B Spline interpolation is broken for some documents. Open the test document attached to Bug 47632 and switch to edit mode. Somewhere in Splines.cxx must be an error implementing the algorithm mentioned in ODF 1.2.
Algorithm is implemented in chart2/source/view/charttypes/Splines.cxx
This one is getting really nasty. I have more or less implemented the algorithm totally new and added unit tests but the algorithm results in memory corruption. Have to spend some time on other calc bugs.
Created attachment 59314 [details] File for experiments Hi Markus. I think, that the problem is caused by identical y-values. When you increase the x- or y-values step by step, you can notice, that the amplitude of the curves increases too. I tend to think, that this cannot be avoided, because B-Spline interpolation curves are parametric. I guess, that it is a property of this kind of interpolation. When you agree to that and not find an error in the algorithm, I suggest, that we implement some functional interpolation. For those of cause the x-values have to be sorted as it has been in older versions of OOo. Perhaps we can discuss this on the Hackfest?
Hey Regina, I don't think that the B-Spline algorithm itself has a problem with identical y values. I fear more that one of our assumptions in the implementation is wrong. I think I remember from my Numerical Math 2 lecture that there is no such limitation for B splines but I would need to check with my script. I have now to fix some more calc bugs before I can come back to this problem but I will finally try to run this data through MATLAB and compare the result of each individual step with the MATLAB result. I already did that for the creation of t and u with my reworked implementation and they were the same in matlab and in my implementation. I will try to get the splitted up implementation into master before the hackfest and hopefully the test data ready until then. Sadly we are not free to implement another algorithm because ODF1.2 explicitly mentions this algorithm. Nevertheless if there is really a problem with the ODF algorithm we may talk to Kohei/Thorsten how to proceed.
*** Bug 57234 has been marked as a duplicate of this bug. ***
Is there any development in working on this bug or should it be unassigned? Last comment is from 2012.
Dear developer, This bug has been in ASSIGNED status for more than 3 months without any activity. Resetting it to NEW. Please assigned it back to yourself if you're still working on this.
** Please read this message in its entirety before responding ** To make sure we're focusing on the bugs that affect our users today, LibreOffice QA is asking bug reporters and confirmers to retest open, confirmed bugs which have not been touched for over a year. There have been thousands of bug fixes and commits since anyone checked on this bug report. During that time, it's possible that the bug has been fixed, or the details of the problem have changed. We'd really appreciate your help in getting confirmation that the bug is still present. If you have time, please do the following: Test to see if the bug is still present with the latest version of LibreOffice from https://www.libreoffice.org/download/ If the bug is present, please leave a comment that includes the information from Help - About LibreOffice. If the bug is NOT present, please set the bug's Status field to RESOLVED-WORKSFORME and leave a comment that includes the information from Help - About LibreOffice. Please DO NOT Update the version field Reply via email (please reply directly on the bug tracker) Set the bug's Status field to RESOLVED - FIXED (this status has a particular meaning that is not appropriate in this case) If you want to do more to help you can test to see if your issue is a REGRESSION. To do so: 1. Download and install oldest version of LibreOffice (usually 3.3 unless your bug pertains to a feature added after 3.3) from http://downloadarchive.documentfoundation.org/libreoffice/old/ 2. Test your bug 3. Leave a comment with your results. 4a. If the bug was present with 3.3 - set version to 'inherited from OOo'; 4b. If the bug was not present in 3.3 - add 'regression' to keyword Feel free to come ask questions or to say hello in our QA chat: https://kiwiirc.com/nextclient/irc.freenode.net/#libreoffice-qa Thank you for helping us make LibreOffice even better for everyone! Warm Regards, QA Team MassPing-UntouchedBug
Dear Markus Mohrhard, To make sure we're focusing on the bugs that affect our users today, LibreOffice QA is asking bug reporters and confirmers to retest open, confirmed bugs which have not been touched for over a year. There have been thousands of bug fixes and commits since anyone checked on this bug report. During that time, it's possible that the bug has been fixed, or the details of the problem have changed. We'd really appreciate your help in getting confirmation that the bug is still present. If you have time, please do the following: Test to see if the bug is still present with the latest version of LibreOffice from https://www.libreoffice.org/download/ If the bug is present, please leave a comment that includes the information from Help - About LibreOffice. If the bug is NOT present, please set the bug's Status field to RESOLVED-WORKSFORME and leave a comment that includes the information from Help - About LibreOffice. Please DO NOT Update the version field Reply via email (please reply directly on the bug tracker) Set the bug's Status field to RESOLVED - FIXED (this status has a particular meaning that is not appropriate in this case) If you want to do more to help you can test to see if your issue is a REGRESSION. To do so: 1. Download and install oldest version of LibreOffice (usually 3.3 unless your bug pertains to a feature added after 3.3) from https://downloadarchive.documentfoundation.org/libreoffice/old/ 2. Test your bug 3. Leave a comment with your results. 4a. If the bug was present with 3.3 - set version to 'inherited from OOo'; 4b. If the bug was not present in 3.3 - add 'regression' to keyword Feel free to come ask questions or to say hello in our QA chat: https://kiwiirc.com/nextclient/irc.freenode.net/#libreoffice-qa Thank you for helping us make LibreOffice even better for everyone! Warm Regards, QA Team MassPing-UntouchedBug
Created attachment 169987 [details] B-spline chart that loops all around
This feature is obviously completely abandoned, despite being broken; I propose that it be deprecated, with text in the GUI to that effect (since it can't be outright removed due to being incorporated into the ODF spec, despite being completely broken then as now). I just tried to switch to B-splines to eliminate the hilariously long overshoots in the cubic algorithm, and instead it gave me loop-de-loops. My experience working with B-spline interpolation in image resizing tells me this is not correct, but if you've already specified an incorrect algorithm, better to just deprecate it.
Dear Markus Mohrhard, To make sure we're focusing on the bugs that affect our users today, LibreOffice QA is asking bug reporters and confirmers to retest open, confirmed bugs which have not been touched for over a year. There have been thousands of bug fixes and commits since anyone checked on this bug report. During that time, it's possible that the bug has been fixed, or the details of the problem have changed. We'd really appreciate your help in getting confirmation that the bug is still present. If you have time, please do the following: Test to see if the bug is still present with the latest version of LibreOffice from https://www.libreoffice.org/download/ If the bug is present, please leave a comment that includes the information from Help - About LibreOffice. If the bug is NOT present, please set the bug's Status field to RESOLVED-WORKSFORME and leave a comment that includes the information from Help - About LibreOffice. Please DO NOT Update the version field Reply via email (please reply directly on the bug tracker) Set the bug's Status field to RESOLVED - FIXED (this status has a particular meaning that is not appropriate in this case) If you want to do more to help you can test to see if your issue is a REGRESSION. To do so: 1. Download and install oldest version of LibreOffice (usually 3.3 unless your bug pertains to a feature added after 3.3) from https://downloadarchive.documentfoundation.org/libreoffice/old/ 2. Test your bug 3. Leave a comment with your results. 4a. If the bug was present with 3.3 - set version to 'inherited from OOo'; 4b. If the bug was not present in 3.3 - add 'regression' to keyword Feel free to come ask questions or to say hello in our QA chat: https://web.libera.chat/?settings=#libreoffice-qa Thank you for helping us make LibreOffice even better for everyone! Warm Regards, QA Team MassPing-UntouchedBug