# Tikz: Shading a path without any filling

How can I shade a path witout filling? In particular, I wand to draw a curved arrow that starts colored blue and ends colored green, where in between it gradually changes its color. I can't find a way to shade a path without filling it.

The following code does not work, as it shades the filling area, although it compiles.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,automata,patterns,decorations,decorations.pathmorphing}
\begin{document}
\begin{tikzpicture}

bottom color=green!80!white,->] (0,0) .. controls +(0,-1) and +(0,1) .. (1,-2);

\end{tikzpicture}
\end{document}


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Do you mean that you want the path colour to change? –  Loop Space Sep 20 '13 at 15:57
@Andrew: Yes, precisely - the color of the path (in this case, an arrow) should change. –  DCTLib Sep 20 '13 at 16:17
Related: Fading a path in TikZ –  Qrrbrbirlbel Sep 20 '13 at 16:23
Also related: How to draw an arrow with two colors? –  Qrrbrbirlbel Oct 11 '13 at 18:45

I don't remember why the scaling was happening but please let me know the missing detail or fix it so I can delete this. ( Stolen from How to draw multiple lines inside the circle )

Something along these lines can be a very impractical but a possible way to do it. I can't think of anything clever how to automate it other than the obvious tedious way.

\documentclass[tikz,border=5mm]{standalone}

\path(-0.2cm,0.2cm) rectangle (1.2cm,-2cm); % Arrow line is an overlay!
\pgfinterruptboundingbox
\draw[very thick,transparent!20,->] (0cm,0cm) .. controls +(0cm,-1cm) and +(0cm,1cm) .. (1cm,-2cm);
\endpgfinterruptboundingbox

\begin{document}

\begin{tikzpicture}
\draw[style=help lines] (0,-2) grid[step=1cm] (2,0);