ios - 这个效果叫什么？

Question

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Answer 1

问:

Is this an existing effect that I can use in Xcode?

答:没有

然而，一种方法是从“轻弹”手势创建一个CGVector。然后将该矢量作为插入力应用到您正在“轻弹”的对象上。以下是与 SpriteKit 一起使用的，但是其他框架可以采用从“flick”手势获取矢量的原则。

#define FLICK_SCALAR 0.5 // tweak this to alter sensitivity

我们需要一个辅助结构 -

typedef struct TouchData {
CGPoint point;
NSTimeInterval time;
} TouchData;

还有一个属性——

@property TouchData touchOriginData;

// Touch Handling
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    // store the start data
    for (UITouch *touch in touches) {
        _touchOriginData.point = [touch locationInNode:self];
        _touchOriginData.time = [touch timestamp];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    // store the end data
    TouchData touchEndData;
    for (UITouch *touch in touches) {
        touchEndData.point = [touch locationInNode:self];
        touchEndData.time = touch.timestamp;
    }
    // calculate the impulse vector from TouchData structs
    NSTimeInterval timeTaken = touchEndData.time - _touchOriginData.time;
    CGFloat vector_x = (touchEndData.point.x - _touchOriginData.point.x) / timeTaken * FLICK_SCALAR;
    CGFloat vector_y = (touchEndData.point.y - _touchOriginData.point.y) / timeTaken * FLICK_SCALAR;
    CGVector impulseVector = CGVectorMake(vector_x, vector_y);
    // fire projectile node
    [self someMethodThatFiresWithVector:impulseVector];
}