javax.swing.JViewport — clojure-interop/javax.swing 1.0.5

The "viewport" or "porthole" through which you see the underlying information. When you scroll, what moves is the viewport. It is like peering through a camera's viewfinder. Moving the viewfinder upwards brings new things into view at the top of the picture and loses things that were at the bottom.

By default, JViewport is opaque. To change this, use the setOpaque method.

NOTE:We have implemented a faster scrolling algorithm that does not require a buffer to draw in. The algorithm works as follows: The view and parent view and checked to see if they are JComponents, if they aren't, stop and repaint the whole viewport. If the viewport is obscured by an ancestor, stop and repaint the whole viewport. Compute the region that will become visible, if it is as big as the viewport, stop and repaint the whole view region. Obtain the ancestor Window's graphics and do a copyArea on the scrolled region. Message the view to repaint the newly visible region. The next time paint is invoked on the viewport, if the clip region is smaller than the viewport size a timer is kicked off to repaint the whole region.

In general this approach is much faster. Compared to the backing store approach this avoids the overhead of maintaining an offscreen buffer and having to do two copyAreas. Compared to the non backing store case this approach will greatly reduce the painted region.

This approach can cause slower times than the backing store approach when the viewport is obscured by another window, or partially offscreen. When another window obscures the viewport the copyArea will copy garbage and a paint event will be generated by the system to inform us we need to paint the newly exposed region. The only way to handle this is to repaint the whole viewport, which can cause slower performance than the backing store case. In most applications very rarely will the user be scrolling while the viewport is obscured by another window or offscreen, so this optimization is usually worth the performance hit when obscured.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

*-backingstore-scroll-mode clj

Static Constant.

Draws viewport contents into an offscreen image. This was previously the default mode for JTable. This mode may offer advantages over "blit mode" in some cases, but it requires a large chunk of extra RAM.

type: int

*-blit-scroll-mode clj

Static Constant.

Use graphics.copyArea to implement scrolling. This is the fastest for most applications.

type: int

*-simple-scroll-mode clj

Static Constant.

This mode uses the very simple method of redrawing the entire contents of the scrollpane each time it is scrolled. This was the default behavior in Swing 1.0 and Swing 1.1. Either of the other two options will provide better performance in most cases.

type: int

->j-viewport clj

(->j-viewport)

Constructor.

Creates a JViewport.

add-change-listener clj

(add-change-listener this l)

Adds a ChangeListener to the list that is notified each time the view's size, position, or the viewport's extent size has changed.

l - the ChangeListener to add - javax.swing.event.ChangeListener

backing-store-enabled? clj

(backing-store-enabled? this)

Deprecated. As of Java 2 platform v1.3, replaced by getScrollMode().

returns: true if scrollMode is BACKINGSTORE_SCROLL_MODE - boolean

get-accessible-context clj

(get-accessible-context this)

Gets the AccessibleContext associated with this JViewport. For viewports, the AccessibleContext takes the form of an AccessibleJViewport. A new AccessibleJViewport instance is created if necessary.

returns: an AccessibleJViewport that serves as the AccessibleContext of this JViewport - javax.accessibility.AccessibleContext

get-change-listeners clj

(get-change-listeners this)

Returns an array of all the ChangeListeners added to this JViewport with addChangeListener().

returns: all of the ChangeListeners added or an empty array if no listeners have been added - javax.swing.event.ChangeListener[]

get-extent-size clj

(get-extent-size this)

Returns the size of the visible part of the view in view coordinates.

returns: a Dimension object giving the size of the view - java.awt.Dimension

get-insets clj

(get-insets this)

(get-insets this insets)

Returns an Insets object containing this JViewports inset values. The passed-in Insets object will be reinitialized, and all existing values within this object are overwritten.

insets - the Insets object which can be reused - java.awt.Insets

returns: this viewports inset values - java.awt.Insets

get-scroll-mode clj

(get-scroll-mode this)

Returns the current scrolling mode.

returns: the scrollMode property - int

get-ui clj

(get-ui this)

Returns the L&F object that renders this component.

returns: a ViewportUI object - javax.swing.plaf.ViewportUI

get-ui-class-id clj

(get-ui-class-id this)

Returns a string that specifies the name of the L&F class that renders this component.

returns: the string "ViewportUI" - java.lang.String

get-view clj

(get-view this)

Returns the JViewport's one child or null.

returns: the viewports child, or null if none exists - java.awt.Component

get-view-position clj

(get-view-position this)

Returns the view coordinates that appear in the upper left hand corner of the viewport, or 0,0 if there's no view.

returns: a Point object giving the upper left coordinates - java.awt.Point

get-view-rect clj

(get-view-rect this)

Returns a rectangle whose origin is getViewPosition and size is getExtentSize. This is the visible part of the view, in view coordinates.

returns: a Rectangle giving the visible part of the view using view coordinates. - java.awt.Rectangle

get-view-size clj

(get-view-size this)

If the view's size hasn't been explicitly set, return the preferred size, otherwise return the view's current size. If there is no view, return 0,0.

returns: a Dimension object specifying the size of the view - java.awt.Dimension

optimized-drawing-enabled? clj

(optimized-drawing-enabled? this)

The JViewport overrides the default implementation of this method (in JComponent) to return false. This ensures that the drawing machinery will call the Viewport's paint implementation rather than messaging the JViewport's children directly.

returns: false - boolean

paint clj

(paint this g)

Depending on whether the backingStore is enabled, either paint the image through the backing store or paint just the recently exposed part, using the backing store to "blit" the remainder.

The term "blit" is the pronounced version of the PDP-10 BLT (BLock Transfer) instruction, which copied a block of bits. (In case you were curious.)

g - the Graphics context within which to paint - java.awt.Graphics

remove clj

(remove this child)

Removes the Viewports one lightweight child.

child - the component to be removed - java.awt.Component

remove-change-listener clj

(remove-change-listener this l)

Removes a ChangeListener from the list that's notified each time the views size, position, or the viewports extent size has changed.

l - the ChangeListener to remove - javax.swing.event.ChangeListener

repaint clj

(repaint this tm x y w h)

Always repaint in the parents coordinate system to make sure only one paint is performed by the RepaintManager.

tm - maximum time in milliseconds before update - long x - the x coordinate (pixels over from left) - int y - the y coordinate (pixels down from top) - int w - the width - int h - the height - int

reshape clj

(reshape this x y w h)

Sets the bounds of this viewport. If the viewport's width or height has changed, fire a StateChanged event.

x - left edge of the origin - int y - top edge of the origin - int w - width in pixels - int h - height in pixels - int

scroll-rect-to-visible clj

(scroll-rect-to-visible this content-rect)

Scrolls the view so that Rectangle within the view becomes visible.

This attempts to validate the view before scrolling if the view is currently not valid - isValid returns false. To avoid excessive validation when the containment hierarchy is being created this will not validate if one of the ancestors does not have a peer, or there is no validate root ancestor, or one of the ancestors is not a Window or Applet.

Note that this method will not scroll outside of the valid viewport; for example, if contentRect is larger than the viewport, scrolling will be confined to the viewport's bounds.

content-rect - the Rectangle to display - java.awt.Rectangle

set-backing-store-enabled clj

(set-backing-store-enabled this enabled)

Deprecated. As of Java 2 platform v1.3, replaced by setScrollMode().

enabled - if true, maintain an offscreen backing store - boolean

set-border clj

(set-border this border)

The viewport "scrolls" its child (called the "view") by the normal parent/child clipping (typically the view is moved in the opposite direction of the scroll). A non-null border, or non-zero insets, isn't supported, to prevent the geometry of this component from becoming complex enough to inhibit subclassing. To create a JViewport with a border, add it to a JPanel that has a border. Note: If border is non-null, this method will throw an exception as borders are not supported on a JViewPort.

border - the Border to set - javax.swing.border.Border

throws: java.lang.IllegalArgumentException - this method is not implemented

set-extent-size clj

(set-extent-size this new-extent)

Sets the size of the visible part of the view using view coordinates.

new-extent - a Dimension object specifying the size of the view - java.awt.Dimension

set-scroll-mode clj

(set-scroll-mode this mode)

Used to control the method of scrolling the viewport contents. You may want to change this mode to get maximum performance for your use case.

mode - one of the following values: JViewport.BLIT_SCROLL_MODE JViewport.BACKINGSTORE_SCROLL_MODE JViewport.SIMPLE_SCROLL_MODE - int

set-ui clj

(set-ui this ui)

Sets the L&F object that renders this component.

ui - the ViewportUI L&F object - javax.swing.plaf.ViewportUI

set-view clj

(set-view this view)

Sets the JViewport's one lightweight child (view), which can be null.

view - the viewport's new lightweight child - java.awt.Component

set-view-position clj

(set-view-position this p)

Sets the view coordinates that appear in the upper left hand corner of the viewport, does nothing if there's no view.

p - a Point object giving the upper left coordinates - java.awt.Point

set-view-size clj

(set-view-size this new-size)

Sets the size of the view. A state changed event will be fired.

new-size - a Dimension object specifying the new size of the view - java.awt.Dimension

to-view-coordinates clj

(to-view-coordinates this size)

Converts a size in pixel coordinates to view coordinates. Subclasses of viewport that support "logical coordinates" will override this method.

size - a Dimension object using pixel coordinates - java.awt.Dimension

returns: a Dimension object converted to view coordinates - java.awt.Dimension

update-ui clj

(update-ui this)

Resets the UI property to a value from the current look and feel.