/*

     File: DraggableItemView.m 

 Abstract: Part of the DraggableItemView project referenced in the 

 View Programming Guide for Cocoa documentation.

 Short Circuting the Event Loop Edition. 

  Version: 1.1 

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 */

#import "DraggableItemView.h"

@implementation DraggableItemView

// -----------------------------------

// Initialize the View

// -----------------------------------

- (id)initWithFrame:(NSRect)frame {

    self = [super initWithFrame:frame];

    if (self) {

    // setup the starting location of the 

    // draggable item

    [self setItemPropertiesToDefault:self];

    }

    return self;

}

// -----------------------------------

// Release the View

// -----------------------------------

- (void)dealloc

{

    // release the color items and set

    // the instance variables to nil

    [itemColor release];

    itemColor=nil;

    [backgroundColor release];

    backgroundColor=nil;

    // call super

    [super dealloc];  

}

// -----------------------------------

// Draw the View Content

// -----------------------------------

- (void)drawRect:(NSRect)rect

{

    // erase the background by drawing white

    [[NSColor whiteColor] set];

    [NSBezierPath fillRect:rect];

    // set the current color for the draggable item

    [[self itemColor] set];

    // draw the draggable item

    [NSBezierPath fillRect:[self calculatedItemBounds]];

}

- (BOOL)isOpaque

{

    // If the background color is opaque, return YES

    // otherwise, return NO

    return [[self backgroundColor] alphaComponent] >= 1.0 ? YES : NO;

}

// -----------------------------------

// Modify the item location 

// -----------------------------------

- (void)offsetLocationByX:(float)x andY:(float)y

{

    // tell the display to redraw the old rect

    [self setNeedsDisplayInRect:[self calculatedItemBounds]];

    // since the offset can be generated by both mouse moves

    // and moveUp:, moveDown:, etc.. actions, we'll invert

    // the deltaY amount based on if the view is flipped or 

    // not.

    int invertDeltaY = [self isFlipped] ? -1: 1;

    location.x=location.x+x;

    location.y=location.y+y*invertDeltaY;

    // invalidate the new rect location so that it'll

    // be redrawn

    [self setNeedsDisplayInRect:[self calculatedItemBounds]];

}

// -----------------------------------

// Hit test the item

// -----------------------------------

- (BOOL)isPointInItem:(NSPoint)testPoint

{

    BOOL itemHit=NO;

    // test first if we're in the rough bounds

    itemHit = NSPointInRect(testPoint,[self calculatedItemBounds]);

    // yes, lets further refine the testing

    if (itemHit) {

    }

    return itemHit;

}

// -----------------------------------

// Handle Mouse Events 

// -----------------------------------

// -----------------------------------

// Short Circuited mouseDown: handler

// -----------------------------------

-(void)mouseDown:(NSEvent *)event

{

    BOOL loop = YES;

    NSPoint clickLocation;

    // convert the initial click location into the view coords

    clickLocation = [self convertPoint:[event locationInWindow]

                  fromView:nil];

    // did the click occur in the draggable item?

    if ([self isPointInItem:clickLocation]) {

        // we're dragging, so let's set the cursor

    // to the closed hand

    [[NSCursor closedHandCursor] push];

    NSPoint newDragLocation;

    // the tight event loop pattern doesn't require the use

    // of any instance variables, so we'll use a local

    // variable localLastDragLocation instead.

    NSPoint localLastDragLocation;

    // save the starting location as the first relative point

    localLastDragLocation=clickLocation;

    while (loop) {

        // get the next event that is a mouse-up or mouse-dragged event

        NSEvent *localEvent;

        localEvent= [[self window] nextEventMatchingMask:NSLeftMouseUpMask | NSLeftMouseDraggedMask];

        switch ([localEvent type]) {

        case NSLeftMouseDragged:

            // convert the new drag location into the view coords

            newDragLocation = [self convertPoint:[localEvent locationInWindow]

                        fromView:nil];

            // offset the item and update the display

            [self offsetLocationByX:(float)(newDragLocation.x-localLastDragLocation.x)

                       andY:(float)(newDragLocation.y-localLastDragLocation.y)];

            // update the relative drag location;

            localLastDragLocation=newDragLocation;

            // support automatic scrolling during a drag

            // by calling NSView's autoscroll: method

            [self autoscroll:localEvent];

            break;

        case NSLeftMouseUp:

            // mouse up has been detected, 

            // we can exit the loop

            loop = NO;

            // finished dragging, restore the cursor

            [NSCursor pop];

            // the rectangle has moved, we need to reset our cursor

            // rectangle

            [[self window] invalidateCursorRectsForView:self];

            break;

        default:

            // Ignore any other kind of event. 

            break;

        }

    }

    };

    return;

}

// -----------------------------------

// First Responder Methods

// -----------------------------------

- (BOOL)acceptsFirstResponder

{

    return YES;

}

// -----------------------------------

// Handle KeyDown Events 

// -----------------------------------

- (void)keyDown:(NSEvent *)event

{

    BOOL handled = NO;

    NSString  *characters;

    // get the pressed key

    characters = [event charactersIgnoringModifiers];

    // is the "r" key pressed?

    if ([characters isEqual:@"r"]) {

    // Yes, it is

    handled = YES;

    // set the rectangle properties

    [self setItemPropertiesToDefault:self];

    }

    if (!handled)

    [super keyDown:event];

}

// -----------------------------------

// Handle NSResponder Actions 

// -----------------------------------

-(IBAction)moveUp:(id)sender

{

    [self offsetLocationByX:0.0f andY:10.0f];

    [[self window] invalidateCursorRectsForView:self];

}

-(IBAction)moveDown:(id)sender

{

    [self offsetLocationByX:0.0f andY:-10.0f];

    [[self window] invalidateCursorRectsForView:self];

}

-(IBAction)moveLeft:(id)sender

{

    [self offsetLocationByX:-10.0f andY:0.0f];

    [[self window] invalidateCursorRectsForView:self];

}

-(IBAction)moveRight:(id)sender

{

    [self offsetLocationByX:10.0f andY:0.0f];

    [[self window] invalidateCursorRectsForView:self];

}

- (IBAction)setItemPropertiesToDefault:(id)sender

{

    [self setLocation:NSMakePoint(0.0f,0.0f)];

    [self setItemColor:[NSColor redColor]];

    [self setBackgroundColor:[NSColor whiteColor]];

}

// -----------------------------------

// Handle color changes via first responder 

// -----------------------------------

- (void)changeColor:(id)sender

{

    // Set the color in response

    // to the color changing in the color panel.

    // get the new color by asking the sender, the color panel

    [self setItemColor:[sender color]];

}

// -----------------------------------

// Reset Cursor Rects 

// -----------------------------------

-(void)resetCursorRects

{

    // remove the existing cursor rects

    [self discardCursorRects];

    // add the draggable item's bounds as a cursor rect

    [self addCursorRect:[self calculatedItemBounds] cursor:[NSCursor openHandCursor]];

}

// -----------------------------------

//  Accessor Methods

// -----------------------------------

- (void)setItemColor:(NSColor *)aColor

{

    if (![itemColor isEqual:aColor]) {

        [itemColor release];

        itemColor = [aColor retain];

        // if the colors are not equal, mark the

        // draggable rect as needing display

        [self setNeedsDisplayInRect:[self calculatedItemBounds]];

    }

}

- (NSColor *)itemColor

{

    return [[itemColor retain] autorelease];

}

- (void)setBackgroundColor:(NSColor *)aColor

{

    if (![backgroundColor isEqual:aColor]) {

        [backgroundColor release];

        backgroundColor = [aColor retain];

        // if the colors are not equal, mark the

        // draggable rect as needing display

        [self setNeedsDisplayInRect:[self calculatedItemBounds]];

    }

}

- (NSColor *)backgroundColor

{

    return [[backgroundColor retain] autorelease];

}

- (void)setLocation:(NSPoint)point

{

    // test to see if the point actually changed

    if (!NSEqualPoints(point,location)) {

        // tell the display to redraw the old rect

    [self setNeedsDisplayInRect:[self calculatedItemBounds]];

        // reassign the rect

    location=point;

        // display the new rect

    [self setNeedsDisplayInRect:[self calculatedItemBounds]];

        // invalidate the cursor rects 

    [[self window] invalidateCursorRectsForView:self];

    }

}

- (NSPoint)location {

    return location;

}

- (NSRect)calculatedItemBounds

{

    NSRect calculatedRect;

    // calculate the bounds of the draggable item

    // relative to the location

    calculatedRect.origin=location;

    // the example assumes that the width and height

    // are fixed values

    calculatedRect.size.width=60.0f;

    calculatedRect.size.height=20.0f;

    return calculatedRect;

}

@end