Re: zoom with scroll bars

Posted by Adrian Daerr on May 21, 2007; 2:17pm
URL: http://imagej.273.s1.nabble.com/Automatic-Generation-of-ROIs-Based-on-Binary-Mask-tp3699387p3699392.html

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On 2005-09-01, Wayne Rasband wrote:
> You can pan a zoomed image by holding down the space bar and dragging
> with the mouse.

Nice feature, just discoverd it. However there seems to be a small bug
when panning while defining a ROI (e.g. rectangular). Here is what I see
with version 1.38r:
- - zoom into an image sufficiently to see only a fraction of it (and the
"zoom locator" appears in the top left corner).
- - start defining a rectangular ROI
- - press space-bar and move the mouse: sometimes the portion of the image
shown in the window jumps here already (so that the lower-right corner
of the rectangle ROI doesn't coincide with the mouse cursor any more).
- - in any case, if you pan, release the space bar, change the ROI and
press the space bar again, the window will jump back more or less to the
vicinity of the upper left corner of the ROI.

In particular, it seems impossible to define a ROI that extends more
than twice the zoomed portion of the image away from the starting point
(i.e. when you are defining a ROI like rectangle, circle or line, you
cannot pan more than one screenfull away from the starting point). The
problem doesn't appear when the mouse-button can be released before
panning (e.g. polyline selections).
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