gradient angles

[Regina Henschel]

Hi Christine,

continuing..

Christina Roßmanith schrieb:
> Hi,
>
> just to be sure before I continue my work:
>
> SVG gradient with angle=0° changes color from left to right
>       (I'm taking this from
> http://www.w3.org/TR/SVG/pservers.html#LinearGradientElement)
>
> ODF gradient with angle=0° changes color from top to bottom
>       (I can't find any meaning of the angle attribute here
> http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html#__RefHeading__1416460_253892949)

I have now looked, which way PowerPoint2013 does it:
The angle of 0° in the UI means that the gradient vector goes from left 
to right.
The angle in the UI rotates this gradient vector clockwise on screen. 
Values from 0 to 359.9 are allowed.

In file format it is the same as from LO, for example:
draw:angle="700" results from
   PP UI-angle=20° clockwise on screen
   LO UI-angle=70° counterclockwise on screen
draw:angle="3300" results form
   PP UI-angle=120° clockwise on screen
   LO UI-angle=330° counterclockwise on screen

So it seems, that PP follows the way how it is stored in file, but has a 
different UI.

My conclusion is, that a mail to OASIS is needed with the points:
(1) Define "axis at which the gradient values are interpolated" as vector
(2) Define untransformed direction of this vector as going in positive 
y-axis direction.
(3) Define direction of rotation as clockwise in respect to the internal 
coordinate system
(4) Do not define draw:angle as SVG-angle but as double to be multiplied 
with 0.1°.

What do you think?

Kind regards
Regina