On 2007-February-20 , at 22:51 , John Pybus wrote:
Bryce Harrington wrote:
On Tue, Feb 20, 2007 at 08:35:56PM +0000, Ted Gould wrote:
There are situations where I've found this would be useful. For instance, in doing room designs, I achieve scaling by setting the grid to one unit per inch. From a zoomed out view, it would be nice to be able to draw a 123 inch long wall, but because the grid point corresponding to "123" wouldn't be displayed, I find myself approximating, then zooming in a few levels and tweaking it to get it right. This isn't a huge deal - it only takes a moment to zoom in, fix the line, and go back, but it's definitely a case where snapping to a non-visible grid point would be useful. If I'm in a hurry I sometimes just use the arrow keys to nudge things closer to where I want.
This is pretty close to what I was doing.
I selected Document Properties > Grid/Guides > Grid units == mm Then under "Grid Snapping" in Document Properties > Snap, I enabled "Snap bounding boxes to grid", "Snap nodes to grid", and "Always snap". None of these gave me any impression that I was enabling snapping only to a visible grid, I believed it was the grid I'd just specified on the "Grid/Guides" tab.
The Snap tab is fairly crowded, but perhaps an "even hidden gridlines" tickbox (disabled by default) would both provide the option and alert the user that grid snapping mightn't blindly work to the specified grid.
In the end I used a mixture of zooming in/out and, when it was hard to place points relative to each other without seeing the context, I disabled snapping, put points in roughly the right place, before (with snap re-enabled) jiggling the points individually to snap them again. I estimate this was, overall, 3 times slower than with snapping to all grid positions.
I think there is a usability argument behind this decision of not snapping to invisible grid lines, beyond the surprise effect. If you set grid lines to small distances (e.g. 1px) and zoom out a little, they become so close to each other that even snapping to those does not give you the impression of snapping at all: the next pixel is so close to the position your mouse is in that the effect of actually "snapping" is not visible anymore. Therefore I think that enabling snapping to invisible grid can lead to the impression of no snapping at all, even to the grid lines that are visible. A solution would probably be to set the threshold under which minor grid lines disappear to something smaller (or to give a preference for this), as Ted Gould suggested. Typically this cannot be smaller than at least a few screen pixels for the snapping effect to be visually noticeable. How is this threshold computed/set currently?
JiHO --- http://jo.irisson.free.fr/