Am 07.03.2011 18:27 schrieb Markus Ernst:
Reading 4.10.7.1.15 on the "Color" state of the input element, I miss a
possibility how to define a set of allowed colors. For other states of
the input element there are such possibilities, such as setting min, max
and step attributes for input type=date.
As UAs are encouraged to provide a user interface, such as a color
picker, there should be a way to define a limited set of colors to be
included in the picker.
Use case:
A content management or blog system for a corporate website allows to
set font and background colors. The designers define allowed color sets
the way that the corporate design guidelines are respected, and that the
text is always readable - e.g. three light color shades for backgrounds,
and two corporate colors and black for text.
Possible solution:
Slightly strengthen the impact of the list attribute for this input
type. If there is a suggestion source element with one or more valid
colors, color pickers are required to only display the colors specified
there.
Searching for implementations of input type=color, I found that Opera
actually implemented the color picker quite similar to my suggestion. If
there is a suggestion source element, Opera displays a color palette
with the colors listed there, and an "Other..." button that leads to the
detailled color picker.
I personnally would like a possibility to hide the "Other..." button,
but this is not really a need. Opera's behaviour makes it possible to
provide a consistent validation message, saying something like: "Please
choose one of the suggested colors. Sorry, other colors are not allowed
here."
Is it possible to spec Opera's behaviour as a standard for color picking
UIs?
