Thread Subject:

Very strange alphadata problem

I have a weird problem concerning the alphadata property of an image. If I set the alphadata like:

set(imageHandle,'Alphadata',0.5)

the x- and y-axis labels are mirrored (the numbers are actually mirrored as if you were looking on the screen through a mirror), and only half the image is shown, the bottom half is white. By resizing the figure window the bottom half of the image appears above and slightly ontop of the top half. What the h*ll is going on?

I'm using windows xp sp2, R2007a with an ATI Radeon X1300/X1500 graphics card.

On 24 Sep, 14:06, "Patrik " <patrik_brynolfs...@yahoo.com> wrote:
> I have a weird problem concerning the alphadata property of an image. If I set the alphadata like:
>
> set(imageHandle,'Alphadata',0.5)
>
> the x- and y-axis labels are mirrored (the numbers are actually mirrored as if you were looking on the screen through a mirror), and only half the image is shown, the bottom half is white. By resizing the figure window the bottom half of the image appears above and slightly ontop of the top half. What the h*ll is going on?
>
> I'm using windows xp sp2, R2007a with an ATI Radeon X1300/X1500 graphics card.

Please post a code example that replicates the effect.

Rune

Well it isn't very much more than in my first post. The variable "image" can be any 2D image or matrix.

image = rand(384);
h = imagesc(image);
set(h,'AlphaData',0.5)

That's it.

"Patrik " <patrik_brynolfsson@yahoo.com> wrote in message news:h9fnbc$clp$1@fred.mathworks.com...
>I have a weird problem concerning the alphadata property of an image. If I set the alphadata like:
>
> set(imageHandle,'Alphadata',0.5)
>
> the x- and y-axis labels are mirrored (the numbers are actually mirrored as if you were looking on the screen through a mirror),
> and only half the image is shown, the bottom half is white. By resizing the figure window the bottom half of the image appears
> above and slightly ontop of the top half. What the h*ll is going on?
>
> I'm using windows xp sp2, R2007a with an ATI Radeon X1300/X1500 graphics card.
>
The alpha flipped your renderer to OpenGL. We've seen a particular
graphics card driver version where glBitmap (the command that is
used to implement text in OpenGL) is exactly backwards. I'm sorry,
but I don't remember the details of the version numbers, but I would
suggest upgrading/downgrading your driver. Also, as always, pass
details on to support.

    -Mike Garrity
    -The MathWorks

Hi Patrik and Mike Garrity,

I know that this is very old post, but I am having the same problem of x and y tick lables mirrored when using alphadata.
Please can you tell me what was the solution, what do I have to do on my renderer?

Thanks in advance for your suggestions and help

Camille.

"Camille Couzi" <camillecouzi@yahoo.fr> wrote in message <iet5g3$knj$1@fred.mathworks.com>...
> Hi Patrik and Mike Garrity,
>
> I know that this is very old post, but I am having the same problem of x and y tick lables mirrored when using alphadata.
> Please can you tell me what was the solution, what do I have to do on my renderer?
>
> Thanks in advance for your suggestions and help
>
> Camille.

I have the same problem with an ATI card. The workaround is the following:

gl = opengl('data');
if strfind(gl.Vendor,'ATI')
    opengl('software')
end

Simon