Developer CD Series 1995…tember: Reference Library/Dev.CD Sep 95 RL/Dev.CD Sep 95 RL.toast/mac/Technical Documentation/develop/develop Issue 20 code/Scripting the Finder/Finder Tricks/EventHandler.cp

Text File | 1994-10-04 | 11.6 KB | 470 lines | [TEXT/MMCC]

/*================================================================================
    EventHandler.c

    ©1991-4 Greg Anderson
    [e-mail]

    This code handles the main macintosh event loop
================================================================================*/
#include <EPPC.h>
#include <AppleEvents.h>
#include <Errors.h>

#include "EventHandler.h"
#include "NextEvent.h"
#include "MenuHandler.h"
#include "WindowHandler.h"

#include "Main.h"

#include "MacUtilities.h"
#include "ReportError.h"

#ifndef Exceptions_h
#include "Exceptions.h"
#endif

//
// Prototypes for private functions:
//
void Idle(EventRecord* nullEvent);

void                ProcessModelessDialog( EventRecord* theEvent  );
Boolean                ProcessMouseEvent( EventRecord* theEvent  );
void                SetupCursorShape( Point theMouse, RgnHandle mouseRgn );

//----------------------------------------------------------------------------------------
// Idle:
//----------------------------------------------------------------------------------------
void Idle(EventRecord* nullEvent)
{

} // Idle

//----------------------------------------------------------------------------------------
// HandleEvents:
//
// Main event processor
//----------------------------------------------------------------------------------------
void HandleEvents( RgnHandle mouseRegion )
{
    EventRecord        theEvent;
    Boolean            isDialogEvent;
    long            theSleep;
    Point            mouse;
    char            keyPressed;
    OSErr            err = noErr;

    //
    // This routine watches the cursor as it moves across the
    // window & changes its shape as necessary.
    //
    GetMouse( &mouse );
    LocalToGlobal( &mouse );
    // SetupCursorShape( mouse, mouseRegion);

    //
    // Get the next event, whatever type it might be.
    //
    // 'NextEvent' calls either GetNextEvent or WaitNextEvent
    // (preferably the later).  It does some processing
    // to make deactivate, suspend, resume and mouse-moved
    // events easier to interpret.
    //
    // If 'GetNextEvent' is called, mouse-moved events are
    // simulated, so the same cursor-tracking code may be
    // used in multifinder and non-multifinder environments.
    //
    theSleep = 10;
    isDialogEvent = NextEvent( everyEvent, &theEvent, theSleep, mouseRegion );

#ifdef ShowMouseRgn
    SetPort(gWindowMgrPort);
    SetClip(gUniverseRgn);
    InvertRgn(mouseRegion);
    InvertRgn(mouseRegion);
#endif

    //
    // It seems that the only way to do accurate mouse tracking
    // is to call SetupCursorShape before and after NextEvent.
    //
    // Passing nil as the mouseRgn prevents all of the complex region
    // calculations from being done twice.
    //
    // SetupCursorShape( theEvent.where, nil );

    //
    // Set up a failure handler for commands that just cannot be completed
    //
    Try
    {
        Boolean eventHandled = false;

        //
        // Here is the dreaded Event Switch Statement.
        //
        // I should write a better event processor -- or better yet,
        // switch to MacApp.  :>
        //
        // A word of warning for the unwary:  NextEvent() mauls
        // theEvent.what, so some of the items in this switch statement
        // might be undefined if GetNextEvent or WaitNextEvent is
        // called directly.  Activate, deactivate, suspend and resume
        // events are all mauled by NextEvent.  See NextEvent.c for
        // code that detects these events (or better yet, include
        // NextEvent.c in your project and use this code as a sample,
        // and you'll be MultiFinder aware).
        //
        switch( theEvent.what )
        {
            //
            // First check for high-level events (e.g. AppleEvents)
            //
            case kHighLevelEvent:
            {
                AEProcessAppleEvent( &theEvent );
                eventHandled = true;
                break;
            }

            //
            // If the event is a mousedown event, theEvent.message is undefined,
            // but theEvent.where specifies where the mouse was located when the
            // button went down.
            //
            case mouseDown:
            {
                eventHandled = ProcessMouseEvent( &theEvent );
                break;
            }

            //
            // If the event is a keyDown or autoKey event, theEvent.message
            // contains the character code & key code of the key pressed
            // in its low word.
            //
            case autoKey:
            {
                //
                // Don't allow autokeys to work with menu equivalents
                //
                if( (theEvent.modifiers & cmdKey) != 0 )
                {
                    eventHandled = true;
                    break;
                }
            }

            case keyDown:
            {
                keyPressed = (char)(theEvent.message & charCodeMask);

                //
                // Handle command-key equivalents of menu functions
                //
                if( (theEvent.modifiers & cmdKey) != 0)
                {
                    SetupMenuItems();
                    ProcessMenuSelection( MenuKey(keyPressed) );
                    eventHandled = true;
                }
                else
                {
                    eventHandled = FrontWindowHandler()->KeyDown(&theEvent, keyPressed);
                }

                break;
            }

            //
            // If the event is an update event or an activate event,
            // theEvent.message contains a pointer to the window
            // receiving the event
            //
            case updateEvt:
            {
                GetWindowHandler((WindowPtr)(theEvent.message))->Update(&theEvent);
                break;
            }

            //
            // An activate event can mean that a window is being activated,
            // OR it could mean that a window is being deactivated.
            //
            // However, NextEvent decodes the event record and returns
            // 'deactivateEvt' if the event was a deactivate; this
            // simplifies this switch statement.  Be careful when copying
            // this code--if you call WaitNextEvent directly, the
            // translation will not be done and this code won't work.
            //
            case activateEvt:
            {
                GetWindowHandler((WindowPtr)(theEvent.message))->Activate(&theEvent);
                break;
            }

            case deactivateEvt:
            {
                GetWindowHandler((WindowPtr)(theEvent.message))->Deactivate(&theEvent);
                break;
            }

            //
            // Suspend and resume events are treated like activate and
            // deactivate messages.  (Note that FrontWindow() might
            // return nil; ActivateWindow and DeactivateWindow should
            // catch this and exit gracefully.)
            //
            // Note that NextEvent decodes app4Evt's and returns either
            // resumeEvt, suspendEvt or mouseMovedEvt.
            //
            case resumeEvt:
            {
                GetWindowHandler((WindowPtr)(theEvent.message))->Resume(&theEvent);
                break;
            }

            case suspendEvt:
            {
                GetWindowHandler((WindowPtr)(theEvent.message))->Suspend(&theEvent);
                break;
            }

            //
            // The mouseRegion is recalculated on every event,
            // so nothing special needs to be done on mouseMovedEvt.
            //
            case mouseMovedEvt:
            {
                break;
            }
        }

        //
        // Check for modeless dialog events & pass them to the
        // appropriate modeless dialog box.
        //
        // Do not pass events already handled above, though.
        //
        if( isDialogEvent && (eventHandled == false))
        {
            ProcessModelessDialog( &theEvent );
        }

        //
        // Do idle-type-stuff
        //
        Idle(&theEvent);
    }
    Catch(err)
    {
        if((err != eNoWindowHandler) && (err != userCanceledErr))
        {
            //
            // It would be nice if we had better error reporting
            //
            ReportError( "\pThe command could not be completed", err );
        }
    }
} // HandleEvents

//----------------------------------------------------------------------------------------
// ProcessModelessDialog:
//
// Modeless-dialog event.
//----------------------------------------------------------------------------------------
void ProcessModelessDialog( EventRecord* theEvent  )
{
    DialogPtr            theDialog;
    short                itemHit;

    //
    // If the event is a modeless dialog event, pass it to
    // DialogSelect.
    //
    // If DialogSelect returns 'true', that indicates that
    // the user has interacted with the dialog in some way.
    // If this is the case, theDialog will point to the
    // dialog box in question, and itemHit will contain the
    // number of the item clicked on.
    //
    // We determine which dialog was clicked on by examining
    // a field in the record pointed to by the dialog's
    // refCon.
    //
    if( DialogSelect( theEvent, &theDialog, &itemHit ) )
    {
        //
        // Pass the event record and itemHit to the window handler
        //
        GetWindowHandler(theDialog)->DialogManagerEvent(theEvent, itemHit);
    }
} // ProcessModelessDialog

//----------------------------------------------------------------------------------------
// ProcessMouseEvent:
//
// Mouse-click event.
//
// Strangely enough, theEvent->message doesn't tell us which window
// was clicked on.  The Macintosh toolbox function 'FindWindow' can
// determine this for us, however.
//----------------------------------------------------------------------------------------
Boolean ProcessMouseEvent( EventRecord* theEvent  )
{
    WindowPtr    whichWindow;
    Boolean        eventHandled = false;

    switch( FindWindow( theEvent->where, &whichWindow ) )
    {
        case inMenuBar:
        {
            SetupMenuItems();
            ProcessMenuSelection( MenuSelect(theEvent->where) );
            eventHandled = true;
            break;
        }

        case inSysWindow:
        {
            SystemClick( theEvent,(WindowPtr)whichWindow );
            eventHandled = true;
            break;
        }

        case inContent:
        {
            //
            // If the window clicked on is not frontmost, make it frontmost.
            //
            if( whichWindow != FrontWindow() )
            {
                SelectWindow(whichWindow);
                eventHandled = true;
            }
            else
            {
                eventHandled = GetWindowHandler(whichWindow)->ContentClick(theEvent);
            }
            break;
        }

        case inDrag:
        {
            DragWindow( (WindowPtr)whichWindow,theEvent->where,&gUniverseRect);
            eventHandled = true;
            break;
        }

        case inGrow:
        {
            GetWindowHandler(whichWindow)->ResizeWindow(theEvent->where);
            eventHandled = true;
            break;
        }

        case inGoAway:
        {
            if( TrackGoAway(whichWindow,theEvent->where) )
            {
                //
                // We only have one window, so close it
                //
                GetWindowHandler(whichWindow)->CloseWindowByUser();
            }
            eventHandled = true;
            break;
        }
    }
    return eventHandled;
} // ProcessMouseEvent

//----------------------------------------------------------------------------------------
// SetupCursorShape:
//
// Change the shape of the cursor based on its location
//----------------------------------------------------------------------------------------
void SetupCursorShape( Point theMouse, RgnHandle mouseRgn )
{
    OSErr err = noErr;

    //
    // Try to set the shape of the cursor
    //
    Try
    {
        WindowPtr inWindow = nil;
        Rect tRect;
        Rect windowRect;

        //
        // Is there a window?  If not, fail (error code is ignored, so it
        // doesn't matter what it is)
        //
        inWindow = FrontWindow();
        if(inWindow == nil)
            Throw(-1);

        SetPort(inWindow);
        GetGlobalWindowLocation(inWindow, &windowRect);    // inWindow->port.portRect

        //
        // If the point is not inside the front window,
        // then set the cursor to an arrow, and set the mouse
        // region to the universe minus the space taken by
        // the front window
        //
        if(PtInRect(theMouse, &windowRect) == false)
        {
            ChangeCursor(0);
            if(mouseRgn != nil)
            {
                RectRgn(mouseRgn, &windowRect);
                XorRgn(mouseRgn, gUniverseRgn, mouseRgn);
            }
        }
        else
        {
            //
            // Do all of our work in local coordinates
            //
            GlobalToLocal(&theMouse);

            //
            // By default, the mouse region is a one-pixel region
            // that just surrounds the cursor.  TWindowHandler::SetupCursorShape
            // may change this region to something else
            //
            SetRect(&tRect, theMouse.h, theMouse.v, theMouse.h + 1, theMouse.v + 1);
            if(mouseRgn != nil)
                RectRgn(mouseRgn, &tRect);

            //
            // If this window doesn't have a window handler, then
            // GetWindowHandler will fail.  If SetupCursorShape
            // returns false, then the handler did not have a specific
            // shape to set the cursor to; set it to an arrow.
            //
            if(GetWindowHandler(inWindow)->SetupCursorShape(theMouse, mouseRgn) == false)
                ChangeCursor(0);

            //
            // Translate the region back to global coordinates
            //
            if(mouseRgn != nil)
                RgnToGlobal(mouseRgn);
        }
    }
    Catch(err)
    {
        //
        // If we couldn't handle the SetupCursorShape event, then
        // the cursor is an arrow everywhere
        //
        ChangeCursor(0);
        if(mouseRgn != nil)
            RectRgn(mouseRgn, &gUniverseRect);
    }
} // SetupCursorShape