Plot 2-D vector field with arrow3

Hi, I would like to use the arrow3 function (https://uk.mathworks.com/matlabcentral/fileexchange/14056-arrow3-version-5) to plot a 2-D vector field P (P_x,P_y) with the direction and colour of the arrows representing the direction and magnitude of the field vector P.

I have read the arrow3 file. As far as I understood, the arrow3 will draw an arrow from point 1 to point 2 but I don't know how to represent the magnitude by the colour of the arrows. Could you please help? Thanks

 [x,y] = meshgrid(linspace(-10,10,100),linspace(-20,20,200));
P_x=rand(200,100);
P_x=rand(200,100);

[Star Strider]

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