PSView.m #2

//
//  PSView.m
//  Perforce
//
//  Created by Adam Czubernat on 06.06.2013.
//  Copyright (c) 2013 Perforce Software, Inc. All rights reserved.
//

#import "PSView.h"
#import <objc/message.h>

@interface PSView () {
	NSDictionary *targets;
	NSDictionary *selectors;
}
- (void)drawImage:(NSRect)dirtyRect;
@end

@implementation PSView
@synthesize backgroundColor, drawingBlock, image, contentMode;

- (id)initWithCoder:(NSCoder *)coder {
    if (self = [super initWithCoder:coder]) {
		image = [coder decodeObjectForKey:@"image"];
		backgroundColor = [coder decodeObjectForKey:@"backgroundColor"];
		drawingBlock = [coder decodeObjectForKey:@"drawingBlock"];
		contentMode = [[coder decodeObjectForKey:@"contentMode"] intValue];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)coder {
	[super encodeWithCoder:coder];
	[coder encodeObject:image forKey:@"image"];
	[coder encodeObject:backgroundColor forKey:@"backgroundColor"];
	[coder encodeObject:drawingBlock forKey:@"drawingBlock"];
	[coder encodeObject:@(contentMode) forKey:@"contentMode"];
}

- (void)drawRect:(NSRect)dirtyRect {
	
	// Draw background
	if (backgroundColor) {
		[backgroundColor setFill];
		NSRectFillUsingOperation(dirtyRect, NSCompositeSourceOver);
	}
	
	// Draw image
	if (image)
		[self drawImage:dirtyRect];
	
	// Custom drawing block
    if (drawingBlock)
		drawingBlock(self, dirtyRect);
}

- (void)mouseDown:(NSEvent *)theEvent {
		
	PSView *strongSelf = self;
	[super mouseDown:theEvent];
	
	if ([theEvent clickCount] == 1) {
		[strongSelf sendActionsForEvents:PSViewEventClick];
	} else if ([theEvent clickCount] > 1) {
		[strongSelf sendActionsForEvents:PSViewEventDoubleClick];
	}
}

// Fix to NSScrollview bottom
- (NSRect)adjustScroll:(NSRect)newVisible {
	CGRect scrollRect = [self enclosingScrollView].frame;
	if (scrollRect.size.height > self.frame.size.height) {
		newVisible.origin.y = -scrollRect.size.height + self.frame.size.height;
		return newVisible;
	}
	return [super adjustScroll:newVisible];
}

#pragma mark - Private

- (void)drawImage:(NSRect)dirtyRect {
	
	NSRect drawRect = self.bounds;
	NSRect imageRect = NSZeroRect;
	
	PSViewContentMode mode = contentMode;
	
	// Get best size
	CGSize size = (image.representations.count ?
				   [image bestRepresentationForRect:drawRect context:NULL hints:nil].size :
				   image.size);

	// Resizable image filling by default
	if (image.isResizable && mode == PSViewContentModeAspectFit)
		mode = PSViewContentModeFill;
	
	if (mode == PSViewContentModeAspectFit || mode == PSViewContentModeAspectFill) {
		BOOL max = mode == PSViewContentModeAspectFill;
		CGFloat factor = (max ? fmax : fmin)(drawRect.size.width / size.width,
											 drawRect.size.height / size.height);
		size = (CGSize) { size.width * factor, size.height * factor };
		drawRect = (CGRect) {
			trunc((drawRect.size.width - size.width) * 0.5f),
			trunc((drawRect.size.height - size.height) * 0.5f),
			size,
		};
	} else if (mode == PSViewContentModeCenter) {
		imageRect = (CGRect) {
			trunc((drawRect.size.width - size.width) * 0.5f),
			trunc((drawRect.size.height - size.height) * 0.5f),
			size,
		};
		imageRect = CGRectIntersection(imageRect, drawRect);
	} else if (mode == PSViewContentModeFillHorizontal) {
		drawRect = (CGRect) {
			0.0f, trunc((drawRect.size.height - size.height) * 0.5f),
			drawRect.size.width, size.height,
		};
	} else if (mode == PSViewContentModeFillVertical) {
		drawRect = (CGRect) {
			trunc((drawRect.size.width - size.width) * 0.5f), 0.0f,
			size.width, drawRect.size.height,
		};
	}
	
	[image
	 drawInRect:drawRect
	 fromRect:imageRect
	 operation:NSCompositeSourceOver
	 fraction:1.0f
	 respectFlipped:YES
	 hints:nil];
}

#pragma mark - Public

- (void)setBackgroundColor:(NSColor *)aBackgroundColor {
	backgroundColor = aBackgroundColor;
	[self setNeedsDisplay:YES];	
}

- (void)setImage:(NSImage *)anImage {
	image = anImage;
	[self setNeedsDisplay:YES];
}

- (void)setDrawingBlock:(void (^)(NSView *, NSRect))aDrawingBlock {
	drawingBlock = [aDrawingBlock copy];
	[self setNeedsDisplay:YES];
}

#pragma mark - Target/Observer pattern

- (void)addTarget:(id)target action:(SEL)action forEvents:(PSViewEvent)events {

	if (!targets) {
		NSMutableArray *(^weakArray)(void) = ^{ // Create non-retaining array
			CFArrayCallBacks callbacks = { 0, NULL, NULL, CFCopyDescription, CFEqual };
			return CFBridgingRelease(CFArrayCreateMutable(NULL, 0, &callbacks));
		};
		
		targets = @{
			@(PSViewEventClick) : weakArray(),
			@(PSViewEventDoubleClick) : weakArray(),
		};
		selectors = @{
			@(PSViewEventClick) : [NSMutableArray array],
			@(PSViewEventDoubleClick) : [NSMutableArray array],
		};
	}

	for (NSNumber *eventNumber in targets) {

		if (!(events & eventNumber.intValue))
			continue;
		
		NSMutableArray *eventTargets = [targets objectForKey:eventNumber];
		NSMutableArray *eventSelectors = [selectors objectForKey:eventNumber];
		[eventTargets addObject:target];
		[eventSelectors addObject:NSStringFromSelector(action)];
	}
}

- (void)sendActionsForEvents:(PSViewEvent)events {

	for (NSNumber *eventNumber in targets) {
	
		if (!(events & eventNumber.intValue))
			continue;
		
		NSMutableArray *eventTargets = [targets objectForKey:eventNumber];
		NSMutableArray *eventSelectors = [selectors objectForKey:eventNumber];
		[eventTargets enumerateObjectsUsingBlock:^(id target, NSUInteger idx, BOOL *stop) {
			SEL selector = NSSelectorFromString([eventSelectors objectAtIndex:idx]);
			objc_msgSend(target, selector);
		}];
	}
}

@end