How to change x and y of CGRect?

Question

I draw a rectangle. When I touch screen, I can change width and height. By default I make x = 50, y = self.view.frame.height/2. I need to stretch rectangle relative to x and y. How can I change x and y?

var scanRectangleRect = CGRect.zero
var scanRectangle: UIView = UIView()


func drawLine() {
    self.view.addSubview(scanRectangle)
    scanRectangle.backgroundColor = UIColor.gray
    scanRectangleRect = CGRect(x: 50, y: self.view.frame.height/2, width: 400, height: 150)

    scanRectangle.frame  = scanRectangleRect
    scanRectangle.center = CGPoint(x: scanRectangle.center.x, y: self.view.frame.height/2)
    scanRectangle.isHidden = false
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    scanRectangle.frame.size.height += 10
    scanRectangle.frame.size.width += 10
}

Sulthan · Answer 1 · 2017-09-04T18:31:00.997

3

scanRectangle.frame.origin.x += 10
scanRectangle.frame.origin.y += 10

See https://developer.apple.com/documentation/coregraphics/cgrect/1454354-origin

If you want to increase the rect but keeping it centered on the same position:

let delta = 10

scanRectangle.frame.origin.x -= delta / 2
scanRectangle.frame.origin.y -= delta / 2
scanRectangle.frame.size.width += delta
scanRectangle.frame.size.height += delta

or

scanRectangle.frame = scanRectangle.frame.insetBy(dx: -10, dy: -10)

edited Sep 04 '17 at 18:31

answered Sep 04 '17 at 18:09

Sulthan

128,090
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218
270

Rectangle is moving but I need to stretch it. – kvv Sep 04 '17 at 18:16
@Kazak Did you read https://developer.apple.com/documentation/coregraphics/cgrect as sulthan linked? – Sep 04 '17 at 18:30
@Sneak Yes, I did. – kvv Sep 04 '17 at 18:42

score 3 · Accepted Answer · answered Sep 04 '17 at 18:29

let distance: CGFloat = 10
scanRectangle.frame = CGRect(x: scanRectangle.frame.origin.x + distance, 
                             y: scanRectangle.frame.origin.y + distance, 
                         width: scanRectangle.frame.size.width - distance, 
                        height: scanRectangle.frame.size.height - distance)

I think what you mean is to scale the rectangle upon some base point.

score 0 · Answer 3 · answered Sep 04 '17 at 18:11

0

scanRectangle.frame.origin.x += 10;
scanRectangle.frame.origin.y += 10;

is that what you are asking for?

answered Sep 04 '17 at 18:11

wheeler

647
8
17

I need to stretch rectangle relative to x and y – kvv Sep 04 '17 at 18:18

How to change x and y of CGRect?

3 Answers3