it's a great initiative but too damm slow

[N30Z3N]

like literally the slowest app will you please fix it :D ? because this has great potential

[molecule-man]

@N30Z3N Thanks for the "great potential". It's not that slow on my machine so I 'd appreciate some pdfs that are especially slow for you. Also would be nice if you'd share your machine characteristics. Is it some action that is slow? Is it scrolling, resize, document loading, or everything is slow?

[N30Z3N]

That's quickest response thanks, found this out of the blue and no other pdf app can do horizontal scroll as I want. In general the pdf loads a bit slow and also horizontal scrolling is slow too like page flickers while loading next page, I used touchpad and keyboard shortcuts too

well my machine info :

        _,met$$$$$gg.          xx@xx
     ,g$$$$$$$$$$$$$$$P.       -------------------
   ,g$$P""       """Y$$.".     OS: Debian GNU/Linux 13 (trixie) x86_64
  ,$$P'              `$$$.     Host: ASUS TUF Gaming A15 FA506QM (1.0)
',$$P       ,ggs.     `$$b:    Kernel: Linux 6.12.94+deb13-amd64
`d$$'     ,$P"'   .    $$$     Uptime: 11 hours, 48 mins
 $$P      d$'     ,    $$P     Packages: 2938 (dpkg)
 $$:      $$.   -    ,d$$'     Shell: bash 5.2.37
 $$;      Y$b._   _,d$P'       Display (NCP004D): 1920x1080 @ 60 Hz (as 1601x900) in 16" [Built-in]
 Y$$.    `.`"Y$$$$P"'          DE: KDE Plasma 6.3.6
 `$$b      "-.__               WM: KWin (Wayland)
  `Y$$b                        WM Theme: Breeze
   `Y$$.                       Theme: Breeze (Dark) [Qt], Breeze-Dark [GTK2], Breeze [GTK3]
     `$$b.                     Icons: breeze-dark [Qt], breeze-dark [GTK2/3/4]
       `Y$$b.                  Font: Noto Sans (10pt) [Qt], Noto Sans (10pt) [GTK2/3/4]
         `"Y$b._               Cursor: breeze (24px)
             `""""             Terminal: konsole 25.4.2
                               CPU: AMD Ryzen 9 5900HX (16) @ 3.30 GHz
                               GPU 1: NVIDIA GeForce RTX 3060 Mobile / Max-Q [Discrete]
                               GPU 2: AMD Radeon Vega Series / Radeon Vega Mobile Series [Integrated]
                               Memory: 7.68 GiB / 15.03 GiB (51%)
                               Swap: 442.78 MiB / 3.10 GiB (14%)
                               Disk (/): 26.67 GiB / 54.77 GiB (49%) - ext4
                               Disk (/media/xx/---): 163.19 GiB / 194.33 GiB (84%) - ntfs3
                               Disk (/media/xx/New Volume): 71.17 GiB / 140.00 GiB (51%) - ntfs3
                               Disk (/media/xx/New Volume1): 49.79 GiB / 81.63 GiB (61%) - ntfs3                            

[molecule-man]

Hm, thanks for the details. Looking into it

[molecule-man]

@N30Z3N the touchpad has indeed caused some issues:

• touchpad was handled by gtk-native handler which was fighting with app's custom scrolling
• touchpad changed app's focus and shortcuts didn't work after that

The app was designed with efficient mouse wheel scrolling in mind (my personal workflow) so I never tested it with touchpad before. Anyways this issues should be fixed now. Try https://github.com/molecule-man/scrolex/releases/tag/0.2.0 https://github.com/molecule-man/scrolex/releases/tag/0.2.1 if it works better for you.

Note that

• horizontal touchpad scroll gesture might still feel slow. Try vertical scroll gesture - it scrolls the whole page at a time
• I added animated scrolling to make the scrolling feel more responsive. There is a button in the top bar to disable it if it plays not nicely with touchpad
• I couldn't reproduce slow doc loading. I added -v flag to produce more logging. Run scrolex -v in terminal and send me the logs if you still experience any slowness issues

[N30Z3N]

So I tried a pdf with 700 pages and it was slow but one of 44 pages worked normally these are logs, that animate scroll button does nothing for me, pages when are loading as blank in many page doc it scrolls faster else the slower speed

(scrolex:53492): Gtk-WARNING **: 11:01:57.299: Unknown key gtk-modules in /home/xx/.config/gtk-4.0/settings.ini

(scrolex:53492): Gtk-WARNING **: 11:01:57.688: GtkGizmo 0x564522c5e970 (slider) reported min width -2, but sizes must be >= 0

(scrolex:53492): Gtk-WARNING **: 11:01:57.688: GtkGizmo 0x564522ccce20 (slider) reported min height -2, but sizes must be >= 0
[2026-07-05T05:32:12.972Z INFO  scrolex::state] Loaded document: 724 pages, 75354028 bytes, first page Some((597.6, 792.0)) pt, start page 0, zoom 1, crop false
[2026-07-05T05:32:13.538Z DEBUG scrolex::page::imp] Rendered page 0 on main thread (sync mode) in 549.082463ms
[2026-07-05T05:32:13.538Z WARN  scrolex::page::imp] Rendering took too long: 549.082463ms. Switching to multithreading mode.
[2026-07-05T05:32:13.538Z DEBUG scrolex::page::imp] draw page 1: cache miss (white flash), scheduling render
[2026-07-05T05:32:13.539Z DEBUG scrolex::page::imp] draw page 2: cache miss (white flash), render already in flight
[2026-07-05T05:32:13.562Z DEBUG scrolex::page::imp] Rendered page 3 on background thread in 20.234228ms
[2026-07-05T05:32:13.631Z DEBUG scrolex::page::imp] Rendered page 1 on background thread in 89.198767ms
[2026-07-05T05:32:13.712Z DEBUG scrolex::page::imp] draw page 1: cache hit
[2026-07-05T05:32:13.822Z DEBUG scrolex::page::imp] Rendered page 4 on background thread in 280.042406ms
[2026-07-05T05:32:13.940Z DEBUG scrolex::page::imp] Rendered page 2 on background thread in 398.50474ms
[2026-07-05T05:32:13.953Z DEBUG scrolex::page::imp] draw page 2: cache hit
[2026-07-05T05:32:14.191Z DEBUG scrolex::page::imp] Rendered page 0 on background thread in 623.544684ms
[2026-07-05T05:32:14.510Z DEBUG scrolex::window::imp] scroll event: dx=171.68359375, dy=0, unit=Surface
[2026-07-05T05:32:14.511Z DEBUG scrolex::page::imp] draw page 3: cache hit
[2026-07-05T05:32:14.530Z DEBUG scrolex::page::imp] Rendered page 5 on background thread in 18.928898ms
[2026-07-05T05:32:14.997Z DEBUG scrolex::window::imp] scroll event: dx=-274.640625, dy=0, unit=Surface
[2026-07-05T05:32:15.143Z DEBUG scrolex::window::imp] scroll event: dx=-20.3828125, dy=0, unit=Surface
[2026-07-05T05:32:15.611Z DEBUG scrolex::window::imp] scroll event: dx=292.421875, dy=0, unit=Surface
[2026-07-05T05:32:15.764Z DEBUG scrolex::page::imp] draw page 3: cache hit
[2026-07-05T05:32:15.764Z DEBUG scrolex::page::imp] draw page 4: cache hit
[2026-07-05T05:32:15.936Z DEBUG scrolex::page::imp] Rendered page 6 on background thread in 171.609396ms
[2026-07-05T05:32:16.148Z DEBUG scrolex::page::imp] draw page 2: cache hit
[2026-07-05T05:32:16.148Z DEBUG scrolex::page::imp] draw page 5: cache hit
[2026-07-05T05:32:16.300Z DEBUG scrolex::page::imp] Rendered page 7 on background thread in 151.568558ms
[2026-07-05T05:32:16.869Z DEBUG scrolex::window::imp] scroll event: dx=156.71875, dy=0, unit=Surface
[2026-07-05T05:32:17.052Z DEBUG scrolex::page::imp] draw page 6: cache hit
[2026-07-05T05:32:17.073Z DEBUG scrolex::page::imp] Rendered page 8 on background thread in 21.027273ms
[2026-07-05T05:32:17.250Z DEBUG scrolex::page::imp] draw page 7: cache hit
[2026-07-05T05:32:17.259Z DEBUG scrolex::page::imp] Rendered page 9 on background thread in 9.175237ms
[2026-07-05T05:32:17.633Z DEBUG scrolex::window::imp] scroll event: dx=233.046875, dy=0, unit=Surface
[2026-07-05T05:32:17.835Z DEBUG scrolex::page::imp] draw page 8: cache hit
[2026-07-05T05:32:17.835Z DEBUG scrolex::page::imp] draw page 9: cache hit
[2026-07-05T05:32:17.835Z DEBUG scrolex::page::imp] draw page 10: cache miss (white flash), render already in flight
[2026-07-05T05:32:17.949Z DEBUG scrolex::page::imp] Rendered page 10 on background thread in 113.893258ms
[2026-07-05T05:32:17.950Z DEBUG scrolex::page::imp] Rendered page 12 on background thread in 113.809657ms
[2026-07-05T05:32:17.958Z DEBUG scrolex::page::imp] Rendered page 11 on background thread in 122.868749ms
[2026-07-05T05:32:18.019Z DEBUG scrolex::page::imp] draw page 10: cache hit
[2026-07-05T05:32:18.019Z DEBUG scrolex::page::imp] draw page 11: cache hit
[2026-07-05T05:32:18.130Z DEBUG scrolex::page::imp] Rendered page 13 on background thread in 110.111431ms
[2026-07-05T05:32:18.204Z DEBUG scrolex::page::imp] draw page 8: cache hit
[2026-07-05T05:32:20.452Z DEBUG scrolex::window::imp] scroll event: dx=184.859375, dy=0, unit=Surface
[2026-07-05T05:32:20.636Z DEBUG scrolex::page::imp] draw page 10: cache hit
[2026-07-05T05:32:20.636Z DEBUG scrolex::page::imp] draw page 12: cache hit
[2026-07-05T05:32:20.731Z DEBUG scrolex::page::imp] Rendered page 14 on background thread in 93.373658ms
[2026-07-05T05:32:21.167Z DEBUG scrolex::window::imp] scroll event: dx=134.99609375, dy=0, unit=Surface
[2026-07-05T05:32:21.168Z DEBUG scrolex::page::imp] draw page 13: cache hit
[2026-07-05T05:32:21.275Z DEBUG scrolex::page::imp] Rendered page 15 on background thread in 105.540958ms
[2026-07-05T05:32:22.886Z DEBUG scrolex::window::imp] scroll event: dx=220.875, dy=0, unit=Surface
[2026-07-05T05:32:23.417Z DEBUG scrolex::window::imp] scroll event: dx=86.96484375, dy=0, unit=Surface
[2026-07-05T05:32:23.601Z DEBUG scrolex::window::imp] scroll event: dx=128.41015625, dy=0, unit=Surface
[2026-07-05T05:32:23.786Z DEBUG scrolex::page::imp] draw page 10: cache hit
[2026-07-05T05:32:23.969Z DEBUG scrolex::page::imp] draw page 14: cache hit
[2026-07-05T05:32:23.970Z DEBUG scrolex::page::imp] draw page 15: cache hit
[2026-07-05T05:32:23.970Z DEBUG scrolex::page::imp] draw page 16: cache miss (white flash), render already in flight
[2026-07-05T05:32:23.970Z DEBUG scrolex::page::imp] draw page 17: cache miss (white flash), render already in flight
[2026-07-05T05:32:24.078Z DEBUG scrolex::page::imp] Rendered page 16 on background thread in 107.108122ms
[2026-07-05T05:32:24.087Z DEBUG scrolex::page::imp] Rendered page 17 on background thread in 115.44289ms
[2026-07-05T05:32:24.088Z DEBUG scrolex::page::imp] draw page 15: cache hit
[2026-07-05T05:32:24.088Z DEBUG scrolex::page::imp] draw page 18: cache miss (white flash), render already in flight
[2026-07-05T05:32:24.089Z DEBUG scrolex::page::imp] Rendered page 19 on background thread in 117.530721ms
[2026-07-05T05:32:24.097Z DEBUG scrolex::page::imp] Rendered page 18 on background thread in 125.318913ms
[2026-07-05T05:32:24.136Z DEBUG scrolex::page::imp] draw page 16: cache hit
[2026-07-05T05:32:24.136Z DEBUG scrolex::page::imp] draw page 17: cache hit
[2026-07-05T05:32:24.136Z DEBUG scrolex::page::imp] draw page 18: cache hit
[2026-07-05T05:32:24.198Z DEBUG scrolex::page::imp] Rendered page 20 on background thread in 108.331738ms
[2026-07-05T05:32:24.318Z DEBUG scrolex::page::imp] draw page 17: cache hit
[2026-07-05T05:32:24.318Z DEBUG scrolex::page::imp] draw page 19: cache hit
[2026-07-05T05:32:24.419Z DEBUG scrolex::page::imp] Rendered page 21 on background thread in 98.621798ms
[2026-07-05T05:32:24.519Z DEBUG scrolex::window::imp] scroll event: dx=176.6328125, dy=0, unit=Surface
[2026-07-05T05:32:24.737Z DEBUG scrolex::page::imp] draw page 20: cache hit
[2026-07-05T05:32:24.737Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:24.737Z DEBUG scrolex::page::imp] draw page 22: cache miss (white flash), render already in flight
[2026-07-05T05:32:24.838Z DEBUG scrolex::page::imp] Rendered page 22 on background thread in 99.924894ms
[2026-07-05T05:32:24.841Z DEBUG scrolex::page::imp] Rendered page 24 on background thread in 102.576901ms
[2026-07-05T05:32:24.850Z DEBUG scrolex::page::imp] Rendered page 23 on background thread in 111.420811ms
[2026-07-05T05:32:24.918Z DEBUG scrolex::page::imp] draw page 20: cache hit
[2026-07-05T05:32:24.918Z DEBUG scrolex::page::imp] draw page 22: cache hit
[2026-07-05T05:32:25.777Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:25.953Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:26.035Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:26.125Z DEBUG scrolex::page::imp] draw page 20: cache hit
[2026-07-05T05:32:26.859Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:27.003Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:27.077Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:30.180Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:31.016Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:31.853Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:44.967Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:45.254Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:45.633Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:46.036Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:46.115Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:47.214Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:51.041Z DEBUG scrolex::page::imp] draw page 21: cache hit
[2026-07-05T05:32:51.321Z INFO  scrolex::state] Loaded document: 44 pages, 516139 bytes, first page Some((595.4399999999999, 841.6800000000001)) pt, start page 0, zoom 1, crop false
[2026-07-05T05:32:51.352Z DEBUG scrolex::page::imp] Rendered page 0 on main thread (sync mode) in 15.657818ms
[2026-07-05T05:32:51.364Z DEBUG scrolex::page::imp] Rendered page 1 on main thread (sync mode) in 11.635459ms
[2026-07-05T05:32:51.370Z DEBUG scrolex::page::imp] Rendered page 2 on main thread (sync mode) in 6.334519ms
[2026-07-05T05:32:52.198Z DEBUG scrolex::page::imp] Rendered page 3 on main thread (sync mode) in 6.2505ms
[2026-07-05T05:32:52.228Z DEBUG scrolex::window::imp] scroll event: dx=89.80078125, dy=0, unit=Surface
[2026-07-05T05:32:52.259Z DEBUG scrolex::window::imp] scroll event: dx=62.33203125, dy=0, unit=Surface
[2026-07-05T05:32:52.292Z DEBUG scrolex::window::imp] scroll event: dx=39.80078125, dy=0, unit=Surface
[2026-07-05T05:32:52.355Z DEBUG scrolex::page::imp] Rendered page 2 on main thread (sync mode) in 12.902656ms
[2026-07-05T05:32:52.402Z DEBUG scrolex::page::imp] Rendered page 2 on main thread (sync mode) in 7.334713ms
[2026-07-05T05:32:52.408Z DEBUG scrolex::page::imp] Rendered page 4 on main thread (sync mode) in 5.950463ms
[2026-07-05T05:32:52.517Z DEBUG scrolex::page::imp] Rendered page 2 on main thread (sync mode) in 6.913781ms
[2026-07-05T05:32:52.552Z DEBUG scrolex::page::imp] Rendered page 5 on main thread (sync mode) in 6.987812ms
[2026-07-05T05:32:52.681Z DEBUG scrolex::window::imp] scroll event: dx=75.4921875, dy=0, unit=Surface
[2026-07-05T05:32:52.709Z DEBUG scrolex::window::imp] scroll event: dx=83.87890625, dy=0, unit=Surface
[2026-07-05T05:32:52.741Z DEBUG scrolex::window::imp] scroll event: dx=16.94140625, dy=0, unit=Surface
[2026-07-05T05:32:52.748Z DEBUG scrolex::page::imp] Rendered page 2 on main thread (sync mode) in 6.61074ms
[2026-07-05T05:32:52.754Z DEBUG scrolex::page::imp] Rendered page 4 on main thread (sync mode) in 5.865466ms
[2026-07-05T05:32:52.802Z DEBUG scrolex::page::imp] Rendered page 6 on main thread (sync mode) in 8.050794ms
[2026-07-05T05:32:52.851Z DEBUG scrolex::page::imp] Rendered page 4 on main thread (sync mode) in 7.134199ms
[2026-07-05T05:32:52.858Z DEBUG scrolex::page::imp] Rendered page 7 on main thread (sync mode) in 6.851623ms
[2026-07-05T05:32:52.900Z DEBUG scrolex::page::imp] Rendered page 8 on main thread (sync mode) in 6.245471ms
[2026-07-05T05:32:52.984Z DEBUG scrolex::page::imp] Rendered page 6 on main thread (sync mode) in 7.595431ms
[2026-07-05T05:32:52.989Z DEBUG scrolex::page::imp] Rendered page 9 on main thread (sync mode) in 4.678237ms
[2026-07-05T05:32:53.179Z DEBUG scrolex::window::imp] scroll event: dx=53.94140625, dy=0, unit=Surface
[2026-07-05T05:32:53.210Z DEBUG scrolex::window::imp] scroll event: dx=88.98046875, dy=0, unit=Surface
[2026-07-05T05:32:53.242Z DEBUG scrolex::window::imp] scroll event: dx=77.296875, dy=0, unit=Surface
[2026-07-05T05:32:53.333Z DEBUG scrolex::page::imp] Rendered page 8 on main thread (sync mode) in 5.679619ms
[2026-07-05T05:32:53.340Z DEBUG scrolex::page::imp] Rendered page 10 on main thread (sync mode) in 6.704816ms
[2026-07-05T05:32:53.383Z DEBUG scrolex::page::imp] Rendered page 8 on main thread (sync mode) in 5.899548ms
[2026-07-05T05:32:53.391Z DEBUG scrolex::page::imp] Rendered page 11 on main thread (sync mode) in 7.027133ms
[2026-07-05T05:32:53.435Z DEBUG scrolex::page::imp] Rendered page 8 on main thread (sync mode) in 5.902342ms
[2026-07-05T05:32:53.485Z DEBUG scrolex::page::imp] Rendered page 10 on main thread (sync mode) in 7.407069ms
[2026-07-05T05:32:53.492Z DEBUG scrolex::page::imp] Rendered page 12 on main thread (sync mode) in 6.939692ms
[2026-07-05T05:32:53.538Z DEBUG scrolex::page::imp] Rendered page 10 on main thread (sync mode) in 7.352593ms
[2026-07-05T05:32:53.711Z DEBUG scrolex::window::imp] scroll event: dx=162.828125, dy=0, unit=Surface
[2026-07-05T05:32:53.719Z DEBUG scrolex::page::imp] Rendered page 10 on main thread (sync mode) in 7.189374ms
[2026-07-05T05:32:53.761Z DEBUG scrolex::window::imp] scroll event: dx=95.06640625, dy=0, unit=Surface
[2026-07-05T05:32:53.789Z DEBUG scrolex::page::imp] Rendered page 13 on main thread (sync mode) in 8.448959ms
[2026-07-05T05:32:53.835Z DEBUG scrolex::page::imp] Rendered page 14 on main thread (sync mode) in 7.221641ms
[2026-07-05T05:32:53.889Z DEBUG scrolex::page::imp] Rendered page 13 on main thread (sync mode) in 8.52725ms
[2026-07-05T05:32:53.895Z DEBUG scrolex::page::imp] Rendered page 15 on main thread (sync mode) in 6.149999ms
[2026-07-05T05:32:53.939Z DEBUG scrolex::page::imp] Rendered page 13 on main thread (sync mode) in 8.475498ms
[2026-07-05T05:32:53.946Z DEBUG scrolex::page::imp] Rendered page 16 on main thread (sync mode) in 6.198748ms
[2026-07-05T05:32:54.022Z DEBUG scrolex::page::imp] Rendered page 17 on main thread (sync mode) in 8.600863ms
[2026-07-05T05:32:54.103Z DEBUG scrolex::page::imp] Rendered page 15 on main thread (sync mode) in 7.119952ms
[2026-07-05T05:32:54.110Z DEBUG scrolex::page::imp] Rendered page 18 on main thread (sync mode) in 6.94067ms
[2026-07-05T05:32:54.737Z DEBUG scrolex::window::imp] scroll event: dx=2.30078125, dy=0, unit=Surface
[2026-07-05T05:32:55.621Z DEBUG scrolex::page::imp] Rendered page 15 on main thread (sync mode) in 6.675692ms
[2026-07-05T05:32:55.628Z DEBUG scrolex::page::imp] Rendered page 17 on main thread (sync mode) in 6.716201ms
[2026-07-05T05:32:55.875Z DEBUG scrolex::page::imp] Rendered page 17 on main thread (sync mode) in 8.46565ms
[2026-07-05T05:32:55.958Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.12273ms
[2026-07-05T05:32:56.363Z DEBUG scrolex::window::imp] scroll event: dx=106.90234375, dy=0, unit=Surface
[2026-07-05T05:32:56.373Z DEBUG scrolex::page::imp] Rendered page 17 on main thread (sync mode) in 8.09647ms
[2026-07-05T05:32:56.398Z DEBUG scrolex::window::imp] scroll event: dx=98.02734375, dy=0, unit=Surface
[2026-07-05T05:32:56.407Z DEBUG scrolex::page::imp] Rendered page 20 on main thread (sync mode) in 8.356978ms
[2026-07-05T05:32:56.431Z DEBUG scrolex::window::imp] scroll event: dx=19.90234375, dy=0, unit=Surface
[2026-07-05T05:32:56.525Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 8.257105ms
[2026-07-05T05:32:56.606Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.148572ms
[2026-07-05T05:32:56.612Z DEBUG scrolex::page::imp] Rendered page 22 on main thread (sync mode) in 6.526931ms
[2026-07-05T05:32:57.992Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.34706ms
[2026-07-05T05:32:58.041Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.484298ms
[2026-07-05T05:32:58.470Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.165613ms
[2026-07-05T05:32:58.478Z DEBUG scrolex::page::imp] Rendered page 20 on main thread (sync mode) in 7.285615ms
[2026-07-05T05:32:58.485Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 7.345329ms
[2026-07-05T05:32:58.492Z DEBUG scrolex::page::imp] Rendered page 22 on main thread (sync mode) in 6.436697ms
[2026-07-05T05:32:59.349Z DEBUG scrolex::window::imp] scroll event: dx=57.23046875, dy=0, unit=Surface
[2026-07-05T05:32:59.359Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 8.223791ms
[2026-07-05T05:32:59.400Z DEBUG scrolex::window::imp] scroll event: dx=59.6953125, dy=0, unit=Surface
[2026-07-05T05:32:59.557Z DEBUG scrolex::page::imp] Rendered page 23 on main thread (sync mode) in 8.010845ms
[2026-07-05T05:32:59.624Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 7.398618ms
[2026-07-05T05:32:59.785Z DEBUG scrolex::window::imp] scroll event: dx=-64.9609375, dy=0, unit=Surface
[2026-07-05T05:32:59.795Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 8.695567ms
[2026-07-05T05:32:59.833Z DEBUG scrolex::window::imp] scroll event: dx=-49.1640625, dy=0, unit=Surface
[2026-07-05T05:32:59.925Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 8.199696ms
[2026-07-05T05:33:00.833Z DEBUG scrolex::window::imp] scroll event: dx=-93.58203125, dy=0, unit=Surface
[2026-07-05T05:33:00.896Z DEBUG scrolex::page::imp] Rendered page 18 on main thread (sync mode) in 7.664363ms
[2026-07-05T05:33:00.975Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 7.551501ms
[2026-07-05T05:33:06.057Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 7.830516ms
[2026-07-05T05:33:06.097Z DEBUG scrolex::window::imp] scroll event: dx=221.37890625, dy=0, unit=Surface
[2026-07-05T05:33:06.130Z DEBUG scrolex::window::imp] scroll event: dx=49.17578125, dy=0, unit=Surface
[2026-07-05T05:33:06.139Z DEBUG scrolex::page::imp] Rendered page 19 on main thread (sync mode) in 7.889251ms
[2026-07-05T05:33:06.173Z DEBUG scrolex::page::imp] Rendered page 22 on main thread (sync mode) in 7.364257ms
[2026-07-05T05:33:06.241Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 8.199347ms
[2026-07-05T05:33:06.290Z DEBUG scrolex::page::imp] Rendered page 23 on main thread (sync mode) in 7.846649ms
[2026-07-05T05:33:06.324Z DEBUG scrolex::page::imp] Rendered page 21 on main thread (sync mode) in 7.701658ms
[2026-07-05T05:33:06.539Z DEBUG scrolex::page::imp] Rendered page 24 on main thread (sync mode) in 8.257385ms
[2026-07-05T05:33:06.564Z DEBUG scrolex::window::imp] scroll event: dx=215.62109375, dy=0, unit=Surface
[2026-07-05T05:33:06.597Z DEBUG scrolex::window::imp] scroll event: dx=35.19921875, dy=0, unit=Surface
[2026-07-05T05:33:06.605Z DEBUG scrolex::page::imp] Rendered page 23 on main thread (sync mode) in 7.274161ms
[2026-07-05T05:33:06.674Z DEBUG scrolex::page::imp] Rendered page 25 on main thread (sync mode) in 7.646834ms
[2026-07-05T05:33:06.706Z DEBUG scrolex::page::imp] Rendered page 23 on main thread (sync mode) in 6.970701ms
[2026-07-05T05:33:06.712Z DEBUG scrolex::page::imp] Rendered page 26 on main thread (sync mode) in 5.498939ms
[2026-07-05T05:33:06.792Z DEBUG scrolex::page::imp] Rendered page 25 on main thread (sync mode) in 7.440592ms
[2026-07-05T05:33:06.801Z DEBUG scrolex::page::imp] Rendered page 27 on main thread (sync mode) in 8.696056ms
[2026-07-05T05:33:06.841Z DEBUG scrolex::page::imp] Rendered page 25 on main thread (sync mode) in 6.832067ms
[2026-07-05T05:33:06.848Z DEBUG scrolex::page::imp] Rendered page 28 on main thread (sync mode) in 6.873273ms
[2026-07-05T05:33:06.999Z DEBUG scrolex::window::imp] scroll event: dx=148.35546875, dy=0, unit=Surface
[2026-07-05T05:33:07.007Z DEBUG scrolex::page::imp] Rendered page 25 on main thread (sync mode) in 6.957152ms
[2026-07-05T05:33:07.033Z DEBUG scrolex::window::imp] scroll event: dx=38.15625, dy=0, unit=Surface
[2026-07-05T05:33:07.042Z DEBUG scrolex::page::imp] Rendered page 27 on main thread (sync mode) in 8.335467ms
[2026-07-05T05:33:07.122Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 6.615978ms
[2026-07-05T05:33:07.159Z DEBUG scrolex::page::imp] Rendered page 27 on main thread (sync mode) in 8.392806ms
[2026-07-05T05:33:07.167Z DEBUG scrolex::page::imp] Rendered page 30 on main thread (sync mode) in 7.598153ms
[2026-07-05T05:33:07.242Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 7.595151ms
[2026-07-05T05:33:07.248Z DEBUG scrolex::page::imp] Rendered page 31 on main thread (sync mode) in 6.269637ms
[2026-07-05T05:33:07.291Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 7.053323ms
[2026-07-05T05:33:12.501Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 7.069736ms
[2026-07-05T05:33:12.989Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 9.411508ms
[2026-07-05T05:33:13.070Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 7.914255ms
[2026-07-05T05:33:13.349Z DEBUG scrolex::page::imp] Rendered page 29 on main thread (sync mode) in 7.128332ms

I know it's a lot like too much to ask but these are some things this can app can have if your time permits :D,

• search function
• bigger files handling like many pages
• touchpad zoom in and out
• features like okular and pdf annotation tools

[molecule-man]

I released new version https://github.com/molecule-man/scrolex/releases/tag/0.3.0 which covers some of the things you mention

search function

yes, added in 0.3.0

bigger files handling like many pages

Added pages prefetching. You can prefetch more by increasing number of threads (but this increases memory consumption)

touchpad zoom in and out

Added Ctrl+scroll. Works both with touchpad and mouse wheel. I also added touchpad pinch-to-zoom but to be honest it turned out to be finicky on my touchpad - it fights with page scrolling - I wouldn't use it.

features like okular and pdf annotation tools

I want to keep my pdf viewer minimalist so for now it's out of scope. If you have any particular features in mind then please feel free to open issues.

[N30Z3N]

I tested it and here are some observations (while installing got this Notice: Download is performed unsandboxed as root as file '/home/xx/Downloads/scrolex_0.3.0.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied))

1. When I zoom into pdf and start scrolling it would do left and right but not up and down, tried both with touchpad two finder scroll and mouse middle click pan option
2. Search is really fast :D
3. Problem still persists when I open 100+ pages pdf, it will work smoothly with around 40 - 50 pages pdf but beyond that same lag, tried increased threads to 10 still no difference tried on both searchable and photo scanned pdfs

btw should I stay on wayland or x11-libre for this app ?

[molecule-man]

First of all thanks for being tester of the app. It's very valuable to get real-user experience.

while installing got this Notice: Download is performed unsandboxed as root as file '/home/xx/Downloads/scrolex_0.3.0.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

That's expected. It's harmless, no worries.

1. When I zoom into pdf and start scrolling it would do left and right but not up and down, tried both with touchpad two finder scroll and mouse middle click pan option

The mouse wheel scroll and vertical two-finger-touchpad gesture move pages horizontally one page at a time (I built it around fast mouse-wheel navigation, counterintuitive, I know 🤷) .

There's currently no good way to pan up/down. I'll add that.

3. Problem still persists when I open 100+ pages pdf, it will work smoothly with around 40 - 50 pages pdf but beyond that same lag, tried increased threads to 10 still no difference tried on both searchable and photo scanned pdfs

Aha, scanned pdfs! Any chance the slow searchable pdfs are OCRs? Scanned pdfs and OCRs were slow because of the poppler backend. I partially fixed it in https://github.com/molecule-man/scrolex/releases/tag/0.4.0 (the annotated pdfs and OCRs with non-transparent text may still be slow).

btw should I stay on wayland or x11-libre for this app ?

Stay on wayland 👍

[molecule-man]

There's currently no good way to pan up/down. I'll add that.

and now there is, added. https://github.com/molecule-man/scrolex/releases/tag/0.5.0 introduces vertical pan (via 2-finger touchpad, mouse middle button drag, arrow keys and j and k keys)

[N30Z3N]

Aha, scanned pdfs! Any chance the slow searchable pdfs are OCRs? Scanned pdfs and OCRs were slow because of the poppler backend. I partially fixed it in https://github.com/molecule-man/scrolex/releases/tag/0.4.0 (the annotated pdfs and OCRs with non-transparent text may still be slow).

No tried on all three Photoscanned, OCR searchable and Normal searchable pdf, also tried one normal searchable pdf but with heavy annotations from professor it's 24 pages and others more than 100 pages each : same slow speed in scrolling and loading in all 4 even when threads maxed to 15 (around 1Gb ram usage, even more when zoomed in a bit), while only normal searchable pdf NON OCR works smoothly in 0.5.0 everything as expected bit jagged but still fine

[molecule-man]

the scanned/OCR files I have here all render fast enough that I simply can't reproduce the lag. So I'm guessing at what makes yours different, and I've kind of run out of guesses. To get unstuck I really need to look at the actual documents.

Could you please share one example of each slow type?

• the photo-scanned one
• the OCR searchable one
• the annotated one from your professor

Full documents would be ideal, but a few-page excerpt that still feels slow is totally fine too.

[molecule-man]

@N30Z3N could you please check if https://github.com/molecule-man/scrolex/releases/tag/0.5.1 fixes any of the slowness issues especially the heavily annotated pdfs?

[N30Z3N]

I can give you those can we speak on somewhere telegram maybe ?

Full documents would be ideal, but a few-page excerpt that still feels slow is totally fine too.

@N30Z3N could you please check if https://github.com/molecule-man/scrolex/releases/tag/0.5.1 fixes any of the slowness issues especially the heavily annotated pdfs?

tried it different pdfs giving me different results

[molecule-man]

I can give you those can we speak on somewhere telegram maybe ?

Unfortunately I don't. Could you please send them at shallot-posh-catty@duck.com ? Thanks

[molecule-man]

@N30Z3N I decided to replace poppler backend with mupdf. It should fix all the slowness issues. Please try https://github.com/molecule-man/scrolex/releases/tag/0.6.0-rc1

This was a huge rewrite, so some bugs are expected.