From c50e2dcc76baabf905dea1388bfbf0fe85b0c5b7 Mon Sep 17 00:00:00 2001
From: SimonDanisch <sdanisch@protonmail.com>
Date: Thu, 12 Oct 2023 11:04:12 +0200
Subject: [PATCH] Revert "Add "How to get a transparent background" page
 (#3236)"

This reverts commit ed836a05a4a99285db28ce26d1d8ababbee80771.
---
 docs/_layout/masthead.html                   |  1 -
 docs/explanations.md                         |  2 +-
 docs/how-to.md                               |  5 --
 docs/how-to/save-figure-with-transparency.md | 79 --------------------
 src/figures.jl                               |  2 +-
 5 files changed, 2 insertions(+), 87 deletions(-)
 delete mode 100644 docs/how-to.md
 delete mode 100644 docs/how-to/save-figure-with-transparency.md

diff --git a/docs/_layout/masthead.html b/docs/_layout/masthead.html
index 665d52fa67a..a8e5492f125 100644
--- a/docs/_layout/masthead.html
+++ b/docs/_layout/masthead.html
@@ -12,7 +12,6 @@
                     </li>
                     <li class="masthead__menu-item"><a href="/reference/">Reference</a></li>
                     <li class="masthead__menu-item"><a href="/tutorials/">Tutorials</a></li>
-                    <li class="masthead__menu-item"><a href="/how-to/">How-Tos</a></li>
                     <li class="masthead__menu-item"><a href="/explanations/">Explanations</a></li>
                     <li class="masthead__menu-item"><a href="/api/">API</a></li>
                     <li class="masthead__menu-item"><a href="/news/">News</a></li>
diff --git a/docs/explanations.md b/docs/explanations.md
index eae0ca075fa..3542f41c3d7 100644
--- a/docs/explanations.md
+++ b/docs/explanations.md
@@ -1,4 +1,4 @@
-@def order = 4
+@def order = 3
 
 # Explanations
 
diff --git a/docs/how-to.md b/docs/how-to.md
deleted file mode 100644
index 9423ac5e16a..00000000000
--- a/docs/how-to.md
+++ /dev/null
@@ -1,5 +0,0 @@
-@def order = 3
-
-# How-Tos
-
-{{list_folder how-to}}
diff --git a/docs/how-to/save-figure-with-transparency.md b/docs/how-to/save-figure-with-transparency.md
deleted file mode 100644
index aec0522f3a1..00000000000
--- a/docs/how-to/save-figure-with-transparency.md
+++ /dev/null
@@ -1,79 +0,0 @@
-# How to save a `Figure` with transparency
-
-## CairoMakie
-
-In CairoMakie, set the background color to `:transparent` (converts to `RGBAf(0, 0, 0, 0)`) to get a fully transparent background.
-In the following examples, I use a partially transparent blue because a transparent background is indistinguishable from the usual white on a white page.
-
-\begin{examplefigure}{svg = true}
-```julia
-using CairoMakie
-CairoMakie.activate!() # hide
-
-f = Figure(backgroundcolor = (:blue, 0.4))
-Axis(f[1, 1], backgroundcolor = (:tomato, 0.5))
-f
-```
-\end{examplefigure}
-
-## GLMakie
-
-For technical reasons, GLMakie's color buffer does not have an alpha component:
-
-\begin{examplefigure}{}
-```julia
-using GLMakie
-GLMakie.activate!() # hide
-Makie.inline!(true) # hide
-
-f = Figure(backgroundcolor = (:blue, 0.4))
-Axis(f[1, 1], backgroundcolor = (:tomato, 0.5))
-f
-```
-\end{examplefigure}
-
-
-With the following trick you can still save an image with transparent background.
-It works by setting two different background colors and calculating the foreground color with alpha from the difference.
-
-```julia:transparent-glmakie
-using GLMakie
-GLMakie.activate!() # hide
-Makie.inline!(true) # hide
-
-function calculate_rgba(rgb1, rgb2, rgba_bg)::RGBAf
-    rgb1 == rgb2 && return RGBAf(rgb1.r, rgb1.g, rgb1.b, 1)
-    c1 = Float64.((rgb1.r, rgb1.g, rgb1.b))
-    c2 = Float64.((rgb2.r, rgb2.g, rgb2.b))
-    alphas_fg = 1 .+ c1 .- c2
-    alpha_fg = clamp(sum(alphas_fg) / 3, 0, 1)
-    alpha_fg == 0 && return rgba_bg
-    rgb_fg = clamp.((c1 ./ alpha_fg), 0, 1)
-    rgb_bg = Float64.((rgba_bg.r, rgba_bg.g, rgba_bg.b))
-    alpha_final = alpha_fg + (1 - alpha_fg) * rgba_bg.alpha
-    rgb_final = @. 1 / alpha_final * (alpha_fg * rgb_fg + (1 - alpha_fg) * rgba_bg.alpha * rgb_bg)
-    return RGBAf(rgb_final..., alpha_final)
-end
-
-function alpha_colorbuffer(figure)
-    scene = figure.scene
-    bg = scene.backgroundcolor[]
-    scene.backgroundcolor[] = RGBAf(0, 0, 0, 1)
-    b1 = copy(colorbuffer(scene))
-    scene.backgroundcolor[] = RGBAf(1, 1, 1, 1)
-    b2 = colorbuffer(scene)
-    scene.backgroundcolor[] = bg
-    return map(b1, b2) do b1, b2
-        calculate_rgba(b1, b2, bg)
-    end
-end
-
-f = Figure(backgroundcolor = (:blue, 0.4))
-Axis(f[1, 1], backgroundcolor = (:tomato, 0.5))
-f
-
-save(joinpath(@OUTPUT, "transparent.png"), alpha_colorbuffer(f)) # hide
-save("transparent.png", alpha_colorbuffer(f))
-```
-
-\fig{transparent.png}
\ No newline at end of file
diff --git a/src/figures.jl b/src/figures.jl
index 6590571dfec..b7d60ac8c6d 100644
--- a/src/figures.jl
+++ b/src/figures.jl
@@ -98,7 +98,7 @@ function Figure(; kwargs...)
 
     kwargs_dict = Dict(kwargs)
     padding = pop!(kwargs_dict, :figure_padding, theme(:figure_padding))
-    scene = Scene(; camera=campixel!, clear = true, kwargs_dict...)
+    scene = Scene(; camera=campixel!, kwargs_dict...)
     padding = convert(Observable{Any}, padding)
     alignmode = lift(Outside ∘ to_rectsides, padding)