Review Request: Add support for AlphaChannel to KColorDialog

Tue Apr 27 14:48:40 BST 2010

On Tuesday 27 April 2010 15.20.50 Christoph Feck wrote:
> > On 2010-04-13 06:23:09, Johannes Christenson wrote:
> > > I can't see any reason to treat the alpha channel different from other
> > > channels?
> > 
> > Christoph Feck wrote:
> >     Can you clarify? Behavior that you see vs. expected behavior?
> > 
> > Johannes Christenson wrote:
> >     I meant that you gave the alpha channel a separate gradient bar
> >     instead of letting it use the one the other channels are using by
> >     selecting it with a radio button.
> > 
> > Christoph Feck wrote:
> >     The color selection is three-dimensional, with two dimension
> >     displayed in the large area, and the third dimension displayed in
> >     the slider next to it. With the radio buttons, you select which
> >     dimension is shown in the slider, and the remaining two are shown in
> >     the large area.
> >     
> >     When you add a fourth dimension (which is not actually related to the
> >     color space), and you select this one for the slider, which two of
> >     the remaining three should be displayed in the large area?
> > 
> > Johannes Christenson wrote:
> >     You're right! I should have been thinking more before my comment!:)
> >     Although if it's not part of the color space there is little reason
> >     to have it lined up with the rgb values either! But I think that's
> >     ok. The placement would, IMHO, look best if the labels (the text)
> >     where lined up. Have you been thinking about other alternatives for
> >     visualization? (Not criticism! Just brainstorming around the fact
> >     that we actually have four dimensions to visualize and are doing it
> >     in 2+1+1 dimensions. How would it for example look with 2+2
> >     dimensions?) I find this a very interesting subject!
> >     Maybe I should make it my next project to add more color spaces, like
> >     LAB, to the dialog? Though this would have to be thought through so
> >     it doesn't clutter up the dialog. BTW, I definitively like that
> >     you're adding the alpha channel.
> > 
> > Christoph Feck wrote:
> >     I would rather not use 2+2, because the user maybe does not want
> >     alpha to be changed, and that would be very hard this way. Qt's
> >     dialog simply does not offer a slider, it merely adds a spin box
> >     below RGB spin boxes. Additionally, users might associate the "A"
> >     channel with ARGB or RGBA and these were the reasons why I put them
> >     in line with the RGB spin boxes.
> >     
> >     Another idea would be to move the slider below the spin boxes
> >     (horizontally), so that it is more visible that it applies both to
> >     RGBA as well as HSVA. This way the actual 3D color selection would
> >     be visually separated from the "A" selection.
> >     
> >     So it would look like this:
> >      .----------------.-------.
> >      
> >      | "3D" colorarea | table |
> >      
> >      +----------------+-------+
> >      
> >      |   spin boxes   | result|
> >      
> >      +----------------+ (color|
> >      
> >      | optional Alpha | /HTML)|
> >      
> >      '----------------'-------'
> >     
> >     Other ideas?
> >     
> >     Regarding other color schemes, I would really like to have Qt 4.6's
> >     HSL or even KDE's KCY color modes inside the dialog, maybe even
> >     L*a*b or something else, if it is computationally possible. Or some
> >     wheel that better represents the Hue circularity... But that all
> >     probably requires "color selection widget plugins" to not further
> >     blow kdelibs. The color dialog is already quite big :)
> >     
> >     So, what about the API addition? Is the property name
> >     "alphaChannelEnabled" OK? Details about the layout of the widget can
> >     be changed any time.
> > 
> > Johannes Christenson wrote:
> >      .-------------.--.-------.
> >      
> >      |             |C |       |
> >      | 
> >      | "2D"        |o | table |
> >      | colorarea   |l |       |
> >      
> >      +-------------+  +-------+
> >      
> >      | Alpha          | result|
> >      
> >      +----------------+ (color|
> >      
> >      |   spin boxes   | /HTML)|
> >      
> >      '----------------'-------'
> >     
> >     Might be worth looking at.
> >     "alphaChannelEnabled" is , imho, a good propertyname. If someone 
else
> >     thinks differently they should speak up.
> 
> Sorry, I meant "suggestion by Johannes", not Christian...
No problem! :-)
> 
> The other idea I head was to move the slider between the HSV/ARGB and 
the
> Alpha spinboxes, but that of course does not look as nice.
> 
> 
> - Christoph
> 
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviewboard.kde.org/r/3566/#review4996
> -----------------------------------------------------------
> 
> On 2010-04-27 13:13:40, Christoph Feck wrote:
> > -----------------------------------------------------------
> > This is an automatically generated e-mail. To reply, visit:
> > http://reviewboard.kde.org/r/3566/
> > -----------------------------------------------------------
> > 
> > (Updated 2010-04-27 13:13:40)
> > 
> > 
> > Review request for Gwenview, kdelibs and usability.
> > 
> > 
> > Summary
> > -------
> > 
> > Add an "alphaChannelEnabled" property to KColorDialog to support
> > QColorDialog::ShowAlphaChannel. Requires the patch from
> > http://reviewboard.kde.org/r/3565 to show the alpha gradient.
> > 
> > Please comment on:
> > * name/description of newly added methods in KColorDialog
> > * visible "Alpha" label ("Opacity"?)
> > * placement of widgets (yes, Alpha label should be aligned to RGB labels,
> > but how?)
> > 
> > 
> > Diffs
> > -----
> > 
> >   
/trunk/KDE/kdebase/workspace/qguiplatformplugin_kde/qguiplatformplugin_
> >   kde.cpp 1119552 /trunk/KDE/kdelibs/kdeui/colors/kcolordialog.h 1119552
> >   /trunk/KDE/kdelibs/kdeui/colors/kcolordialog.cpp 1119552
> > 
> > Diff: http://reviewboard.kde.org/r/3566/diff
> > 
> > 
> > Testing
> > -------
> > 
> > I used this to test integration with QColorDialog:
> > 
> > #include <QtGui/QApplication>
> > #include <QtGui/QColorDialog>
> > #include <QtCore/QDebug>
> > 
> > int main(int argc, char *argv[])
> > {
> > 
> >     QApplication app(argc, argv);
> >     QColor color = QColorDialog::getColor(QColor(255, 0, 0, 100), 0,
> >     "Select ARGB Color",
> >     
> >                                           QColorDialog::ShowAlphaChannel)
> >                                           ;
> >     
> >     qDebug() << color;
> > 
> > }
> > 
> > 
> > Screenshots
> > -----------
> > 
> > KColorDialog with enabled AlphaChannel
> > 
> >   http://reviewboard.kde.org/r/3566/s/376/
> > 
> > Thanks,
> > 
> > Christoph