RGBAppController.m

 
//
//  RGBAppController.m
//  RGB Image
//
//  Created by jcr on Thu Feb 21 2002.
//  Copyright (c) 2002  Apple Computer, Inc. All rights reserved.
 
static NSString *imageKey = @"image";
static NSString *combinedImageKey = @"combinedImage";
static NSString *showsRedKey = @"showsRed";
static NSString *showsGreenKey = @"showsGreen";
static NSString *showsBlueKey = @"showsBlue";
static NSString *showsAlphaKey = @"showsAlpha";
 
@implementation RGBAppController
 
+ (void) initialize
    {
    // ValueTransformers need to be created before the nib loads.
    [NSValueTransformer setValueTransformer:[RGBTransformer transformerWithColor:[NSColor redColor]] forName:@"redTransformer"];
    [NSValueTransformer setValueTransformer:[RGBTransformer transformerWithColor:[NSColor greenColor]] forName:@"greenTransformer"];
    [NSValueTransformer setValueTransformer:[RGBTransformer transformerWithColor:[NSColor blueColor]] forName:@"blueTransformer"];
    [NSValueTransformer setValueTransformer:[RGBTransformer transformerWithColor:[NSColor blackColor] operation:NSCompositeSourceAtop] forName:@"alphaTransformer"];
    // Make sure that anything bound to "combinedImage" updates when the image or the checkboxes are changed.
    [self setKeys:[NSArray arrayWithObjects: imageKey, showsRedKey, showsGreenKey, showsBlueKey, showsAlphaKey, nil] triggerChangeNotificationsForDependentKey:combinedImageKey];
    }
 
- (void) awakeFromNib // Set all these values with key-value coding, so that the checkboxes notice the change.
    {
    [self setValue:[NSNumber numberWithBool:YES] forKey:showsRedKey];
    [self setValue:[NSNumber numberWithBool:YES] forKey:showsGreenKey];
    [self setValue:[NSNumber numberWithBool:YES] forKey:showsBlueKey];
    [self setValue:[NSNumber numberWithBool:YES] forKey:showsAlphaKey];
    }
    
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
    {
    [self showTheMandrill:nil];  // Just so that we're not looking at a blank when we start.
    }
    
- (IBAction) showTheMandrill:sender  // Load up a test image.
    {
    [self setValue:[NSImage imageNamed:@"mandrill"] forKey:imageKey];
    }
 
- (IBAction)imageChanged:(id)sender
    {
    [self setValue:[sender image] forKey:imageKey];  // Again, using KVC ensures that the observers notice.
    [[sender cell] setHighlighted:NO];
    }
 
- (NSImage *) image { return image; }
- (void) setImage:(NSImage *) anImage  // Standard paranoid accessor method.
    {
    if (anImage != image)
      {
        [anImage retain]; 
        [image release];
        image = anImage;
        }
    }
 
- (NSImage *) RGBImage  // image consisting of the selected components, not including alpha.
    {
    NSImage 
        *rgbImage = [[[NSImage alloc] initWithSize:[image size]] autorelease];
        
  [rgbImage lockFocus];
            
        if (showsRed)   
            [[image transformedValueWithTransformer:[NSValueTransformer valueTransformerForName:@"redTransformer"]] 
            compositeToPoint:NSZeroPoint operation:NSCompositePlusLighter];
        
        if (showsGreen)     
            [[image transformedValueWithTransformer:[NSValueTransformer valueTransformerForName:@"greenTransformer"]] 
                compositeToPoint:NSZeroPoint operation:NSCompositePlusLighter];
 
        if (showsBlue)  
            [[image transformedValueWithTransformer:[NSValueTransformer valueTransformerForName:@"blueTransformer"]] 
            compositeToPoint:NSZeroPoint operation:NSCompositePlusLighter];
            
    [rgbImage unlockFocus];
    
    return rgbImage;
    }
    
- (NSImage *) combinedImage  // Reconstitute the image from the selected components
    {
    if (image) // Must have an image to have a combinedImage.
        {
        NSSize 
            imageSize = [image size];
            
        NSImage 
            *newImage = [[NSImage alloc] initWithSize:imageSize];
        
        NSRect 
            imageRect = NSMakeRect(0, 0, imageSize.width, imageSize.height);
            
        [newImage lockFocus];
            
            if (showsAlpha)  
                {
                [[NSColor clearColor] set];
                NSRectFill(imageRect);
                [[[NSValueTransformer valueTransformerForName:@"alphaTransformer"] transformedValue:image] 
                    compositeToPoint:NSZeroPoint operation:NSCompositeCopy];
                }
            else  // Not using alpha, so give something to draw the RGB image over.
                {
                [[NSColor whiteColor] set];
                NSRectFill(imageRect);
                }
    
            [[self RGBImage] compositeToPoint:NSZeroPoint operation:NSCompositeSourceAtop];
        [newImage unlockFocus];
        return [newImage autorelease];
        }
    return nil;
    }
 
- (void) setCombinedImage:(NSImage *) anImage {}  // This is just here so that key-value coding won't complain.
- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)theApplication { return YES; }
 
@end
 
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