Faulty handle position in shapes imported from MS Office
rb.henschel at t-online.de
Mon Apr 8 23:06:12 UTC 2019
I'm looking at https://bugs.documentfoundation.org/show_bug.cgi?id=115813
"Position shifted while moving the handle of OOXML Callout shape".
Unfortunately not only the Callout shape is affected.
There are 106 shapes in MS Office, which have handles. 38 are OK with
the current implementation and 68 have at least one handle, which reacts
wrongly. These are only those from ooxml, not from binary format.
The calculation is in method
svx\source\customshapes\EnhancedCustomShape2d.cxx. The relevant part
starts about #1230
The relation ship between handle position and adjustment value is in
most cases not direct but via formulas. For to get an adjustment value
from a handle position you need to apply the formulas backwards.
It might be possible to identify handles, which behave similar. For
example some Star-shapes use the adjust value as factor to the radius
with 0 in center and 1 at the edge. But other adjust values are used in
other ways. I have not tried to find groups of similar usage yet.
What to do? In principle you can get the needed operations from the
presets as defined in the standard. But how to organize that, so that it
can be done step by step and perhaps can be done by several people?
And, of course, the code should still be readable and clear.
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