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jscrollpane slow with inital viewing of complex image

I am having problems with scrolling on a JScrollPane.
I have a list of images in a JList which I am placing on a JScrollPane. The list can be very long, sometimes hundreds or thousands of images. I add the JScrollPane to a JPanel, and the image gets drawn successfully, the JScrollPane adds scroll bars when needed and the scroll bars can move the image. The response from the scrollbars are good if the list of images is simple (10 - 20).
However, lists that run into the hundreds cause the vertical scrolling to initially run very slowly until all the images have been shown, then the scrolling speed returns to normal.
Can anyone suggest a technique to speed the initial scrolling response? I have experimented with adjusting the viewport settings (eg JViewport.BACKINGSTORE_SCROLL_MODE, JViewport.BLIT_SCROLL_MODE) but these did not lead to any improvement in the initial scrolling response.
The code that I am using is represented below.
prList = new JList(prListModel); // a list of interactive images for the JScrollPane
MouseAdapter listener = new PrChangeListener(prList, this);
prList.addMouseListener(listener);
prList.addMouseMotionListener(listener);
renderer = new PrRenderer();
renderer.setPreferredSize(getIconPreferredSize());
prList.setCellRenderer(renderer);
prList.setBackground(Color.WHITE);
prList.setSelectionBackground(new Color(225,225,225));
setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
//try separate linked scroll bar for scale bar ...
prListModel scaleBarListModel = new prListModel();
scaleBarListModel.addElement(intArray[0]); // a scale bar to sit above the JScrollPane
scaleBarList = new JList(scaleBarListModel);
scaleBarList.setCellRenderer(renderer);
scaleBarList.setBackground(Color.WHITE);
scaleBarList.setSelectionBackground(Color.WHITE);
scaleBarScrollPane = new JScrollPane(scaleBarList,JScrollPane.VERTICAL_SCROLLBAR_NEVER, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
prListModel.removeElementAt(0);
prScrollPane = new JScrollPane(prList);
prScrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
prScrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scaleBarScrollPane.getHorizontalScrollBar().setModel(prScrollPane.getHorizontalScrollBar().getModel());
JPanel twoPanePanel= new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.VERTICAL;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.fill = GridBagConstraints.BOTH;
gbc.gridx=0;
gbc.gridy=0;
gbc.weightx=1;
gbc.weighty=0.1;
twoPanePanel.add(scaleBarScrollPane, gbc);
gbc.gridx=0;
gbc.gridy=1;
gbc.weighty=0.9;
twoPanePanel.add(prScrollPane,gbc);
add(twoPanePanel);

Please suggest me a basic layout to use, other than the GridBag layout

OK I have a panel, and I want to place two panels on to it, left and right, such that the right panel should be double the width of the left side panel.
I want to add a menu to the left side panel, and the details of the selected item will appear in the right side panel.
Secondly, the size of the panels and their components should increase proportionately when the window is expanded (If any methods can be used for the purpose, please suggest!)
I did try to use the GridBagLayout but I think I have not yet been able to grasp it well. So please suggest the simplest layout manager which can serve my purpose.
EDIT:- PROBLEMS WITH WHAT I HAD TRIED WITH THE GRIDBAG
//Set Layout
setLayout(new GridBagLayout());
GridBagConstraints c= new GridBagConstraints();
//Set Layout constraints of components and add them to the MainPanel
c.gridx=0;
c.gridy=0;
c.weightx=0.5;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iListPanel);
iListPanel.setBorder(BorderFactory.createTitledBorder("Check") );
GridBagConstraints c1= new GridBagConstraints();
c.gridx=1;
c.gridy=0;
c.weightx=1;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iDetailsPanel);
iDetailsPanel.setBorder(BorderFactory.createTitledBorder("Check"));

Of the layout managers that come with Java, I think GridBagLayout is the simplest one that will do that. It's worth the time to learn it, because it's about the only layout manager that's halfway-competent. This should do it:
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
GridBagConstraints c;
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
c = new GridBagConstraints();
c.weightx = 1;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(left, c);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
c = new GridBagConstraints();
c.weightx = 2;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(right, c);
However, from the description of your problem, it sounds like JSplitPane will serve you better for this. It's a ready-made component to do more-or-less what you're asking, and has a user-resizeable separator as well. An example:
JSplitPane pane = new JSplitPane();
pane.setResizeWeight(1/3f); // right will be twice size of left
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
pane.setLeftComponent(left);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
pane.setRightComponent(right);
Edit: The problem with your original code is that it does not use the constraints.
add(iListPanel);
should be:
add(iListPanel, c);
and likewise for iDetailsPanel.

You want to use a BorderLayout.
panel.add(panelLeft,"West");
panel.add(panelRight,"East");
North, South and Center is also available

Starting GridBagLayout from top left corner in Java Swing

I'm new to Java Swing and I have been struggling to start the GridBagLayout from top left corner so that c.gridx=0 c.gridy=0 will put my object on the top left corner.
I'd appreciate if you could help me by telling what I need to do after this point:
JPanel panel = new JPanel(new GridBagLayout());
frame.add(panel);
GridBagConstraints c = new GridBagConstraints();
I know that I have to use NORTHWEST or FIRST_LINE_START constants, but I don't know how. I tried to do it this way' but it did not realize the constants.
frame.getContentPane().add(panel, BorderLayout.NORTHWEST);
Thanks for your help.

Read the section from the Swing tutorial on How to Use GridBagLayout. The secton on "weightx,weighty" states:
Unless you specify at least one non-zero value for weightx or weighty, all the components clump together in the center of their container.

You need to use your GridBagConstraints' anchor property. This should do it for you:
frame.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.NORTHWEST;
frame.add(panel, gbc);
I'm not guaranteeing that you won't have to set other properties of the constraints object to get the layout you desire. In particular, you may need to set weightx and weighty to be 1 so that the panel takes up all of the available space given to it.

For those, who use IDE (e.g. NetBeans), I finally found nice trick: if you want to add components to top and use their preferred sizes: add another empty panel with weighty = 1.0. Copied from auto-generated code (NetBeans):
gridBagConstraints = new java.awt.GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 2;
gridBagConstraints.weighty = 1.0;
jPanelOptions.add(jPanelFiller, gridBagConstraints);

a quick and simple way:
add a blank JLabel to end of page:
// your code goes here
gbc.weightx = 1;
gbc.weighty = 1;
bg.add(new JLabel(" "), gbc); // blank JLabel

There's a workaround. You can put the GridBagLayout panel in a BorderLayout panel with BorderLayout.NORTH. Then Component in GridBagLayout panel will start from top position.
static void test4(){
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(480, 360);
JPanel borderLayoutPanel=new JPanel(new BorderLayout());
JPanel gridBagLayoutPanel = new JPanel(new GridBagLayout());
borderLayoutPanel.add(gridBagLayoutPanel, BorderLayout.NORTH);
frame.add(borderLayoutPanel);
JButton testButton=new JButton("test button");
GridBagConstraints c = new GridBagConstraints();
c.gridx=0;
c.gridy=0;
gridBagLayoutPanel.add(testButton, c);
frame.setVisible(true);
}

if you want the grid to go all the way to the top, simply set all your weighty = 0 until the last item, set it to any number greater than 0, it will effectively push the rest of the buttons to the top.
Don't forget to also increment your button's gridy value.
Otherwise it will be centered.
(the same can be done using gridx and weightx value if you arent using the c.fill = GridBagConstraints.HORIZONTAL property.)

GridBagLayout padding

I am using a GridBagLayout to (currently) display two rows. I am aware this layout is overkill for this task, but am trying to learn how to use it. The problem is that I have added the two panels to the two separate rows and there is a huge gap around the content (see image and code below):
alt text http://www.imagechicken.com/uploads/1264533379009864500.png
Image background;
public Table(){
super();
ImageIcon ii = new ImageIcon(this.getClass().getResource("pokerTableV2.png"));
background = ii.getImage();
setSize(Constants.FRAME_WIDTH, Constants.TABLE_HEIGHT);
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.gridx = 0;
constraints.gridy = 0;
constraints.fill = GridBagConstraints.HORIZONTAL;
JButton button = new JButton("hello world");
JPanel panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(800,100));
panel1.add(button, BorderLayout.CENTER);
panel1.setBackground(Color.yellow);
add(panel1, constraints);
constraints.gridx = 0;
constraints.gridy = 1;
JPanel middlePanel = new JPanel();
middlePanel.setPreferredSize(new Dimension(800,350));
middlePanel.add(button, BorderLayout.CENTER);
middlePanel.setBackground(Color.blue);
add(middlePanel, constraints);
}

Use
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1d;
constraints.weighty = 1d;
JavaDoc for weightx/weighty says:
Specifies how to distribute extra horizontal/vertical space.
JavaDoc for fill:
This field is used when the component's display area is larger
than the component's requested size. It determines whether to
resize the component, and if so, how.

Unfortunately, with GridBagLayout, if the contents do not fill the entire container that it is in, it will automatically center all its contents within its container. That is why you are getting a really large gap.
There are essentially two ways to fix this:
The hard way: Fiddle with the GridBagConstraints. I had limited success with this when trying to avoid the centre-ing behaviour.
The easy way: Put the GridBagLayout inside of a FlowLayout, and then set the alignment of the FlowLayout to top-left, or whatever you wish.
I have asked, and answered, this question myself sometime last week.
So in your case you are adding your panel1 and middlePanel directly to the JFrame (?), with a GridBagLayout
JFrame (GridBagLayout)
- panel1
- middlePanel
I would suggest this alternative structure instead, to get rid of all the extra space (and centre alignment as well, if you like).
JFrame (FlowLayout)
- JPanel (GridBagLayout)
- panel1
- middlePanel
HTH

How to have a specific component resize based on available, visible space?

In my application, I have a layout similar to what is shown below:
#######
XXXXXXX***
XXXXXXX***
XXXXXXX***
%%%%%%%
In this layout, X is a JTable. The other components can remain the same size. Is there a layout or strategy that will have the JTable (X) resize based on available screen size and have everything else stay on the sides properly?
Thanks.

That looks very much like a BorderLayout to me. Have you tried that?

It can also be done with GroupLayout, but it is designed for GUI builders, as it's very verbose. So if you already have existing code, you might not want to try it first.

I am a big fan of JGoodies FormLayout. Here is some sample code of one way to do this with FormLayout.
JPanel panel = new JPanel();
FormLayout layout = new FormLayout("100dlu, 20dlu:grow", "pref, pref, pref");
panel.setLayout(layout);
JTextField t1 = new JTextField();
JTextField t2 = new JTextField();
JTable tb = new JTable();
JScrollPane sp = new JScrollPane();
sp.setViewportView(tb);
CellConstraints cc = new CellConstraints();
panel.add(t1, cc.xy(1, 1));
panel.add(t2, cc.xy(1, 3));
panel.add(sp, cc.xyw(1, 2, 2));