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RadiAnt DICOM Viewer - Discussion Forum
Scrolling Issues

Nov 14, 2018 01:41 PM
by SG

Thank you for a great DICOM viewer. Normally to scroll through a series I hover my (bluetooth) mouse over the series and scroll, even if Radiant is not the active program. This usually works well. However recently when I hover and scroll over a series, the scrolling is no longer fluid and very jumpy e.g. I have to scroll 4 times to scroll to the next image in the series. I am not having this issue scrolling though other programs on my computer, or even during scrolling within the "Open multiple series" dialog box within Radiant Viewer itself. The problem only happens when hovering over a series (e.g. MRI or ultrasound) and trying to scroll through images in that series.

If you have any suggestions that'd be great.

Thank you.
Nov 16, 2018 10:57 AM
by SG
I think I may have found an explanation. The mouse I've been using is the Microsoft precision mouse, and it only causes this non-fluid scrolling issue in radiant viewer. I tested a standard microsoft surface bluetooth (non-precision) mouse in radiant and did not have any issues with scrolling. I found this on the microsoft website:

Under "Method 5" it says:
"With newer “high-resolution” mouse devices, some applications may not correctly interpret partial scrolling messages. When low resolution wheels scroll up and down, the mouse driver sends a scroll magnitude of 120 for each tick of the wheel up and 120 for each tick down. According to the official documentation, a scrolling value of 120 (or -120) indicates one line of scrolling. If the application receives less than a full line, it should either scroll part of a line (which is what Microsoft Word and some other applications do) or if that’s not possible, save up the value until a total of 120 is reached (which is what Notepad does). Most current Microsoft mouse devices are designed to give a smoother scroll experience, so the wheels are higher resolution and send four times as many scroll events, but at one-quarter of the magnitude. So instead of 120, they send 30 (or instead of -120 when scrolling back, they send -30). This should result in scrolling at the same speed, just more smoothly.

Some applications may not handle this correctly.

For example, they may ignore partial scroll events, or they may interpret a partial (30) event as a full line (120). There have been instances of some applications that actually combine both of these incorrect behaviors. For example, some applications may ignore the positive partial events and treat negative partial events as a full line, which would result in slow scrolling forward and fast scrolling backward.

To test whether this is an application-specific problem, compare the behavior in that application to how scrolling works in Notepad or Microsoft Word."

I think that explains it. The strange thing is radiant used to handle scrolling with my precision mouse just fine, this problem came out of the blue, maybe around the time I upgraded to the newest version of radiant. However I tried uninstalling it and installing the previous version of radiant and still the problem is there. Not sure if you have any insight into what is going on?

Nov 16, 2018 11:35 AM
by RadiAnt
SG, thank you for reporting this issue and the additional info you provided.
We will try to resolve this issue in the next beta version.
Can you drop us a line at so that we can notify you when the fix is available?
Nov 16, 2018 12:23 PM
by SG
Thank you, just wrote to you as advised. Many thanks.
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