Re: that gives 2 blank windows:( Re: hello, Mr. Ronald Bultje

[Hing-Wah Wan <50191914 ee cityu edu hk>]

On Thu, Mar 21, 2002 at 04:57:29PM +0000, guo li wrote:
> Hi, ronald,
>  I did try as you said, and realized the widget, but always get errors. 
> otherwise, I would not have such a headache and bother you again and  
> again,believe me, it is not so simple to me :(
> 
> I made my short program based on your code,
> hope you can point out which part is wrong. if you compile and run the 
> codes listed here
> 
> #include <gtk/gtk.h>
> #include <gdk-pixbuf/gdk-pixbuf.h>
> int main( int   argc,char *argv[] )
>                 {
>                     GtkWidget *window;
>                     GdkPixbuf *pixbuf;
>                     GtkWidget *widget;
> 
> 
>                     gtk_init (&argc, &argv);
> 
>                     window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
> 
>               	    widget = gtk_drawing_area_new();
> 
> 
>                     pixbuf = gdk_pixbuf_new_from_file("rose.jpg");
> 
>                     gtk_widget_set_usize(widget, 
> gdk_pixbuf_get_width(pixbuf),gdk_pixbuf_get_height(pixbuf));
>                     gtk_widget_realize(widget);
> 
> 
>                     printf("widget realized\n");
> 
>                     gdk_pixbuf_render_to_drawable (
>                                                    pixbuf, 
> widget->window,window->style->fg_gc[GTK_STATE_NORMAL],0, 0,0,0,
>                                                    
> gdk_pixbuf_get_width(pixbuf),
>                                                    
> gdk_pixbuf_get_height(pixbuf),
>                                                    GDK_RGB_DITHER_NORMAL, 
> 0, 0);
>                     printf("rendered\n");
> 
>                     gtk_container_add(GTK_CONTAINER(window), widget);
>                     printf("widget added to window\n");
> 
> 
>                     gtk_widget_show(widget);
>                     gtk_widget_show(window);
>                     gtk_main ();
> 
> 
> 
> 
> 
>                 }
> 
> 
> you will get 2 windows!!! and the errors like:
> 
> [gli olympia GTK]$ gcc base3.c `gtk-config --cflags --libs` 
> `gdk-pixbuf-config --cflags --libs`
> [gli olympia GTK]$ ./a.out
> 
gdk-pixbuf is included in gtk+2.0 so you no need have `gdk-pixbuf-config --cflags --libs`

also gdk_pix_buf_new_from_file("rose.jpg",NULL) instead of
gdk_pix_buf_new_from_file("rose.jpg");

you should have all drawing in the expose event,the following will work:

#include <gtk/gtk.h>                                                            
#include <gdk-pixbuf/gdk-pixbuf.h>                                              
#include <stdio.h>
void expose(GtkWidget* widget,GdkEvent *expose,GdkPixbuf *pixbuf)
{
		    gdk_pixbuf_render_to_drawable (                             
						   pixbuf,                      
						   widget->window,widget->style->fg_gc[GTK_STATE_NORMAL],
						   0,
						   0,
						   0,
						   0,                 
						   
						   gdk_pixbuf_get_width(pixbuf),                                                   
						   
						   gdk_pixbuf_get_height(pixbuf),                                                  
                                                   GDK_RGB_DITHER_NORMAL, 
						   0,
						   0);      

}
int main( int   argc,char *argv[] )                                             
{                                                               
  GtkWidget *window;                                          
  GtkWidget *widget;
  GdkPixbuf *pixbuf;
  gtk_init (&argc, &argv);                                    
  
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);              
  widget=gtk_drawing_area_new();
  pixbuf = gdk_pixbuf_new_from_file("rose.jpg",NULL);              
  
  gtk_widget_set_usize(widget,
		       gdk_pixbuf_get_width(pixbuf),
		       gdk_pixbuf_get_height(pixbuf));                    
  g_signal_connect(widget,"expose_event",(GCallback)expose,pixbuf);
  
  gtk_container_add(GTK_CONTAINER(window),widget);
  gtk_widget_show(widget);                                    
  gtk_widget_show(window);                                    
  gtk_main ();                                                
  return 0;
  
  
}



however,u can save all the trouble by GtkImage :

#include <gtk/gtk.h>                                                            

int main( int   argc,char *argv[] )                                             
{                                                               
  GtkWidget *window;                                          
  GtkWidget *w;
  gtk_init (&argc, &argv);                                    
  
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);              
  widget=gtk_image_new_from_file("rose.jpg");
  gtk_container_add(GTK_CONTAINER(window),widget);
  gtk_widget_show(widget);                                    
  gtk_widget_show(window);                                    
  gtk_main ();                                                
  return 0;
}