<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Evaristo,<div class=""><br class=""></div><div class="">I have experienced this problem too but in different way. Backgroung mooving is accidental very often if I only touch scroll function on mouse. So I have to use undo several times to restore correct state.</div><div class=""><br class=""></div><div class="">m.s.</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">21. 1. 2018 v 20:01, Evaristo Quiroga via Therion <<a href="mailto:therion@speleo.sk" class="">therion@speleo.sk</a>>:</div><br class="Apple-interchange-newline"><div class="">
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<div class="moz-cite-prefix">Hi John,<br class="">
<span id="result_box" class="" lang="en"><br class="">
I have experienced the same zoom problems in Windows with the
scroll wheel use or + -. If you play with the + - you see, the
trace and the background image are well placed at 25%, 50%,
100% ,200% and 400%. When you push further this scales the
trace and background image are wrong placed. With the scroll
wheel they are wrong always because the % zoom are normally
further or between this scales. <br class="">
<br class="">
I think is a program bug. <br class="">
<br class="">
But we have a trick to overcome the problem. Only use the zoom
button in the "Drawing Area" (above the "Background image"
control) to choose the scales </span><span id="result_box" class="" lang="en">25%, 50%,
100% ,200% or 400%, when you want the trace and background
image well placed. And use scroll wheel or + - when you
want zoom only the trace quickly. <br class="">
<br class="">
Evaristo. <br class="">
<br class="">
</span>El 19/01/2018 a las 18:57, John
Stevens via Therion escribió:<br class="">
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<div class="">A method I used to copy from a previous survey was to
export the centreline as a xvi file. Then take a jpg of the
old survey and scale it so the pixel count matches that of
the xvi file. </div>
<div class="">The next step was to use both images as background images
in the th2 file. A bit of adjustment of the position
location to make them match then it was simple to copy the
old survey. </div>
<div class=""> </div>
<div class="">Now I cant align the images as the zoom function now
changes the scales of the two images differently. If I use a
jpg to trace over and zoom in to trace a detailed area the
scaling goes off. The resultant lines are to the wrong scale
and/or are misplaced.</div>
<div class=""> </div>
<div class="">Is there a way of fixing the scale of a background image
so it scales properly. It seems to go wrong with the + – and
scroll wheel.</div>
<div class=""> </div>
<div class="">John</div>
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