[Kdenlive-devel] Color correction tools: How and where to implement them?

[Till Theato]

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On 07/15/2010 10:21 PM, Simon Eugster wrote:
> 2010/7/15 Dan Dennedy <dan at dennedy.org>:
>> On Thu, Jul 15, 2010 at 1:49 AM, Till Theato <root at ttill.de> wrote:
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>>> On 07/15/2010 09:52 AM, Simon Eugster wrote:
>>>> 2010/7/14 Till Theato <root at ttill.de>:
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>>>>> On 07/14/2010 07:13 PM, Dan Dennedy wrote:
>>>>>> On Wed, Jul 14, 2010 at 9:00 AM, Simon Eugster <simon.eu at gmail.com> wrote:
>>>>>>>>> * 3-Way color correction works basically quite well,
>>>>>>>>>   but the usability is terrible.
>>>>>>>>>   If you want to change the blacks, you have to rise the black
>>>>>>>>>   value to see colors in the color picker, and at the end make
>>>>>>>>>   it nearly black again. Would be much better to just chose a
>>>>>>>>>   color and not having to worry about black.
>>>>>>>>>   Also is it not very convenient not to have a live preview.
>>>>>>>>
>>>>>>>> All Kdenlive effects have live preview. So, a simple enhancement to
>>>>>>>> toggle that would help.
>>>>>>>
>>>>>>> Well, there is live preview as soon as the color has changed in the
>>>>>>> widget. But this is only the case when the color picker has been
>>>>>>> closed already. There should be a built-in color picker.
>>>>>>
>>>>>> Yeah, like I suggested for white balance.
>>>>>>
>>>>>
>>>>> I will take a look at this one. Maybe we could also reuse a color
>>>>> selector from krita.
>>>>
>>>> Perhaps something like the HSV color wheel here
>>>> http://en.wikipedia.org/wiki/Color_wheel would be good because even
>>>> for high black values you still see the color.
>>>>
>>>> Perhaps a wheel that just ignores the black value (like a YUV wheel
>>>> with fixed Y) would suit even better. Especially as the vectorscope
>>>> uses YUV as well, this would make color corrections much easier. I'm
>>>> currently trying (or, intending to try, should be learning actually)
>>>> to produce a YUV circle for the vectorscope as background, but this
>>>> could also be used for a color wheel later. When I get it, this
>>>> shouldn't even be too difficult.
>>>> Perhaps we'd still need to add the Y component separately.
>>>>
>>> What I thought of was Krita's Triangle Color Selector
>>> (http://lukast.mediablog.sk/i/colorchoosers/krita-color-choosers.png).
>>> However it is RGB based.
>>
>> I just realized that for White Balance, I was thinking about the
>> eye-dropper. It would be nice to choose a color via eyedropper for
>> White Balance and/or color-palette for other effects without the
>> issues of a modal dialog.
> 
> I think that is exactly what I tried to express :)

Hi,
in svn r4662 I now added a color picker ("eyedropper").

> Please take a look at r4582. I've added a method
> Vectorscope::yuvColorWheel which creates a YUV color wheel.
> It is totally amazing what graphical effects you get when ignoring
> char overflows.
> I mean. The modified color wheel might suit quite well as color
> picker. Perhaps it would require some more modifications to get more
> differentiable saturation. (Actually the modified one was the original
> YUV wheel which I identified as being just wrong. But it does seem
> useful.)
> 
> You can see the wheel in the vectorscope, when changing the background
> (via combo box there). Works in an empty project as well.

@Granjow: Do you want to implement a color chooser? If not I will adopt
one from krita.
Also take a look at this post:
http://celarek.at/2010/07/krita-gsoc-colour-selectors-with-colourspaces-support/
If they are finished we might want to adopt some to give the user
several color choosers.

till


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