An implementation of Cassowary contraint based system. It contains a Windows WPF control called AutoLayoutPanel that allows you to add controls and define their layout in y=m*x + c model. Where y and x are either the Left, Center, Right, Top, Middle, Bottom, Width and Height property of the control listed previously.

• Ability to express nearly any layout by describing layout in terms of relationships with math.
• Support for RTL, LTR auto layouts for localization and cross-lingual interfaces.
• Incremental solving that's signficantly faster than resolving on each render loop.

AutoLayoutPanel panel = new AutoLayoutPanel();
Window.Content = panel;
Button b = new Button();
b.Content = "Button Title";
panel.Children.Add(b);

// Assign the left (X) value to the left panel.
// panel.AddLayoutConstraint(b,"Left",panel,"Left",0,0);

// Vertically and horizontally center:
// panel.AddLayoutConstraint(button, "Middle", "=", panel, "Middle", 1, 0);
// panel.AddLayoutConstraint(button, "Center", "=", panel, "Center", 1, 0);

// Set the width by defining where the left and right values of the button
// should be set.  The button will always have 30 pixel margin on left and right sides.
// panel.AddLayoutConstraint(button, "Left", "=", panel, "Left", 0, 30);
// panel.AddLayoutConstraint(button, "Right", "=", panel, "Right", 0, -30);

Dead simple, AutoLayoutPanel inherits from System.Windows.Controls.Panel and adds two new methods:

int AutoLayoutPanel.AddLayoutConstraint(UIElement firstProperty, String firstPropertyName, String equality, UIElement secondProperty, String secondPropertyName, double multiplier, double constant);

Equality can be "=", "<", or ">"

The returned integer is an ID that can be passed back into RemoveLayoutConstraint to remove the constraint.

void AutoLayoutPanel.RemoveLayoutConstraint(int constraintId);