OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

office message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: [OASIS Issue Tracker] Commented: (OFFICE-3830) draw:gamma has no algorithm for calculating the output color

    [ http://tools.oasis-open.org/issues/browse/OFFICE-3830?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=33395#action_33395 ] 

Robert Weir  commented on OFFICE-3830:

Discussed on TC call of 2013-05-13, need to see how applications are treating this, whether a single definition would suit all or most current implementations.

For reference, SVG Filters defines gamma here:

For gamma, the function is defined by the following exponential function:

C' = amplitude * pow(C, exponent) + offset


> draw:gamma has no algorithm for calculating the output color
> ------------------------------------------------------------
>                 Key: OFFICE-3830
>                 URL: http://tools.oasis-open.org/issues/browse/OFFICE-3830
>             Project: OASIS Open Document Format for Office Applications (OpenDocument) TC
>          Issue Type: Sub-task
>          Components: Graphics
>    Affects Versions: ODF 1.2
>            Reporter: Regina Henschel
>             Fix For: ODF 1.3
> The attribute draw:gamma (section 20.128, ODF1.2 part 1) has no description, how to calculate the output color. Such description is needed, because there exists no standard for "gamma". For example in some situations ^value and in other situations ^(1/value) is used.
> The .png format has a chunk gAMA, which holds a gamma value. http://www.w3.org/TR/PNG/#3gamma. And in that specification you get a detailed description, how this value is to be used for displaying a .png picture. http://www.w3.org/TR/PNG/#13Decoder-gamma-handling.
> ODF should provide a description too. The mail https://www.oasis-open.org/apps/org/workgroup/office/email/archives/201304/msg00030.html has an attachment, which describes how Apache OpenOffice calculates the output color. I don't know how other application do it. 
> The specification needs in addition a rule for the order in which the color and tone adjustments are applied, see other subtask.
> The value of draw:gamma should be restricted to positive values, because negative values and zero make no sense. 

This message is automatically generated by JIRA.
If you think it was sent incorrectly contact one of the administrators: http://tools.oasis-open.org/issues/secure/Administrators.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]