Proposal: Canvas Interaction Enhancements

T Hall tahall256 at
Tue May 15 16:25:43 UTC 2012

On Tue, 15 May 2012 08:49:07 -0500
Cyrille Berger Skott <cberger at> wrote:

> On Tuesday 15 May 2012, Boudewijn Rempt wrote:
> > * Ideally, we'd be able to completely get rid of the zoom and pan
> > tool -- the color picker tool has an extra information panel and
> > settings like the radius, but maybe we can put the information in
> > the overview panel. I'm not sure artists actually use the radius to
> > sample the average color?
> Right now, color picking works like this: "color is selected on click
> release"
> Here is a suggestion. which would remove the need for radius to
> sample and might make it more usefull for artists: the user press and
> hold the mouse button, then the colour get continuously mixed with
> the colour on the canvas, until the user release the mouse.
> So basically, as long as the user click and release, it is the same
> behaviour as now. But if he wants some kind of radius to sample, he
> just have to keep the button down and move his mouse pointer.

I think there are two main reasons the colour picker radius is not used:
1) People aren't aware it exists
2) It only works with the colour picker selected as a tool, not when
you pick a colour using another tool, e.g. brush and holding control.

With this in mind, I think it is important to firstly make *all* the
functionality of the colour picker tool available to the user via
ctrl+click. This would require all the tool's settings to be available
via a global docker. If the user is not interested in radius, add to
palette, etc., they can ignore the settings and it will still work as
it does now, sampling single pixels.

With regards to dragging to sample, I would argue that a radius is
still useful. In areas where partitive mixing is significant (Where the
apparent colour comes from lots of tiny areas of different colours),
average results will differ wildly depending on which pixels you happen
to hit as you drag a single-pixel-wide trail. Dragging a slightly
broader path with a radius should get a more 'complete' sample of the

On a slightly different note, an idea I had was to allow the user to
pick a colour with a single key press, as an alternative to holding
control and clicking. I am told this should work with Arjens's,
"alternate tool invocation" action, though I must admit I haven't quite
digested all the details of the proposal.

Some thoughts:
- Clicking with a stylus, while not difficult, isn't the
most intuitive thing in the world. I don't think there are any other
actions that require me to *click* on a specific point on the canvas.

- I often have a split second of hovering over the colour I want,
  holding control and realising I still have to click.

- Might be partly obviated by Cyrille's idea, which replaces a click
  with a stroke, although for single-pixel colour-picking it could
  complement the idea by providing a precise way to pick a single colour
  without risking a slightly sloppy click sampling a few adjacent
  colours as well.

- Could potentially allow the user to pick a colour in the middle of
  a brush stroke. I've never been able to try this, so I've no idea if
  it would be useful.


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