Classes/AtomicElementView.m

/*
     File: AtomicElementView.m
 Abstract: Displays the Atomic Element information in a large format tile.
  Version: 1.12
 
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#import "AtomicElementView.h"
#import "AtomicElementViewController.h"
#import "AtomicElement.h"
 
#import <QuartzCore/QuartzCore.h>
 
@implementation AtomicElementView
 
// the preferred size of this view is the size of the background image
+ (CGSize)preferredViewSize {
    
    return CGSizeMake(256,256);
}
 
// initialize the view, calling super and setting the properties to nil
- (id)initWithFrame:(CGRect)frame {
    
    if (self = [super initWithFrame:frame]) {
        // Initialization code here.
        _element = nil;
        _viewController = nil;
        // set the background color of the view to clearn
        self.backgroundColor=[UIColor clearColor];
        
        // attach a tap gesture recognizer to this view so it can flip
        UITapGestureRecognizer *tapGestureRecognizer =
            [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];
        [self addGestureRecognizer:tapGestureRecognizer];
    }
    return self;
}
 
// yes this view can become first responder
- (BOOL)canBecomeFirstResponder {
    
    return YES;
}
 
- (void)tapAction:(UIGestureRecognizer *)gestureRecognizer {
    
    // when a tap gesture occurs tell the view controller to flip this view to the
    // back and show the AtomicElementFlippedView instead
    //
    [self.viewController flipCurrentView];
}
 
- (void)drawRect:(CGRect)rect {
    
    // get the background image for the state of the element
    // position it appropriately and draw the image
    UIImage *backgroundImage = [self.element stateImageForAtomicElementView];
    CGRect elementSymbolRectangle = CGRectMake(0, 0, [backgroundImage size].width, [backgroundImage size].height);
    [backgroundImage drawInRect:elementSymbolRectangle];
    
    // all the text is drawn in white
    [[UIColor whiteColor] set];
    
    // draw the element name
    UIFont *font = [UIFont boldSystemFontOfSize:36];
    CGSize stringSize = [self.element.name sizeWithFont:font];
    CGPoint point = CGPointMake((self.bounds.size.width-stringSize.width)/2, 256/2-50);
    [self.element.name drawAtPoint:point withFont:font];
    
    // draw the element number
    font = [UIFont boldSystemFontOfSize:48];
    point = CGPointMake(10,0);
    [[NSString stringWithFormat:@"%@", self.element.atomicNumber] drawAtPoint:point withFont:font];
    
    // draw the element symbol
    font = [UIFont boldSystemFontOfSize:96];
    stringSize = [self.element.symbol sizeWithFont:font];
    point = CGPointMake((self.bounds.size.width-stringSize.width)/2,256-120);
    [self.element.symbol drawAtPoint:point withFont:font];
}
 
 
CGImageRef AEViewCreateGradientImage (int pixelsWide, int pixelsHigh) {
    
    CGImageRef theCGImage = NULL;
    CGContextRef gradientBitmapContext = NULL;
    CGColorSpaceRef colorSpace;
    CGGradientRef grayScaleGradient;
    CGPoint gradientStartPoint, gradientEndPoint;
    
    // Our gradient is always black-white and the mask
    // must be in the gray colorspace
    colorSpace = CGColorSpaceCreateDeviceGray();
    
    // create the bitmap context
    gradientBitmapContext = CGBitmapContextCreate (NULL, pixelsWide, pixelsHigh,
                                                   8, 0, colorSpace, kCGImageAlphaNone);
    
    if (gradientBitmapContext != NULL) {
        // define the start and end grayscale values (with the alpha, even though
        // our bitmap context doesn't support alpha the gradient requires it)
        CGFloat colors[] = {0.0, 1.0,1.0, 1.0,};
        
        // create the CGGradient and then release the gray color space
        grayScaleGradient = CGGradientCreateWithColorComponents(colorSpace, colors, NULL, 2);
        
        // create the start and end points for the gradient vector (straight down)
        gradientStartPoint = CGPointZero;
        gradientEndPoint = CGPointMake(0,pixelsHigh);
        
        // draw the gradient into the gray bitmap context
        CGContextDrawLinearGradient (gradientBitmapContext, grayScaleGradient, gradientStartPoint, gradientEndPoint, kCGGradientDrawsAfterEndLocation);
        
        // clean up the gradient
        CGGradientRelease(grayScaleGradient);
        
        // convert the context into a CGImageRef and release the context
        theCGImage = CGBitmapContextCreateImage(gradientBitmapContext);
        CGContextRelease(gradientBitmapContext);
    }
    
    // clean up the colorspace
    CGColorSpaceRelease(colorSpace);
    
    // return the imageref containing the gradient
    return theCGImage;
}
 
- (UIImage *)reflectedImageRepresentationWithHeight:(NSUInteger)height {
    
    CGContextRef mainViewContentContext;
    CGColorSpaceRef colorSpace;
    
    colorSpace = CGColorSpaceCreateDeviceRGB();
    
    // create a bitmap graphics context the size of the image
    mainViewContentContext = CGBitmapContextCreate (NULL, self.bounds.size.width,height, 8,0, colorSpace, kCGImageAlphaPremultipliedLast);
    
    // free the rgb colorspace
    CGColorSpaceRelease(colorSpace);    
    
    if (mainViewContentContext == NULL)
        return NULL;
    
    // offset the context. This is necessary because, by default, the layer created by a view for
    // caching its content is flipped. But when you actually access the layer content and have
    // it rendered it is inverted. Since we're only creating a context the size of our 
    // reflection view (a fraction of the size of the main view) we have to translate the context the
    // delta in size, render it, and then translate back
    
    CGFloat translateVertical = self.bounds.size.height-height;
    CGContextTranslateCTM(mainViewContentContext, 0, -translateVertical);
    
    // render the layer into the bitmap context
    [self.layer renderInContext:mainViewContentContext];
    
    // translate the context back
    CGContextTranslateCTM(mainViewContentContext, 0, translateVertical);
    
    // Create CGImageRef of the main view bitmap content, and then release that bitmap context
    CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext);
    CGContextRelease(mainViewContentContext);
    
    // create a 2 bit CGImage containing a gradient that will be used for masking the 
    // main view content to create the 'fade' of the reflection.  The CGImageCreateWithMask
    // function will stretch the bitmap image as required, so we can create a 1 pixel wide gradient
    CGImageRef gradientMaskImage = AEViewCreateGradientImage(1, height);
    
    // Create an image by masking the bitmap of the mainView content with the gradient view
    // then release the pre-masked content bitmap and the gradient bitmap
    CGImageRef reflectionImage = CGImageCreateWithMask(mainViewContentBitmapContext, gradientMaskImage);
    CGImageRelease(mainViewContentBitmapContext);
    CGImageRelease(gradientMaskImage);
    
    // convert the finished reflection image to a UIImage 
    UIImage *theImage = [UIImage imageWithCGImage:reflectionImage];
 
    CGImageRelease(reflectionImage);
 
    return theImage;
}
 
@end