Extended color

[Regina Henschel]

Hi Armin,

Armin Le Grand schrieb am 31.03.2023 um 13:29:
> Hi,
> 
> On 3/24/23 11:01, Regina Henschel wrote:
>> The ColorTransformType determines how the number in Value has to be 
>> interpreted.
>> Examples: Type="LumMod" Value="6000" means to modify the luminance of 
>> the color with 60% as specified in OOXML.
>>
>> struct ColorStop
>>     double               StopOffset
>>     css::awt::ExtColor   StopColor
>>
> We should split it here from my POV.
> 
> (a) There is the model data in the XFillGradientItem and 
> XFillFloatTransparenceItem expressed as XGradient
> 
> (b) There is FillGradientAttribute used in primitives

I'm only thinking about API and ODF. My proposals do not touch 
primitives and FillGradientAttribute.

> 
> Both use currently basegfx::ColorStops and thus ColorStop which just 
> uses a basegfx::BColor as color definition. I agree that we should use 
> css::awt::ExtColor in the model data (a), but not in (b).

Then we agree.

Nevertheless, we need to track the relationship to themes and color 
transformations. Those are needed in export to OOXML and ODF.

> 
> The issue is that primitives are designed to be self-contained, thus 
> should contain a 'complete' data set to describe their content, also to 
> be able to implement as simple as possible, and *local*, decomposition. 
> If they would contain the ColorType 'Theme' always some kind of 'solver' 
> would be necessary to be in reach to get the end result of the color to 
> be used in the visualization.
> 
> Thus the primitives in (b) should already contain the result of that 
> processing that converts from a theme color to the render color. This 
> fits well together, so in the primitive creating step where (a) is 
> processed the probability to have such a 'solver' is high (should be 
> e.g. in the same ItemSet?). Just 'solve' it there and use the result in 
> a single representation form in the to-be-created primitive.

It would be good, if Tomaž Vajngerl could give an overview over his 
plans, especially how _he_ things to integrate theme colors and 
multi-color gradients.

Kind regards,
Regina