Add property to adjust width ratio in window (#165)

* Add `maxWidthRatio`

Demo/RootViewController.swift

@@ -41,6 +41,7 @@ final class RootViewController: UIViewController {
     appearance.textInsets = UIEdgeInsets(top: 15, left: 20, bottom: 15, right: 20)
     appearance.bottomOffsetPortrait = 100
     appearance.cornerRadius = 20
+    appearance.maxWidthRatio = 0.7
   }
 
   func configureAccessibility() {

DemoObjC/RootViewController.m

@@ -52,6 +52,7 @@
     appearance.textInsets = UIEdgeInsetsMake(15, 20, 15, 20);
     appearance.bottomOffsetPortrait = 100;
     appearance.cornerRadius = 20;
+    appearance.maxWidthRatio = 0.7;
 }
 
 - (void)configureAccessibility {

Sources/ToastView.swift

@@ -72,6 +72,9 @@ open class ToastView: UIView {
     }
   }()
 
+  /// The width ratio of toast view in window, specified as a value from 0.0 to 1.0.
+  /// Default value: 0.875
+  @objc open dynamic var maxWidthRatio: CGFloat = (280.0 / 320.0)
 
   // MARK: UI
 
@@ -124,7 +127,7 @@ open class ToastView: UIView {
     super.layoutSubviews()
     let containerSize = ToastWindow.shared.frame.size
     let constraintSize = CGSize(
-      width: containerSize.width * (280.0 / 320.0) - self.textInsets.left - self.textInsets.right,
+      width: containerSize.width * maxWidthRatio - self.textInsets.left - self.textInsets.right,
       height: CGFloat.greatestFiniteMagnitude
     )
     let textLabelSize = self.textLabel.sizeThatFits(constraintSize)