FunkyOverlayWindow/OverlayWindow.m

/*
     File: OverlayWindow.m 
 Abstract: This class does the bulk of the work of this sample, drawing a transparent overlay
 style of window that fades in and out based on where the mouse is, and controlling
 a blue selection box implemented as another transparent child window. 
  Version: 1.1 
  
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 */
 
 
#import "OverlayWindow.h"
#import "ColorView.h"
#include <Carbon/Carbon.h>
 
// A bunch of defines to handle hotkeys - if command-return is pressed, we switch modes on the blue selection box (another overlay window), switching between vertical/horizontal tracking.
const UInt32 kMyHotKeyIdentifier='folw';
const UInt32 kMyHotKey = 36; //the return key
 
EventHotKeyRef gMyHotKeyRef;
EventHotKeyID gMyHotKeyID;
EventHandlerUPP gAppHotKeyFunction;
 
pascal OSStatus MyHotKeyHandler(EventHandlerCallRef nextHandler,EventRef theEvent,void *userData);
 
@interface OverlayWindow (private)
 
- (void)switchDirection;
 
@end
 
// This routine is called when the command-return hotkey is pressed.  It means it's time to change modes for the blue selection box overlay window.
pascal OSStatus MyHotKeyHandler(EventHandlerCallRef nextHandler,EventRef theEvent,void *userData)
{
    // We can assume our hotkey was pressed
 
        // Get the reference to our window and call -switchDirection to reverse the trackingWin's direction.
    OverlayWindow *window = (OverlayWindow *)userData;
    [window switchDirection];
    
    return noErr;
    
}
 
@implementation OverlayWindow
 
// We override this initializer so we can set the NSBorderlessWindowMask styleMask, and set a few other important settings
- (id)initWithContentRect:(NSRect)contentRect styleMask:(NSUInteger)aStyle backing:(NSBackingStoreType)bufferingType defer:(BOOL)flag
{
    self = [super initWithContentRect:contentRect styleMask:NSBorderlessWindowMask backing:bufferingType defer:flag];
    
    if ( self ) {
        [self setOpaque:NO]; // Needed so we can see through it when we have clear stuff on top
        [self setHasShadow:YES];
        [self setLevel:NSFloatingWindowLevel]; // Let's make it sit on top of everything else
        [self setAlphaValue:0.2]; // It'll start out mostly transparent
    }
    
    contentRect.origin.x=100;
    contentRect.origin.y=100;
    
    return self;
}
 
- (void)awakeFromNib
{
    NSSize cellSize = [[(ColorView *)[self contentView] myButtons] cellSize];
    
        // First we setup the blue selection box - another window that will be attached as a child window
        // to this one, and will be moved by timers as needed.
    trackingWin=[[NSWindow alloc] 
                        // NOTE: The coordinates of NSWindow are anchored at the bottom left
                    initWithContentRect:NSMakeRect(self.frame.origin.x, 
                                                   self.frame.origin.y + self.frame.size.height - cellSize.height, 
                                                   self.frame.size.width, 
                                                   cellSize.height) 
                    styleMask:NSBorderlessWindowMask 
                    backing:NSBackingStoreBuffered 
                    defer:YES];
    [trackingWin setOpaque:NO];
    [trackingWin setAlphaValue:0.2];
    [trackingWin setHasShadow:YES];
    [trackingWin setLevel:NSFloatingWindowLevel];
    
        // This next line sets things so that we can click through the blue selection box to
        // click buttons in the matrix underneath.
    [trackingWin setIgnoresMouseEvents:YES];
    
        // The content should be filled with a color, so we setup our ColorView
    [trackingWin setContentView:[[[ColorView alloc] initWithFrame:NSZeroRect] autorelease]];
    [(ColorView *)[trackingWin contentView] setColor:[[NSColor blueColor] colorWithAlphaComponent:0.5]];
        // Move the trackingWin to the front
    [trackingWin orderFront:self];
    
        // The blue tracking window is attached as a child window to the main window, so that moving
        // The main window will move the child window (even though currently you can't move the main
        // window)
    [self addChildWindow:trackingWin ordered:NSWindowAbove];
    
        // Tracking areas need to be setup to handle when the mouse moves into or out of the main window
    NSTrackingArea *trackingArea = [[NSTrackingArea alloc] initWithRect:[[self contentView] bounds] 
                                                            options:NSTrackingMouseEnteredAndExited|NSTrackingActiveAlways 
                                                            owner:self 
                                                            userInfo:nil];
    [[self contentView] addTrackingArea:trackingArea];
    [trackingArea release];
    
        // We also must determine whether the mouse is initially inside or outside the windows.
    if ( NSPointInRect([NSEvent mouseLocation],[self frame]) )
        [self mouseEntered:nil];
    else
        [self mouseExited:nil];
    
        // Start with vertical movement
    movingVertically = YES;
    
        // Now lets go setup the hotkey handler, using Carbon APIs (there is no ObjC Cocoa HotKey API as of 10.7)
    EventTypeSpec eventType;
    
    gAppHotKeyFunction = NewEventHandlerUPP(MyHotKeyHandler);
    eventType.eventClass=kEventClassKeyboard;
    eventType.eventKind=kEventHotKeyPressed;
    InstallApplicationEventHandler(gAppHotKeyFunction,1,&eventType,self,NULL);
    gMyHotKeyID.signature=kMyHotKeyIdentifier;
    gMyHotKeyID.id=1;
    
    RegisterEventHotKey(kMyHotKey, cmdKey, gMyHotKeyID, GetApplicationEventTarget(), 0, &gMyHotKeyRef);
}
 
// Windows created with NSBorderlessWindowMask normally can't be key, but we want ours to be
- (BOOL)canBecomeKeyWindow
{
    return YES;
}
 
// Here we use NSWindow's -setFrame:display:animate: method to move the trackingWin one cell
// down/right.
- (void)moveCursor
{
    NSSize cellSize = [[(ColorView *)[self contentView] myButtons] cellSize];
    NSPoint trackingWindowOrigin = [trackingWin frame].origin;
    BOOL animate = NO;
        // There is 1 exta pixel between the cells in the NSMatrix.  Unless taken into account
        // this will cause a problem for our check down below unless taken into account.
    NSUInteger rowSpacing = [[(ColorView *)[self contentView] myButtons] numberOfRows] - 1;
    NSUInteger columnSpacing = [[(ColorView *)[self contentView] myButtons] numberOfColumns] - 1;
    
    
    if ( movingVertically ) {
            // Move down by the height of one cell
        trackingWindowOrigin.y -= cellSize.height;
            // Check if we moved to far down and reset to the top
        if ( trackingWindowOrigin.y < [self frame].origin.y - rowSpacing)
            trackingWindowOrigin.y = [self frame].origin.y + [self frame].size.height - cellSize.height;
        else
                // Don't animate the reset movement
            animate = YES;
        
    } else {
            // Move right by the height of one cell
        trackingWindowOrigin.x += cellSize.width;
            // Check if we moved to far right and reset to the left side
        if ( trackingWindowOrigin.x >= [self frame].origin.x + [self frame].size.width + columnSpacing )
            trackingWindowOrigin.x = [self frame].origin.x;
        else
                // Don't animate the reset movement
            animate = YES;
    }
    
        // Apply the new origin to the trackingWin.
    NSRect newRect = { trackingWindowOrigin, [trackingWin frame].size };
    [[trackingWin animator] setFrame:newRect display:YES animate:animate];
        
        // Call this method again in 1 second to animate to the next state.
    [self performSelector:@selector(moveCursor) withObject:nil afterDelay:1];
}
 
// Switches the movement direction of the trackingWin
- (void)switchDirection
{
    NSSize cellSize = [[(ColorView *)[self contentView] myButtons] cellSize];
    NSRect trackingWindowFrame = [trackingWin frame];
        
        // Stop any pending calls to -moveCursor since we may issue our own at the end
        // of this method.
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    
    if ( movingVertically ) {
            // To switch to horizontal movement, we shrink the frame to the trackingWin of a cell
            // in the NSMatrix.
        trackingWindowFrame.size.width = cellSize.width;
    } else {
            // To return to vertical movement, we restore the width of the trackingWin to the width
            // of the main window.  We must also move the trackingWin back to the left edge of the
            // main window.
        trackingWindowFrame.origin.x = [self frame].origin.x;
        trackingWindowFrame.size.width = [self frame].size.width;
    }
    
    movingVertically = !movingVertically;
    
        // Apply the new frame and animate the change.
    [[trackingWin animator] setFrame:trackingWindowFrame display:YES animate:YES];
    
    if ( NSPointInRect([NSEvent mouseLocation],[self frame]) )
        [self performSelector:@selector(moveCursor) withObject:nil afterDelay:1];
}
 
#pragma mark - Mouse
 
// If the mouse enters a window, go make sure we fade in
- (void)mouseEntered:(NSEvent *)theEvent
{
        // Use Core Animation to fade in both windows.
    [NSAnimationContext runAnimationGroup:^(NSAnimationContext *context) {
        
        [[self animator] setAlphaValue:1.0];
        [[trackingWin animator] setAlphaValue:1.0];
        
    } completionHandler:^{
        
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
            // Begin moving the trackingWin.
        [self performSelector:@selector(moveCursor) withObject:nil afterDelay:0];
    }];
}
 
// If the mouse exits a window, go make sure we fade out
- (void)mouseExited:(NSEvent *)theEvent
{
    [NSAnimationContext runAnimationGroup:^(NSAnimationContext *context) {
        
        [[self animator] setAlphaValue:0.2];
        [[trackingWin animator] setAlphaValue:0.2];
        
    } completionHandler:^{
        
            // Stop all calls to moveCursor to suspend the movement of the trackingWin.
        [NSObject cancelPreviousPerformRequestsWithTarget:self];
    }];
}
 
@end