[Tex/LaTex] TikZ: Bend text so that it follows a line


I have two arrows going from a node on the left to a node on the right. Both arrows are slightly bent. I want to label the arrows with text that is bent just like the arrows. This is as far as I've got:

\node (One) at (-3,0) [shape=circle,draw] {One}; 
\node (Two) at (3,0) [shape=circle,draw] {Two};
\draw [->, thick] (One) to [bend right=45]  (Two);
\draw [->, thick] (One) to  [bend left=45] (Two);
\node (mental) at (0,1.75) {Some bent text};
\node (non-mental) at (0,-1.75) {Some more bent text};

Best Answer

This can be done by the decorations.text library gives you a text along path decoration. See the PGF/TikZ manual (v2.10) on page 337, section 30.6 Text decorations for more details. You can't draw and decorate the path at the same time directly, but can use postaction={..} to decorate the path after you have drawn it (Thanks goes to Alan Munn for this tip).

To format the text place the style macros between | in the text argument. Non-English characters need to be included in braces, e.g. text={|\itshape|Some Text {รถ} more text}. One issue is to raise the font (it is just placed really on the path!). I looked into the source code and found out that the font macros are placed before each single processed character but with an \relax between it, i.e. <your style>\relax<character>. You could define a macro which takes two arguments, the first is the \relax and the second the character, then use \raisebox{<length>}{<content>} to raise or lower the character.




\node (One) at (-3,0) [shape=circle,draw] {$One$}; 
\node (Two) at (3,0) [shape=circle,draw] {$Two$};
\draw [->,thick,postaction={decorate,decoration={text along path,text align=center,text={|\sffamily\myshift|Some more bent text}}}] (One) to [bend right=45]  (Two);
\draw [->,thick,postaction={decorate,decoration={text along path,text align=center,text={|\sffamily\myshift|Some bent text}}}]      (One) to [bend left=45] (Two);