Java Swing O Reilly The visibleRect property is (Tomcat web server)
Java Swing O Reilly The visibleRect property is a Rectangle that indicates the intersection of the component’s visible rectangles with the visible rectangles of all of its ancestors. Why the intersection? Remember that you can have a contained object that is clipped by its parent. For example, you can move an internal frame so that a portion of it falls outside the parent window’s clipping region. Therefore, the visible portion (the portion that is actually drawn to the screen) will consist only of the intersection of the parent’s visible portion and the child’s visible portion. You typically will not need to access this property. The validateRoot property is false by default. If it is set to true, it designates this component as the root component in a validation tree. Recall that each time a component in a container is invalidated, its container is invalidated as well, along with all of its children. This causes an invalidation to move all the way up the component hierarchy, stopping only when it reaches a component for which isValidateRoot() returns true. Currently, the only components that set this property to true are JRootPane (which is used by all the Swing top-level components), JScrollPane, and JTextField. The topLevelAncestor property contains a reference to the top-level window that contains this component, usually a JWindow or JApplet. The rootPane property contains the low-level JRootPane for this component; JRootPane is covered in more detail in Chapter 8. Finally, JComponent contains a property called autoscrolls , which indicates whether a component is capable of supporting autoscrolling. This property is false by default. If the property is true, an Autoscroller object has been set over this component. The Autoscroller object monitors mouse events on the target component. If the mouse is dragged outside the component, the autoscroller will force the target component to scroll itself. Autoscrolling is typically used in containers such as JViewport. 3.3.2.4 Position, Size, and Alignment You can set and retrieve a Swing component’s current position and size on the screen through the bounds property, or more precisely, through the location and size properties of JComponent. The location property is defined as a Point in the parent’s coordinate space where the upper-left corner of the component’s bounding box resides. The size property is a Dimension that specifies the current width and height of the component. The bounds property is a Rectangle object that gives the same information: it bundles both the location and the size properties. Figure 3.6 shows how Swing measures the size and location of a component. Figure 3.6. Working with the bounds, size, and location properties - 59 -
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