Filtering in Canvas2D and CanvasMap

[tlecomte]

Dear Icy masters,

Here is a pull request for filtering in canvas2d and canvasMap.

-Commit 629c5b2 enables bicubic interpolation on the canvas when the view is not moving.

-Commut 652ebf3 reduces the scale limit between nearest-neighbour and bicubic. Before, NR was used when the scale is larger than 400%. It is now used when the scale is larger than 300%. I find it clearer.

-Commits 83e1991 and 242ae87 add a downsampling step when the scale is smaller than 1. This removes aliasing artefacts. The downsampling is a high-quality Lanczos3 filter provided by a library named java-image-scaling. The correspoding jar has to be added to the build path ! It can be downloaded from there: http://code.google.com/p/java-image-scaling/

• Finally, commit 20da898 enables the downsampling filter and the bicubic interpolation on the CanvasMap. I think it looks much nicer...

What do you think about these modifications ?

Timothée

[tlecomte]

For comparison, here is a screenshot:

http://i.imgur.com/owYFC.png

On the left, after the modifications. On the right, before (and filtering option disabled).

[Stephane-D]

Because of synchronized viewer we need to apply filter only on idle time (use a timer in ImageCache).