rendering artifacts with high-resolution data

[ssfrr]

I'm seeing some weird artifacts where functions that should have smooth decay don't appear that way when zoomed out. I suspect it has to do with aliasing introduced when downsampling the given signal for display. This signal is a little pathological in the sense that it has a lot of high-frequency content, but I ran into this issue looking at actual data and had some plots that weren't showing what I expected. This is using the default GR backend, within Juno.

Here's an example:

using Plots

plot(sinc.(-1000:0.5:1000), fmt=:png)

gives this plot:

Notice how the amplitude doesn't smoothly decay as it should, and instead has some weird bumps. Changing the output format to :svg gives a more correct-looking plot:

[daschw]

I cannot reproduce the issue in Juno with GR and fmt=:png. What are your versions of Plots and GR?

[ssfrr]

Also I tried plotting outside of Juno into a regular GR window doesn't reproduce, but I still see it inside of Juno.

Here's my full version info (Plots v0.28.4 and GR v0.44.0)

julia> versioninfo()
Julia Version 1.3.1
Commit 2d5741174c (2019-12-30 21:36 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, skylake)
Environment:
  JULIA_EDITOR = atom  -a
  JULIA_NUM_THREADS = 2
  JULIA_PKG_DEVDIR = /home/sfr/Dropbox/juliadev

(v1.3) pkg> st -m
    Status `~/.julia/environments/v1.3/Manifest.toml`
  [621f4979] AbstractFFTs v0.5.0
  [bf4720bc] AssetRegistry v0.1.0
  [c52e3926] Atom v0.11.3
  [15f4f7f2] AutoHashEquals v0.2.0
  [6e4b80f9] BenchmarkTools v0.4.3
  [9e28174c] BinDeps v1.0.0
  [12aac903] BinaryBuilder v0.2.1 [`~/Dropbox/juliadev/BinaryBuilder`]
  [b99e7846] BinaryProvider v0.5.8
  [e1450e63] BufferedStreams v1.0.0
  [00ebfdb7] CSTParser v0.6.2
  [7057c7e9] Cassette v0.3.1
  [53a63b46] CodeTools v0.6.5
  [da1fd8a2] CodeTracking v0.5.8
  [944b1d66] CodecZlib v0.6.0
  [3da002f7] ColorTypes v0.9.1
  [5ae59095] Colors v0.11.2
  [34da2185] Compat v2.2.0
  [d38c429a] Contour v0.5.1
  [717857b8] DSP v0.6.2
  [9a962f9c] DataAPI v1.1.0
  [864edb3b] DataStructures v0.17.9
  [e2d170a0] DataValueInterfaces v1.0.0
  [b4f34e82] Distances v0.8.2
  [33d173f1] DocSeeker v0.3.2
  [2e619515] Expat_jll v2.2.7+0
  [c87230d0] FFMPEG v0.2.4
  [7a1cc6ca] FFTW v1.2.0
  [f5851436] FFTW_jll v3.3.9+3
  [1d38b3a6] FLAC_jll v1.3.3+1
  [5789e2e9] FileIO v1.2.1
  [53c48c17] FixedPointNumbers v0.6.1
  [de31a74c] FunctionalCollections v0.5.0
  [28b8d3ca] GR v0.44.0
  [4d00f742] GeometryTypes v0.7.7
  [8f6bce27] GitForge v0.1.5
  [bc5e4493] GitHub v5.1.3
  [cd3eb016] HTTP v0.8.8
  [0862f596] HTTPClient v0.2.1
  [9fb69e20] Hiccup v0.2.2
  [83e8ac13] IniFile v0.5.0
  [1d5cc7b8] IntelOpenMP_jll v2018.0.3+0
  [8197267c] IntervalSets v0.3.2
  [82899510] IteratorInterfaceExtensions v1.0.0
  [033835bb] JLD2 v0.1.11
  [682c06a0] JSON v0.21.0
  [2535ab7d] JSON2 v0.3.1
  [98e50ef6] JuliaFormatter v0.1.19
  [aa1ae85d] JuliaInterpreter v0.7.8
  [e5e0dc1b] Juno v0.7.2
  [7c4cb9fa] LNR v0.2.0
  [50d2b5c4] Lazy v0.14.0
  [b27032c2] LibCURL v0.5.2
  [522f3ed2] LibExpat v0.6.0
  [b13ce0c6] LibSndFile v2.2.0
  [2ec943e9] Libz v1.0.1
  [6f1432cf] LoweredCodeUtils v0.4.2
  [856f044c] MKL_jll v2019.0.117+2
  [1914dd2f] MacroTools v0.5.3
  [739be429] MbedTLS v0.7.0
  [442fdcdd] Measures v0.3.1
  [e89f7d12] Media v0.5.0
  [e1d29d7a] Missings v0.4.3
  [ffc61752] Mustache v1.0.0
  [a975b10e] Mux v0.7.1
  [77ba4419] NaNMath v0.3.3
  [d8793406] ObjectFile v0.3.3
  [510215fc] Observables v0.2.3
  [e7412a2a] Ogg_jll v1.3.3+0
  [efe28fd5] OpenSpecFun_jll v0.5.3+1
  [bac558e1] OrderedCollections v1.1.0
  [9b87118b] PackageCompiler v0.6.5
  [69de0a69] Parsers v0.3.10
  [fa939f87] Pidfile v1.1.0
  [fc669557] PkgLicenses v0.2.0
  [14b8a8f1] PkgTemplates v0.6.3
  [ccf2f8ad] PlotThemes v1.0.1
  [995b91a9] PlotUtils v0.6.2
  [91a5bcddc
  [f27b6e38] Polynomials v0.6.0
  [80ea8bcb] PortAudio v1.1.0 [`~/Dropbox/juliadev/PortAudio`]
  [92933f4c] ProgressMeter v1.2.0
  [3cdcf5f2] RecipesBase v0.7.0
  [189a3867] Reexport v0.2.0
  [4418983a] Registrator v1.0.0
  [d1eb7eb1] RegistryTools v1.2.1
  [ae029012] Requires v0.5.2
  [295af30f] Revise v2.5.0
  [bd7594eb] SampledSignals v2.1.0
  [992d4aef] Showoff v0.3.1
  [a2af1166] SortingAlgorithms v0.3.1
  [276daf66] SpecialFunctions v0.9.0
  [90137ffa] StaticArrays v0.12.1
  [2913bbd2] StatsBase v0.32.0
  [88034a9c] StringDistances v0.4.0
  [53d494c1] StructIO v0.3.0
  [3783bdb8] TableTraits v1.0.0
  [bd369af6] Tables v0.2.11
  [37f0c46e] TimeToLive v0.3.0
  [0796e94c] Tokenize v0.5.7
  [37b6cedf] Traceur v0.3.0
  [3bb67fe8] TranscodingStreams v0.9.5
  [a2a6695c] TreeViews v0.3.0
  [30578b45] URIParser v0.4.0
  [1986cc42] Unitful v0.17.0
  [0f1e0344] WebIO v0.8.13
  [104b5d7c] WebSockets v1.5.2
  [cc8bc4a8] Widgets v0.6.2
  [c17dfb99] WinRPM v0.4.3
  [c2297ded] ZMQ v1.2.0
  [8f1865be] ZeroMQ_jll v4.3.1+0
  [45378030] alsa_jll v1.2.1-1+0
  [07c12ed4] ghr_jll v0.13.0+0
  [2d7b7beb] libportaudio_jll v19.6.0+1
  [5bf562c0] libsndfile_jll v1.0.28+0
  [f27f6e37] libvorbis_jll v1.3.6+2
  [2a0f44e3] Base64 
  [ade2ca70] Dates 
  [8bb1440f] DelimitedFiles 
  [8ba89e20] Distributed 
  [7b1f6079] FileWatching 
  [b77e0a4c] InteractiveUtils 
  [76f85450] LibGit2 
  [8f399da3] Libdl 
  [37e2e46d] LinearAlgebra 
  [56ddb016] Logging 
  [d6f4376e] Markdown 
  [a63ad114] Mmap 
  [44cfe95a] Pkg 
  [de0858da] Printf 
  [9abbd945] Profile 
  [3fa0cd96] REPL 
  [9a3f8284] Random 
  [ea8e919c] SHA 
  [9e88b42a] Serialization 
  [1a1011a3] SharedArrays 
  [6462fe0b] Sockets 
  [2f01184e] SparseArrays 
  [10745b16] Statistics 
  [8dfed614] Test 
  [cf7118a7] UUIDs 
  [4ec0a83e] Unicode 

[ssfrr]

hmm, actually I see it for SVG plots as well, but only if I enlarge the plot window. Maybe see if you can reproduce if you make the plot window very large?

[daschw]

OK, I can reproduce it now. Not sure about my Plots version, when I could not.