Re: gdk pixbufs, rgbbufs, efficiency, painting onto them

["cali" <calculus softhome net>]

> > I've tried this, it is fine but the problem is the availability of
> > primatives for drawing directly onto the buffer; especially stuff like 
> > text,
> > splines and stuff. Unless I am mistaken, are such primatives available 
> > that
> > write directly to a gchar buffer?
>
> Ah, sorry, I hadn't understood. There are a number of graphics
> libraries which will render to a gchar buffer for you, for example
> libart:

OK, I took a look at GnomeCanvas, looks pretty cool. However, I want to be 
perverse and still write directly to the buffer. I seem to be going round in 
circles, somebody please help me, I'm going mad.

The reason I wanted to draw directly to a buffer is because when drawing a 
CA, or a fractal for that matter, I set the color of each pixel 
individually. Calling gdk_draw_point on a pixbuf and using graphics contexts 
is going to be pretty slow to do this?

So intially I started using a gchar buffer (side note, I didn't realise I 
should have used a guchar buffer), and I was using the gdk_draw_image to 
draw this onto a drawing area. This was fine until I started wanting to zoom 
in and render different areas of the screen, I didn't want to waste time 
writing that code if it was available elsewhere.

So I looked at libart after suggestions for this list, but then noticed that 
gnomecanvas had cool features like the set pixel width and the scrollable 
area and so on, so I wanted to use that instead.

I have no idea what is going on with a gnomecanvas though. I am using 
gnome_canvas_new_aa(), because I wanted the buffer.

Now can someone tell me, can I still access the underlying buffer? or is 
this a completely ridiculous suggestion? Do I have to call a draw_point 
function instead? what is this function for the gnome-canvas?

Does the gnome canvas buffer automatically resize itself? Because presumably 
I should be allowed to access the buffer as long as it is not in the middle 
of being resized? Is access to the buffer thread safe? If I change the pixel 
width, does this alter the size of the underlying buffer, i.e and mess up 
any potential direct writing to the buffer, or is the pixel expansion done 
at the rendering stage?

As you can see, I've gone slightly mad, please help.

cali