[davidmanpearl]

I am using 4 channel images for my MIDlet icon, for my Display.ALERT icon, and for various image displays in forms. I am having confusing difficulties with transparancy.

This discussion is for Nokia 6682 (I believe that Nokia 6620 cannot handle 4-channel .png images at all and I have read many similar complaints on this forum regarding 6230).
I get the exact same behavior with .png and .bmp images on 6682.

MIDlet icon:
This icon is most bizarre because depending on polarity of the alpha channel, it behaves oppositly in the System Main Menu and in the Title of my MIDlet Display. This icon is 42x29 pixels.
When the alpha value for transparent areas are white (255) and opaque is black (0), then the icon displays correctly on the desktop and is 100% white within my MIDlet.
When the alpha is inverted to transparent black (0) and opaque white (255), then it is displayed inverted on the desktop and correctly in the MIDlet.

My hunch is that not all 8-bits of the alpha channel are used. I have tried various levels of gray to the limits of my Photoshop skills, and I am not there yet.

Please tell me...
What should the alpha value be for opaque?
What should the alpha value be for invisible?
Are various levels of transparency supported? If so, do they use the full 8-bit range?

Finally: If you want to help and you are not sure about alpha channels but you have a working transparent MIDlet icon in either .png or .bmp, please send it to me at the eMail address below (replace "_at_" and "_dot_" with their symbol counterparts).

- Thank you, David Manpearl <dmanpearl_at_imatte_dot_com>

P.S. Display.numAlphaLevels() returns 256 for the Nokia 6682, so I believe that 0 should be transparent and 255 should be opaque (2^8bits - 1 = 255, of course).

I don't think a png tRNS chunk is contributing to the problem because bmp and png files behave identically. Any ideas?

[soku123]

for setting transperancy the alpha value should be ax00 and the remaining rgb values...
Regards
Soku

[davidmanpearl]

Hi, thank you very much for your response. In addition to the remaining rgb values I have been setting the alpha to 0x00 (0) for invisible pixels and 0xff (255) for opaque as above. I assume that your recommendation of "ax00" is equivalent to 0x00.

I am using combinations of Adobe Photoshop and XnView to write the .png files and there are many options. In Photoshop, the matte information can be maintained in a Transparency layer or a 4th "Alpha" channel. In XnView there is a .png compression value (def 6) and an interesting option to "Set the transparency value to pallette entry:" and then a number field.

I tried many combinations and options for .png and .bmp and I can get the MIDlet icon 42x29 to display correctly in either the System Main Menu **OR** in the MIDlet title, but never both.

This is why I requested (and still request) that someone please send a working MIDlet icon with transparency from their J2ME development environment directly to <dmanpearl_at_imatte_dot_com>.

- Thanks again, David

[davidmanpearl]

Would someone please send an example of a working MIDlet icon with transparency. What program do you use to write your icon image files?

- David <dmanpearl_at_imatte_dot_com>

[doug4pres]

Hi,

I am/was having the same problem.
No matter what I did, the icon that shows up in the menus is an inverted version of the one that looks just fine inside the application.

Don't know whether this is still an issue for you, but I got sick of messing with the PNG settings and tried a GIF with transparency enabled.

Works perfectly - both icons look fine.

Doug

[wuuikok]

hi

i am newbie and i have the same problem.

what is the meaning of "GIF with transparency enabled" and how to create it. is it using the adobe photoshop? what should i do to create it?

thanks.

wu ui kok
cellcity