[LAD] OT: gtk rectangle with opacity

[Patrick Shirkey]

On 12/28/2009 05:43 AM, hermann wrote:
> Am Sonntag, den 27.12.2009, 19:39 +0100 schrieb hermann:
>    
>> gboolean box_expose(GtkWidget *wi, GdkEventExpose *ev, gpointer data)
>>      {
>>        cairo_t *cr;
>>        // create a cairo context //
>>        cr = gdk_cairo_create(wi->window);
>>
>>        double x0      = wi->allocation.x;
>>        double y0      = wi->allocation.y;
>>        double rect_width  = wi->allocation.width;
>>        double rect_height = wi->allocation.height;
>>
>>        cairo_rectangle (cr, x0,y0,rect_width,rect_height+3);
>>        cairo_set_source_rgba (cr, 0, 0, 0, 0.5); // a set the opacity
>> level
>>        cairo_fill (cr);
>>        cairo_destroy(cr);
>>      
>    // EDIT:// don't forget to
>         return false;
>    //
>    
>>       }
>> draw a transparent black rectangle to the calling widget.
>> You can connect it with to make sure it will redraw when needed.
>>
>> g_signal_connect(widget, "expose-event", G_CALLBACK(box_expose), NULL);
>>
>> more examples you could found here
>>   http://cairographics.org/samples/
>>
>> regards  hermann
>>      



Thanks. That's what I was looking for. I was getting close but this code 
definitely saves me some time.

FYI, I am have merged the gtkmeter.c and gtkmeterscale.c classes into 
one widget. With the transparent levels it looks very nice now.

If anyone wants this class let me know.


Cheers.


Patrick Shirkey
Boost Hardware Ltd






>> Am Montag, den 28.12.2009, 04:30 +1100 schrieb Patrick Shirkey:
>>      
>>> Hi,
>>>
>>> Does anyone have an example in c of drawing a gdk_rectangle with opacity
>>> in the foreground color?
>>>
>>> There's several examples in python floating around that use the cairo
>>> but I can't find a nice example in c.
>>>
>>>
>>>
>>>
>>> Cheers.
>>>
>>>        
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>