[Lazarus] create bng with transparent background

Luca Olivetti luca at wetron.es
Wed Jun 10 15:04:05 CEST 2020

El 10/6/20 a les 14:52, R.Smith via lazarus ha escrit:

> I think the best way to make a transparent PNG currently, is to do what 
> you did, but then paint at least the upper left corner pixel with a 
> transparency of 1 and not Zero, which you still won't see, however, may 
> I suggest using the very useful BGRA Bitmap package? Then it simply 
> becomes a question of:

Yes, that's what I finally did, but it's overkill considering that I 
just need to generate a circle with a specified color.

> Also, how do you know the output PNG file is not transparent? I ask 
> because windows and windows viewers will sometimes show a perfectly 
> transaprent PNG with a Black/White background. The only safe way to know 
> is to open it in Paint or GIMP or such. (Linux typically doesn't lie 
> like that, but any specific viewer may of course still do it some 
> arbitrary way. A graphic editor is obliged to show the real content.)

I loaded them in firefox (which is the intended usage since the 
application is a webserver).

Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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