Codejock Developer Community : Mouse location to graph scale http://forum.codejock.com/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Thu, 21 May 2026 05:22:10 +0000 Thu, 20 Jun 2013 10:10:59 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.04 360 forum.codejock.com/RSS_post_feed.asp?TID=21729 <![CDATA[Codejock Developer Community]]> http://forum.codejock.com/forum_images/codejock-logo.gif http://forum.codejock.com/ <![CDATA[Mouse location to graph scale : Hi, I&#039;m trying to develop...]]> http://forum.codejock.com/forum_posts.asp?TID=21729&PID=71173&title=mouse-location-to-graph-scale#71173 Author: BLW
Subject: 21729
Posted: 20 June 2013 at 10:10am

Hi, I'm trying to develop a drag-drop concept with a bar chart.  We have a threshold parameter that we plot on the graph along with results.  The idea is to allow the user to "grab" the threshold and drag it to a new setting directly on the graph.
 
I have figured out most of the steps involved.  But I have not been able to locate a conversion between a mouse location on the screen and an X-Y graph scale value.  I'm using "HitTest()" to figure out which series and element is being pointed at.  But that isn't quite what I need.  I believe that I found some internal logic that might work (see specifics below), but I do not see how to get access to that information.
 
In XTPChartStackedBarSeriesStyle.cpp, function GetScreenRect() they call a function GetScreenPoint() which converts a scaled XY value to image coordinates.  From that I could compute the scale and get the drag-drop logic to work.  But this is a Style operation and that appears to be dynamically created in OnPaint() and is not available to access.
 
What I really need is a function similar to HitTest() to get the conversion back and forth between a screen location and scales series value.

Thank you,
 
Brad
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