Regression in compose-xx-with-transformation

[Daniel Kochmański]

The easy fix is to wrap draw-chart body in with-drawing-options -
you change destructively the medium transformation in a function adjust-for-axes
and the next invocation adds another transformation on top of that.

That said it is (rather) a regression that McCLIM invokes the function
multiple times despite of incremental-redisplay being T. I'll investigate that
when I have some time.

Thank you for reporting this regression.

Best regards,
Daniel


--
Daniel Kochmański ;; aka jackdaniel | Przemyśl, Poland
TurtleWare - Daniel Kochmański      | www.turtleware.eu

"Be the change that you wish to see in the world." - Mahatma Gandhi

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Tuesday, March 23, 2021 6:15 AM, Daniel Kochmański <daniel at turtleware.eu> wrote:

> Hey Paul
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Monday, March 22, 2021 9:02 PM, Paul Werkowski pw at snoopy.qozzy.com wrote:
>
> > A recent change in master branch seems to have reversed the argument
> > order in the subject definitions. I've only checked
> > compose-scaling-with-transformation which is again wrong causing my
> > graphics to be written way off screen.
>
> Indeed we had problems with transformations, but the issue was fixed; maybe
> your code depended on invalid behavior?
>
> compose-scaling-with-transformation is defined to first apply scaling, then
> transformation (http://bauhh.dyndns.org:8000/clim-spec/5-3.html#_208)
>
> (c:transform-position
> (c:compose-scaling-with-transformation
> (c:make-translation-transformation -100 -100) 100 100)
> 1 1) ;-> (values 0 0)
>
> (c:transform-position (c:make-scaling-transformation 100 100) 1 1) ;-> (values 100 100)
> (c:transform-position (c:make-translation-transformation -100 -100) 100 100) ; -> (values 0 0)
>
> Seems correct. The reverse order would give:
>
> (c:transform-position (c:make-translation-transformation -100 -100) 1 1) ;-> (values -99 -99)
> (c:transform-position (c:make-scaling-transformation 100 100) -99 -99) ;-> (values -9900 -9900)
>
> Evaluating the former in clim-tos confirms that. IMO it is quite counterintuitive, because:
>
> (compose-transformations A B) first applies B, then A
> (compose-X-with-transformation T , at X-parameters) first applies X then T
> (compose-transformation-with-X T , at X-parameters) first applies T then X
>
> Do you agree?
>
> > Paul
>
> Best regards,
> Daniel
>
>
> ------------------------
>
> Daniel Kochmański ;; aka jackdaniel | Przemyśl, Poland
> TurtleWare - Daniel Kochmański | www.turtleware.eu
>
> "Be the change that you wish to see in the world." - Mahatma Gandhi