René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: axes3d.py's _on_move() converts the roll angle to radians, but then passes it to view_init() as if it were still in degrees","articleBody":"### Bug summary\n\nIn \\lib\\mpl_toolkits\\mplot3d\\axes3d.py, `_on_move()` deals with rotation of 3d axes using the mouse.  In line 1522, the roll angle (in degrees) is converted to radians:\r\n`    roll = np.deg2rad(self.roll)`\r\nThis roll in radians is used to calculate a new elevation and azimuth, like so:\r\n```\r\n    delev = -(dy/h)*180*np.cos(roll) + (dx/w)*180*np.sin(roll)\r\n    dazim = -(dy/h)*180*np.sin(roll) - (dx/w)*180*np.cos(roll)\r\n    elev = self.elev + delev\r\n    azim = self.azim + dazim\r\n```\r\nA moment later, the view is updated:\r\n```\r\n    self.view_init(\r\n        elev=elev,\r\n        azim=azim,\r\n        roll=roll,\r\n        vertical_axis=vertical_axis,\r\n        share=True,\r\n    )\r\n```\r\nHowever, `view_init()` expects its parameters to be in degrees, not radians. As a consequence, the roll now diminishes by a factor pi/180 with every mouse movement. Not intended.\r\n\n\n### Code for reproduction\n\n```Python\n# Run the surface3d.py example, adding\r\nax.roll = 45\r\n# It shows the plot, in the intended funny orientation (roll=45)\r\n# Then move the mouse - you will see the orientation jump suddenly (to roll=0)\n```\n\n\n### Actual outcome\n\nThe figure orientation has jumped to roll=0, after trying to rotate it only slightly by dragging the mouse:\r\n![Figure_rotated](https://github.com/matplotlib/matplotlib/assets/122418839/ccbc7f47-dc27-499c-bee4-296b5b5164cb)\r\n\n\n### Expected outcome\n\nThe figure is close to its original orientation (before dragging the mouse), at roll=45:\r\n![Figure_1](https://github.com/matplotlib/matplotlib/assets/122418839/6e572bc9-e1f4-4a87-87f3-4b571ef06288)\r\n\n\n### Additional information\n\nFix: add a line:\r\n`roll = self.roll`\r\nright after updating `elev` and `azim` (i.e., after line 1526).\r\n\n\n### Operating system\n\nAll, presumably; but I noticed it on Windows\n\n### Matplotlib Version\n\n3.10.0.dev191+ge5af947d1b.d20240517\n\n### Matplotlib Backend\n\ntkagg\n\n### Python version\n\nPython 3.12.3\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/MischaMegens2","@type":"Person","name":"MischaMegens2"},"datePublished":"2024-05-17T22:45:44.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/28256/matplotlib/issues/28256"}