[PD-dev] adding a built-in [change] object to the built-in GUI objects

[Hans-Christoph Steiner]

On Dec 1, 2012, at 3:28 AM, Jonathan Wilkes wrote:

> ----- Original Message -----
> 
>> From: Hans-Christoph Steiner <hans at at.or.at>
>> To: "pd-dev at iem.at List" <pd-dev at iem.at>
>> Cc: 
>> Sent: Friday, November 30, 2012 11:20 PM
>> Subject: [PD-dev] adding a built-in [change] object to the built-in GUI objects
>> 
>> 
>> Lots of patches use the built-in GUI objects for displays, and often a fast 
>> stream of events is hooked straight up to the GUI object, causing the GUI object 
>> to send many pointless updates, like draw commands when the number hasn't 
>> changed, or multiple draw commands per screen refresh cycle.
> 
> The multiple draw commands per screen refresh cycle seems like the more common
> source of needless draw commands.

That should be addressed too, but that's a lot more complicated.  Honestly, I think it would be better to rewrite the basic GUI objects from scratch rather than put more into the current ones.


>> I propose to only send the GUI update commands when the relevant value has 
>> changed.  I think this should apply to both the main element, like the slider 
>> knob, and the label for that GUI object, since that's often used as a 
>> display.  The code change is pretty simple, but I was wondering if people 
>> thought there could be any problems caused by this
> 
> At the end of hslider_set, why not just check if x->x_value==(int)(100.0*g + 0.49999)
> before assigning it?  If its already equal just return.

Good idea, that's what I ended up doing:
http://pure-data.svn.sourceforge.net/viewvc/pure-data?view=revision&revision=16643

Then I did something similar for the [label ( draws:
http://pure-data.git.sourceforge.net/git/gitweb.cgi?p=pure-data/pd-extended.git;a=commitdiff;h=0271c92082c6db85eccba0f0b1226b9dbff09ceb

.hc

> 
>> 
>> Here is the needed change, for example, for the hslider knob:
>> 
>> index b352fb9..88681fc 100644
>> --- a/src/g_all_guis.h
>> +++ b/src/g_all_guis.h
>> @@ -185,6 +185,7 @@ typedef struct _hslider
>>      t_iemgui x_gui;
>>      int      x_pos;
>>      int      x_val;
>> +    int      x_prev_val;
>>      int      x_center;
>>      int      x_thick;
>>      int      x_lin0_log1;
>> index 470771a..e1a3c83 100644
>> --- a/src/g_hslider.c
>> +++ b/src/g_hslider.c
>> @@ -33,7 +33,7 @@ static t_class *hslider_class;
>> static void hslider_draw_update(t_gobj *client, t_glist *glist)
>> {
>>      t_hslider *x = (t_hslider *)client;
>> -    if (glist_isvisible(glist))
>> +    if (glist_isvisible(glist) && x->x_val != x->x_prev_val)
>>      {
>>          int r = text_xpix(&x->x_gui.x_obj, glist) + (x->x_val + 
>> 50)/100;
>>          int ypos=text_ypix(&x->x_gui.x_obj, glist);
>> @@ -57,6 +57,7 @@ static void hslider_draw_update(t_gobj *client, t_glist 
>> *glist)
>>                  x->x_thick = 0;
>>              }
>>          }
>> +        x->x_prev_val = x->x_val;
>>      }
>> }
>> 
>> 
>> 
>> _______________________________________________
>> Pd-dev mailing list
>> Pd-dev at iem.at
>> http://lists.puredata.info/listinfo/pd-dev
>>