Issue 111487 - Add support for constant B-spline (zero order hold)
Summary: Add support for constant B-spline (zero order hold)
Status: CLOSED WONT_FIX
Alias: None
Product: General
Classification: Code
Component: chart (show other issues)
Version: 3.3.0 or older (OOo)
Hardware: All All
: P3 Trivial (vote)
Target Milestone: ---
Assignee: AOO issues mailing list
QA Contact:
URL:
Keywords: needmoreinfo
Depends on:
Blocks:
 
Reported: 2010-05-09 08:58 UTC by nmarci
Modified: 2017-05-20 10:03 UTC (History)
3 users (show)

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Issue Type: ENHANCEMENT
Latest Confirmation in: ---
Developer Difficulty: ---

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Description nmarci 2010-05-09 08:58:38 UTC 
When drawing an X-Y type diagram it is possible to configure the order of the
B-spline for smooth lines. Currently the minimum order of the B-spline is 1.

However, there are cases when the constant B-spline is wanted. This would be a
B-spline with order 0, see also
http://en.wikipedia.org/wiki/B-spline#Constant_B-spline . In other places this
is called zero order hold, see http://en.wikipedia.org/wiki/Zero_Order_Hold .

Imagine a data series where the first column contains a timestamp in seconds and
the second column contains the current state of a switch: 0 or 1. The data
series only contains the point where a change happened in the switch. In this
case the chart to be drawn should be a constant line starting at the first
timestamp value, then jump to the next constant value at the following timestamp.
Comment 1 kla 2010-08-04 13:05:41 UTC 
@iha:one for you.
kla
Comment 2 Regina Henschel 2011-05-09 14:59:34 UTC 
This is not possible, because the calculation of the knots uses the degree p as denominator.

The way, a B-spline is calculated is specified in the OASIS norm, see http://docs.oasis-open.org/office/v1.2/OpenDocument-v1.2-part1.odt
You can sent a request to http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=office
Comment 3 Regina Henschel 2011-06-17 14:10:58 UTC 
Please have a look whether the chart types 'step-start', 'step-end, 'step-center-x', or 'step-center-y' in Gnumeric would meet your requirement. [Gnumeric is free software.] There is a request to the OASIS TC to include this kind of interpolation into the next version of ODF standard.
Comment 4 Edwin Sharp 2014-03-02 19:58:34 UTC 
Please attach example.
Comment 5 Edwin Sharp 2014-03-15 16:22:26 UTC 
No info from author.