優化，以CAShapeLayer

Question

可能的替代方案，我需要在屏幕上繪製多行（在50-75的範圍內），目前使用這下面的函數工作正常。這些畫線，下面的代碼的40-50後，該應用程序明顯減慢在我的iPhone 4要優化我試圖消除線陰影它幫助，但仍應用程序沒有運行，因爲我想那樣順利。我需要優化下面的代碼，我的第一個想法是與巴紐線圖像更換cashapelayers。但是，新的方法應該支持線旋轉，具有相同的寬度不同長度的線，並繪製動畫（似乎很多關於我做cgaffinetransforms）。任何想法可以幫助我？

+ (CAShapeLayer *) drawLineOnView:(UIView *) view BetweenPoint1:(CGPoint) point1 Point2:(CGPoint) point2 lineWidth:(CGFloat)lineWidth lineColor:(UIColor *) color Animated:(BOOL) animed 
{ 
    CAShapeLayer *lineShape = [CAShapeLayer layer]; 
    CGMutablePathRef linePath = nil; 
    linePath = CGPathCreateMutable(); 

    //lineShape.opacity = 0.6; 
    lineShape.lineWidth = lineWidth; 
    lineShape.lineCap = kCALineCapRound; 

    if(color==nil) color = [UIColor orangeColor]; //Default value 
    lineShape.shadowColor = [color CGColor]; 
    lineShape.shadowOpacity = 1.0; 
    lineShape.shadowRadius = 5.0; 
    lineShape.strokeColor = [color CGColor]; 

    CGPathMoveToPoint(linePath, NULL, point1.x, point1.y); 
    CGPathAddLineToPoint(linePath, NULL, point2.x, point2.y); 

    if(animed) 
    { 
     CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"]; 
     pathAnimation.duration = 1.0; 
     pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f]; 
     pathAnimation.toValue = [NSNumber numberWithFloat:1.0f]; 
     [lineShape addAnimation:pathAnimation forKey:@"strokeEndAnimation"]; 
    } 

    lineShape.path = linePath; 
    CGPathRelease(linePath); 
    [view.layer addSublayer:lineShape]; 

    return lineShape; 
} 

部分解決（優化永不結束）

我打破了我的線繪圖功能分爲2個互補部分並繪製多條線到所述一個形狀層，而不是創建新的層各一次。如果不是很好，它會更好。以下是更新後的代碼：

+ (CAShapeLayer *) createNewShapeLayerForDrawingLinesOnView:(UIView *) view lineWidth:(CGFloat)lineWidth lineColor:(UIColor *) color 
{ 
    CAShapeLayer *lineShape = [CAShapeLayer layer]; 

    //lineShape.opacity = 0.6; 
    lineShape.lineWidth = lineWidth; 
    lineShape.lineCap = kCALineCapRound; 

    if(color==nil) color = [UIColor orangeColor]; //Default value 
    lineShape.shadowColor = [color CGColor]; 
    lineShape.shadowOpacity = 1.0; 
    lineShape.shadowRadius = 5.0; 
    lineShape.strokeColor = [color CGColor]; 

    [view.layer addSublayer:lineShape]; 
    return lineShape; 
} 

+ (void) addNewLineToShapeLayer:(CAShapeLayer *) shapeLayer BetweenPoint1:(CGPoint) point1 Point2:(CGPoint) point2 
{ 
    CGMutablePathRef combinedPath = CGPathCreateMutableCopy(shapeLayer.path); 

    CGMutablePathRef linePath = CGPathCreateMutable(); 

    CGPathMoveToPoint(linePath, NULL, point1.x, point1.y); 
    CGPathAddLineToPoint(linePath, NULL, point2.x, point2.y); 

    //No paths drawn before 
    if(combinedPath == NULL) 
    { 
     combinedPath = linePath; 
    } 
    else 
    { 
     CGPathAddPath(combinedPath, NULL, linePath); 
    } 

    shapeLayer.path = combinedPath; 
    CGPathRelease(linePath); 
} 

Answer 1

雖然我明白要創建多個圖層，這將是更有效的將所有線畫成一個，並從那裏管理行的列表的動畫和旋轉。您可以在形狀層像（標有無漏碼「......」）合併路徑做到這一點：

CGMutablePathRef combinedPath = CGPathCreateMutableCopy(path.CGPath); 
for(...) 
    CGPathAddPath(combinedPath, NULL, [self makeNewPathFrom:...].CGPath); 
myLayer.path = combinedPath; 

再快，你可以畫線的名單，直接到graphics context of a CALayer。這個例子的視圖的drawRect:方法是未經測試，但應該給你一個想法：

CGContextRef context = UIGraphicsGetCurrentContext(); 

CGContextSetLineWidth(context, lineWidth); 
CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0); //red 

for(MyLine *line in lines) 
{ 
    CGContextMoveToPoint(context, point1.x, point1.y); 
    CGContextAddLineToPoint(context, point2.x, point2.y); 
} 

如果您需要進一步的優化，你應該考慮的OpenGL。

Answer 2

你絕對不希望 75層，每個都有自己的線路。你確定你不能在單一層中繪製一條更復雜的路徑嗎？