[rrd-users] alpha channel on rrdtool PNG vs. TCPDF

Valter Douglas Lisbôa Jr. douglas at trenix.com.br
Sun Jun 29 17:39:09 CEST 2008

Hello All!

I'm new on this list, and this is my first post.

Creating a System to load the graph generated in PNG format from rrdtool with 
PHP 5, I was very sucefull. However, when I try to put it on a PDF utilizing 
TCPDF 3.1.001 PHP class, I got a error. 

TCPDF error: Alpha channel not supported: file.png

This class has a limitation from loading PNG with transparent colors, it's a 
known bug not corrected yet, and this is the only format in common with 
rrdtool. So, I try to remove the PNG's alpha channel by rrdtool, definning 
every color with -c or in LINE/AREA/etc with the solid attribute (FF) on the 
end of color. It wasn't exactly a success :-( the error continues.

Then I "googling" for PHP functions to find a way to remove the alpha channel, 
I already try to detect if exists a color with imagecolortransparent(), with 
another failure (it returns -1).

Going to the point! How can I generate with rrdtool 1.2.x a PNG without a 
alpha channel? Or does anyone can point me the way to do this with another 
software on-the-fly?

Thanks in advance

Valter Douglas Lisbôa Jr.
Trenix - IT Solutions
"Nossas Idéias, suas Soluções!"
contato at trenix.com.br
Tel. +55 19 3402.2957
Cel. +55 19 9183.4244

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