Re: Type conversions

[turkaye dre vanderbilt edu (Emre Turkay)]

Hi Mert,

   Using the X-lib, IMHO, generally not a good idea, because it
   is too complex and platform dependent. Instead you can use gdk or
   other performance sensitive approaches.

   Excerpt from GTK+ FAQ at http://www.gtk.org/faq:

   * How do I get the Window ID of a GtkWindow? [GTK 2.x]
   The actual Gdk/X window will be created when the widget gets realized. You
   can get the Window ID with:

   #include <gdk/gdkx.h>
   Window xwin = GDK_WINDOW_XWINDOW (GTK_WIDGET (my_window)->window);

   * How do I render pixels (image data) to the screen?
   There are several ways to approach this. The simplest way is to use
   GdkRGB, see gdk/gdkrgb.h. You create an RGB buffer, render to your
   RGB buffer, then use GdkRGB routines to copy your RGB buffer to a
   drawing area or custom widget. The book "GTK+/Gnome Application
   Development" gives some details; GdkRGB is also documented in the
   GTK+ reference documentation.

   If you're writing a game or other graphics-intensive application, you
   might consider a more elaborate solution. OpenGL is the graphics
   standard that will let you access hardware accelaration in future
   versions of XFree86; so for maximum speed, you probably want to use
   OpenGL. A GtkGLArea widget is available for using OpenGL with GTK+
   (but GtkGLArea does not come with GTK+ itself). There are also
   several open source game libraries, such as ClanLib and Loki's Simple
   DirectMedia Layer library (SDL).

   You do NOT want to use gdk_draw_point(), that will be extremely slow.

HTH,

  Emre

On Thu, Apr 21, 2005 at 01:33:34AM -0500, MERT TUGCU wrote:
> Hi everyone,
> 
> I am trying to use X11 library to draw incoming video frames to a drawing 
> area. I have found out that Gdk::Pixbuf::render_to_drawable method is very 
> slow to draw the incoming frames. The first thing to do is to query your 
> video adapter in X11. The function prototype is:
> XvQueryAdaptors(Display*, Window*, int, XvAdaptorInfo). However, I don't 
> know how to make the type conversions. I have created a class for my 
> drawing area like as follows:
> class CustomDrawingArea : public Gtk::DrawingArea
> Next I've creat an object from this class and add it to my GUI. In order to 
> get the display and the window I used:
> Window* window = (Window*)(drawingarea->get_window()); //drawingarea is the 
> object from the above class
> Of course this didn't work out. get_window() method returns 
> Glib::RefPtr<Gdk::Window> and this does not match to Window class in X11. 
> Would you please tell me how to make this type conversion or am I 
> completely doing something wrong? I really have to use the X11 library to 
> draw fast. Thank you very much for your response and your time.
> 
> 
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