swift : Anchor SKSpriteNode

Question

我正在尝试复制音乐应用程序中流行的外观，您会看到一系列条形音箱随着音乐的节拍上下移动。我的问题是，我无法让条形音箱将其底部边框固定在屏幕底部并仅调整其高度。我的缩放算法是正确的并且效果很好，但我的问题是我的条形音箱在屏幕上上下移动，而不是粘在底部并仅调整其高度。这是我所拥有的。

func setUpSoundBars(){
    //I have this as a skspritenode because i need to adjust its Z position
    //"SoundBars" is just a red background image sized to the iphone6 plus
    soundbar = SKSpriteNode(imageNamed: "SoundBars")
    self.addChild(soundbar!)
}

//updateBeatParticle() is being called constantly by CADisplayLink
func updateBeatParticle(){

//Algorithm to get scale according to music
//DO NOT WORRY ABOUT Below
//-------------------------------------------------------
    if let audio = backgroundMusic?.backgroundAudio {

        var scale: CGFloat = 0

        if (audio.playing) { // Only do this if the audio is actually playing
            audio.updateMeters() // Tell the audio player to update and fetch the latest readings

            let channels = audio.numberOfChannels

            var power: Float = 0
            //Loop over each channel and add its average power
            for i in 0..<channels {
                power += audio.averagePowerForChannel(i)
            }
            power /= Float(channels) // This will give the average power across all the channels in decibels

            // Convert power in decibels to a more appropriate percentage representation
            scale = CGFloat(getIntensityFromPower(power))
            scale -= 0.6
            if scale < 0 {
                scale = 0
            }
            scale *= 2
        }
//----------------------------------------------------
    //DO NOT WORRY ABOUT ABOVE    

        //This is where sound bar is adjusted to the and its size is changed 
        //to match the beat of the music
        //WHERE I NEED HELP!
        if let view = self.view {
            let height: CGFloat = view.frame.height * scale

            soundbar?.position = CGPoint(x: 0, y: view.frame.height - height)
            soundbar?.size = CGSize(width: (self.view?.bounds.width)! * 0.20, height: height)
        }

    }
}

Answer 1

解决此问题的另一种方法是修改 SKSpriteNode 的 yScale。

例如，如果您拍摄竖条图像并设置:

soundbar.anchorPoint = CGPoint(x: 0, y: 0)

您可以简单地缩放 y 轴来修改高度，并且它不会移动位置。

soundbar.yScale = 2

就您而言，我确信这可以很好地与您现有的规模计算联系起来。