Pyxplot 
Examples  Labelled triangles 
Using the polygon command and Pyxplot's maths environment to construct triangles In this example, we make a subroutine to draw labelled diagrams of the interior angles of triangles, taking as its inputs the lengths of the three sides of the triangle to be drawn and the position of its lowerleft corner. The subroutine calculates the positions of the three vertices of the triangle and then labels them. We use Pyxplot's automatic handling of physical units to generate the LaTeX strings required to label the side lengths in centimetres and the angles in degrees. We use Pyxplot's arc command to draw angle symbols in the three corners of a triangle. Scriptset unit angle nodimensionless set unit of length cm # Display lengths in cm set unit of angle degree # Display angles in degrees set numeric sigfig 3 display latex # Correct to 3 significant figure cm = unit(cm) # Shorthand to save space deg = unit(deg) turn(a) = matrix( [cos(a),sin(a)], \ [sin(a), cos(a)] ) # Define subroutine for drawing triangles subroutine triangleDraw(B,AB,AC,BC) { # Use cosine rule to find interior angles ABC = acos((AB**2 + BC**2  AC**2) / (2*AB*BC)) BCA = acos((BC**2 + AC**2  AB**2) / (2*BC*AC)) CAB = acos((AC**2 + AB**2  BC**2) / (2*AC*AB)) # Positions of three corners of triangle C = B + vector(BC,0*cm) A = B + turn(ABC)*vector(AB,0*cm) # Draw triangle polygon [A,B,C] # Draw angle symbols arcRad = 0.4*cm # Radius of angle arcs arc at B radius arcRad from 90*degABC to 90*deg arc at C radius arcRad from 90*deg to 90*deg+BCA arc at A radius arcRad from 90*deg+BCA to 270*degABC # Label lengths of sides textGap = 0.1*cm text "%s"%(BC) at (B+C)/2 gap textGap hal c val t text "%s"%(AB) at (A+B)/2 gap textGap rot ABC hal c val b text "%s"%(AC) at (A+C)/2 gap textGap rot BCA hal c val b # Label angles arcRad2 = vector(1.4*arcRad , 0*cm) text "%s"%CAB at A+turn(90*deg+ABCBCA)*arcRad2 hal c val t text "%s"%ABC at B+turn( ABC/2)*arcRad2 hal l val c text "%s"%BCA at C+turn(180*deg  BCA/2)*arcRad2 hal r val c # Label points ABC text "A" at A gap textGap hal c val b text "B" at B gap textGap hal r val c text "C" at C gap textGap hal l val c } # Display diagram with three triangles set multiplot ; set nodisplay call triangleDraw(vector([2.8,3.2])*cm, 3*cm, 4*cm, 4*cm) call triangleDraw(vector([0.0,0.0])*cm, 3*cm, 4*cm, 5*cm) call triangleDraw(vector([6.5,0.0])*cm, 3*cm, 3*cm, 3*cm) set display ; refresh
