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/*
ControlKnob.swift
Nikhil Singh, Dr. Richard Boulanger
Adapted from the Csound iOS Examples by Steven Yi and Victor Lazzarini
This file is part of Csound iOS SwiftExamples.
The Csound for iOS Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA
*/
import UIKit
class ControlKnob: UIControl {
// Use a computed property so we have a custom setter
fileprivate var _value: Float32 = 1.0
var value: Float32 {
set {
self._value = newValue
angle = CGFloat(_value/maximumValue) * 270.0
}
get { return self._value }
}
// Initial default, min, and max values
var defaultValue: Float32 = 1.0
var minimumValue: Float32 = 0.5
var maximumValue: Float32 = 2.0
fileprivate var channelValue: Float = 0
fileprivate var channelPtr: UnsafeMutablePointer<Float>?
private var angle: CGFloat = 0
private var lastTouchPoint: CGPoint = CGPoint(x: 0, y: 0)
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = .clear
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
backgroundColor = .clear
}
// MARK: UIControl overrides
override func beginTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {
return tracking(touch)
}
override func continueTracking(_ touch: UITouch, with event: UIEvent?) -> Bool {
return tracking(touch)
}
private func tracking(_ touch: UITouch) -> Bool {
let touchPoint = touch.location(in: superview)
if touchPoint.y < lastTouchPoint.y {
angle += angle < 270 ? 5 : 0
} else {
angle -= angle > 0 ? 5 : 0
}
_value = minimumValue + Float32(angle/270.0) * (maximumValue - minimumValue)
lastTouchPoint = touchPoint
setNeedsDisplay()
sendActions(for: .valueChanged)
return true
}
override func cancelTracking(with event: UIEvent?) { }
// MARK: Drawing
override func draw(_ rect: CGRect) {
if angle >= 360 {
angle -= 360
}
transform = CGAffineTransform(rotationAngle: (angle * .pi)/180.0) // Degrees to radians
let context = UIGraphicsGetCurrentContext()
let colorSpace = CGColorSpaceCreateDeviceRGB()
context?.translateBy(x: 0, y: rect.size.height)
context?.scaleBy(x: 1.0, y: -1.0) // Invert vertical (so 0 is at the bottom)
// Draw knob
let redComponents: [CGFloat] = [1, 0.1, 0, 1]
let redColor = CGColor(colorSpace: colorSpace, components: redComponents)
context?.setFillColor(redColor!)
context?.addEllipse(in: rect)
context?.fillEllipse(in: rect)
// Draw position indicator
context?.move(to: CGPoint(x: rect.size.width/4.0, y: rect.size.height/4.0))
context?.addLine(to: CGPoint(x: rect.size.width/2.0, y: rect.size.height/2.0))
let blackComponents: [CGFloat] = [0, 0, 0, 1]
let blackColor = CGColor(colorSpace: colorSpace, components: blackComponents)
context?.setStrokeColor(blackColor!)
context?.strokePath()
}
}
// MARK: Csound Binding
extension ControlKnob: CsoundBinding {
func setup(_ csoundObj: CsoundObj!) {
channelPtr = csoundObj.getInputChannelPtr("pitch", channelType: CSOUND_CONTROL_CHANNEL)
channelValue = _value
addTarget(self, action: #selector(updateChannelValue(_:)), for: .valueChanged)
}
@objc func updateChannelValue(_ sender: ControlKnob) {
channelValue = sender._value
}
func updateValuesToCsound() {
channelPtr?.pointee = channelValue
}
}
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