Black border lines appearing on images.

Model Acer Aspire 8942G
OS Windows 7
CPU Intel (R) Core ™ i7 CPU Q720 @ 1.60GHz 1.60Ghz
Memory 6GB RAM
Graphics card ATI Mobility Radeon HD 5850
Vassal 3.1.14
Java Version 6 update 22
Module Vasl 5.9.2.

I created an extension to provide some draggable overlays within Vasl and have come across some strange behaviour.

The overlay images are fine at zoom levels of 100% or greater, but when zooming to less than 100% black edge lines appear on the images – on some images the lines are top and bottom and on others at the sides or at sides and top or bottom. The lines differ from image to image, but are always the same for a particular image.

On some images the orientation of the lines changes as you zoom out for example instead of being at the top and bottom they move to the left and right edges.

If you rotate the overlay the black edge lines disappear, but reappear when rotated back to the original orientation. Is this a bug in Vassal/Vasl or am I doing something wrong?

I have created previous extensions for providing draggable overlays with Vasl and they have worked fine, in an effort to try and isolate the problem I recreated an old extension using the same image files that I used before and am now getting the black border lines on these images in the new extension. I cannot remember which versions of Vassal and Vasl I use to create this extension originally, I thought it was also with Vassal 3.1.14 and Vasl 5.9.2, but I could be wrong.

Any help would be greatly appreciated.

Can you post a minimal example of the problem here? It’s hard to troubleshoot things like this if we can’t try them out ourselves.

I am assuming some knowledge of Vasl – if more information is required please let me know.

Apologies for being dense but I cannot work out how to post files on the forum so I have put a copy of a small demo Vasl extension showing the problem on Mediafire:

With the extension loaded start a game in Vasl and load any map. Three draggable overlays are available from the the draggable overlays menu option under a tab called “Afrika Korps” – HM2 under Hillocks and SH6 and SH8 under Shellholes.

When dragged to the map at zoom level 67%, SH8 has a black line at bottom edge, HM2 at right and bottom edges and SH6 at left and right edges. All images are OK at zoom levels 100% or better, at zoom levels below 67% the edge lines change their position. If the overlays are rotated (using the shift key to select the overlay and then right click rotate) the edge lines disappear until rotated back to their original position.

Some more info on this problem if anyone is looking into it. When the extension was used by someone else using the same version of Vasl they do not see the black lines on the overlay images, and when I use the extension on another laptop using Win XP and Vasl 5.9.1 and an earlier version of Java I still see the black lines.

Has aAnyone any idea what area might be causing this problem - could it be a preference setting and if so any pointers as to where to start looking?

I think I have resolved my problem, but I am far from understanding what has been going on.

The method I used for creating the image files was to create a XCF file using GIMP with several layers, some of which were redundant to the final image and were therefore turned off but not deleted. The image was then saved as a GIF file.

By a process of elimination it would appear that if I delete the unused layers in the XCF file and then save as a GIF file I no longer have the problem.

So although I have solved the problem I do not understand it, I am specifically perplexed as to why I was seeing the black edge lines but others who loaded the extension did not – I would be interested in any thoughts.

Could you post both the offending GIF and the XCF file here, so we can have a look at them?

Hopefully i have attached one of the offending Gifs and its corresponding XCF file (the XCF file had to be zipped as it could not be uploaded with xcf file extension).