ImageIcon vs. BufferedImage

Question

I'm making an applet that will be using a fair number of transparent gifs (a total of ~5-20 megs), and don't know which type of image object would be best suited. Each image will only be a few kilobytes in size and only a few of them need to be displayed at any given time (but the set being displayed will change every now and then).
I need thumbmails to be displayed centered in two columns and then displayed in full size seperately. To do this, I'm currently using JLabels with ImageIcons for the thumbnails. I change the set being displayed by using 'myJLabel.setIcon(myImageIcon)'. I have not yet implement the part to make them display at full size. Would I have to use something like this:
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(myImageIcon.getImage(), x, y, this);
Would this create a new Image object? And hence slow the applet (or would it be unnoticable if it's only a few images)? I need to be able to display the image at precise coordinates.
Would using BufferedImages better suite my needs? I understand that they will perform faster, but I'm not sure if they might cause a problem in terms of storage space. When a BufferedImage is created, is it stored in the user's computer's RAM or their local drive? How about ImageIcons, where are they stored? If the images total 5-20 megs, will either of these methords cause a problem?

Answer 1

Hi,
I'm making an applet that will be using a fair number
of transparent gifs (a total of ~5-20 megs), and don't
know which type of image object would be best suited.
Each image will only be a few kilobytes in size and
only a few of them need to be displayed at any given
time (but the set being displayed will change every
now and then).Normally, I would say definitely use ImageIcons because the images that they create can be hardware accelerated behind the scenes. However, transparency currently is not accelerated. This means that most likely, the images stored inside your ImageIcons, are going to be BufferedImages anyway :-)
>
I need thumbmails to be displayed centered in two
columns and then displayed in full size seperately. To
do this, I'm currently using JLabels with ImageIcons
for the thumbnails. I change the set being displayed
by using 'myJLabel.setIcon(myImageIcon)'. I have not
yet implement the part to make them display at full
size. Would I have to use something like this:
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(myImageIcon.getImage(), x, y, this);
}Sure, that's fine! ImageIcon is not going to create a new image every time. You can make the image larger too by using:
g.drawImage(image, x, y, w, h, this);
My article on The Swing Connection talks about a couple of the drawImage calls:
http://java.sun.com/products/jfc/tsc/articles/swing2d/index.html
>
Would this create a new Image object? And hence slow
the applet (or would it be unnoticable if it's only a
few images)? I need to be able to display the image at
precise coordinates.
Would using BufferedImages better suite my needs? I
understand that they will perform faster, but I'm not
sure if they might cause a problem in terms of storage
space. When a BufferedImage is created, is it stored
in the user's computer's RAM or their local drive? How
about ImageIcons, where are they stored? If the images
total 5-20 megs, will either of these methords cause a
problem?BufferedImages are stored in RAM, as are the images inside ImageIcons. ImageIcons CAN be faster for non-transparent images. They may currently perform slightly slower for transparent images. You might just have to test it out.
By the way, if you find you're running out of memory (ie. OutOfMemoryError), you can increase the Java heap size when you run your application.
Use the -Xms and -Xmx flags to set the initial and maximum heap sizes.
For example, to give your application 64 Megs of ram to start and allow up to 128 Megs:
java -Xms64M -Xmx128M YourClassName
Good luck!
Shannon Hickey (Swing Team)