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% |
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% DRAWVEC draw arrows for vectors |
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% |
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% DRAWVEC drawvec(xo,yo,um,vm,atheta,lcolor) is a routine to |
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% draw vectors. This is a fairly low-level routine |
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% in that in does no scaling to the vectors. This function |
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% is called primarily by VECPLOT and returns the handle |
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% of the vector object drawn. |
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% |
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% Inputs: xo,yo - vector origins; arrow eminates from this point |
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% um,vm - vector magnitudes |
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% atheta - arrow-head angle, in degrees |
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% lcolor - linecolor , 'r' = red, etc. |
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% |
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% Outputs: hp - the handle to the vector object drawn |
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% |
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% Call as: hp=drawvec(xo,yo,um,vm,atheta,lcolor) |
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% |
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% Written by: Brian O. Blanton |
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% |
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function hp=drawvec(xo,yo,um,vm,atheta,lcolor) |
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fac = 3.14159/180.; |
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arrowtheta = atheta*fac; |
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% columnate the input vectors to ensure they are |
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% column-vectors, not row-vectors |
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xo=xo(:); |
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yo=yo(:); |
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um=um(:); |
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vm=vm(:); |
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|
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% compute and draw arrow shaft |
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xe = xo + um; |
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ye = yo + vm; |
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arrowmag = .25*(sqrt((xo-xe).*(xo-xe)+(yo-ye).*(yo-ye))); |
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shafttheta = -atan2((ye-yo),(xe-xo)); |
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xt = xe-arrowmag.*cos(arrowtheta); |
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yt = ye-arrowmag.*sin(arrowtheta); |
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x1 = (xt-xe).*cos(shafttheta)+(yt-ye).*sin(shafttheta)+xe; |
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y1 = (yt-ye).*cos(shafttheta)-(xt-xe).*sin(shafttheta)+ye; |
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xt = xe-arrowmag.*cos(-arrowtheta); |
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yt = ye-arrowmag.*sin(-arrowtheta); |
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x2 = (xt-xe).*cos(shafttheta)+(yt-ye).*sin(shafttheta)+xe; |
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y2 = (yt-ye).*cos(shafttheta)-(xt-xe).*sin(shafttheta)+ye; |
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x=ones(length(xo),6); |
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y=ones(length(xo),6); |
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x=[xo xe x1 xe x2 NaN*ones(size(xo))]'; |
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y=[yo ye y1 ye y2 NaN*ones(size(yo))]'; |
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x=x(:); |
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y=y(:); |
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hp=line(x,y,'LineStyle','-','Color',lcolor); |
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% |
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% Brian O. Blanton |
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% Curr. in Marine Sciences |
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% 15-1A Venable Hall |
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% CB# 3300 |
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% Uni. of North Carolina |
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% Chapel Hill, NC |
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% 27599-3300 |
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% |
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% 919-962-4466 |
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% blanton@marine.unc.edu |
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% |
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