iOS Bezier montre le chemin avec zig-zags

Question

en essayant d'apprendre quelques graphiques Quartz et en essayant de faire un dessin en douceur. Je suis en train de combiner 2 tutoriels

http://mobile.tutsplus.com/tutorials/iphone/ios-sdk_freehand-drawing/

http://www.raywenderlich.com/18840/how-to-make-a-simple-drawing-app-with-uikit

Et cela est jusqu'à présent mon code

#import "ViewController.h" 

@interface ViewController() 
{ 
    UIBezierPath *path; 
    CGPoint pts[5]; 
    uint ctr; 
} 
@end 

@implementation ViewController 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view, typically from a nib. 


    [self setupData]; 

} 

- (void)didReceiveMemoryWarning 
{ 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 
} 



-(void) setupData 
{ 
    [self.mainImage setMultipleTouchEnabled:NO]; 
    [self.tempImage setMultipleTouchEnabled:NO]; 
    path = [UIBezierPath bezierPath]; 
    [path setLineWidth:2.0]; 

} 


- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    ctr = 0; 
    UITouch *touch = [touches anyObject]; 
    pts[0] = [touch locationInView:self.tempImage]; 
} 


- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    UITouch *touch = [touches anyObject]; 
    CGPoint p = [touch locationInView:self.tempImage]; 
    ctr++; 
    pts[ctr] = p; 
    if (ctr == 4) 
    { 
     pts[3] = CGPointMake((pts[2].x + pts[4].x)/2.0, (pts[2].y + pts[4].y)/2.0); // move the endpoint to the middle of the line joining the second control point of the first Bezier segment and the first control point of the second Bezier segment 
     [path moveToPoint:pts[0]]; 
     [path addCurveToPoint:pts[3] controlPoint1:pts[1] controlPoint2:pts[2]]; // add a cubic Bezier from pt[0] to pt[3], with control points pt[1] and pt[2] 

     [self draw]; 

     [self.mainImage setNeedsDisplay]; 
     [self.tempImage setNeedsDisplay]; 
     // replace points and get ready to handle the next segment 
     pts[0] = pts[3]; 
     pts[1] = pts[4]; 
     ctr = 1; 
    } 
} 



- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
{ 

    [path removeAllPoints]; 
    ctr = 0; 


    UIGraphicsBeginImageContext(self.tempImage.frame.size); 
    [self.mainImage.image drawInRect:CGRectMake(0, 0, self.tempImage.frame.size.width, self.tempImage.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0]; 
    [self.tempImage.image drawInRect:CGRectMake(0, 0, self.tempImage.frame.size.width, self.tempImage.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0]; 
    self.mainImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
    self.tempImage.image = nil; 

    [self.tempImage setNeedsDisplay]; 
    [self.mainImage setNeedsDisplay]; 

    UIGraphicsEndImageContext(); 



} 

- (void)draw 
{ 
    UIGraphicsBeginImageContext(self.tempImage.frame.size); 
    [self.tempImage.image drawInRect:CGRectMake(0, 0, self.tempImage.frame.size.width, self.tempImage.frame.size.height)]; 

    pts[3] = CGPointMake((pts[2].x + pts[4].x)/2.0, (pts[2].y + pts[4].y)/2.0); // move the endpoint to the middle of the line joining the second control point of the first Bezier segment and the first control point of the second Bezier segment 
    [path moveToPoint:pts[0]]; 
    [path addCurveToPoint:pts[3] controlPoint1:pts[1] controlPoint2:pts[2]]; // add a cubic Bezier from pt[0] to pt[3], with control points pt[1] and pt[2] 
    [path stroke]; 

    CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal); 

    // CGContextStrokePath(UIGraphicsGetCurrentContext()); 
    self.tempImage.image = UIGraphicsGetImageFromCurrentImageContext(); 
    [self.tempImage setAlpha:1.0]; 


    UIGraphicsEndImageContext(); 

} 

Les coins avaient l'air beaucoup mieux, mais les lignes lui-même ressemble à des zigzags. J'apprécierais si vous pouviez me signaler mon erreur. Merci

Answer 1

Je pense que l'image que vous dessinez est de taille non rétinienne car self.tempImage.frame.size renvoie la taille de l'image en points et non en pixels. Ensuite, lorsque vous dessinez l'image à l'écran, elle est agrandie et pixélisée. Si vous faites correspondre l'image tampon à la taille de pixel du composant à l'écran, cela devrait fonctionner.