[iup] Fix mismatch in behaviour with fonttools #663
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rsheeter
reviewed
Oct 17, 2023
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| let contour_ends = vec![17]; | ||
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| iup_delta_optimize(deltas, coords, 0.5, &contour_ends).unwrap(); |
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can the test be further simplified? Do we need the entire outline to reproduce the problem?
(my intuition is it should simplify)
rsheeter
approved these changes
Oct 17, 2023
This patch fixes an issue with iup not resolving, although I do not fully understand the problem. Basically: in comparing our implementation with the one in fonttools, there is clear divergence in some of the numerical code, where we are using Option<usize> in places where python is just using an integer. More importantly, we are using None where Python is using -1, but our comparison code is never checking if a value == None, whereas python *does* check if a value == -1, which means that python is setting the solution in cases where we are not. This can be fixed by using `checked_sub` instead of `saturating_sub`, at least for this input. It feels like this is probably fine, since the structure of this loop is such that the only negative value that is possible is -1 (at the start) but it feels a little loose.
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This patch fixes an issue with iup not resolving, although I do not fully understand the problem.
Basically: in comparing our implementation with the one in fonttools, there is clear divergence in some of the numerical code, where we are using Option in places where python is just using an integer. More importantly, we are using None where Python is using -1, but our comparison code is never checking if a value == None, whereas python does check if a value == -1, which means that python is setting the solution in cases where we are not.
This can be fixed by using
checked_subinstead ofsaturating_sub, at least for this input.It feels like this is probably fine, since the structure of this loop is such that the only negative value that is possible is -1 (at the start) but it feels a little loose.