Weird negative effect with semi-transparent pngs

[Tom Brokaw]

I like the idea of a shiny yet semi-transparent panel. If you select an image, say one with a simple gradient and highlight, then you can't change the transparency.

I am trying to get around this by creating semi-transparent .pngs in the gimp. However, whenever I apply them to my panel, the colors are weird. Not exactly negative, but off. If I make a red image, it comes out green. If I make an aqua image, it comes out pink. If I make a black image, it comes out blue.

I'm pretty new to the gimp and to Ubuntu/Linux. Can anyone pick what I'm doing wrong?

I create a new image, 24x24. I select the gradient I want, and if no highlight is inherently present, I add one in a new layer, by selecting a rectangle along the lighter side of the gradient and filling with white.

I merge the two layers if necessary and set the layer opacity to whatever I fancy - 50, 35, whatever. Then I save as .png. It gives me a message saying I should export it first, with the option to export it. I choose export, click OK, and then set the newly created image as the background image in Panel Properties.

I've messed around for a while trying to suss out what the final color will be, but screw that. How do I get it to work the way I want to, or rather, what do I need to learn to get it to do what I want?

Thanks!

[xmastree]

That is bizarre.

It can be done, I used a similar principle for this panel. I created a new image, and used a gradient from foreground colour to transparent so that it shows the menu titles but then fades to nothing about one third of the way across (for obvious reasons).

Mine is 24x800, the width of the desktop. That might be an issue with yours being square.

How about posting a screenshot, and the png itself so we can see what's happening?

[Tom Brokaw]

I'll try making the panels the full size instead of tiling the background image.

Here's what I have. I used the default gradient in The Gimp called "brushed aluminum. As you can see, it comes out fine until I apply it to the panel. Then it turns blue.

[xmastree]

Strange. I downloaded your brushed_aluminium, made a panel and set that as the background.
panel1.png
Looks fine.

Then I set the opacity to 40%, saved it
brushed_aluminum_trans.png
and used that.

The panel became transparent.
Panel2.png
There you can see the new file in the lower right, against part of the desktop which shows the transparency better.

[Tom Brokaw]

Hmmm. Well, two things come to mind. The first is the way my video card handles transparencies. It's a Nvidia 5900, a little bit older but a good gaming and all-around card. What is your graphics card?

The other thing is maybe it's something with Dapper? I noticed you're using Breezy (at least that's what's in your profile) so maybe that's it, but it seems less likely.

I was messing around and set the transparency of the image to 0. This gave me a transparent green stripe for the panel. I ended up making new panels using the "crown molding" gradient and "burlwood" pattern fill, and I like them OK for now.

[xmastree]

What is your graphics card?

It's built in. xorg.conf is using the sis driver, and reckons it's an SiS 630/730.

I noticed you're using Breezy

Yep, I couldn't get the dapper installation to work.

What happens if you set a solid colour, and make it partially transparent? If that works then a transparent png ought to.

[bvc]

it's either a dapper gnome-panel bug or it's a gnome-panel bug. It can't handle transparent images any more. It happened about half way through dapper development. Sad....very sad....I miss my trans panels

[red_Marvin]

I'm using dapper and have no problem... Are you sure you run at a hi-color mode?

[Tom Brokaw]

I'm using dapper and have no problem... Are you sure you run at a hi-color mode?

I can't think why I wouldn't be, and it looks like millions of colors to me - how do I check?

Do you have a Nvidia card as well?

[Tom Brokaw]

What happens if you set a solid colour, and make it partially transparent? If that works then a transparent png ought to.

That works fine, and setting it to white and making it transparent looks good. My original idea was to just add a highlight to that to make it look glassy.