https://bugs.kde.org/show_bug.cgi?id=399190
Bug ID: 399190
Summary: Instant Preview causes severe canvas slowdown with
non-painting tools on large documents
Product: krita
Version: unspecified
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: Instant Preview
Assignee: krita-bugs-n...@kde.org
Reporter: tyson...@mail.com
Target Milestone: ---
SUMMARY
Instant Preview causes severe canvas slowdown with non-painting tools on large
documents. Tested on Manjato 17.1.2 with
krita-4.2.0-pre-alpha-4f31265-x86_64.appimage, i7-6567U+16GB+Iris550
(Turboburst and Framebuffer Compression disabled)
STEPS TO REPRODUCE
1. Create a A3 600 dpi document
2. Draw something
3. Compare the performance between Instant Preview ON/FF when using tools like
Zoom / Selection Add-Subtract / Transform / Undo-Redo
OBSERVED RESULT
When I was working with a 14000x14000 document with only 2 layers (one of them
is lineart and the other is white), Instant Preview caused severe slowdown all
the time. Krita needs 1-3 seconds to respond to any action (Zoom / Selection
Add-Subtract / Transform / Undo-Redo) on the canvas when Instant Preview is ON.
Only drawing is usable. Everything else is extremely slow and choppy. When
Instant Preview was turned OFF, everything went back to normal.
EXPECTED RESULT
Instant Preview should not cause any slowdown, or should be set to OFF by
default. Since the majority of users would not use crazy big brushes, leaving
such a function that causes constant, huge slowdowns is not wise.
At least from my experience, I gave it a chance every time when a new Krita
version was released, but never once did it worked sufficiently fast on A4 300
dpi. It made drawing unpleasant at its best, and it made Krita totally unusable
at its worst, like this reported instance. And for what reason this time it
actually affected tools that does not paint.
Of all the questions I was asked by other artists about Krita's slow
performance, more than a half of them were caused by Instant Preview. Artists
are very sensitive to even small slowdowns, not to mention slowdowns at such
level. Many new users told me they just gave up Krita the moment when the first
few strokes were drawn. I suggest keep Instant Preview OFF by default and let
people enable it on demand when they want to use it with a huge brush.
SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version:
KDE Frameworks Version:
Qt Version:
ADDITIONAL INFORMATION
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