Speed regression on 3.5.2

[dzarda]

SumatraPDF version

• Version 3.5.2

Describe the bug
We encountered a rendering speed regression. The previous quick version was probably 3.3.x

To Reproduce
Steps to reproduce the behavior:

1. Open the PDF in attachment
2. See slow rendering when zooming

Expected behavior
Navigation should be as quick as before.

File that reproduces the problem
BTC050.2AAAA.001 - CB.pdf

Additional context
We really enjoy using Sumatra PDF, been fans for years. Keep up the good work ❤️

[sergsako]

Really very quick rendering at maximal zoom was in version 3.2, not in 3.3.3, as I see using these two versions (portable x64). But I did not test versions 3.3 -- 3.3.2.

[dzarda]

@sergsako It must have been 3.2 then. Do you have an idea what change caused the slowdown?

[GitHubRulesOK]

That is a very high density VECTOR image took me 24 seconds to open in a PDF editor to look at construction but SumatraPDF viewer takes only a few (or 4)

CreateControllerForEngineOrFile: 'C:\Users\WDAGUtilityAccount\Downloads\BTC050.2AAAA.001.-.CB.pdf', 1 pages, took 109 ms
LoadDocument: 108.66 ms, 1 pages for 'C:\Users\WDAGUtilityAccount\Downloads\BTC050.2AAAA.001.-.CB.pdf'
DisplayModel::BuildPagesInfo started
DisplayModel::BuildPagesInfo took 0.01 ms
StartMonitoringDirForChangesAPC() C:\Users\WDAGUtilityAccount\Downloads
SaveSettings
StartMonitoringDirForChangesAPC() C:\Users\WDAGUtilityAccount\Desktop\Apps\PDF\SumatraPDF\SumatraPDF
DeleteStaleFiles: dir: 'C:\Users\WDAGUtilityAccount\AppData\Local\SumatraPDF-data', gIsPreRelaseBuild: 1, ver: prerel-3.6.17021-64
Slow rendering: 1591.00 ms, page: 1 in 'C:\Users\WDAGUtilityAccount\Downloads\BTC050.2AAAA.001.-.CB.pdf'
Slow rendering: 868.93 ms, page: 1 in 'C:\Users\WDAGUtilityAccount\Downloads\BTC050.2AAAA.001.-.CB.pdf'
currTabIdx: 4

[sergsako]

@dzarda

It must have been 3.2 then. Do you have an idea what change caused the slowdown?

Version history of SumatraPDF tells that there was "update mupdf to latest version" in version 3.3.

[GitHubRulesOK]

@dzarda @sergsako
there are always updates to use latest MuPDF for many reasons and thus you would need to check at what point there were speed changes in MuPDF file handling.

However SumatraPDF needs to compound those changes by balancing a tradeoff between many different behaviours. So some files suffer at the cost of speeding up others since there can never be a one speed suites ALL.

This file is unusually large for a single page that would commonly be a FEW 1000 sub objects. I have a 4000 page file with probably as many items that is stored in 2MB and is thus fast as only dozens of items per page. if the average contents of 1000 pages are all cramed into one chart it takes far far longer to render that one page.

[dzarda]

I appreciate the responses and understand completely that things are messy and development efforts must be spent tactically. On the nutty document Sumatra still loads faster than Adobe but navigates slower. UI freezes while the chunks are rendered. Still usable.

❤️