Dear list,

With GEM I've implemented a drawing application (using buffer 1) in which I can draw freehand images using a graphics tablet. I'm trying to store snapshots of my drawings at different stages. pix_write seems to be the thing to use, but I've been banging my head all day against tiff files containing a solid black only.

The most helpful bit of documentation seemed to be contained in the pd documentation itself, the patch 09.SnapshotSave.pd . To my surprise, even with this example the images I get are all black! Am I missing any obvious point at even simply running the example? I've tried the same thing in two different computers, both running windows xp, with the same black result in both cases.

I'll REALLY appreciate your help on this!

Are you using [alpha] ? it might be that you are drawing in black and its defaulting the alpha channel to black also.

I do use [alpha] in my application. I've tried removing it and drawing solid colours, but I keep only getting black pictures when I snapshot them.
However, the example in the documentation does not work for me either. Can any of you try the example patch:

...\pd\doc\examples\Gem\02.Advanced\09.SnapshotSave.pd

If you manage to get anything other than black image files, please let me know how've gone about it (any particular sequence in which to run the patch...?)

Many thanks

The example ...\pd\doc\examples\Gem\02.Advanced\09.SnapshotSave.pd is working fine here.

I am using pd-extended 0.41.4 and GEM 0.92.1 on Ubuntu 9.04

What I do is just click create, click the toggle to swich on the render, choose a file name and a location using the bang on top of the [savepanel].

When I click the other bang I get a .tiff image that is not black.

Thanks for the feedback, excalibur.

Might it be a windows problem...?

I've tried it with 3 different machines running WinXP sp2 and with various of the later versions of Pd and Gem, including the very latest Pd0.41.4 and Gem0.91.3... but no success. Black TIFFs every single time.

Is there anybody using windows for whom this patch works well???
...\pd\doc\examples\Gem\02.Advanced\09.SnapshotSave.pd

Or put another way, is there any windows user that is taking snapshots successfully with pix_write?

I've managed to take some snapshots of my Gem window with pix_write, although quite erratically. There seems to be a problem with the length of the path where the patch is stored, or where the image will be stored... I got a hint for this from a very old discussion thread about this patch, where a bug along these lines was briefly mentioned.

However, the example patch 09.SnapshotSave.pd has never worked for me, no matter where I store the patch or the image.

There are some problems with the snaps I've managed to take. When taken as TIFF they're always black. If taken as jpeg, the colours are subdued, washed out, and edges are blurred. I've tried to change the quality of the jpeg, but the quality of the image looks equally poor with higher numbers, and eventually the whole Pd application crashes if I try higher values. So I'm only being able to take very poor quality images.

Does anybody know the range of values that pix_write is supposed to be able to take for jpeg quality?

I've got some tifs on Win XP, but had to use GIMP to view them.