Tutorial: A simple triangle shape

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import simetri.graphics as sg # (1)!

canvas = sg.Canvas() # (2)!
canvas.help_lines(pos=(-50, -50), width=300, height=300, spacing=25)

points = [(25, 25), (50, 75), (100, 0)] # (3)!
triangle = sg.Shape(points) # (4)!
canvas.draw(triangle, line_width=2) # (5)!

triangle2 = sg.Shape([(25, 125), (50, 175), (100, 100)], closed=True)
canvas.draw(triangle2, fill=False, line_dash_array=[5, 3, 2, 3])
triangle2.translate(dx=100, dy=0)
canvas.draw(triangle2, line_width=2)

triangle2.fill_color = sg.amber
triangle2.rotate(-sg.pi/4) # (6)!
canvas.draw(triangle2, line_width=2)
canvas.display() # (7)!

1. Always import the library like this!

   And never use from simetri import *
   since it may create a lot of problems! Your namespace will be polluted and debugging will be very difficult.
2. • We do not need to specify size for the canvas. It will be automatically computed if it is not used.
     
   • canvas = sg.Canvas(back_color=sg.yellow) can be used to set the background color.
     
   • canvas is the conventional variable name for the Canvas instances but you can use any valid variable name.

3. Points

   • Points can be any sequence of (x, y) or (x, y, 1) values.
     [(10, 20), (30, 40), ...], ([15.5, 20., 1], [35, 40, 1], ...) are all valid.
   • simetri internally converts them to floating point numpyarrays.
   • The units for cooordinates is pnts.
     72pnts = 1in
     
   • Point sizes should be reasonable. If a shape is too large to fit into a page or too small to see clearly, we may have numerical problems.
4. By default shape.closed = False unless the start and end points are equivalent.
   sg.Shape(points, closed=True) can be used to create a closed shape.
5. The default value for shape.line_width = 1 but canvas.draw() can overwrite any style attributes.
6. All angles in SİMETRİ is counterclockwise positive and in radians. To convert between radians and angles, you can use sg.radians(angle) and sg.degrees(angle) utility functions to convert an angle from degrees to radians and from radians to degrees respectively.
7. You can use canvas.save("/your/path/here.pdf") or in Windows canvas.save("c:/your/path/here.svg") to generate an output file. The supported formats are: .tex, .pdf, .svg, .ps, .eps, and .png. You can also use the show flag to show the output in a web-browser (the default value for show is True). Only .pdf, .svg, and .png files can be shown) You can use the overwrite flag to overwrite any existing files.
   canvas.save("/your/path/here.pdf", show=False, overwrite=True)

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