[Glade-devel] Scalable GtkImage for an HMI builder.

[Damon Chaplin]

On Thu, 2004-02-19 at 02:04, Juan Carlos Orozco wrote:
> Hello,
> 
> I implemented a HMI (Human Machine Interface) for the MatPLC project
> http://mat.sf.net (an OSS project) that uses Glade as its graphical
> builder. It is actually the official HMI editor for this project. There
> is a type of HMI where one draws a representation of the machine and
> then places widgets to view or control parts of the machine. There is a
> library of standard parts of a machine like pipes, valves, etc. Using
> the "Fixed Positions" type of layout one should be able to draw the
> machine from the library images, the problem is that there is no way of
> scaling the images. How difficult would it be to add a scaled toggle to
> the Properties dialog of the GtkImage and to have the image scaled to
> the whole widget size. When the widget gets rescaled the image will
> reflect this.
> 
> Maybe this screenshots of an application built using glade and executed
> using hmi_gtk and MatPLC can help visualize what is this all about.
> http://www.ace-lab.com/jorozco/
> 
> We are upgrading the HMI_GTK module to glade2. In the glade1 version we
> used GnomePixmap to do this. It did not scale to the widget size but
> instead used two parameters "scaled width" and "scaled height". This is
> not very practical but it worked, also this is deprecated widget and
> when we use libglade-convert this widget gets converted to a GtkImage.
> So we would prefer to use GtkImage if only we could scale the images and
> see a feedback of it.

GtkImage doesn't support scaling the image, so we can't really support
it in Glade.

I think you'll have to use a custom widget to do this. (You could use
some of the old GnomePixmap code.)


> BTW, I am also interested in custom widgets with visual feedback, this
> is that one can see the custom widget in the design window in its real
> form. I am thinking something similar to the way a graphical java bean
> is represented in a IDE tool. Is something like this planned in the new
> Glade3 development? Bonobo components perhaps? I know there is a custom
> widget in Glade2 but it gets drawed as a plain square. I am pushing my
> luck here, but it would be great if this custom widgets could be placed
> in a palette.

It is planned in Glade3. Bonobo components are partially supported in
Glade2, though I'm not sure how well they work.

Damon