
 
 switch ( thePart )
 {
 case inSysWindow : 
 SystemClick( eventPtr, window );
 break;
 case inContent:
 SelectWindow( window );
 break;
 case inDrag : 
 DragWindow( window, eventPtr->where, 
 &screenBits.bounds );
 break;
 case inGoAway :
 if ( TrackGoAway( window, eventPtr->where ) )
 gDone = true;
 break;
 case inGrow:
 growRect.top = kMinWindowHeight;
 growRect.left = kMinWindowWidth;
 growRect.bottom = MAXSHORT;
 growRect.right = MAXSHORT;
 
 windSize = GrowWindow( window, eventPtr->where, 
 &growRect );
 if ( windSize != 0 )
 {
 GetPort( &oldPort );
 SetPort( window );
 EraseRect( &window->portRect );
 SizeWindow( window, LoWord( windSize ),
 HiWord( windSize ), kNormalUpdates );
 InvalRect( &window->portRect );
 SetPort( oldPort );
 }
 break;
 case inZoomIn:
 case inZoomOut:
 if ( TrackBox( window, eventPtr->where, thePart ) )
 {
 GetPort( &oldPort );
 SetPort( window );
 EraseRect( &window->portRect );
 ZoomWindow( window, thePart, kLeaveWhereItIs );
 InvalRect( &window->portRect );
 SetPort( oldPort );
 }
 break;
 }
}

/************************************* DoUpdate     */

void  DoUpdate( EventRecord *eventPtr )
{
 short  pictureID;
 PicHandlepicture;
 WindowPtrwindow;
 
 window = (WindowPtr)eventPtr->message;
 
 BeginUpdate( window );
 
 picture = GetPicture( kBaseResID );
 
 if ( picture == nil )
 {
 SysBeep( 10 );  /*  Couldn't load the PICT resource!!!  */
 ExitToShell();
 }
 
 DoPicture( window, picture );
 
 EndUpdate( window );
}

/******************************** DoPicture *********/

void  DoPicture( WindowPtr window, PicHandle picture )
{
 Rect   drawingClipRect, destRect;
 RgnHandletempRgn;
 
 SetPort( window );
 
 EraseRect( &window->portRect );
 
 tempRgn = NewRgn();
 GetClip( tempRgn );

 drawingClipRect = window->portRect;
 drawingClipRect.right -= kScrollBarAdjust;
 drawingClipRect.bottom -= kScrollBarAdjust;
 
 ClipRect( &drawingClipRect );
 
 CenterPict( picture, &drawingClipRect, &destRect );
 DrawPicture( picture, &destRect );
 
 SetClip( tempRgn );
 DisposeRgn( tempRgn );
 
 DrawGrowIcon( window );
}

/************************************* DoActivate   */



void  DoActivate( WindowPtr window, Boolean becomingActive )
{
 DrawGrowIcon( window );
}

/************************************* DoSuspendResume    */

void  DoSuspendResume( Boolean resuming )
{
 WindowPtrwindow;
 
 window = FrontWindow();
 
 DrawGrowIcon( window );
}

/****************** CenterPict ********************/

void  CenterPict( PicHandle picture, Rect *srcRectPtr,
 Rect *destRectPtr )
{
 Rect pictRect;
 
 pictRect = (**( picture )).picFrame;
 
 OffsetRect( &pictRect, srcRectPtr->left - pictRect.left,
    srcRectPtr->top - pictRect.top);
 OffsetRect( &pictRect,
 (srcRectPtr->right - pictRect.right)/2,
 (srcRectPtr->bottom - pictRect.bottom)/2);
 
 *destRectPtr = pictRect;
}

Once your code is typed in, save it under the name WindowMaster.c, then add the window to the project by selecting Add from the Project menu.

Running WindowMaster

Select Run from the Project menu to run WindowMaster. A single window, like the one shown in Figure 4 should appear. Click the mouse in the title bar and drag the window around on the screen. Next, click in the grow box and resize the window. Try making it tall and skinny, then short and fat. Notice that there is a limit to how small you can make the window. Next, click on the zoom box in the upper-right corner of the window. The window should expand to fill the main screen. Click the zoom-box again to return the window to its previous size.

Next, drag the window downwards, so it is halfway off the screen, obscuring part of the picture. Now drag it back up. The picture will be redrawn in full. Finally, click in the window’s close box to exit the program.

Walking Through the Source Code

Just like last month’s program, WindowMaster is based on an event loop architecture. Also, like last month’s column, the program starts off by including <Values.h> to get the constant MAXLONG, used for the #define kSleep. The #defines will be explained as they are used.

/* 2 */
#include <Values.h>

#define kBaseResID 128
#define kMoveToFront (WindowPtr)-1L
#define kSleep   MAXLONG

#define kScrollBarAdjust  (16-1)
#define kLeaveWhereItIs   false
#define kNormalUpdates    true

#define kMinWindowHeight  50
#define kMinWindowWidth   80

gDone is initialized to false, then set to true when a click occurs in the window’s close box. Note that this is not the way Mac applications normally exit, but we haven’t got to menus yet, so a click in the close box will have to do for now.

/* 3 */
Boolean gDone;

As always, the code includes prototypes for all functions.

/* 4 */
void  ToolBoxInit( void );
void  WindowInit( void );
void  EventLoop( void );
void  DoEvent( EventRecord *eventPtr );
void  HandleMouseDown( EventRecord *eventPtr );
void  DoUpdate( EventRecord *eventPtr );
void  DoPicture( WindowPtr window, PicHandle picture );
void  DoActivate( WindowPtr window, Boolean becomingActive );
void  DoSuspendResume( Boolean resuming );
void  CenterPict( PicHandle picture, Rect *srcRectPtr,
 Rect *destRectPtr );

main() initializes the Toolbox, creates a window, then enters the main event loop.

/* 5*/
/******************************** main *********/

void  main( void )
{
 ToolBoxInit();
 WindowInit();
 
 EventLoop();
}

ToolBoxInit() is the same as it ever was.

/* 6 */
/*********************************** ToolBoxInit */

void  ToolBoxInit( void )
{
 InitGraf( &thePort );
 InitFonts();
 InitWindows();
 InitMenus();
 TEInit();
 InitDialogs( nil );
 InitCursor();
}

WindowInit() calls GetNewWindow() to load the WIND resource from the resource file.

/* 7 */
/******************************** WindowInit *********/

void  WindowInit( void )
{
 WindowPtrwindow;
 
 window = GetNewWindow( kBaseResID, nil, kMoveToFront );

If the resource wasn’t found, beep once, then exit.

/* 8 */
 if ( window == nil )
 {
 SysBeep( 10 );  /*  Couldn't load the WIND resource!!!  */
 ExitToShell();
 }

Once the window is created, make it visible, then make it the current port. Notice that this routine does not do any drawing. We’ll draw our picture in response to an update event.

/* 9 */
 ShowWindow( window );
 SetPort( window );
}

EventLoop() sets gDone to false, then loops around a call to WaitNextEvent(). If WaitNextEvent() returns true, the event is passed to DoEvent().

/* 10 */
/******************************** EventLoop *********/

void  EventLoop( void )
{
 EventRecordevent;
 
 gDone = false;
 while ( gDone == false )
 {
 if ( WaitNextEvent( everyEvent, &event, kSleep, nil ) )
 DoEvent( &event );
 }
}
DoEvent() switches on the event’s what field.

/************************************* DoEvent      */

void  DoEvent( EventRecord *eventPtr )
{
 BooleanbecomingActive, resuming;
 
 switch ( eventPtr->what )
 {

A mouseDown event is passed to HandleMouseDown(). An updateEvt is passed on to DoUpdate().

/* 11 */
 case mouseDown: 
 HandleMouseDown( eventPtr );
 break;
 case updateEvt:
 DoUpdate( eventPtr );
 break;

In the case of an activate event, the event’s modifiers field holds the key to whether the event is an activate or deactivate event. activeFlag is a mask that designates one of the bits in the modifiers field. If the bit is set, the event is an activate event. If the bit is clear, the event is a deactivate event. The Boolean becomingActive is true if the event is an activate event. Once becomingActive is set, it is passed on to DoActivate(). The event’s message field holds a pointer to the window being activated or deactivated.

/* 12 */
 case activateEvt:
 becomingActive = ( (eventPtr->modifiers & activeFlag)
 == activeFlag );
 DoActivate( (WindowPtr)eventPtr->message,
 becomingActive );
 break;

Similarly, an osEvt is used to indicate either a suspend or resume event. suspendResumeMessage is a predefined constant that designates the suspend/resume bit in the message field. resuming is set to true if the event is a resume event. Once set, resuming is passed on to DoSuspendResume().

/* 13 */
 case osEvt:
 resuming = ( eventPtr->message & suspendResumeMessage )
 == resumeFlag;
 DoSuspendResume( resuming );
 break;
 }
}

HandleMouseDown() handles the mouseDown event.

/* 14 */
/************************************* HandleMouseDown */

void  HandleMouseDown( EventRecord *eventPtr )
{
 WindowPtrwindow;
 short  thePart;
 GrafPtroldPort;
 long   windSize;
 Rect   growRect;

FindWindow() takes the event’s where field and returns the window at those coordinates. thePart indicates the part of the window the mouse click occurred in.

/* 15 */
 thePart = FindWindow( eventPtr->where, &window );

If the click was in a portion of the screen not belonging to our application (like a desk accessory window), thePart is set to inSysWindow and we’ll pass the event back to the system with SystemClick().

/* 16 */
 switch ( thePart )
 {
 case inSysWindow : 
 SystemClick( eventPtr, window );
 break;

If the event was in the content region of the window, we’ll typically call SelectWindow() to bring the window to the front. Since we only have one window, this line isn’t particularly useful. Later on though, you’ll add another window to this program and you’ll want to keep this code in here.

As your windows get more complex, you’ll want to do more with inContent clicks than just select the window. You might have a button or scroll bar in the window that needs action, or you might have some text that needs selection. This is the jumping off point for all clicks that occur in the window. Eventually, we’ll add a routine named DoContentClick() to process clicks in a window’s content region.

/* 17 */
 case inContent:
 SelectWindow( window );
 break;

If the click was in the window’s drag region (title bar), we’ll pass the window (retrieved by FindWindow()), and the mouse click coordinates to the Toolbox routine DragWindow(). The third parameter is a bounding rectangle that determines where on the screen the window may be dragged. screenBits.bounds is a System global variable that defines the boundaries of the main display.

If you have two monitors, this code works fine, however. DragWindow() checks for screenBits.bounds as a parameter and, if it finds it, allows dragging anywhere on any monitor attached to the system.

/* 18 */
 case inDrag : 
 DragWindow( window, eventPtr->where, 
 &screenBits.bounds );
 break;

If the mouseDown was in the close box, we’ll call TrackGoAway() to see if the mouse was released while still inside the close box. If so, gDone is set to true. TrackGoAway() is the routine that does the little animation in the close box.

/* 19 */
 case inGoAway :
 if ( TrackGoAway( window, eventPtr->where ) )
 gDone = true;
 break;

If the click was in the grow box, we set up a rectangle that defines how large and how small the window is allowed to grow [See Inside Macintosh, Vol. 1 - Tech Ed.]. Basically, it’s good policy to put a limit on how small a window can get, but, unless you’ve got a pressing reason, you should allow windows to get as large as the user wants.

/* 20 */
 case inGrow:
 growRect.top = kMinWindowHeight;
 growRect.left = kMinWindowWidth;
 growRect.bottom = MAXSHORT;
 growRect.right = MAXSHORT;

Next, this rectangle is passed on to GrowWindow(), which tracks the mouse, allowing the user to specify the new window size.

/* 21 */
 windSize = GrowWindow( window, eventPtr->where, &growRect );

The return value contains two 2-byte values, indicating the new height and width of the window [Both zero means no change - Tech Ed.].

/* 22 */
 if ( windSize != 0 )
 {

First, we’ll save away the current port (in case it’s not this window), then make this window the current port. Next, we erase the entire window and change the window’s size by calling SizeWindow(). The last parameter tells the system we want this resizing to generate an update event.

/* 23 */
 GetPort( &oldPort );
 SetPort( window );
 EraseRect( &window->portRect );
 SizeWindow( window, LoWord( windSize ),
 HiWord( windSize ), kNormalUpdates );

Next, we call InvalRect() to tell the system that the entire window should be redrawn with the next update event, not just the new area revealed by the grow box. In fact, this call will force an update even if the window was shrunk.

/* 24 */
 InvalRect( &window->portRect );

Because we center our picture in the window, we need to redraw the window contents whenever the window changes size. To see why this is true, try commenting out the previous line of code.

Update events are tricky. It is definitely worth reading the section of Inside Macintosh that covers the Window Manager. You might also check out Chapter 4’s Updater program in Volume I of the Mac Primer.

Once the window is resized, the port is set back to its old value. Since InvalRect() applies to the current port, it was important that we make the window being grown the current port.

/* 25 */
 SetPort( oldPort );
 }
 break;

Finally, a click in the zoom box follows a similar strategy. Again, TrackBox() is called to verify that the mouse was released inside the zoom box. If so, ZoomWindow() is called to zoom the window, or return it to its old position, depending on its current state.

/* 26 */
 case inZoomIn:
 case inZoomOut:
 if ( TrackBox( window, eventPtr->where, thePart ) )
 {
 GetPort( &oldPort );
 SetPort( window );
 EraseRect( &window->portRect );
 ZoomWindow( window, thePart, kLeaveWhereItIs );
 InvalRect( &window->portRect );
 SetPort( oldPort );
 }
 break;
 }
}

DoUpdate() is called whenever an update event occurs. First, the window is retrieved from the event’s message field. Next, BeginUpdate() is called, telling the Window Manager that we’re handling updates for this window. BeginUpdate() will restrict drawing to the region of the window that needs updating, also known as the update region. If you call InvalRect() on the whole window, the whole window is available for drawing.

/* 27 */
/************************************* DoUpdate     */

void  DoUpdate( EventRecord *eventPtr )
{
 short  pictureID;
 PicHandlepicture;
 WindowPtrwindow;
 
 window = (WindowPtr)eventPtr->message;
 
 BeginUpdate( window );

Next, we load the picture and pass it on to DoPicture().

/* 28 */
 picture = GetPicture( kBaseResID );
 
 if ( picture == nil )
 {
 SysBeep( 10 );  /*  Couldn't load the PICT resource!!!  */
 ExitToShell();
 }
 
 DoPicture( window, picture );
 
 EndUpdate( window );
}

DoPicture() makes the window the current port, then erases the entire window. Note that this will already have been done if the update event was caused by a resize or zoom, but there’s no harm in this minor duplication of code.

/* 29 */

/******************************** DoPicture *********/

void  DoPicture( WindowPtr window, PicHandle picture )
{
 Rect   drawingClipRect, destRect;
 RgnHandletempRgn;
 
 SetPort( window );
 
 EraseRect( &window->portRect );

Next, a new region is created. We pass this region handle on to GetClip(), which places a copy of the window’s clipping region in tempRgn. The clipping region defines which parts of the window can be drawn in and which parts can’t. Again, it is a good idea to read the entire Window Manager chapter in Inside Macintosh, as there’s not enough space to cover all of it in this column.

/* 30 */
 tempRgn = NewRgn();
 GetClip( tempRgn );

Since we want to center the picture in the part of the window not covered by the grow region and scroll bar areas, we’ll subtract those areas from the window’s portRect. Next, we’ll pass this rectangle on to ClipRect() making it the new clip region.

/* 31 */
 drawingClipRect = window->portRect;
 drawingClipRect.right -= kScrollBarAdjust;
 drawingClipRect.bottom -= kScrollBarAdjust;
 
 ClipRect( &drawingClipRect );

Next, we’ll call CenterPict() to center the picture in drawingClipRect, returning the rectangle the picture should be drawn in as its third parameter. We then draw the picture with DrawPicture().

/* 32 */
 CenterPict( picture, &drawingClipRect, &destRect );
 DrawPicture( picture, &destRect );

Next, the clipping region is set back to its old value and the grow icon is redrawn, completing our update.

/* 33 */
 SetClip( tempRgn );
 DisposeRgn( tempRgn );
 
 DrawGrowIcon( window );
}

It’s important to remember that your application can receive update events even if it’s running in the background. If a foreground application’s window covers your application’s windows and is then moved, the Window Manager will send your application update events asking you to redraw the effected windows.

DoActivate() is pretty simple. It redraws the grow icon in the specified window. DrawGrowIcon() will draw a different grow icon, depending on whether your window is frontmost or not. When your application starts handling more than one window, you’ll start making use of the second parameter, becomingActive.

/* 34 */

/************************************* DoActivate   */

void  DoActivate( WindowPtr window, Boolean becomingActive )
{
 DrawGrowIcon( window );
}

DoSuspendResume() is also pretty simple. This time the frontmost window’s grow icon is redrawn. A front window, which has been suspended gets the same grow icon as any other window. DrawGrowIcon() is smart enough to know the state of your application.

Once again, as your programs get more complex, you’ll make use of the second parameter, resuming.

/* 35 */
/************************************* DoSuspendResume    */

void  DoSuspendResume( Boolean resuming )
{
 WindowPtrwindow;
 
 window = FrontWindow();
 
 DrawGrowIcon( window );
}

CenterPict() centers the picture in the rectangle pointed to by srcRectPtr, returning the result in the rectangle pointed to by destRectPtr.


/* 36 */
/****************** CenterPict ********************/

void  CenterPict( PicHandle picture, Rect *srcRectPtr,
 Rect *destRectPtr )
{
 Rect pictRect;
 
 pictRect = (**( picture )).picFrame;
 
 OffsetRect( &pictRect, srcRectPtr->left - pictRect.left,
    srcRectPtr->top - pictRect.top);
 OffsetRect( &pictRect,
 (srcRectPtr->right - pictRect.right)/2,
 (srcRectPtr->bottom - pictRect.bottom)/2);
   
 *destRectPtr = pictRect;
}

Till Next Month

There’s a lot going on in this program. As I’ve said before, do yourself a favor and read the Window Manager chapter in Inside Macintosh. If a concept in this program seems fuzzy, try commenting out some of the code to see what happens. This is especially useful with the code that effects or handles update events. You might also try commenting out the calls to DrawGrowIcon() just to see what happens.

Finally, try adding another window to the program. Add a second WIND and a second PICT resource to the resource file, then create the new window in WindowInit(). You’ll be amazed how easy it is to add a second window. Go ahead, try it!

By the way, you may have noticed that this month’s program comes in C only. Sorry Pascal fans, but the programs (and this column) are just getting too big and I had to choose one language or the other. Hopefully, you now have enough examples of C and Pascal that you’ll be able to either come up to speed on C (my preference) or translate the code to Pascal yourself.

By the way, for those of you following Daniel’s career, he’s getting big (would you believe he’s already 16 pounds, and he’s only 12 weeks old!), and he smiles an awful lot. Till next month, keep programming and Happy Holidays!!!

 

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OneNote is your very own digital notebook. With OneNote, you can capture that flash of genius, that moment of inspiration, or that list of errands that's too important to forget. Whether you're at... Read more
Apple Pages 8.2.1 - Apple's word pr...
Apple Pages is a powerful word processor that gives you everything you need to create documents that look beautiful. And read beautifully. It lets you work seamlessly between Mac and iOS devices, and... Read more
Numbers 6.2.1 - Apple's spreadsheet...
With Apple Numbers, sophisticated spreadsheets are just the start. The whole sheet is your canvas. Just add dramatic interactive charts, tables, and images that paint a revealing picture of your data... Read more
f.lux 39.9873 - Adjusts the color of you...
f.lux makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day. Ever notice how people texting at night have that eerie blue glow? Or wake... Read more
Deeper 2.5.0 - Enable hidden features in...
Deeper is a personalization utility for macOS which allows you to enable and disable the hidden functions of the Finder, Dock, QuickTime, Safari, iTunes, login window, Spotlight, and many of Apple's... Read more
NTFS 15.5.71 - Provides full read and wr...
NTFS breaks down the barriers between Windows and macOS. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS. Write, edit, copy, move, delete files on NTFS... Read more
MTR 5.3.0.0 - The Mac's oldest and...
MTR (was MacTheRipper)--the Mac's oldest and smartest DVD-backup app. MTR - the complete toolbox, not a one-trick, point-and-click extractor. MTR is intended for making fair-use, backup copies of... Read more
Keynote 9.2.1 - Apple's presentatio...
Easily create gorgeous presentations with the all-new Keynote, featuring powerful yet easy-to-use tools and dazzling effects that will make you a very hard act to follow. The Theme Chooser lets you... Read more

Latest Forum Discussions

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Black Desert Mobile gets an official rel...
Pearl Abyss has just announced that its highly-anticipated MMO, Black Desert Mobile, will launch globally for iOS and Android on December 11th. [Read more] | Read more »
Another Eden receives new a episode, cha...
Another Eden, WFS' popular RPG, has received another update that brings new story content to the game alongside a few new heroes to discover. [Read more] | Read more »
Overdox guide - Tips and tricks for begi...
Overdox is a clever battle royale that changes things up by adding MOBA mechanics and melee combat to the mix. This new hybrid game can be quite a bit to take in at first, so we’ve put together a list of tips to help you get a leg up on the... | Read more »
Roterra Extreme - Great Escape is a pers...
Roterra Extreme – Great Escape has been described by developers Dig-It Games as a mini-sequel to their acclaimed title Roterra: Flip the Fairytale. It continues that game's tradition of messing with which way is up, tasking you with solving... | Read more »
Hearthstone: Battlegrounds open beta lau...
Remember earlier this year when auto battlers were the latest hotness? We had Auto Chess, DOTA Underlords, Chess Rush, and more all gunning for our attention. They all had their own reasons to play, but, at least from where I'm standing, most... | Read more »
The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »
Shoot 'em up action awaits in Battl...
BattleBrew Productions has just introduced another entry into its award winning, barrelpunk inspired, BattleSky Brigade series. Whilst its previous title BattleSky Brigade TapTap provided fans with idle town building gameplay, this time the... | Read more »
Arcade classic R-Type Dimensions EX blas...
If you're a long time fan of shmups and have been looking for something to play lately, Tozai Games may have just released an ideal game for you on iOS. R-Type Dimensions EX brings the first R-Type and its sequel to iOS devices. [Read more] | Read more »
Intense VR first-person shooter Colonicl...
Our latest VR obsession is Colonicle, an intense VR FPS, recently released on Oculus and Google Play, courtesy of From Fake Eyes and Goboogie Games. It's a pulse-pounding multiplayer shooter which should appeal to genre fanatics and newcomers alike... | Read more »
PUBG Mobile's incoming update bring...
PUGB Mobile's newest Royale Pass season they're calling Fury of the Wasteland arrives tomorrow and with it comes a fair chunk of new content to the game. We'll be seeing a new map, weapon and even a companion system. [Read more] | Read more »

Price Scanner via MacPrices.net

Weekend Sale: Apple AirPods Pro for $234.98 a...
Abt Electronics has Apple’s new AirPods Pro in stock and on sale today for $234.98 including free shipping and free returns. Their price is $15 off Apple’s MSRP for these AirPods and tie Amazon... Read more
New 2019 16″ MacBook Pros on sale for $100 of...
Apple Authorized Reseller Adorama has new 2019 16″ MacBook Pros on sale today for $100 off Apple’s MSRP, each including free shipping. In addition, Adorama charges sales tax for NY & NJ residents... Read more
Apple Watch Series 3 GPS models on sale for l...
Amazon has Apple Watch Series 3 GPS models on sale starting at only $179. There prices are the lowest we’ve ever seen for these models from any Apple reseller. Choose Amazon as the seller rather than... Read more
iOS Bug In Facebook News Feed Lets Device Ca...
NEWS: 11.15.19- Users of the Facebook social media platform’s mobile app running on iOS devices won’t, like, this piece of news one bit in where a bug in the News Feed gave access to the camera... Read more
16″ MacBook Pros on sale! Preorder at Amazon...
Apple’s new 16″ MacBook Pros were only introduced yesterday, but Amazon is already offering a $100 discount on preorders. Prices for the base 6-Core 16″ MacBook Pros start at $2299: – 2019 16″ 2.6GHz... Read more
Use our exclusive MacBook Price Trackers to f...
Our Apple award-winning MacBook price trackers are the best place to look for the best sales & lowest prices on new and clearance MacBook Airs and MacBook Pros–including Apple’s new 16″ MacBook... Read more
New November Verizon iPhone deal: Get an iPho...
Verizon has the 64GB iPhone Xr on sale for 50% off for a limited time, plus they will include a free $200 prepaid MasterCard and a free Amazon Echo Dot. That reduces their price for the 64GB iPhone... Read more
Apple cuts prices on clearance, refurbished 2...
Apple has clearance 2018 15″ 6-Core Touch Bar MacBook Pros, Certified Refurbished, now available starting at only $1829. Each model features a new outer case, shipping is free, and an Apple 1-year... Read more
Up to $450 price drop on clearance 15″ MacBoo...
B&H Photo has dropped prices Apple’s 2019 15″ 6-Core and 8-Core MacBook Pros by $400-$450 off original MSRP, starting at $1999, with free overnight shipping available to many addresses in the US... Read more
Here’s how to save $200 on Apple’s new 16″ Ma...
Apple has released details of their Education discount associated with the new 2019 16″ 6-Core and 8-Core MacBook Pros. Take $200 off the price of the new 8-Core model (now $2599) and $200 off the 16... Read more

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Best Buy *Apple* Computing Master - Best Bu...
**746887BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 001512-Ankeny-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**746836BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 000341-Scranton-Store **Job Description:** **What Read more
QA Manager, *Apple* - CBS Corporation (Unit...
# QA Manager, Apple **REF#:** 35331 **CBS BUSINESS UNIT:** CBS Interactive **JOB TYPE:** Full-Time Staff **JOB SCHEDULE:** **JOB LOCATION:** Burbank, CA **ABOUT Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**744315BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000662-Auburn AL-Store **Job Description:** At Best Read more
Nurse Practitioner - Field Based (San Bernard...
Nurse Practitioner - Field Based (San Bernardino, CA, Apple Valley, Hesperia) **Location:** **United States** **New** **Requisition #:** PS30312 **Post Date:** 4 Read more
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