Get screen coordinates on iPhone

How do iPhone screen coordinates work? I need element coordinates to use swipe within Appium::TouchAction in my automation test for native application.
Also is there any analogue in iOS to Pointer location in Android?

@quo_vadis

MobileElement element = driver.findElement(MobileBy.xpath("//android.widget.TextView[@text = ‘Top Charts’]"));
Point point = topCharts.getLocation();
int startY = point.y;
int endY = point.y;

int startX = (int) ((driver.manage().window().getSize().getWidth()) * 0.80);
int endX = (int) ((driver.manage().window().getSize().getWidth()) * 0.20);

Thanks, but I am using Ruby

Oh my goodness …sry