Re: GdkPixbuf questions

[David Nečas (Yeti) <yeti physics muni cz>]

On Wed, Mar 21, 2007 at 03:50:44PM +0800, s88 wrote:
>       I have some questions when I using the drawable area with the
> gtk+2.0.
> First, I'm building a data analyzer under thr Linux, so there is a process
> to generate the data and  my analyzer display the data.
> My idea is to use a drawable area(I use the GtkDrawingArea) and get the pix
> buffer of it by the gdk_pixbuf_get_from_drawable(),

There is no such thing as `the pixbuf of it'.  Every time
you call gdk_pixbuf_get_from_drawable() a new image of the
drawable is created and put to the pixbuf.  Read the first
paragraph of gdk_pixbuf_get_from_drawable() description.
And if parts of the drawable are obscured, you get garbage
there -- see paragraphs 5 and 6.  And the other paragraphs
too.

> then my background
> program can fill the pix buffer pix by pix.

You can do anything you wish with the pixbuf, but it will
have no effect on the widget.

> Question 2: the following code segment is what I done until now...what
> should I do?

If you want to display a pixbuf, just create a pixbuf with
gdk_pixbuf_new(), fill its contents and draw it with
gdk_draw_pixbuf() in the expose event of the widget.

Yeti

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