Transparency of icons does not work

[bronger]

Hallöchen!

I use LV 7 express. I tried to add an own library (llb file) to the
palette, which worked well. However, when I try to change its
icon, the alpha channel seems to be the cross section of the old
and new alpha channel. Thus, the icons looks crippled.

Since there is always a default icon when I add a new submenu, I
can't do something about it.

The icon has been created with the Gimp, indexed to 255 colours and
exported with 255 as the transparent colour.

Any ideas?

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus

[Nli]

Did you edit the icon through the palette editor?
If so, you may want to check if you have provided an image for the "black and white". It serves as a mask. If you don't provide a "black and white" image, the default will be used which is a rectangle as big as the entire image frame.

[bronger]

Hallöchen!

Nancy writes:

> Did you edit the icon through the palette editor?

I used the built-in symbol editor, but imported the bitmap from a
file and pasted it into the editor.

> If so, you may want to check if you have provided an image for the
> "black and white". It serves as a mask.

This can't quite be. Have a look at
http://www-users.rwth-aachen.de/torsten.bronger/labview-issue.png
which is a screenshot. You see that the sun has a white inner area,
although the black-and-white sun should mask it so that it's grey.

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus

[Nli]

Could you upload the screen shot of the problem image? This may help me to understand the problem.

Thanks.

[bronger]

Hallöchen!

Nancy writes:

> Could you upload the screen shot of the problem image? This may
> help me to understand the problem.

But you did see already the screenshot that I gave you?

Additionally, I uploaded
http://www-users.rwth-aachen.de/torsten.bronger/labview-issue2.png
with two sub-images: There you can see the default icon at the
bottom (at "Untermenü"), and aftre the copy-and-paste of the sun
symbol the result at the top. As you can see, there are still
artefacts of the default icon.

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus

[rolfk]

Torsten Bronger wrote:

> This can't quite be. Have a look at
> http://www-users.rwth-aachen.de/torsten.bronger/labview-issue.png
> which is a screenshot. You see that the sun has a white inner area,
> although the black-and-white sun should mask it so that it's grey.

Well LabVIEW calculates the Mask (alpha channel as you call it)
automatically. It takes basically the Black/white icon and removes from
the border up to any pixel which is not white all the pixels. It does
NOT go into any closed areas, so your inner hole will not be masked.
Solutions are to make a connection of that hole with the outside or
color that hole yourself in the background color you want.

PS: I think since about LabVIEW 6.1 it does not only take the
black/white icon
anymore as base for the mask but the intersection of
all icons which are not entirely empty.

Rolf Kalbermatter

[Nli]

That's right. The solutions you mentioned above are also used inside LabVIEW as well.

[bronger]

Hallöchen!

Nancy writes:

> That's right. The solutions you mentioned above are also used
> inside LabVIEW as well.

Well, your hints led me to a solution. I select the B/W version and
say "copy from 256" and then I have a rather good transparency mask.

I can live with this, however two things are strange: First, why is
the B/W version used as a mask? I thought that its purpose is to
be a default icon in the absence of colours. And secondly, why do
I have to explicitly copy from the 256 colour version? Just
manually drawing a B/W mask doesn't seem to work. Odd.

Thank you anyway!

Tschö,
Torsten.

--
Torsten Bronger, aquisgrana, europa vetus

[rolfk]

Torsten Bronger wrote:
> Hallöchen!
>
> Nancy writes:
>
>
>>That's right. The solutions you mentioned above are also used
>>inside LabVIEW as well.
>
>
> Well, your hints led me to a solution. I select the B/W version and
> say "copy from 256" and then I have a rather good transparency mask.
>
> I can live with this, however two things are strange: First, why is
> the B/W version used as a mask? I thought that its purpose is to
> be a default icon in the absence of colours.

I don't think the B/W icon is anymore used exclusively in LabVIEW to
create the mask. As far as I have seen it is an OR combination of all
non-empty icons since about LabVIEW 6.1. This means have a pixel set to
non white in any
icon and it will be added to the mask. The choice to
calculate the mask automatically was done why back in LabVIEW 2 or so
and worked quite well for most users. The issue about embedded holes not
getting excluded from the mask has probably got a few people mildly
annoyed at some point but it is such a minor optical detail that nobody
probably has voiced much anger and nobody at NI has felt that it is a
big enough problem to spend a few days of work to get a better icon
editor. I also guess that such an explicit mask may have influence on
some other parts of LabVIEW which would need to be modified.

> And secondly, why do I have to explicitly copy from the 256 colour
> version? Just manually drawing a B/W mask doesn't seem to work. Odd.

I can't confirm this behaviour. It seems to work as expected here
without the need to copy the 256 icon to B/W, although this usually
makes it easier to create a matching B/W icon.

Rolf Kalbermatter