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StefanSchippers / xschem

A schematic editor for VLSI/Asic/Analog custom designs, netlist backends for VHDL, Spice and Verilog. The tool is focused on hierarchy and parametric designs, to maximize circuit reuse.
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Extended draw shapes capabilities #177

Closed georgtree closed 3 months ago

georgtree commented 4 months ago

Hello! It would be great to see the ability to draw more complex shapes - ellipse, Bézier curve, etc. These shapes will greatly simplify component symbols creation, currently I can only approximate it with segmented line. Also would be great to add scaling ability for already placed shapes.

Thank you in advance, George.

StefanSchippers commented 4 months ago

I have added a first implementation of bezier curves. They are essentially a variation built on top of the polygon shape. Draw a multipoint polygon (key=p) (npoints >= 3) , set attribute bezier=1 on this shape, it will transform into a composite quadratic bezier spline. I have done tests with quadratic and cubic bezier splines. Quadratic beziers seem more useful, since they can be bent more easily than higher order polynomial curves. I have to improve the UI for easier selecting and moving the control points, but it is already useable. You can also transform a closed polygon into a bezier and in this case it can be filled (by adding attribute fill=1).

Attached the example schematic. Please do a test. 1 test_bezier.zip

georgtree commented 4 months ago

Wow, that was really fast, I tested it and all works great, thank you! I will play with it a little bit more!

P.S and have proper ellipsis will be super cool, because it is a main element to create symbols that are circles in direct view but became ellipsis under angled perspective of view

StefanSchippers commented 4 months ago

Thank you for testing. I was a bit scared by the math, but turned out to be simpler than I thought.

For the ellipse I will look at it. One important question is if you need X/Y oriented ellipses or any angle.

In the mean time I see beziers approximate ellipses quite well. Just start at the correct point as shown. 1

georgtree commented 4 months ago

Hello, I need XY only for drawing pretty-looking symbols

StefanSchippers commented 4 months ago

I have improved a bit the bezier editing. If you select one you can click and drag directly the control points. This applies also for normal polygons. Please test. Thanks!

Last thing I need to improve a bit is selection. Now selecting a bezier works well if you click one of the endpoints or close to a control point. I need to let user select the curve also by clicking any location close to the bezier line.

1

georgtree commented 4 months ago

Hello, thank you, it is very convenient and works as expected!

georgtree commented 3 months ago

Hello! Sorry for asking, but do you have any thoughts about the time the ellipsis will be available to draw? I am not pushing you just ask because I have a lot of symbols to modify and want to understand if it is worth to wait for proper ellipsis implementation instead of bezier approximation... Thank you in advance!

georgtree commented 3 months ago

Hello, all works great, thank you! image

georgtree commented 3 months ago

Hello, find the issue - when component is flipped or rotated, I get this behaviour: image image Looks like the issue is in absolute definition of angles...

StefanSchippers commented 3 months ago

Yes this will be fixed soon. Thanks

georgtree commented 3 months ago

Hello, I tried with last commit, it works with ellipse that I place onto schematic, but if I generate symbol from tcl script, the problem is the same. image image

StefanSchippers commented 3 months ago

Yes, bare ellipses are fixed now. Next commit will address symbols with ellipses.

StefanSchippers commented 3 months ago

Last commit hopefully does correct transformations for ellipses inside symbols. Please test. Thank you for the feedback.

georgtree commented 3 months ago

Hello! Just tested, all works fine, thank you :)