When setting a line segment, display jumps one grid point

[nobody]

When I am laying down lines, I often find that clicking
to set a point, say at position (10,10), will cause the
window to jump and the point will actually end up being
set at (10, 11).

I am using a trackpad with a laptop, so to make sure
that I am not inadvertantly moving the mouse, I always
position the end point with the trackpad, then remove
my finger from the trackpad entirely and then press
the button.

I must then 'undo' the change and then try again.
Usually I can get the point where I want if I position
the pointer at the far edge of the grid point, away
from the side it last jumped toward. For example, if
it last jumped one grid spacing to the right, I'll
position my pointer on the left most edge of the point
I want the line segment on.

This is tedious however and sometimes takes multiple
tries. Pressing the mouse button without any mouse
movement should not move the cursor.

[haceaton (haceaton)]

I'm unable to replicate this. Please detail your grid
setting, etc. I suspect this is a problem with how your
X-server handles the track pad. You may want to run xev to
see if what events occur from the trackpad actions you are
describing.

[sf-robot (sf-robot-users)]

This Tracker item was closed automatically by the system. It was
previously set to a Pending status, and the original submitter
did not respond within 14 days (the time period specified by
the administrator of this Tracker).

[garthwebb (garthwebb)]

Grid settings: Enable visible grid, 10 mil spacing.
OS: Fedora Core 5
WM: Gnome 2.14

As far as the trackpad, there is no physical contact between my hand and the pad when I click the left button to place the line segment. If my X-server is somehow tranlating a mouse click into a mouse click plus trackpad scrolling, its not doing this for any other program (and I have other grid based drawing programs). Nevertheless, I will attach the xev output.

The effect becomes more pronounced as the view is zoomed out. For example, if I zoom out to the point where a 'signal' sized line (10mil I think) looks only 1 pixel wide, I find it very difficult to draw a square; the random 'jumping' causes most of the vertecies to be placed at a point just to the left or right of where I clicked giving a short 45 deg line segment.

Additionally, there does not seem to be any way to turn auto-scrolling off in the preferences; if I set the auto pan speed to zero, it just automatically defaults it back to 1. So, I updated 'src/hid/gtk/gui-config.c' and changed line 260 from this:

  ghidgui->auto_pan_on = TRUE;

to this:

  ghidgui->auto_pan_on = FALSE;

and recompiled.

This has fixed my problem as far as I can tell. This also rules out any strange 1995 era X server/mouse interaction. This smells like an edge case triggering the auto pan.

[garthwebb (garthwebb)]

It looks like I can't reopen this bug to add my attachment. I'll open a new bug with the extra information about auto-pan.

[Bert Timmerman (bert-timmerman)]

The mentioned piece of code in ghid_config_init (void) has not been touched as of 2006-03-22.

The suggested change from this:

  ghidgui->auto_pan_on = TRUE;

to this:

  ghidgui->auto_pan_on = FALSE;

has not been committed.

If the problem is fixed elsewhere and released in (or before) pcb-20100929 then the milestone is set to a wrong value.

If the problem is fixed after pcb release 20100929 then the staus should be "Fix Committed".