[RFC] Continuous zoom

[mindhells]

Please see #80 to better understand what we are trying to do here.

[codecov]

Codecov Report

Merging #175 (ef216b8) into master (aab8a8f) will decrease coverage by 0.00%.
The diff coverage is 89.81%.

@@            Coverage Diff             @@
##           master     #175      +/-   ##
==========================================
- Coverage   85.92%   85.91%   -0.01%     
==========================================
  Files          55       55              
  Lines       10389    10475      +86     
==========================================
+ Hits         8927     9000      +73     
- Misses       1462     1475      +13     

Impacted Files	Coverage Δ
fract4d/fractconfig.py	93.13% <ø> (ø)
fract4d/messages.py	84.61% <50.00%> (-3.85%)	⬇️
fract4dgui/gtkfractal.py	83.88% <90.00%> (+0.69%)	⬆️
fract4dgui/preferences.py	77.30% <91.66%> (+0.69%)	⬆️
fract4d/fractal.py	91.94% <100.00%> (+0.03%)	⬆️
fract4dgui/main_window.py	63.96% <100.00%> (+0.08%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update aab8a8f...ef216b8. Read the comment docs.

[edyoung]

Hi folks! Just wanted to say - thanks a ton for all the work that has gone into this! Sorry I have been scarce the last few months. I've been super busy at work. I have some time off over the holidays so will aim to review, merge and release this as soon as we can.

[mindhells]

Hi folks! Just wanted to say - thanks a ton for all the work that has gone into this! Sorry I have been scarce the last few months. I've been super busy at work. I have some time off over the holidays so will aim to review, merge and release this as soon as we can.

That's great news. I'm going to post the last updates in the related issue so you have all the details.
There's a couple of more things to add to this PR before it's ready for review, the idea is to have them before christmas.

[edyoung]

One way of thinking about this: imagine you are taking the previous frame and scaling it up. In frame 1, to get the color for pixel (0,0) we calculated point (x,y,z,w). In Frame 2, point (x,y,z,w) is now at a different pixel location, but if that location is still on screen, we can reuse the calculation and color pixel(a,b) with that point. I'm pretty sure that doesn't really depend on only x changing as we move across the screen or y changing vertically. We have a vector (dx,dy,dz,dw) which is the amount the point changes when we step 1 pixel to the left - we can use that to generalize this to work for rotated images or ones in other planes.

[mindhells]

That was exactly my thought when I first read https://github.com/xaos-project/XaoS/wiki/Developer's-Guide#saving-previous-pixels.
Then I said to myself "ok, let's try only XY plane (no plane rotation)". I was surprised when I found out you can actually change plane rotations and it keeps working. Except in certain cases.
As the Gnofract 4D manual states:

It allows you to treat a fractal which has more than one parameter as a four-dimensional object and interactively view slices of this object from arbitrary angles, giving rise to some very unusual images.

It seems that, as long as the slice you are viewing is parallel to one of the axis X or Y, the assumption is valid. In other words, if you rotate the slice respect to X and Y at the same time, then it doesn't work.
I tried to solve this issue/limitation, being playing around with the rotation matrix, point vectors... but honestly I don't have the math background to.

[mindhells]

@edyoung is it ok if we merge this PR?
We haven't received any additional feedback so far and it would be a shame to leave this here forever. Besides, this feature could be enabled/disabled by configuration.

[edyoung]

yes! go for it

…

On Wed, Apr 7, 2021 at 8:30 AM Alberto Gonzalez ***@***.***> wrote: @edyoung <https://github.com/edyoung> is it ok if we merge this PR? We haven't received any additional feedback so far and it would be a shame to leave this here forever. Besides, this feature could be enabled/disabled by configuration. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#175 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAALECRL6A3W2OS6WAVDX5DTHR3ALANCNFSM4RQFNH2A> .

[da2ce7]

Needs Rebase.

[josebailo]

Rebase done!

@cjmayo I removed the commented line and refactored the create_continuous_zoom_widget.

Regarding the flake8 check, I haven't found anything about using flake8 in the project so I'm not sure how to proceed. Are you using it by yourself or is established for developing?

[mindhells]

Hi @edyoung ,
after rebase, test are failing because this condition is true:

gnofract4d/fract4d/c/model/site.cpp

Lines 24 to 29 in aab8a8f

	if (m_thread.get_id() == std::this_thread::get_id())
	{
	// something is very wrong
	std::cerr << this << "Waiting on own thread in IFractalSite::wait()!" << m_thread.get_id() << "\n";
	throw std::exception();
	}

can you elaborate under what circumstances this may happen? Maybe we're missing something anywhere else

[cjmayo]

Regarding the flake8 check, I haven't found anything about using flake8 in the project so I'm not sure how to proceed. Are you using it by yourself or is established for developing?

It's only me. I just mentioned it because the single blank line before the class was obvious, that's fixed after the rebase.

[josebailo]

Sorry for the delay.

I've been checking why the tests fails. First I thought this was because of some change on this branch, but I found a commit by @edyoung in another branch skipping this test because it fails intermittently.

I've skipped the test and it works now!