Hi Jim,
Can you suggest a way (or a program) to objectively measure the speed of copying an
image from memory to the screen? In a later message, you mentioned that you were
getting 30M pixels/sec and it would be interesting to compare the results I get with
what you found.
My comparison was based on observing applications running on hardware that uses a
Matrox G200 (AGP 2X, 8MB VRAM) at a resolution of 1280x1024 at a color depth of
32-bits.
Although the impression I get from watching Photoshop 5 load and display an image
(jpeg format, 1280x1024x24) seems faster than a second, there is no programmatic way
to accurately measure how fast it is completing the process.
We still use a rather dated application (written around 1994) called ScriptX for some
of our work. [On a nostalgic note, ScriptX was effectively killed by the emergence of
Java. ] ScriptX can load, decode and display the previously specified image on the
same hardware in less than .75 seconds. A cursory look at the .exe reveals lots of
calls to GetDIBits(), SetDIBits() and CreateCompatibleBitmap(). Because of this, I
suspect it is able to take advantage of hardware acceleration if it is present on the
system's graphics card.
After reading the description about the various methods of interfacing Java2D with the
Win32 GDI, I have a question: Why is it such a problem if you lose the ability to
access the pixels directly by using the CreateCompatibleBitmap() family of APIs? It
seems like if you have to use the Win32 GDI as a filter for all pixel access, the
hardware acceleration provided by most graphics cards used today (with Windows at
least) will more than make up for the extra processing time that is required to
interface with it.
Thanks,
Julian L Brown
Opinion One
[EMAIL PROTECTED]
-----Original Message-----
From: Discussion list for Java 2D API
[mailto:[EMAIL PROTECTED]]On Behalf Of Jim Graham
Sent: Thursday, October 28, 1999 8:08 PM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA2D] BufferedImage vs MemoryImageSource
Hi Julian,
The number of possible combinations for source and destination
images and video hardware is rather large for me to make any
definitive estimates of what you will see without further
information .......
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