BF: Amendments to JP fix to getRegionOfFrame - now working

[dvbridges]

Note, getpixel from the returned image object does not work if back buffer is used, or if full screen is used.

[codecov-io]

Codecov Report

Merging #1854 into master will decrease coverage by <.01%.
The diff coverage is 93.75%.

@@            Coverage Diff             @@
##           master    #1854      +/-   ##
==========================================
- Coverage   45.64%   45.64%   -0.01%     
==========================================
  Files         221      221              
  Lines       35174    35168       -6     
  Branches     5864     5864              
==========================================
- Hits        16054    16051       -3     
+ Misses      17541    17539       -2     
+ Partials     1579     1578       -1

Impacted Files	Coverage Δ
psychopy/visual/window.py	70.74% <93.75%> (-0.24%)	⬇️
psychopy/tools/wizard.py	74.45% <0%> (+0.65%)	⬆️

---

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 d6cb9a8...2457eb2. Read the comment docs.

[coveralls]

Coverage decreased (-0.003%) to 50.125% when pulling 2457eb2 on dvbridges:gePixelFromFrame into d6cb9a8 on psychopy:master.

[peircej]

But it looks like you're saying that accepting this change means that we're no longer able to fetch from the back buffer? We do need to be able to do that. We can't just turn off uses of the back-buffer; there are times when it's important to be able to exam pixels before a flip command.

[dvbridges]

I dont think I have made any changes that stop you from fetching from the back buffer. I was just saying that if you do try to use the back buffer, the buffered image does not seem to hold all the components, only the background image. So, when you try to get specific pixels from the back buffer, you cannot get pixels from visual components, such as shape, as they do not appear on the back buffered image.

[peircej]

Ah, you're meaning from a Builder experiment? That's fine, yes the issue is that all stimuli that have been rendered (with .draw() ) should show up in the back buffer, but stimuli rendered using autoDraw=True (as in a Builder experiment) are only rendered when win.flip() is called. So if you grab the backbuffer before win.flip() then yes, visual builder components won't show up. Then again, if you grab it with buffer='front' then you're effectively getting the contents of the previous frame, not the current one.

[dvbridges]

Great thanks. So, should we draw to back buffer if _getFrame is requested with buffer='back'?

[peircej]

should we draw to back buffer if _getFrame is requested with buffer='back'?

I don't follow. Can chat tomorrow though

[dvbridges]

Ok, as this request is ok for now, would you mind merging with master?