proj-imim:
Memory requirements in Java viewers
Helmut Dersch 2000-Apr-16 11:49:19
Java has its own image loading procedure "getImage(url)",
which loads jpeg and gif images. Any java viewer depending
on jpeg images (LivePicture, CylPan, PTViewer) uses this
routine to load images. It is responsible for the slow
startup (almost entirely due to the decompression algorithm).
Unfortunately, this routine does not provide any progress
feedback either. And, even worse, it imposes some stupid
memory limits.
On Netscape (at least to version 4.7) getImage() only handles
images up to 1 Million pixels (4MByte size uncompressed).
For spherical panos, this means 1400x700 pixels works,
but 1500x750 not. Cylindrical panos work to larger widths
(at least on PTViewer, which compresses the vertical coordinate):
I have a 2400pixel wide cylindrical jpeg panorama on my site.
Other java engines don't have this limit, eg MRJ on Macs
which is used in IE and Appletviewer.
Netscape is the most popular browser, so I decided to add a
workaround. The next version of PTViewer will support tiling
of images. This is ugly and cumbersome but should work.
Helmut Dersch