[Tex/LaTex] How to scale an angle’s label with TikZ

tikz-anglestikz-pgf

I would like to be able to scale the label of this angle:

enter image description here

Code:

\documentclass[a4paper,12pt]{article}

\usepackage{siunitx}
\usepackage{tikz}
\usetikzlibrary{angles, quotes}

\begin{document}

\begin{tikzpicture}
% Declare Points
\coordinate (X) at (6,1);
\coordinate (A) at (0,0);
\coordinate (Y) at (3,5);

% Draw Angle
\draw[thick] (X) -- (A) -- (Y)
pic ["\ang{38}", draw, thick, angle eccentricity=1.8] {angle = X--A--Y};

% Label Points
\draw (A) node[below left, scale=0.85] {A};

\end{tikzpicture}

\end{document}

Unsatisfying workaround

Drawing "{\small \ang{38}}" kind of "works", but I'd prefer to scale the label (like the other elements, for instance the vertex' name).

Failed attempt #1

This gave me the idea to try pic ["\ang{38}", draw, thick, angle eccentricity=1.8, text scale=0.85] {angle = X--A--Y};, but text scale doesn't seem to exist, because I get:

! Package pgfkeys Error: I do not know the key '/tikz/text scale', to which you
 passed '0.85', and I am going to ignore it. Perhaps you misspelled it.

See the pgfkeys package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.17 ...ck, angle eccentricity=1.8, text scale=0.85]
                                                   {angle = X--A--Y};

Failed attempt #2

From there I've found this:

You can use a simple string “text” or a string with options, such as
node["text" {red, draw, thick}] to achieve an effect like
node[label={[red,draw,thick]text}] with less writing and more
readability.

But then, in order to simply test the color, as a start, writing pic [node["\ang{38}" {red}], draw, thick, angle eccentricity=1.8] {angle = X--A--Y}; leads to:

\xparse function is not expandable 
l.17 pic [node["\ang{38}" {red}]
                              , draw, thick, angle eccentricity=1.8] {angle ...

And the less readable way also gives an error.

Question

Is there a way I can use this advice, or any other mean, to scale the angle's label?

Best Answer

"\ang{38}"scale=0.5.

In general with the quotes syntax, "label text" {<options for label node>}, <other stuff>. If you only have one option, the braces aren't required.

smaller label

\documentclass[a4paper,12pt]{article}

\usepackage{siunitx}
\usepackage{tikz}
\usetikzlibrary{angles, quotes}

\begin{document}

\begin{tikzpicture}
% Declare Points
\coordinate (X) at (6,1);
\coordinate (A) at (0,0);
\coordinate (Y) at (3,5);

% Draw Angle
\draw[thick] (X) -- (A) -- (Y)
pic ["\ang{38}"scale=0.5, draw, thick, angle eccentricity=1.8] {angle = X--A--Y};

% Label Points
\draw (A) node[below left, scale=0.85] {A};

\end{tikzpicture}

\end{document}