On 19 February 2017 at 14:02, John Hawkinson <jh...@mit.edu> wrote: > As for transparency vs. opacity, as I wrote in that email: > > * Why does QGIS use Transparency sliders instead of Opacity sliders? > Isn't Opacity much more common in graphics software? > > To expand a little more, both Photoshop and Illustrator use Opacity > sliders -- far left is 0% opacity / full transparency. (Although > curiously, Illustrator's is inside the Transparency window.) > > Are there prominent examples of software packages (in the GIS world?) > that use Transparency instead of Opacity in sliders? > > For the tols I use, Opacity wins hands-down. I gather that's not true > for everyone, but I wonder what the tools are that use Transparency > sliders (far left is 100% opacity / no transparency). > > I would say, also, that Opacity is a little more intuitive, because > it basically translates to Brightness. If you ask a user which way > they turn the knob to make a line darker, they'll usually turn it in > the positive director (err, s/knob/slider/).
My preference would be for opacity too. An outstanding question is what range we should allow? Behind the scenes it's generally going to be converted to a 0-255 value, but for users a 0-100% may be more explanatory. Opinions? > I would say, also, that the internal API is very different from the > UI. What's the justification for changing the API on this? Confusion > to API developers? Is that really worth it? The API is ALL OVER THE PLACE here, and should also be fixed. We have a mix of transparency/opacity/alpha and ranges of 0-1, 0-100, 0-255. It's confusing for developers too! Nyall _______________________________________________ Qgis-developer mailing list Qgis-developer@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer