iOS：如何讓繪圖板像繪製一些東西？

Question

我正在研究所需時間以及如何爲小學生製作繪圖板。所以它會類似畫一些東西，但只能用畫板。孩子們將能夠改變不同的顏色來繪製它。那麼我應該看哪些框架？核心圖形？還有別的嗎？任何人都可以指向一個教程或指導？提前致謝。

Answer 1

試試這個代碼....

#pragma mark touches stuff... 

    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 
     UITouch *touch = [touches anyObject]; 
     lastTouch = [touch locationInView:imageView]; 

     } 

    - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
     UITouch *touch = [touches anyObject]; 
     currentTouch = [touch locationInView:imageView]; 

     CGColorRef strokeColor = [UIColor brownColor].CGColor; 
     UIGraphicsBeginImageContext(imageView.frame.size); 
     CGContextRef context = UIGraphicsGetCurrentContext(); 
     [imageView.image drawInRect:CGRectMake(0, 0, imageView.frame.size.width, imageView.frame.size.height)]; 
     CGContextSetLineCap(context, kCGLineCapRound); 
     CGContextSetLineWidth(context,10); // 10 is the pen size 

    CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), [UIColor brownColor].CGColor); // this will be colour u need to change as required 
       CGContextSetBlendMode(context,kCGBlendModeDarken); 



     CGContextBeginPath(context); 
     CGContextMoveToPoint(context, lastTouch.x, lastTouch.y); 
     CGContextAddLineToPoint(context, currentTouch.x, currentTouch.y); 
     CGContextStrokePath(context); 
     imageView.image = UIGraphicsGetImageFromCurrentImageContext(); 
     UIGraphicsEndImageContext(); 

     lastTouch = [touch locationInView:imageView]; 
    } 

    - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event 
    { 
     UITouch *touch = [touches anyObject]; 
     lastTouch = [touch locationInView:imageView]; 
    } 

我希望這將幫助你....