[PD-dev] canvas_* functions and using glist_getcanvas()

[Hans-Christoph Steiner]

Ok, keep me posted.  If that turns out to be wrong, I can change it in  
a lot of externals in SVN too.

.hc

On Jul 14, 2010, at 4:11 PM, Miller Puckette wrote:

> I think those are all wrong and will try changing them over here :)
>
> thanks
> M
>
> On Wed, Jul 14, 2010 at 04:07:16PM -0400, Hans-Christoph Steiner  
> wrote:
>>
>> Sounds like you are saying that calls to canvas_fixlinesfor()
>> shouldn't have calls to glist_getcanvas() in them.  It seems not very
>> straightforward, for example, the iemguis included in Pd-vanilla have
>> this:
>>
>> canvas_fixlinesfor(glist_getcanvas(x->x_gui.x_glist), (t_text*)x);
>>
>> .hc
>>
>> On Jul 14, 2010, at 3:15 PM, Miller Puckette wrote:
>>
>>> I think glist_getcanvas() is only appropriate when getting or  
>>> changing
>>> properties that are inherited from the containing canvas (whether
>>> visible
>>> or not, for example) -- and many canvas_whatever(canvas, object) or
>>> glist_whatever(canvas, object) calls assume tha the oject is indeed
>>> in that
>>> glist itself (glist is synonym for canvas) and will crash if not.
>>>
>>> cheers
>>> Miller
>>>
>>> On Wed, Jul 14, 2010 at 01:17:41PM -0400, Hans-Christoph Steiner
>>> wrote:
>>>>
>>>> I've noticed that in GUI objects, its quite common to call the
>>>> canvas_* functions using glist_getcanvas().  I also just found out
>>>> that this causes a crash in [envgen] when this is done for
>>>> canvas_deletelinesfor().  See bug:
>>>>
>>>> http://sourceforge.net/tracker/index.php?func=detail&aid=2842897&group_id=55736&atid=478070
>>>>
>>>> So it seems to me that glist_getcanvas() should not be called on  
>>>> the
>>>> glist before sending it to one of these canvas functions.  I was
>>>> wondering if this is kind of a blanket rule, and we should be
>>>> removing
>>>> the glist_getcanvas() calls in GUI objects.  For example:
>>>>
>>>> unauthorized/cooled~/cooled~.c:
>>>> canvas_deletelinesfor( glist_getcanvas(glist), (t_text *)z);
>>>> unauthorized/cooled~/cooled~.c:
>>>> canvas_fixlinesfor( glist_getcanvas( x->x_glist ), (t_text*)x );
>>>>
>>>> In ggee/gui/w_envgen.h, I fixed the crasher by replacing:
>>>>
>>>>  canvas_deletelinesfor(glist_getcanvas(glist), x);
>>>>
>>>> with this:
>>>>
>>>>  canvas_deletelinesfor(glist, x);
>>>>
>>>> .hc
>>>>
>>>> ----------------------------------------------------------------------------
>>>>
>>>> "Free software means you control what your computer does. Non-free
>>>> software means someone else controls that, and to some extent
>>>> controls
>>>> you." - Richard M. Stallman
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Pd-dev mailing list
>>>> Pd-dev at iem.at
>>>> http://lists.puredata.info/listinfo/pd-dev
>>
>>
>>
>>
>>
>> ----------------------------------------------------------------------------
>>
>> 'You people have such restrictive dress for women,? she said,  
>> hobbling
>> away in three inch heels and panty hose to finish out another pink-
>> collar temp pool day.  - ?Hijab Scene #2", by Mohja Kahf
>>





----------------------------------------------------------------------------

Programs should be written for people to read, and only incidentally  
for machines to execute.
  - from Structure and Interpretation of Computer Programs