Flip vertical direction of Geometry Applet translation #46

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glen · 2023-10-22T17:38:30Z

glen commented

2023-10-22 17:38:30 +00:00

Joyce wrote the Geometry Applet in a coordinate system in which positive x extended to the right and positive y extended down. Initially, I left the coordinates alone in GeoGebra, which uses the usual mathematical coordinate system with y increasing upward. This reverses the handedness of the coordinate system, so I was also reversing counterclockwise/clockwise in all of the commands. I thought it wouldn't matter, just all the diagrams would be upside down. But then I hit the square construction -- it also screws up the absolute numbering of vertices when a square is constructed. So I need to fix the clockwise/counterclockwise directions of everything, which so far as I can see can only be done by flipping the y-axis to match the system Joyce originally used.

Ugh, scanning through all commands for those embedded handedness assumptions will be annoying. But I don't see a choice.

Joyce wrote the Geometry Applet in a coordinate system in which positive x extended to the right and positive y extended down. Initially, I left the coordinates alone in GeoGebra, which uses the usual mathematical coordinate system with y increasing upward. This reverses the handedness of the coordinate system, so I was also reversing counterclockwise/clockwise in all of the commands. I thought it wouldn't matter, just all the diagrams would be upside down. But then I hit the square construction -- it also screws up the absolute numbering of vertices when a square is constructed. So I need to fix the clockwise/counterclockwise directions of everything, which so far as I can see can only be done by flipping the y-axis to match the system Joyce originally used. Ugh, scanning through all commands for those embedded handedness assumptions will be annoying. But I don't see a choice.

glen added the

bug

label 2023-10-22 17:38:30 +00:00

glen referenced a pull request that will close this issue

2023-11-27 03:39:50 +00:00

fix: conform to Joyce's original axis orientations #47

glen closed this issue

2023-11-27 03:40:04 +00:00

glen referenced this issue from a commit

2023-11-27 03:40:05 +00:00

fix: conform to Joyce's original axis orientations (#47)

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