resizing images is kinda slow

Java 2D
#1

hi, i’m using the following code to resize an image:
http://nopaste.easy-coding.de/?id=91

my machine:
p4 2.8ghz, ht enabled
kernel 2.4.22
jdk 1.4.2_04

unfortunatly, i’ve got the following times:
scaling image: 1280 * 1024 to 640*480
getScaledInstance: 157 msec
drawImage: 53559 msec
dispose: 0 msec
resizing image took: 54880 msec

somehow the drawImage-call is damn slow, is there some other way to do a image-resizing in java in a faster way? or is my code just ‘wrong’?

running that code on windows + jdk 1.5 + p3 500mhz is quite faster (~2sec)

#2

Hey spid. Welcome to the board :wink:

Well, I hadn’t much luck finding anything usefull. However, feel free to try some of those switches:

http://java.sun.com/products/java-media/2D/perf_graphics.html

#3

Try to copy the image retuned from ImageIO to another BufferedImage. Then do the resize in that one instaed.

Try using Toolkit.getDefaultToolkit().getImage() instead it might produce a faster Image. Some images loaded with ImageIO gets some strange pixel format that is a lot slower the non-accelerated normal images. Usually .png with an alpha channel though.

Anyone of those can work. If there’s nothing wrong with your setup of course. :slight_smile:

Cheers,
Mikael

#4

Well, it’s not about acceleration, since it’s a one time operation(*). However, it shouldn’t take 53seconds for drawing one 640x480 image (esp on such hi-end hardware).

(* The default acceleration treshold is 1… so you have to draw it at least twice in order to get it accelerated)

#5

i’ve noticed that if no xserver is running, the code won’t work (exception that no display can be found)
unfortunatly the image-resize has to run in a servlet on a server which has no running xserver (and i can’t decide to start one)

isn’t there another way to resize an image without having a xserver started?

#6

No I didn’t mean to get acceleration but to copy the pixels to another source, on where the pixel data for sure will be ordered in a good way might solve the problem. ImageIO loads certain kinds of image files into some strange pixel format.

However, the problem seems to be related xserver*, something I know absolutely nothing about. :slight_smile:

btw, the ImageIO/png problem is a known one to Sun and they will fix it when time is given.

Cheers,
Mikael

#7

Alright… (I think)

http://java.sun.com/j2se/1.4.2/docs/guide/awt/AWTChanges.html#headless

-Djava.awt.headless=true

is the switch… give it a try :wink:

#8

ah thx, found it too when i googled for ‘java image resizing x server’ :slight_smile:
i’ll just implement it like i already began to and commit everything and try to explain as easy as possible how to start the oracle ias with a vm-argument :wink:

#9

neat link oNyx! It does say that drawing scaled images is faster and more memory efficient now since it no longer draws things to an intermediate buffer. I assume that doesn’t hold true for AffineTransform rendering since profiling my game shows that Graphics2D.drawImage(Image, AffineTransform, ImageObserver) takes up most of the memory of my game :slight_smile: