Re: backgrounds on png pix

Albretch Mueller wrote:
>  I am coding a tabbed window using java/swing
> 
>  Why is it that some png pictures somehow blend their backgrounds with
their
> surroundings' and some other don't?
> 
>  Take a look at both examples
> 
>  http://www.geocities.com/tekmonk2005/pix/example00_OK.jpg
> 
> 
http://www.geocities.com/tekmonk2005/pix/example02_BackGroundNotGood.jpg
> 
>  When users click on "Save" the entire background gets higlighted
(including
> the png pix' itslef), but when they click on "Q & Ans" the background of
> the picture itself doesn't.

PNG is a format that sup****ts transparency. In your examples, it seems 
that the hard drive icon has a transparent background (that is, the 
pixels surrounding the hard drive graphic are transparent). The light 
bulb icon doesn't seem to have the same transparent background.

>  How can you make it consistent like "Save"?

The best way to do it would be to get icon files that were created with 
transparent backgrounds. If such icon files are not available, you can 
try to edit existing icon images and turn their background transparent. 
If the icon images are antialiased, the resulting images may not be
perfect.

>  If you have, say, a jpeg pix and you converted to png using gimp. What
> property of "png" graphix should I look into as I ex****t the file?

Try the following steps and see if the result is good enough for your 
purpose.

1. Open the original icon image in GIMP

2. Use the Fuzzy Select Tool to create a selection of the background. 
Experiment with different threshold settings to obtain a selection that 
doesn't leave too much of an outline of the background color around the 
icon. (A threshold setting of 60 worked reasonably well in my 
experimentation.)

3. Give the selection feathered edges. (From the Select menu, select 
Feather... and set the desired thickness of the feathered edges. A value 
of 2 pixels worked reasonably well in my experimentation.)

4. Use the Color to Alpha function under the Colors menu to convert the 
background to transparent. The "From" color should be the background 
color to be removed.

5. Save the resulting image as a PNG file.

Good luck.