CODEWITHSUNDEEP
iosswiftuiimageviewuiimage
David Seek
David Seek

Reputation: 17132

Set alpha for UIView/Image

I have a table view with a label array and a UIView, with a UIImage array

var menuItems = ["News", "Programm"]
var currentItem = "News"

var menuImages: [UIImage] = [UIImage(named: "news.png")!, UIImage(named: "programm_100.png")!]

The text and its color of the label is set by:

cell.titleLabel.text = menuItems[indexPath.row]
cell.titleLabel.textColor = (menuItems[indexPath.row] == currentItem) ? UIColor.whiteColor() : UIColor.grayColor()

Now I want the Images to appear a bit grey, too. I've tried to set it with cell.titlePicture.alpha.

How can I set UIView's alpha denericly depending on the current item?

menu

Upvotes: 2

Views: 2930

Answers (2)

Marcos Reboucas
Marcos Reboucas

Reputation: 3489

You can use an Extension. Just create a new Swift file and implement this:

import UIKit

extension UIImage{


    func alpha(value:CGFloat)->UIImage
    {
        UIGraphicsBeginImageContextWithOptions(self.size, false, 0.0)

        let ctx = UIGraphicsGetCurrentContext();
        let area = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height);

        CGContextScaleCTM(ctx, 1, -1);
        CGContextTranslateCTM(ctx, 0, -area.size.height);
        CGContextSetBlendMode(ctx, CGBlendMode.Normal);
        CGContextSetAlpha(ctx, value);
        CGContextDrawImage(ctx, area, self.CGImage);

        let newImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        return newImage;
    }
}

Then apply it when setting your image:

UIImage(named: "news.png").alpha(0.5)

Upvotes: 3

JAL
JAL

Reputation: 42449

Assuming titlePicture is a UIImageView, you can edit the alpha of it directly:

cell.titlePicture.alpha = (menuItems[indexPath.row] == currentItem) ? 0.6 : 1.0

Tweak the alpha values to your liking. Example output:

alpha = 1.0:

img1

alpha = 0.6:

img2

Upvotes: 3

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