From 02351a45b4316efbfca501c19495cd7e1e404810 Mon Sep 17 00:00:00 2001
From: t-bltg <tf.bltg@gmail.com>
Date: Tue, 5 Apr 2022 14:56:47 +0200
Subject: [PATCH] `UnicodePlots`: rework `png` output (#4171)

---
 .github/workflows/docs.yml   | 16 ++++++----------
 src/backends/gaston.jl       |  5 ++---
 src/backends/unicodeplots.jl | 28 ++++++++++++++--------------
 3 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index ffca8f0e..93d16b74 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -9,7 +9,7 @@ on:
  
 jobs:
   Build_docs:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
         with:
@@ -29,17 +29,14 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt-get update -y
-          sudo apt-get install -y qt5-default \
+          sudo apt-get install -y \
+            texlive-{latex-{base,extra},binaries,pictures,luatex} \
             ttf-mscorefonts-installer \
             poppler-utils \
-            pdf2svg \
-            texlive-latex-base \
-            texlive-binaries \
-            texlive-pictures \
-            texlive-latex-extra \
-            texlive-luatex \
             ghostscript-x \
-            libgconf2-4 \
+            libgconf-2-4 \
+            qt5-default \
+            pdf2svg \
             gnuplot
       - name: Install fonts
         run: |
@@ -49,7 +46,6 @@ jobs:
           url="$repo/releases/download/$ver/JuliaMono-ttf.tar.gz"
           echo "downloading & extract url=$url"
           wget -q "$url" -O - | tar -xz -C ~/.fonts
-          ls ~/.fonts
           sudo fc-cache -vr
           fc-list | grep 'JuliaMono'
       - name: Build documentation
diff --git a/src/backends/gaston.jl b/src/backends/gaston.jl
index e9d6e30c..a883c00c 100644
--- a/src/backends/gaston.jl
+++ b/src/backends/gaston.jl
@@ -244,10 +244,9 @@ function gaston_add_series(plt::Plot{GastonBackend}, series::Series)
                 if (lx = length(x)) == 2 && lx != nc
                     x = collect(range(x[1], x[2], length = nc))
                 end
-            elseif st == :heatmap
-                length(x) == size(z, 2) + 1 && (x = @view x[1:(end - 1)])
-                length(y) == size(z, 1) + 1 && (y = @view y[1:(end - 1)])
             end
+            length(x) == size(z, 2) + 1 && (x = (x[1:(end - 1)] + x[2:end]) / 2)
+            length(y) == size(z, 1) + 1 && (y = (y[1:(end - 1)] + y[2:end]) / 2)
         end
         if st == :mesh3d
             x, y, z = mesh3d_triangles(x, y, z, series[:connections])
diff --git a/src/backends/unicodeplots.jl b/src/backends/unicodeplots.jl
index 4ce0fa60..7afa3156 100644
--- a/src/backends/unicodeplots.jl
+++ b/src/backends/unicodeplots.jl
@@ -1,8 +1,5 @@
 # https://github.com/JuliaPlots/UnicodePlots.jl
 
-should_warn_on_unsupported(::UnicodePlotsBackend) = false
-
-# ------------------------------------------------------------------------------------------
 const _canvas_map = (
     braille = UnicodePlots.BrailleCanvas,
     density = UnicodePlots.DensityCanvas,
@@ -13,11 +10,10 @@ const _canvas_map = (
     dot = UnicodePlots.DotCanvas,
 )
 
-# do all the magic here... build it all at once,
-# since we need to know about all the series at the very beginning
-function unicodeplots_rebuild(plt::Plot{UnicodePlotsBackend})
-    plt.o = UnicodePlots.Plot[]
+should_warn_on_unsupported(::UnicodePlotsBackend) = false
 
+function _before_layout_calcs(plt::Plot{UnicodePlotsBackend})
+    plt.o = UnicodePlots.Plot[]
     up_width = UnicodePlots.DEFAULT_WIDTH[]
     up_height = UnicodePlots.DEFAULT_HEIGHT[]
 
@@ -254,8 +250,7 @@ end
 
 # ------------------------------------------------------------------------------------------
 
-function png(plt::Plot{UnicodePlotsBackend}, fn::AbstractString)
-    unicodeplots_rebuild(plt)
+function _show(io::IO, ::MIME"image/png", plt::Plot{UnicodePlotsBackend})
     nr, nc = size(plt.layout)
     s1 = zeros(Int, nr, nc)
     s2 = zeros(Int, nr, nc)
@@ -292,18 +287,20 @@ function png(plt::Plot{UnicodePlotsBackend}, fn::AbstractString)
             end
             n1 += m1[r]
         end
-        UnicodePlots.FileIO.save(fn, img)
+        stream = UnicodePlots.FileIO.Stream{UnicodePlots.FileIO.format"PNG"}(io)
+        UnicodePlots.FileIO.save(stream, img)
     end
     nothing
 end
 
-# ------------------------------------------------------------------------------------------
 Base.show(plt::Plot{UnicodePlotsBackend}) = show(stdout, plt)
-Base.show(io::IO, plt::Plot{UnicodePlotsBackend}) = _show(io, MIME("text/plain"), plt)
+function Base.show(io::IO, plt::Plot{UnicodePlotsBackend})
+    prepare_output(plt)
+    _show(io, MIME("text/plain"), plt)
+end
 
 # NOTE: _show(...) must be kept for Base.showable (src/output.jl)
 function _show(io::IO, ::MIME"text/plain", plt::Plot{UnicodePlotsBackend})
-    unicodeplots_rebuild(plt)
     nr, nc = size(plt.layout)
     if nr == 1 && nc == 1  # fast path
         n = length(plt.o)
@@ -367,4 +364,7 @@ function _show(io::IO, ::MIME"text/plain", plt::Plot{UnicodePlotsBackend})
 end
 
 # we only support MIME"text/plain", hence display(...) falls back to plain-text on stdout
-_display(plt::Plot{UnicodePlotsBackend}) = (show(stdout, plt); println(stdout))
+function _display(plt::Plot{UnicodePlotsBackend})
+    show(stdout, plt)
+    println(stdout)
+end