Skip to main content

Java SE 6.0 has smoother rendering

Prior to Java SE 6.0, there were some issues with Swing painting.
  • When a minimized swing window was unobscured, it took a while for it to repaint. Till then the user saw a gray box. I think they also call it the "gray rect" problem :-)
  • Assume that the application is blocking the event dispatch thread (maybe because it is performing a large computation or loading a large file...). If we minimize and application, then it will not show a painted window upon unobscuring untill the event dispatch thread is unblocked. (offcourse we should not block the event dispatch thread for such a large task. Ideally a task larger than 250 ms should be started in a seperate thread)
In Java SE 6.0 these issues are resolved with "true double buffering". Java maintains a buffer that keeps an image of the onscreen window. This buffer is updated whenever the contents of the onscreen window are changed. If we minimize and then maximize the window, the window will not be repainted from scratch, instead it's image from the buffer will be copied to the video memory (using the toolkit thread). This elliminates the "gray rect" problem since the window will be displayed immediately without any time lag. Since the buffer is maintained in the hardware (most likely video RAM), it is true double buffering.

I am not very certain what a toolkit thread is. Will find out, but in the meanwhile if anyone knows, please post a comment.

The fine print:
True double buffering is enabled only on the windows platform at the moment. However it is implemented for other platforms as well, and will be enabled soon.

Comments

Anonymous said…
Cool blog
7:21 PM
Post a Comment

Popular posts from this blog

Inheritance vs. composition depending on how much is same and how much differs

I am reading the excellent Django book right now. In the 4th chapter on Django templates , there is an example of includes and inheritance in Django templates. Without going into details about Django templates, the include is very similar to composition where we can include the text of another template for evaluation. Inheritance in Django templates works in a way similar to object inheritance. Django templates can specify certain blocks which can be redefined in subtemplates. The subtemplates use the rest of the parent template as is. Now we have all learned that inheritance is used when we have a is-a relationship between classes, and composition is used when we have a contains-a relationship. This is absolutely right, but while reading about Django templates, I just realized another pattern in these relationships. This is really simple and perhaps many of you may have already have had this insight... We use inheritance when we want to allow reuse of the bulk of one object in other ...
3 comments
Read more

Commenting your code

Comments are an integral part of any program, even though they do not contribute to the logic. Appropriate comments add to the maintainability of a software. I have heard developers complain about not remembering the logic of some code they wrote a few months back. Can you imagine how difficult it can be to understand programs written by others, when we sometimes find it hard to understand our own code. It is a nightmare to maintain programs that are not appropriately commented. Java classes should contain comments at various levels. There are two types of comments; implementation comments and documentation comments. Implementation comments usually explain design desicisions, or a particularly intricate peice of code. If you find the need to make a lot of implementation comments, then it may signal overly complex code. Documentation comments usually describe the API of a program, they are meant for developers who are going to use your classes. All classes, methods and variables ...
Post a Comment
Read more

Running your own one person company

Recently there was a post on PuneTech on mom's re-entering the IT work force after a break. Two of the biggest concerns mentioned were : Coping with vast advances (changes) in the IT landscape Balancing work and family responsibilities Since I have been running a one person company for a good amount of time, I suggested that as an option. In this post I will discuss various aspects of running a one person company. Advantages: You have full control of your time. You can choose to spend as much or as little time as you would like. There is also a good chance that you will be able to decide when you want to spend that time. You get to work on something that you enjoy doing. Tremendous work satisfaction. You have the option of working from home. Disadvantages: It can take a little while for the work to get set, so you may not be able to see revenues for some time. It takes a huge amount of discipline to work without a boss, and without deadlines. You will not get the benefits (insuranc...
10 comments
Read more