如何平滑繪畫描邊？

Question

我正在創建繪圖..我可以撤消，並把它的顏色。但是當我用我的手指畫的筆畫是不是那麼光滑，並有邊緣線,,

這裏我的代碼。我可以在該視圖上繪製，撤消，更改顏色和不透明度。

stroke.h

#import <UIKit/UIKit.h> 

@interface stroke : UIView{ 
    NSMutableArray *strokeArray; 
    UIColor *strokeColor; 
    int strokeSize; 
    float strokeAlpha; 
    int strokeAlpha2; 
    IBOutlet UISlider *slides; 
    float red; 
    float green; 
    float blue; 
    CGPoint mid1; 
    CGPoint mid2; 
    CGPoint endingPoint,previousPoint1,previousPoint2; 
    CGPoint currentTouch; 
} 

@property (nonatomic, retain) UIColor *strokeColor; 
@property (nonatomic) int strokeSize; 
@property (nonatomic, retain) NSMutableArray *strokeArray; 
- (IBAction)changeAlphaValue; 
-(void)loadSLider; 
-(void)blueColor; 
-(void)darkvioletColor; 
-(void)violetColor; 
-(void)pinkColor; 
-(void)darkbrownColor; 
-(void)redColor; 
-(void)magentaRedColor; 
-(void)lightBrownColor; 
-(void)lightOrangeColor; 
-(void)OrangeColor; 
-(void)YellowColor; 
-(void)greenColor; 
-(void)lightYellowColor; 
-(void)darkGreenColor; 
-(void)TurquioseColor; 
-(void)PaleTurquioseColor; 
-(void)skyBlueColor; 
-(void)whiteColor; 
-(void)DirtyWhiteColor; 
-(void)SilverColor; 
-(void)LightGrayColor; 
-(void)GrayColor; 
-(void)LightBlackColor; 
-(void)BlackColor; 
@end 

stroke.m

#import "stroke.h" 

@implementation stroke 
@synthesize strokeColor; 
@synthesize strokeSize; 
@synthesize strokeArray; 


- (void) awakeFromNib{ 
    self.strokeArray = [[NSMutableArray alloc] init]; 
    self.strokeColor = [UIColor colorWithRed:0 green:0 blue:232 alpha:1]; 
    self.strokeSize = 3; 
} 
- (void)drawRect:(CGRect)rect{ 
    NSMutableArray *stroke; 
    for (stroke in strokeArray) { 
     CGContextRef contextRef = UIGraphicsGetCurrentContext(); 
     CGContextSetLineWidth(contextRef, [[stroke objectAtIndex:1] intValue]); 
     CGFloat *color = CGColorGetComponents([[stroke objectAtIndex:2] CGColor]); 
     CGContextSetRGBStrokeColor(contextRef, color[0], color[1], color[2], color[3]);  
     CGContextBeginPath(contextRef); 
     CGPoint points[[stroke count]]; 
     for (NSUInteger i = 3; i < [stroke count]; i++) { 
      points[i-3] = [[stroke objectAtIndex:i] CGPointValue]; 
     } 
     CGContextAddLines(contextRef, points, [stroke count]-3); 
     CGContextStrokePath(contextRef); 
    } 

} 
-(void)loadSLider{ 

} 
- (IBAction)changeAlphaValue{ 
    strokeAlpha2 =((int)slides.value); 
} 
-(void)blueColor{ 
    red = 0/255.0; 
    green = 0/255.0; 
    blue = 255/255.0; 
} 
-(void)darkvioletColor{ 
    red = 75/255.0; 
    green = 0/255.0; 
    blue = 130/255.0; 
} 
-(void)violetColor{ 
    red = 128/255.0; 
    green = 0/255.0; 
    blue = 128/255.0; 
} 
-(void)pinkColor{ 
    red = 255/255.0; 
    green = 0/255.0; 
    blue = 255/255.0; 
} 
-(void)darkbrownColor{ 
    red = 0.200; 
    green = 0.0; 
    blue = 0.0; 
} 
-(void)redColor{ 
    red = 255/255.0; 
    green = 0/255.0; 
    blue = 0/255.0; 
} 
-(void)magentaRedColor{ 
    red = 0.350; 
    green = 0.0; 
    blue = 0.0; 
} 
-(void)lightBrownColor{ 
    red = 0.480; 
    green = 0.0; 
    blue = 0.0; 
} 
-(void)lightOrangeColor{ 
    red = 0.600; 
    green = 0.200; 
    blue = 0.0; 
} 
-(void)OrangeColor{ 
    red = 1.0; 
    green = 0.300; 
    blue = 0.0; 
} 
-(void)YellowColor{ 
    red = 0.950; 
    green = 0.450; 
    blue = 0.0; 
} 
-(void)greenColor{ 
    red = 0.0; 
    green = 1.0; 
    blue = 0.0; 
} 
-(void)lightYellowColor{ 
    red = 1.0; 
    green = 1.0; 
    blue = 0.0; 

} 
-(void)darkGreenColor{ 
    red = 0.0; 
    green = 0.500; 
    blue = 0.0; 
} 
-(void)TurquioseColor{ 
    red = 0.0; 
    green = 0.700; 
    blue = 0.200; 
} 
-(void)PaleTurquioseColor{ 
    red = 0.0; 
    green = 0.700; 
    blue = 0.600; 
} 
-(void)skyBlueColor{ 
    red = 0.0; 
    green = 0.400; 
    blue = 0.800; 
} 
-(void)whiteColor{ 
    red = 1.0; 
    green = 1.0; 
    blue = 1.0; 
} 
-(void)DirtyWhiteColor{ 
    red = 0.800; 
    green = 0.800; 
    blue = 0.800; 
} 
-(void)SilverColor{ 
    red = 0.600; 
    green = 0.600; 
    blue = 0.600; 
} 
-(void)LightGrayColor{ 
    red = 0.500; 
    green = 0.500; 
    blue = 0.500; 
} 
-(void)GrayColor{ 
    red = 0.300; 
    green = 0.300; 
    blue = 0.300; 
} 
-(void)LightBlackColor{ 
    red = 0.150; 
    green = 0.150; 
    blue = 0.150; 
} 
-(void)BlackColor{ 
    red = 0.0; 
    green = 0.0; 
    blue = 0.0; 
} 
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 

    UITouch *touch; 

    NSEnumerator *counter = [touches objectEnumerator]; 
    while ((touch = (UITouch *)[counter nextObject])) { 
     switch (strokeAlpha2) { 
      case 1: 
       strokeAlpha = .1; 
       break; 
      case 2: 
       strokeAlpha = .2; 
       break; 
      case 3: 
       strokeAlpha = .3; 
       break; 
      case 4: 
       strokeAlpha = .4; 
       break; 
      case 5: 
       strokeAlpha = .5; 
       break; 
      case 6: 
       strokeAlpha = .6; 
       break; 
      case 7: 
       strokeAlpha = .7; 
       break; 
      case 8: 
       strokeAlpha = .8; 
       break; 
      case 9: 
       strokeAlpha = .9; 
       break; 
      case 10: 
       strokeAlpha = 1; 
       break; 
      default: 
       strokeAlpha = 1; 
       break; 
     } 

     self.strokeColor = [UIColor colorWithRed:red green:green blue:blue alpha:strokeAlpha]; 
     NSValue *touchPos = [NSValue valueWithCGPoint:[touch locationInView:self]]; 
     UIColor *color = [UIColor colorWithCGColor:strokeColor.CGColor]; 
     NSNumber *size = [NSNumber numberWithInt:strokeSize]; 
     NSMutableArray *stroke = [NSMutableArray arrayWithObjects: touch, size, color, touchPos, nil]; 
     [strokeArray addObject:stroke]; 
    } 
} 
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 

    UITouch *touch; 

    NSEnumerator *counter = [touches objectEnumerator]; 

    while ((touch = (UITouch *)[counter nextObject])) { 
     NSMutableArray *stroke; 
     for (stroke in strokeArray) { 
      if ([stroke objectAtIndex:0] == touch) { 
       [stroke addObject:[NSValue valueWithCGPoint:[touch locationInView:self]]]; 
      } 
      [self setNeedsDisplay]; 
     } 
    } 
} 



@end 

Answer 1

而不是使用CGContextAddLines()你應該使用CGContextAddCurveToPoint()貝塞爾曲線路徑。你需要用4點來構造它，所以你可能需要使用前面的和後面的2點，或者沿着這些線。