Make VideoStream aware of px_per_unit

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased]
 
 - Fix relocatability of GLMakie [#4461](https://github.com/MakieOrg/Makie.jl/pull/4461).
+- Fix `px_per_unit` not being recognized in `record` and `VideoStream`, leading to errors [#4466](https://github.com/MakieOrg/Makie.jl/pull/4466).
 
 ## [0.21.13] - 2024-10-07
 

src/ffmpeg-util.jl

@@ -260,7 +260,13 @@ function VideoStream(fig::FigureLike;
     get!(config, :visible, visible)
     get!(config, :start_renderloop, false)
     screen = getscreen(backend, scene, config, GLNative)
-    _xdim, _ydim = size(screen)
+    # We extract `px_per_unit` from the screen in order to get the ground truth.
+    px_per_unit = if hasproperty(screen, :config) && hasproperty(screen.config, :px_per_unit)
+        screen.config.px_per_unit
+    else # backend has no screen config, or config has no px_per_unit, so assume 1 px per dip
+        1
+    end
+    _xdim, _ydim = ceil.(Int, size(screen) .* px_per_unit)
     xdim = iseven(_xdim) ? _xdim : _xdim + 1
     ydim = iseven(_ydim) ? _ydim : _ydim + 1
     buffer = Matrix{RGB{N0f8}}(undef, xdim, ydim)

test/record.jl

@@ -2,16 +2,18 @@ using Logging
 
 module VideoBackend
     using Makie
+    Base.@kwdef struct ScreenConfig
+    px_per_unit = 1
+    end
     struct Screen <: MakieScreen
         size::Tuple{Int, Int}
-    end
-    struct ScreenConfig
+        config::ScreenConfig
     end
     Base.size(screen::Screen) = screen.size
-    Screen(scene::Scene, config::ScreenConfig, ::Makie.ImageStorageFormat) = Screen(size(scene))
+    Screen(scene::Scene, config::ScreenConfig, ::Makie.ImageStorageFormat) = Screen(size(scene), config)
     Makie.backend_showable(::Type{Screen}, ::MIME"text/html") = true
     Makie.backend_showable(::Type{Screen}, ::MIME"image/png") = true
-    Makie.colorbuffer(screen::Screen) = zeros(RGBf, reverse(screen.size)...)
+    Makie.colorbuffer(screen::Screen) = zeros(RGBf, ceil.(Int, reverse(screen.size) .* screen.config.px_per_unit)...)
     Base.display(::Screen, ::Scene; kw...) = nothing
 end
 
@@ -39,6 +41,20 @@ mktempdir() do tempdir
             end
         end
 
+        @testset "px_per_unit" begin
+            for fmt in ("mp4", "gif"), px_per_unit in (1, 2)
+                dst = joinpath(tempdir, "out_$px_per_unit.$fmt")
+                @test begin
+                    record(fig, dst, 1:n; px_per_unit) do i
+                        lines!(ax, sin.(i .* x))
+                        return nothing
+                    end
+                    true
+                end
+            end
+        end
+
+
         # test that the proper warnings are thrown
         @testset "Warnings" begin
             function run_record(dst; kwargs...)