[Pan-devel] Re: Partial Patch - Add the ability to scale images

[Danny Milosavljevic]

Hi,

On Wed, 28 Jun 2006 21:51:16 -0400, Darren Albers wrote:
> All,
> 
> Attached is a partial patch that gives the ability to scale images in 
> the body pane.  I am posting it here in hopes that someone can point me 
> in the right direction for the last piece, how do I determine the 
> geometry of the body pane

in body-pane.cc, read GTK_WIDGET(_root)->allocation.width

after you got a "size-allocate" signal (i.e. in your signal handler for
that).

> so I can scale the image appropriately?  The
> GTK toolkit has a number of function to determine window size but not
> the pane itself.  

It's a public member variable. Yeah, weird :)

> [...]
> This patch adds a preference option to scale attached images and
then
> uses the gdk_pixbuf_scale_simple() to scale the image down.  

Don't forget to unreference the pixbuf.

> This patch
> should maintain the proper aspect ratio, I reused some code from eog to
> determine how to properly scale the image and it seems to handle all
> images properly but I thought a bit about it today and I think it is
> flawed for this use and I think I have a better way to handle it that I
> will look at tonight.

In my holy opinion horizontal scrolling sucks but vertical scrolling is
normal. Because of this, I suggest always scaling to the maximum possible
width and adjust height as needed to keep aspect ratio. 

> [...]
> -    return pixbuf;
> +      g_object_unref (G_OBJECT(l));
> +    if (prefs.get_flag ("scale-images-to-fit", true)) +    { 
+ //Hard coding the pane height and width temporarily until I can 
>figure out how to get the pane geometry. 
>+    int height = 600; 
>+    int width = 600; 
>+
>    int image_width = gdk_pixbuf_get_width (pixbuf); 
> +    int image_height = gdk_pixbuf_get_height (pixbuf); 
> +    //stolen from eog eog-image.c, this section determines how we scale
> the image 
> + if (((gdouble) image_height/image_width) > 
> + ((gdouble)width/height)) { 
> +             /* We scale to the top */ 
> +             width = height * (gdouble)image_width/image_height; 
> +     } else { 
+ /* We scale to the sides of the page */ 
> +             height = width * (gdouble)image_height/image_width; 
> +     } 
> +     scaled = gdk_pixbuf_scale_simple (pixbuf, width, height
> ,GDK_INTERP_BILINEAR); 

g_object_unref(G_OBJECT(pixbuf));

> +     return scaled; +    }
> +    else {
> +       return pixbuf;
> +    }
>    }
>  }
>[...]

p.s.: sorry about the weird reply (without the proper 
thread references), but gmane is acting up for me and so
I post this with a mail client :)

cheers,
  Danny