jens@0: /*  This code is based on Apple's "GeekGameBoard" sample code, version 1.0.
jens@0:     http://developer.apple.com/samplecode/GeekGameBoard/
jens@0:     Copyright © 2007 Apple Inc. Copyright © 2008 Jens Alfke. All Rights Reserved.
jens@0: 
jens@0:     Redistribution and use in source and binary forms, with or without modification, are permitted
jens@0:     provided that the following conditions are met:
jens@0: 
jens@0:     * Redistributions of source code must retain the above copyright notice, this list of conditions
jens@0:       and the following disclaimer.
jens@0:     * Redistributions in binary form must reproduce the above copyright notice, this list of
jens@0:       conditions and the following disclaimer in the documentation and/or other materials provided
jens@0:       with the distribution.
jens@0: 
jens@0:     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
jens@0:     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 
jens@0:     FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRI-
jens@0:     BUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
jens@0:     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
jens@0:     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
jens@0:     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 
jens@0:     THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
jens@0: */
jens@1: #import "GGBLayer.h"
jens@0: @class Bit;
jens@0: 
jens@0: 
jens@0: /** Protocol for a layer that acts as a container for Bits. */
jens@0: @protocol BitHolder <NSObject>
jens@0: 
jens@0: /** Current Bit, or nil if empty */
jens@0: @property (retain) Bit* bit;
jens@0: 
jens@0: /** Conveniences for comparing self.bit with nil */
jens@0: @property (readonly, getter=isEmpty) BOOL empty;
jens@0: 
jens@0: /** BitHolders will be highlighted while the target of a drag operation */
jens@0: @property BOOL highlighted;
jens@0: 
jens@0: 
jens@0: /** Tests whether the bit is allowed to be dragged out of me.
jens@0:     Returns the input bit, or possibly a different Bit to drag instead, or nil if not allowed.
jens@0:     Either -cancelDragBit: or -draggedBit:to: must be called next. */
jens@0: - (Bit*) canDragBit: (Bit*)bit;
jens@0: 
jens@0: /** Cancels a pending drag (begun by -canDragBit:). */
jens@0: - (void) cancelDragBit: (Bit*)bit;
jens@0: 
jens@0: /** Called after a drag finishes. */
jens@0: - (void) draggedBit: (Bit*)bit to: (id<BitHolder>)dst;
jens@0: 
jens@0: 
jens@0: /** Tests whether the bit is allowed to be dropped into me.
jens@0:     Either -willNotDropBit: or -dropBit:atPoint: must be called next. */
jens@0: - (BOOL) canDropBit: (Bit*)bit atPoint: (CGPoint)point;
jens@0: 
jens@0: /** Cancels a pending drop (after -canDropBit:atPoint: was already called.) */
jens@0: - (void) willNotDropBit: (Bit*)bit;
jens@0: 
jens@0: /** Finishes a drop. */
jens@0: - (BOOL) dropBit: (Bit*)bit atPoint: (CGPoint)point;
jens@0: 
jens@0: @end
jens@0: 
jens@0: 
jens@0: /** A basic implementation of the BitHolder protocol. */
jens@1: @interface BitHolder : GGBLayer <BitHolder>
jens@0: {
jens@0:     @protected
jens@0:     Bit *_bit;
jens@0:     BOOL _highlighted;
jens@0: }
jens@0: 
jens@0: @end