Cfxtrjtrk

I'm drawing a diagram for a project, but with the n vector going through the angle label it isn't very clear, I'd like to add a white background to the alpha label so it's easier to see. Thanks, see MWE below.

documentclass{article}

usepackage[utf8]{inputenc}

usepackage{amsmath}

usepackage{tikz}

usetikzlibrary{calc,patterns,angles,quotes,arrows}



begin{document}

begin{figure}

        begin{center}

        begin{tikzpicture}

            %Define coordinates

            coordinate (origin) at (0,0);

            coordinate (bhat) at (0,5);

            coordinate (zetahat) at (5,0);

            coordinate (vector) at (3,4);

            coordinate (normal) at (1.581,4.743);



            %Draw axes

            draw[thick, <->] (bhat) node[above]{$hat{b}$} -- (origin) -- (zetahat) node[right]{$hat{zeta}$};



            %Draw vector

            draw[thick, ->, blue] (origin) -- (vector) node[above]{$vec{v_r}$};



            %N vector

            draw[thick, dotted, ->] (origin) -- (normal) node[above]{$hat{n}$};



            %Draw angle

            pic [draw, "$alpha$", angle eccentricity = 1.2, angle radius = 1.5cm, thick] {angle = vector--origin--bhat};



        end{tikzpicture}

        caption{Pitch angle $alpha$ is equal to $2theta_{bn}$, showing specular reflection}

        label{fig:Pitch Angle}

        end{center}

    end{figure}

end{document}

Use "$alpha$"{fill=white} instead of "$alpha$" in pic

documentclass{article}

usepackage[utf8]{inputenc}

usepackage{amsmath}

usepackage{tikz}

usetikzlibrary{calc,patterns,angles,quotes,arrows}



begin{document}

begin{figure}

        begin{center}

        begin{tikzpicture}

            %Define coordinates

            coordinate (origin) at (0,0);

            coordinate (bhat) at (0,5);

            coordinate (zetahat) at (5,0);

            coordinate (vector) at (3,4);

            coordinate (normal) at (1.581,4.743);



            %Draw axes

            draw[thick, <->] (bhat) node[above]{$hat{b}$} -- (origin) -- (zetahat) node[right]{$hat{zeta}$};



            %Draw vector

            draw[thick, ->, blue] (origin) -- (vector) node[above]{$vec{v_r}$};



            %N vector

            draw[thick, dotted, ->] (origin) -- (normal) node[above]{$hat{n}$};



            %Draw angle

            pic [draw,  "$alpha$"{fill=white}, angle eccentricity = 1.2, angle radius = 1.5cm, thick] {angle = vector--origin--bhat};



        end{tikzpicture}

        caption{Pitch angle $alpha$ is equal to $2theta_{bn}$, showing specular reflection}

        label{fig:Pitch Angle}

        end{center}

    end{figure}

end{document}

A PSTricks solution only for comparison purposes. A single * does the job (making the label background solid).

documentclass[pstricks,12pt]{standalone}

begin{document}

pspicture(-1,-1)(6,6)

    psline{<->}(0,5)(0,0)(5,0)

    psline{->}(5;60)

    psline[linestyle=dotted,dotsep=1pt]{->}(5;75)

    uput[90](0,5){$hat{b}$}

    uput[0](5,0){$hat{zeta}$}

    uput[60](5;60){$vec{v}_r$}

    uput[75](5;75){$hat{n}$}

    uput*{2.5}[75](0,0){$alpha$}

    psarc(0,0){2}{60}{90}

endpspicture

end{document}