ios - 如何保存图像和其上绘制的线条的组合？ swift

Question

我已经保存了图像，但是每当我在图像上绘制线条并尝试保存图像时，图像不会与我在其上绘制的线条一起保存。如何保存画有线条的图像？

这是当前绘制线条的代码:

import UIKit
import CoreData

class DrawClass: UIView {
    /*
    // Only override drawRect: if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func drawRect(rect: CGRect) {
        // Drawing code
    }
    */
    ///Creating an array of type Line which accepts a Line object. It is an empty array.
    var lines:[Line] = []
    var lastPoint: CGPoint!

    required init(coder aDecoder: NSCoder)
    {
        super.init(coder: aDecoder)
        self.backgroundColor = UIColor.whiteColor()
        self.layer.zPosition = 1
    }

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent){
        if let touch = touches.first as? UITouch {
            lastPoint =  touch.locationInView(self)
        }
    }

    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent){
        if let touch = touches.first as? UITouch {
            var newPoint = touch.locationInView(self)
            lines.append(Line(start: lastPoint, end: newPoint))
            lastPoint = newPoint
        }
        self.setNeedsDisplay()
    }

    override func drawRect(rect: CGRect) {
        var context = UIGraphicsGetCurrentContext()
        CGContextBeginPath(context)
        for line in lines
        {
            CGContextMoveToPoint(context, line.start.x, line.start.y)
            CGContextAddLineToPoint(context, line.end.x, line.end.y)
        }

        var storage: Float = ViewController.simple.storage1
        var storage2: Float = ViewController.simple.storage2
        var storage3: Float = ViewController.simple.storage3

        CGContextSetRGBStrokeColor(context, CGFloat(storage), CGFloat(storage2), CGFloat(storage3), 1)

        CGContextSetLineWidth(context, 5)
        CGContextStrokePath(context)
    }
}

更新抱歉，我忘记添加保存方法了。顺便说一句，“地球”是我放置在 Storyboard中的图像的名称，它是:

@IBAction func saveImage(sender: UIButton) {


    UIImageWriteToSavedPhotosAlbum(earth.image!, self, "image:didFinishSavingWithError:contextInfo:", nil)

}

func image(image: UIImage, didFinishSavingWithError error: NSError?, contextInfo:UnsafePointer<Void>) {
    if error == nil {
        let ac = UIAlertController(title: "Saved!", message: "Your altered image has been saved to your photos.", preferredStyle: .Alert)
        ac.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
        presentViewController(ac, animated: true, completion: nil)
    } else {
        let ac = UIAlertController(title: "Save error", message: error?.localizedDescription, preferredStyle: .Alert)
        ac.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
        presentViewController(ac, animated: true, completion: nil)
    }
}

Answer 1

更改当前的 saveImage 方法实现。

@IBAction func saveImage(sender: UIButton) {


    UIImageWriteToSavedPhotosAlbum(earth.image!, self, "image:didFinishSavingWithError:contextInfo:", nil)

}

这一切都是为了显式保存 UIImageView 实例 earth 的图像。

要将它们与线条一起保存，您需要从地球 View 创建一个新图像，如下所示:

     @IBAction func saveImage(sender: UIButton) {

            UIGraphicsBeginImageContextWithOptions(earth.frame.size, earth.opaque, 0.0)
            earth.layer.renderInContext(UIGraphicsGetCurrentContext()!)
            let imageWithLines = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()

            // NOW you have the image to save
            UIImageWriteToSavedPhotosAlbum(imageWithLines, self, Selector("saveComplete"), nil)
     }

     func saveComplete () {
         NSLog("Complete!");
     }