Use gradient or picture as fill in split rectangle?

Question

So I have made a split rectangle using Torbjørn T.'s answer in How to split tikz rectangle by half with different colors and text lines.

But could I use gradient (Color gradient in tikzpicture from top to bottom corner) in the upperhalf and pictures (How to create a rectangle filled with image using TikZ?) in the lowerhalf as fills as well?

Answer 1

is this what you like to have? sorry, the question is not clear to me ...

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{shapes.multipart}

\begin{document}
\begin{tikzpicture}[
box/.style={
       rectangle split, rectangle split parts=2,
       draw=black, thick, rounded corners,
       left color=blue, right color=blue!20!white,
       text width=3cm, align= center}
                    ]
\node [box]
       {\nodepart{one} text text
        \nodepart{two} text};
\end{tikzpicture}
\end{document}

or something like this:

\documentclass[tikz,border=3mm] {standalone}
    \usetikzlibrary{arrows,fadings, positioning, shapes.multipart}
    \usepackage{siunitx}
\begin{document}
    \begin{tikzpicture}[
    node distance=3mm,
box/.style args = {#1/#2/#3}{
        rectangle split, rectangle split parts=2,
        draw=black, thick, rounded corners,
        text width=3cm, align=center,
        postaction={path fading =#1,
                    fading angle=#2,
                    fill=#3}}
                        ]
\node (n1) [box=north/45/blue] {text1 \nodepart{two} text 2};
\node (n2) [box=south/-45/orange,
            below=of n1] {text1 \nodepart{two} text 2};
    \end{tikzpicture}
\end{document}

edit (1): regarding to edit of question: in the multi part shapes the gradient coloring and fading separately for each shape parts is not possible to do with known shape's options (your question seems to be new feature request for multi part shapes).

edit (2): as workaround the gradient colors on the background layer separately for each node part in case, can be drawn:

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{shapes.multipart}

\begin{document}
\begin{tikzpicture}[
box/.style args = {#1/#2}{
       rectangle split, rectangle split parts=2,
       rounded corners,
       text width=3cm, align=center,
    draw,  thick,
    append after command={\pgfextra
        \fill[left color=#1, right color=#1!20!white]
    (\tikzlastnode.one west) 
    [rounded corners] |- (\tikzlastnode.north) -| (\tikzlastnode.one east) 
    [sharp corners]   |- (\tikzlastnode.one split) -| cycle;
        \fill[left color=#2, right color=#2!20!white]
    (\tikzlastnode.two west) 
    [rounded corners] |- (\tikzlastnode.south) -| (\tikzlastnode.two east)  
    [sharp corners]   |- (\tikzlastnode.one split) -| cycle;
                                    \endpgfextra}% end of the append after command
                        }% end of the box style definition
                    ]
\node [box=blue/red]
       {\nodepart{one} longer, two lines text in part 1
        \nodepart{two} text 2};
\end{tikzpicture}
\end{document}

where append after command={\pgfextra ...} is used to fill each shape's part separately.