//
//  ImageDragView.m
//  ImageDrag
//
//  Created by Joshua Pennington on 5/14/07.
//

#import "ImageDragView.h"


@implementation ImageDragView

- (void)dealloc {
	[self setImage:nil];
	[super dealloc];
}

- (void)awakeFromNib {
	[self setImage:[NSImage imageNamed:@"testImage"]];
}

- (IBAction)resetImagePosition:(id)sender {
	[self setImagePosition:NSZeroPoint];
}

- (void)drawRect:(NSRect)rect {
	// Draw background
	[[NSColor whiteColor] set];
	NSRectFill(rect);
	
	// Draw the image
	NSRect destRect = {[self imagePosition], [[self image] size]};
	[[self image] drawInRect:destRect fromRect:NSZeroRect operation:NSCompositeCopy fraction:1.0];
	
	// Draw border
	[[NSColor grayColor] set];
	NSFrameRect(rect);
}

- (void)mouseDown:(NSEvent *)theEvent {
	// We don't really care if the user clicks if there is no image.
	if (![self image])
		return;
	
	// Convert the click's window-location to this view's coordinate system	
	NSPoint clickLocation = [self convertPoint:[theEvent locationInWindow] fromView:nil];
	
	// If the mousedown is "on" the image, we want to signal that its okay to drag the image.
	if (NSPointInRect(clickLocation, (NSRect){[self imagePosition], [[self image] size]}))
		[self setIsDragging:YES];
}

- (void)mouseUp:(NSEvent *)theEvent {
	[self setIsDragging:NO];
}

- (void)mouseDragged:(NSEvent *)theEvent {
	if (![self image])
		return;
	
	// If the mousedown was not "on" the image, we don't care about the dragging the user does.
	if (![self isDragging])
		return;

	// Calculate the new "image position" using the delta offset values from the event.
	NSPoint newOrigin = [self imagePosition];
	newOrigin.x += [theEvent deltaX];
	newOrigin.y -= [theEvent deltaY];
	
	// If any portion of the new image rect is outside of the view, adjust the new imagePosition so the image rect will not be outside the frame rect.
	NSRect imageRect = {[self convertPoint:newOrigin toView:nil], [[self image] size]};
	if (NSMaxX(imageRect) > NSMaxX([self frame]))
		newOrigin.x -= (NSMaxX(imageRect) - NSMaxX([self frame]));
	if (NSMaxY(imageRect) > NSMaxY([self frame]))
		newOrigin.y -= (NSMaxY(imageRect) - NSMaxY([self frame]));
	if (NSMinX(imageRect) < NSMinX([self frame]))
		newOrigin.x += NSMinX([self frame]) - NSMinX(imageRect);
	if (NSMinY(imageRect) < NSMinY([self frame]))
		newOrigin.y += NSMinY([self frame]) - NSMinY(imageRect);
	
	[self setImagePosition:newOrigin];
}

- (void)setImage:(NSImage *)newImage {
	if (newImage != image) {
		[image autorelease];
		image = [newImage copy];
	}
}

- (NSImage *)image {
	return [[image retain] autorelease];
}

- (void)setImagePosition:(NSPoint)aPoint {
	// If the image "moved" we need to redraw the view to display the change.
	if (!NSEqualPoints(imagePosition, aPoint))
		[self setNeedsDisplay:YES];
	imagePosition = aPoint;
}

- (NSPoint)imagePosition {
	return imagePosition;
}

- (void)setIsDragging:(BOOL)flag {
	isDragging = flag;
}

- (BOOL)isDragging {
	return isDragging;
}

@end