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iPhone Quartz2D渲染展开圆

quartz-2d graphics iphone

davbryn · 技术社区 · 14 年前

我很好奇使用Quarts2D实现以下功能的“正确”方法:

我想有一个观点,并能够添加一个圆在任何坐标。我一加上圆,它就应该以预定的速率扩展;我还想重复这个过程,如果这些扩展的圆有一个数字。

想想导弹指挥部:

Yellow spots keep expanding

有一个代表“成长圈”的类有一个向量/数组来保存指向我创建的所有“成长圆”的指针。

所有的圆直径将增加每个记号,并在我的renderloop我会迭代列表和绘制适当的圆到我的缓冲区。

然而,这似乎与我在以前的iPhone开发中通常使用的视图不太吻合。

所以我想这是一种开放式的,但有没有一个'正确'的方式像这样的事情?

UIView 对于“圆”对象,并重写 drawRect ? 我想我必须通过创建一个视图并将其添加到主视图来添加每个圆?

CAShapeLayer 类,尽管我猜这可能与实现UIView子类化技术大致相同。

1 回复 | 直到 8 年前

Art Gillespie 14 年前

这里有一个方法。将以下代码添加到UIViewController子类中,您将得到一个圆形,该圆形在您触摸的任何地方都会增长,然后消失:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [self addGrowingCircleAtPoint:[[touches anyObject] locationInView:self.view]];
}

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
    if (flag && [[anim valueForKey:@"name"] isEqual:@"grow"]) {
        // when the grow animation is complete, we fade the layer
        CALayer* lyr = [anim valueForKey:@"layer"];
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation.fromValue = [lyr valueForKey:@"opacity"];
        animation.toValue = [NSNumber numberWithFloat:0.f];
        animation.duration = .5f;
        animation.delegate = self;
        lyr.opacity = 0.f;  
        [animation setValue:@"fade" forKey:@"name"];
        [animation setValue:lyr forKey:@"layer"];
        [lyr addAnimation:animation forKey:@"opacity"];
    } else if (flag && [[anim valueForKey:@"name"] isEqual:@"fade"]) {
        // when the fade animation is complete, we remove the layer
        CALayer* lyr = [anim valueForKey:@"layer"];
        [lyr removeFromSuperlayer];
        [lyr release];
    }

}

- (void)addGrowingCircleAtPoint:(CGPoint)point {
    // create a circle path
    CGMutablePathRef circlePath = CGPathCreateMutable();
    CGPathAddArc(circlePath, NULL, 0.f, 0.f, 20.f, 0.f, (float)2.f*M_PI, true);

    // create a shape layer
    CAShapeLayer* lyr = [[CAShapeLayer alloc] init];
    lyr.path = circlePath;

    // don't leak, please
    CGPathRelease(circlePath);
    lyr.delegate = self;

    // set up the attributes of the shape layer and add it to our view's layer
    lyr.fillColor = [[UIColor redColor] CGColor];
    lyr.position = point;
    lyr.anchorPoint = CGPointMake(.5f, .5f);
    [self.view.layer addSublayer:lyr];

    // set up the growing animation
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform"];
    animation.fromValue = [lyr valueForKey:@"transform"];
    // this will actually grow the circle into an oval
    CATransform3D t = CATransform3DMakeScale(6.f, 4.f, 1.f);
    animation.toValue = [NSValue valueWithCATransform3D:t];
    animation.duration = 2.f;
    animation.delegate = self;
    lyr.transform = t;  
    [animation setValue:@"grow" forKey:@"name"];
    [animation setValue:lyr forKey:@"layer"];
    [lyr addAnimation:animation forKey:@"transform"];
}