绘制字符串与图像

借鉴于斯坦福课程

.h

<span style="font-size:18px;">#import <UIKit/UIKit.h>

@interface DrawingView : UIView
@property (nonatomic) NSInteger rank;
@property (nonatomic, strong) NSString *suit;
@property (nonatomic) BOOL faceUp;
- (void)pinch:(UIPinchGestureRecognizer *)gesture;
@end</span>

.m

<span style="font-size:18px;">#import "DrawingView.h"

@interface DrawingView ()
@property (nonatomic) CGFloat faceCardScaleFactor;
@end


@implementation DrawingView
@synthesize faceCardScaleFactor = _faceCardScaleFactor;//因为同时自定义了setter和getter方法。
#define DEFAULT_FACE_CARD_SCALE_FACTOR 0.90
- (CGFloat)faceCardScaleFactor{
    if (!_faceCardScaleFactor) {
        _faceCardScaleFactor = DEFAULT_FACE_CARD_SCALE_FACTOR;
    }
    return _faceCardScaleFactor;
}
- (void)setFaceCardScaleFactor:(CGFloat)faceCardScaleFactor{
    _faceCardScaleFactor = faceCardScaleFactor;
    [self setNeedsDisplay];
}
- (void)setSuit:(NSString *)suit{
    _suit = suit;
    [self setNeedsDisplay];
}
- (void)setRank:(NSInteger)rank{
    _rank = rank;
    [self setNeedsDisplay];
}
- (void)setFaceUp:(BOOL)faceUp{
    _faceUp = faceUp;
    [self setNeedsDisplay];
}
- (void)pinch:(UIPinchGestureRecognizer *)gesture{
    if ((gesture.state == UIGestureRecognizerStateChanged) || (gesture.state == UIGestureRecognizerStateEnded)) {
        self.faceCardScaleFactor *= gesture.scale;
        gesture.scale = 1.0;
    }
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.

- (NSString *)rankAsString{
    return @[@"?", @"A", @"2", @"3", @"4", @"5", @"6", @"7", @"8", @"9", @"10", @"J", @"Q", @"K", ][self.rank];
}
#define CORNER_FONT_STANDARD_HEIGHT 180.0
#define CORNER_RADIUS 12.0
- (CGFloat)cornerScaleFactor { return self.bounds.size.height / CORNER_FONT_STANDARD_HEIGHT; }
- (CGFloat)cornerRadius { return CORNER_RADIUS * [self cornerScaleFactor]; }
- (CGFloat)cornerOffset { return [self cornerRadius]  / 3.0; }
- (void)drawRect:(CGRect)rect {
    // Drawing code
    UIBezierPath *roundRect = [UIBezierPath bezierPathWithRoundedRect:self.bounds cornerRadius:12.0];
    [roundRect addClip];
    [[UIColor whiteColor] setFill];
    UIRectFill(self.bounds);
    [[UIColor blackColor]setStroke];
    [roundRect stroke];
    if (self.faceUp) {
        UIImage *faceImage = [UIImage imageNamed:@"2"];
        if (faceImage) {
            CGRect imageRect = CGRectInset(self.bounds, self.bounds.size.width * (1.0-self.faceCardScaleFactor), self.bounds.size.height * (1.0-self.faceCardScaleFactor));
            [faceImage drawInRect:imageRect];
        }else {
            [self drawPips];
        }
        
        [self drawCorners];
    }else{
        [[UIImage imageNamed:@"1"]drawInRect:self.bounds];
    }
    
}
- (void)drawPips{
    
}
- (void)drawCorners{
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
    paragraphStyle.alignment = NSTextAlignmentCenter;
    UIFont *cornerFont = [UIFont preferredFontForTextStyle:UIFontTextStyleBody];
    cornerFont = [cornerFont fontWithSize:cornerFont.pointSize *[self cornerScaleFactor]];
    NSAttributedString *cornerText = [[NSAttributedString alloc]initWithString:[NSString stringWithFormat:@"%@\n%@", [self rankAsString], self.suit] attributes:@{NSFontAttributeName:cornerFont, NSParagraphStyleAttributeName:paragraphStyle}];
    CGRect textBounds;
    textBounds.origin = CGPointMake([self cornerOffset], [self cornerOffset]);
    textBounds.size = [cornerText size];
    [cornerText drawInRect:textBounds];
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(context, self.bounds.size.width, self.bounds.size.height);
    CGContextRotateCTM(context, M_PI);
    [cornerText drawInRect:textBounds];
}
- (void)setup{
    self.backgroundColor = nil;
    self.opaque = NO;
    self.contentMode = UIViewContentModeRedraw;
}
- (void)awakeFromNib{
    [self setup];
}

- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        
    }
    return self;
}

@end
</span>

使用举例：

<span style="font-size:18px;">@property (weak, nonatomic) IBOutlet DrawingView *myDrawingView;</span>

<span style="font-size:18px;">self.myDrawingView.suit = @"♥️";
    self.myDrawingView.rank = 13;
    [self.myDrawingView addGestureRecognizer:[[UIPinchGestureRecognizer alloc]initWithTarget:self.myDrawingView action:@selector(pinch:)]];</span>

<span style="font-size:18px;">- (IBAction)swip:(UISwipeGestureRecognizer *)sender {
    self.myDrawingView.faceUp = !self.myDrawingView.faceUp;
}</span>