problem displaying grayscale images

[MSpape]

Hi,
Dammit, so happy I was to suggest something, should have read newer
messages first! Sorry about that, but well found...
Best,
Mich

------------
Hi,
Two things, but sadly I cannot replicate your bug (if it is such), as
I'm still lacking in E-Prime:
* Have you tried converting the images to regular (what is it, 32
bit?) bmps? It might well be that E-Prime does not use 128 colours
grayscale (8
bit) but 128 colours coloured decoding, which would result in far
fewer colours for gray (perhaps about 8, which isn't a lot if you
include white and black!). Recoding the pictures in maximal bitrate
should help.
* Is your screen set to 16 bit (E-Prime default) instead of 32 bit?
The former is recommended since time immemorial, but we do remember
that PCs were much less able to decode fast (so that decoding time
would result in latency). It used to be thought of as 'optimising' to
run your videocard 32-bit style, but (or so I've heard), there are so
few people actually using that now that videocards themselves are
optimised for 32-bit, resulting at best in equal performance for 16-
bit, and possible even slower (for useless conversion). Anyway, I'd
suggest changing the 16-bit in E-Prime to 32-bit - I assume it won't
hurt!
Best,
Mich

(back from being a gentleman of leisure) Research fellow Helsinki
Institute for Information Technology Finland



On Jan 25, 8:31 pm, David Vinson <d.vin... at ucl.ac.uk> wrote:
> Well, we figured out our problem but I thought I'd share it with the
> list anyway, just in case anyone else makes the same silly mistake.
>
> It turns out we had set the ImageDisplay "Use Source Color Key" = Yes
> and Source Color Key = gray.  So any pixels matching the source color
> key (gray in this case) were not displayed.  Switching this off solved
> the problem.
>
> -dv
>
> On 25/01/2012 15:58, David Vinson wrote:
>
>
>
>
>
> > Hi all,
>
> > I'm using E-Prime 2.0 Pro to display some 8-bit grayscale images, and
> > there are constant display artifacts where certain pixels appear white
> > rather than their "correct" grayscale value, but the images are
> > displayed fine otherwise.
>
> > These images are displayed at their original dimensions (ie no
> > stretch), via a simple ImageDisplay object with a relatively long
> > duration.
>
> > I've tried these on a few different machines and it happens reliably
> > across different hardware, using different display resolutions,
> > different timing etc. These artifacts are not apparent when previewing
> > the images in other graphics packages, so it's not simply that my
> > images have become corrupted.
>
> > It seems to be the same pixels every time, and there is sure to be a
> > very simple explanation I'm somehow overlooking?  Anyone?
>
> > [Yes I realise this is a perfect query for E-Prime Support staff. But
> > I bet I'll get a quicker answer this way].
>
> > Thanks!
> > -dv
>
> --
> David Vinson, Ph.D.
> Senior Postdoctoral Researcher
> Cognitive, Perceptual and Brain Sciences Research Department
> University College London
> 26 Bedford Way, London WC1H 0AP
> Tel +44 (0)20 7679 5311  (UCL internal ext. 25311)- Hide quoted text -
>
> - Show quoted text -

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