[Chapter 6] 6.3 Insets

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| Chapter 6 Containers |

## 6.3 Insets

The `Insets` class provides a way to encapsulate the layout margins of the four different sides of a container. The class helps in laying out containers. The `Container` can retrieve their values through the `getInsets()` method, then analyze the settings to position components. The different inset values are measured in pixels. The space reserved by insets can still be used for drawing directly within `paint()`. Also, if the `LayoutManager` associated with the container does not look at the insets, the request will be completely ignored.

### Insets Methods

Variables

There are four variables for insets, one for each border.

public int top

  This variable contains the border width in pixels for the top of a container.

public int bottom

  This variable contains the border width in pixels for the bottom of a container.

public int left

  This variable contains the border width in pixels for the left edge of a container.

public int right

  This variable contains the border width in pixels for the right edge of a container.

Constructors

public Insets (int top, int left, int bottom, int right)

  The constructor creates an `Insets` object with `top`, `left`, `bottom`, and `right` being the size of the insets in pixels. If this object was the return object from the `getInsets()` method of a container, these values represent the size of a border inside that container.

Miscellaneous methods

public Object clone ()

  The `clone()` method creates a clone of the `Insets` so the same `Insets` object can be associated with multiple containers.

public boolean equals(Object object)

  The `equals()` method defines equality for insets. Two `Insets` objects are equal if the four settings for the different values are equal.

public String toString ()

  The `toString()` method of `Insets` returns the current settings. Using the `new Insets (10, 20, 30, 40)` constructor, the results would be:

    java.awt.Insets[top=10,left=20,bottom=30,right=40]

### Insets Example

The following source code demonstrates the use of insets within an applet's `Panel`. The applet displays a button that takes up the entire area of the `Panel`, less the insets, then draws a rectangle around that area. This is shown visually in Figure 6.1. The example demonstrates that if you add components to a container, the `LayoutManager` deals with the insets for you in positioning them. But if you are drawing directly to the `Panel`, you must look at the insets if you want to avoid the requested area within the container.

    import java.awt.*;
    import java.applet.*;
    public class myInsets extends Applet {
        public Insets insets () {
            return new Insets (50, 50, 50, 50);
        }
        public void init () {
            setLayout (new BorderLayout ());
            add ("Center", new Button ("Insets"));
        }
        public void paint (Graphics g) {
            Insets i = insets();
            int width  = size().width - i.left - i.right;
            int height = size().height - i.top - i.bottom;
            g.drawRect (i.left-2, i.top-2, width+4, height+4);
            g.drawString ("Insets Example", 25, size().height - 25);
        }
    }

#### Figure 6.1: Insets

To change the applet's insets from the default, we override the `insets()` method to return a new `Insets` object, with the new values.

Panel |  | Window