Rationale:
- there was a lot of large objects passed by value, so potentially
there's a speed bump from this
- even for implicitly shared classes like QString/QList there's still
a (small) cost for copying the objects when there's no reason to
- it's the right thing to do!
it's a Frankenstein's monster of the best bits of lots of other color
picker implementations. Features include:
- Sliders for hue, saturation, value, red, green, blue color components
- Alpha slider
- Option to copy/paste html color codes (in a variety of formats)
- Before/after color preview, with alpha preview
- Interactive 2D color ramp widget
- Hue wheel/triangle widget
- Editable color swatch lists
- Live color sampler with option to sample over a set radius
- Supports interaction with other apps via drag and drop of colors (OS support
dependant)
- Option to disable the dialog and use the native picker dialog instead (TODO:
make the dialog so awesome that even @dakcarto switches across...)
Credit for icons goes to 3nids!
QToolButton. Features:
- context menu items have been moved to the attached menu button
- new gui widget QgsColorSwatchGrid, which displays a grid of colors
- new class for QgsColorScheme, which generates colors to show in a
color swatch grid
- new class QgsColorSchemeRegistry, with a global instance containing
default color schemes. QgsColorButtonV2 accepts a color scheme
registry, to control which schemes to show in the popup menu as
color swatch grids.
- color button can have a default color
- color button can also be quickly set to a totally transparent color
- c++ and python unit tests for all core components
