Summary: | Halftone angle inverted in specific situations on tiffsep1 | ||
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Product: | Ghostscript | Reporter: | Martin Schulze <martin.schulze> |
Component: | Color | Assignee: | Michael Vrhel <michael.vrhel> |
Status: | RESOLVED LATER | ||
Severity: | normal | CC: | sphinx.pinastri |
Priority: | P4 | ||
Version: | 9.50 | ||
Hardware: | PC | ||
OS: | Linux | ||
Customer: | Word Size: | --- | |
Attachments: |
Comparison of angles for accurate screens with frequency 150 and resolutuion 600,720,750 DPI
Modified sample file with pointed spot function. |
Description
Martin Schulze
2020-02-19 09:11:07 UTC
Assigning to Ray as this is very similar to the problem fixed in this commit: http://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=bf689ee0bff720f202ebc98f301c765f34e2c1fa FWIW its possible the accurate screens case is fixed, though its hard to be sure on such a small sample. The regular screens case is more obviously incorrect. Created attachment 20408 [details]
Modified sample file with pointed spot function.
I confirm that there's a flip between 465 and 466 dpi. One is rotated clockwise, another is rotated counter-clockwise.
The spot function in my halftone draws an isosceles triangle. The halftone angle is a negative of the angle between X axis and a line of symmetry of the triangle. Negation is needed because halftone angles are measured clockwise.
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