pgfplots: Wrong colormap in first `mesh/color input` example

[muzimuzhi]

Describe the bug

In the first example of /pgfplots/mesh/color input, the main plot uses a colormap different from the colorbar next to it, hence different from that in the PDF manual.

Screenshots

• PDF
• HTML (Colormap in colorbar is OK, but in the main plot is wrong.)

I can get the colormap in PDF with

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{width=7cm,compat=1.18}
\usepgfplotslibrary{patchplots}

\begin{document}
% Preamble: \pgfplotsset{width=7cm,compat=1.18}
% \usepgfplotslibrary{patchplots}
\begin{tikzpicture}
\begin{axis}[small,view={0}{90},colorbar]
    \addplot3 [
        surf,
        shader=interp,
        patch type=bilinear,
    ] coordinates {
        (0,0,0) (1,0,0)

        (0,1,0) (1,1,1)
    };
\end{axis}
\end{tikzpicture}
\end{document}

[muzimuzhi]

The last example of /pgfplots/contour lua has a similar problem.

• PDF
• HTML

% !TeX program = lualatex
\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{width=7cm,compat=1.18}

\begin{document}
% Preamble: \pgfplotsset{width=7cm,compat=1.18}
\begin{tikzpicture}
\begin{axis}
    \addplot3 [
        surf,
        shader=interp
    ] coordinates {
        (0,0,0) (1,0,0)   (2,0,0)   (3,0,0)

        (0,1,0) (1,1,0.6) (2,1,0.7) (3,1,0.5)

        (0,2,0) (1,2,0.7) (2,2,0.8) (3,2,0.5)
    };
    \addplot3 [
        contour lua,
        z filter/.code={\def\pgfmathresult{1}},
    ] coordinates {
        (0,0,0) (1,0,0)   (2,0,0)   (3,0,0)

        (0,1,0) (1,1,0.6) (2,1,0.7) (3,1,0.5)

        (0,2,0) (1,2,0.7) (2,2,0.8) (3,2,0.5)
    };
\end{axis}
\end{tikzpicture}
\end{document}

[DominikPeters]

There must be some PDF trickery going on with all these examples. Apple's Preview app shows an empty plot:

and the Chrome browser's PDF viewer shows the same thing as in the HTML version's image:

and evidently so does pdftocairo which is doing the conversion to SVG and PNG. Not sure what to do about it and whether there exist any easily command line callable viewers that do it "correctly" -- I don't think Adobe Acrobat will be very helpful.

EDIT: ImageMagick does it correctly.

[muzimuzhi]

MuPDF does it correctly too. mutool convert -o output.png input.pdf

doc: https://mupdf.readthedocs.io/en/latest/mutool-convert.html

[muzimuzhi]

I can confirm this issue and the similar #30 and #31 are all fixed in "HTML version last updated: 2024-02-26". Thank you.