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Why is swing's getGraphics() so slow?

Tom SchepersMar 8 2024

Hello,

I'm currently working with Swing, and I want to create some custom widgets with mouse hover effects.

I created a superclass of a JComponent and wrote a custom paintComponent and two methods for mouseEntered and mouseExited that change the background color.

When I store the background color in the built-in field using setBackground(), then paintComponent automatically gets called and perfectly draws the thing.

But then, I wanted to write seperate functions for drawing the background and drawing other stuff. So, I wrote a function drawBackground and let paintComponent call that function. And now, when mouseEntered or mouseExited is called, it should only change the background color (I created my own field currentBg for this) and then call drawBackground instead of paintComponent. And I need to have some Graphics2D I can draw the thing on, so I used getGraphics() and passed it to drawBackground.

But somehow, this way is much slower than the other one. It seems like getGraphics() just takes too much time. So, what would be a faster way to re-draw the element? In my first example, the thing gets re-drawn by the setBackground method, because it automatically updates the button and calls paintComponent. But I also tried changing my second example to make it call paintComponent instead of drawBackground, but that didn't change anything.

Somehow, calling paintComponent(getGraphics()) is much slower than the way setBackground updates the Component. So, what would be the best way to update the Component manually?

Thank you for answers!

Comments

The language shown in the Forms runtime is the result of your NLS_LANG setting in the runtime environment configuration (e.g. default.env). However, Forms can only change the language of labels it knows about. For example, the ones you highlighted. The column titles, in your example are labels that you elected to use (or column names from the DB). As a result, we cannot change them automatically because we would have no idea if that is what you wanted to do.

You would need to programmatically change those if desired. For example:

SET_LOV_COLUMN_PROPERTY ('LOV1', 2, TITLE, 'Nombre del empleado (Spanish)');

In this example, I am running a form in English but want one column to show in Spanish. So, I use the code above to make that change at runtime.

xu meng Feb 12 2025

Thanks for your reply, your example has inspired me a bit, but it still can't meet my usage needs.
I'm confused about:
When my system language variable is Chinese, I want to make the LOV component's Query/Confirm/Cancel button appear separately in other languages. As shown in the image above.
I don't know, but you can understand what I mean.

xu meng Feb 12 2025

As shown on the picture you provided. "查询" is displayed when the Chinese environment variable is used, and "FIND" is displayed when it is used in English. At present, I want to make the button of its LOV component window display "FIND" separately in the Chinese system, but I have not found the method in the help document and the network.

As I mentioned, strings built into Forms like “Find”, “Ok”, “Cancel”, and others can be translated into the language you choose in the runtime environment using the NLS_LANG settings. Unfortunately, this cannot be changed after the application has been started. So if the app is started with for example, Chinese-Traditional it cannot later be changed to French while the form is running. This means that you must either configure your server to support multiple languages and create modules for each language. This is often the best approach. There are other ways that customers have used, but what I described here likely would require the smallest effort.

You did not mention which Forms version you are using and therefore I cannot point you to the documentation for that version. However, here is the link to the related documentation for Forms 14.1.2. The concepts are basically the same for earlier versions, although some minor improvements have been introduced in the latest release (14.1.2).

https://docs.oracle.com/en/middleware/developer-tools/forms/14.1.2/working-forms/enabling-language-detection.html

But again, for strings that do not natively belong to Forms (you created them) you would need to programmatically change them as necessary.

xu meng Feb 12 2025

OH! I will try to implement your plan first. Thank you for your patience. My Forms version is 11.1.2.

As you are likely aware, but I feel it necessary to mention in case you are not, Forms 11.1.2 was desupported many years ago. I recommend you consider upgrading to the latest Supported version in order to ensure that you can get the latest bug fixes (including security fixes), the latest features, and improvements like what I mentioned about language support and others.

Details can always be found on the Forms product page.

https://www.oracle.com/application-development/technologies/forms/forms.html

xu meng Feb 12 2025

Thank you for telling me this news. I will consider your suggestion carefully and refer to it later. Thank you for your answer.

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