How does a scroll pane do scrolling - java

In windows, Java, etc, the scroll pane scrolls the widgets inside. What I'm wondering is, how exactly does it do its scrolling? Does it change the location of each nested widget, or does it have a content widget that it moves around? Or is it something else? Also, when both scrollbars are present, how does it mask that little square at the bottom right? That square is sometimes used to resize. Is it a separate nested widget?
Thanks

I think it just changes the location of the widget, button, or thing-a-ma-bober.
But my second guess would be it just draws the components "outside" of the scroll pane without being seen and when you scroll it just redraws dynamically.

Related

Control when the scrolls in a ScrollPane show up

I have a scroll pane that the scrolls show up only when elements like buttons start to disappear, which is pretty small. I want to control when the scrolls show up so they'll appear earlier.
I couldn't find a way to it, is there a property or listener to do this?

How to properly change pane content while dragging a jscrollbar handle

I have a pane that contains image content which changes during scrolling. The content is properly updated via a scrollwheel event because I implemented a wheel listener which repaints the image before setting the new scroll value.
However, when the user drags the scrollbar handle with the mouse, the image content was not being updated during the manual drag-scroll. So I implemented a timer which grabs the current scroll value and repaints the content given the new scroll position.
This solution however (despite 10 millisecond adjustments) results in a jumpy scroll experience. The image moves (without the necessary image adjustments) and then gets corrected after-the-fact every 10 milliseconds.
I had originally tried an adjustmentlistener, but it only gets the event after the handle is released. How can I live-update the pane content during a jscrollbar handle drag BEFORE the scrollbar machinery starts to simply move my content as if it was a static image? Can I somehow give the scrollbar machinery a clue that content has changed or something every time it tries to redraw the content? Or can I disable the scrollbar's ability to move the image and just rely on my timer to do it?
I would recommend that you add a ChangeListener to the JScrollBar's model, a BounderedRangeModel, and then based on the value of the model as well as its maximum and minimum, change your image. If you're swapping images, the easiest way to do this is by swapping a JLabel's ImageIcon.

Windows Builder Can't Adjust Sizes

so I have adding some components and layouts, but the problem is I cant resize it.
Whenever I put a JLabel, it automatically goes to the far left. I want to position the size by clicking on the top-left corner, but it doesnt drag for some reason. And dragging the JLabel to another position doesnt work as well. Any ideas?

How to get tab pane tabs rotated and visible when oriented on the left side?

I am currently trying to get the tabs on the tab pane to be rotated 90 degrees and visible completely.
My attempt has ended in this
Image
I was able to rotate it by adding a rotate styling to the tab itself, but i cannot resize the anchorpane, or tab at all.
After googling for a long time, I could only find this http:// javafx-jira.kenai.com/browse/RT-19547. It says that the only way they could do it is to "put the text into the tab's 'Graphic' to achieve this". I'm not sure what that means or how to accomplish that.
My end goal is to create tabs that have the same shape and feel as these (image)
In this solution:
http://oreilly.com/pub/a/mac/2002/03/22/vertical_text.html
The text was painted vertically and tried as an icon on the tab. This way you don't have to modify JTabbedPane you just use a custom Icon in the tab.
Of course you would also have to specify the tab placement to be on the Left.

JSplitPane resize behavior

I have a vertically split JSplitPane and when I move the divider down, it shifts the bottom component and the bottom gets cut off. Is there a way to specify the resize behavior of a JSplitPane so the top (of the bottom component) gets covered by the split pane and the bottom is the last thing to get covered?
thanks,
Jeff
The components are painted at the "(0,0)" position for each part of the split pane.
I guess you could create your own custom UI that does whatever you want.
A simpler approach might be to add the component to a scroll pane. You could then just let the scrollbars appear if required.
Or, if you really want only the bottom part of the component to be shown you could control the viewport position whenever the divider is moved. You can handle this by listening for a "dividerLocation" PropertyChangeEvent.
I think you might need to attach an event to the JSplitPane's resize event (I forget exactly what it's called). The event should then move the content up to suit.

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