990740 - Make eyedropper movement smoother

Status: RESOLVED FIXED

(DevTools :: Inspector, defect)

Description

[Heather Arthur [:harth]]

On Linux especially (tried on Ubuntu), the eyedropper doesn't move smoothly as you move the mouse around. This is because of the code that's being called on each mouse move. The code has a few steps: drawing the area of the window to the panel, drawing a grid over it, extracting the center pixel color and displaying that.

Two areas with potential room for improvement on Linux are the call to getImageData() to get the color of the center pixel, and the call to draw a grid on the canvas, which could be replaced by an overlayed grid image.

Another option if we can't optimize is to just ignore every other mousemove event. I don't know the implications of that, but it's worth looking into.

Comment 1

[Heather Arthur [:harth]]

Attachment: Skip every other mouse move

Here's a patch that will ignore every other mouse move. It makes it less smooth on my OS X (so we wouldn't do it on that), but I suspect it might alleviate the jumping around on Linux.

Comment 2

[Heather Arthur [:harth]]

Attachment: Skip drawing every other mouse move on Linux

Just tried this out on Linux, and it's much better with this. This will check for Linux, but we already have to do this elsewhere in the eyedropper.

Comment 3

[Heather Arthur [:harth]]

Try: 

https://tbpl.mozilla.org/?tree=Try&rev=9dbb06dc840f

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/fx-team/rev/c376ff82cd3e

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/c376ff82cd3e