/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Demonstrates Quartz line drawing facilities including stroke width, line cap and line join.

 */

import UIKit

class QuartzCapJointWidthView: QuartzView {

    var cap: CGLineCap = .butt {

        didSet(prevCapValue) {

            if prevCapValue != cap {

                setNeedsDisplay()

            }

        }

    }

    var join: CGLineJoin = .miter {

        didSet(prevJoinValue) {

            if prevJoinValue != join {

                setNeedsDisplay()

            }

        }

    }

    var width: CGFloat = 1.0 {

        didSet(prevLineWidth) {

            if prevLineWidth != width {

                setNeedsDisplay()

            }

        }

    }

    override func drawInContext(_ context: CGContext) {

        let drawnBounds = CGRect(x:0.0, y:0.0, width:290.0, height:80.0)

        // Drawing lines with a white stroke color

        context.setStrokeColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)

        // Preserve the current drawing state

        context.savingGState {

            // center the drawing

            centerDrawing(inContext: context, drawingExtent: drawnBounds)

            // Setup the horizontal line to demostrate caps

            context.move(to: CGPoint(x: 40.0, y: 30.0))

            context.addLine(to: CGPoint(x: 280.0, y: 30.0))

            // Set the line width & cap for the cap demo

            context.setLineWidth(width)

            context.setLineCap(cap)

            context.strokePath()

        }

        context.savingGState {

            // center the drawing

            centerDrawing(inContext: context, drawingExtent: drawnBounds)

            // Setup the angled line to demonstrate joins

            context.move(to: CGPoint(x: 40.0, y: 190.0))

            context.addLine(to: CGPoint(x: 160.0, y: 70.0))

            context.addLine(to: CGPoint(x: 280.0, y: 190.0))

            // Set the line width, join, & cap for the cap/join demo

            context.setLineWidth(width)

            context.setLineJoin(join)

            context.setLineCap(cap)

            context.strokePath()

        }

        // center the drawing

        centerDrawing(inContext: context, drawingExtent: drawnBounds)

        // If the stroke width is large enough, display the path that generated these lines

        if width >= 4.0 {  // arbitrarily only show when the line is at least twice as wide as our target stroke

            context.setStrokeColor(red: 1.0, green: 0.0, blue: 0.0, alpha: 1.0)

            context.move(to: CGPoint(x: 40.0, y: 30.0))

            context.addLine(to: CGPoint(x: 280.0, y: 30.0))

            context.move(to: CGPoint(x: 40.0, y: 190.0))

            context.addLine(to: CGPoint(x: 160.0, y: 70.0))

            context.addLine(to: CGPoint(x: 280.0, y: 190.0))

            context.setLineWidth(2.0)

            context.strokePath()

        }

    }

}