Graphical input

[jbrohan]

Hello

I need to offer a program for editing and making new Fetal Herart Monitor tracings. Does anyone have examples or ideas of how to interactively change the line on a graph. This will involve coying segments and moving graphical features to a different time.

Yours SIncerely

John

[Norm Kirchner]

What do you mean by "Change the Line" on a graph. Change the style or change the data by dragging points around?

What are the graphical features that need to be moved to a different time. (I'm assuming you mean time as the X-scale)

The quick and dirty answer will be to use the cursors. You can place one on mouse down and the other at mouse up, determine the data between the two, create a duplicate of that data as another trace and allow the person to move that other trace around by some other means like a scroll bar or be really smooth and change the cursor to a hand and allow them to drag it left and right, right on the graph.

ooooooh this could be cool if you do it right.

[Norm Kirchner]

<ping>

[jbrohan]

What do you mean by "Change the Line" on a graph. Change the style or change the data by dragging points around?

What are the graphical features that need to be moved to a different time. (I'm assuming you mean time as the X-scale)

The quick and dirty answer will be to use the cursors. You can place one on mouse down and the other at mouse up, determine the data between the two, create a duplicate of that data as another trace and allow the person to move that other trace around by some other means like a scroll bar or be really smooth and change the cursor to a hand and allow them to drag it left and right, right on the graph.

ooooooh this could be cool if you do it right.

The lines (trace) on a fetal heart rate graph represent the fetal heat rate plotted against time. There are some characteristic shapes or features that occur in many babies, and these features have names "variable deceleration" for example caused by the contraction compressing the umbilicus and causing the fetus to be oxygen deprived momentarily.

An artificial intelligence program monitoring this and several other conditions can assess the degree of risk and even make reccommendations about what to do about it.

So if you pass a tracing through the AI program it plots risk against time as the features of the tracing are observed and interpreted.

The customer is interested to know if the risk assessment is overly sensitive to some features and not to others. He needs to change them, making the decelerations deeper and longer to see if the AI takes a more ominous view of the risk.

So in answer to your question I need to "grab" a "section" of the tracing and move it in time or heartrate (x or y) to change the shape and severity of the feature. Or (and more likely) erase a bit of trace and re draw it freehand.

Yours Sincerley

John

[Norm Kirchner]

Does the phrase 'Free Transform' sound like it applies here. This sounds very do'able, but to make it a smooth and robust interface will be tricky.

I mean you would effectively have to re-create a picture editor-esque interface where you could draw a selection rectangle around a portion of trace and give drag handles in either direction and also allow the user to select individual points and move those around. You would have to do some fancy spline interpolation at this point to make sure that the data still had a flow to it and didn't get all jaggy on you.

I think that it would be a .... wait a minute... 'CODING CHALLENGE!!!' This is a great candidate.

Create an interface that would allow a person to intuitively modify the data on a graph interactively.

That aside, are you getting paid enough for this, becasue to do it right is gonna be a Job w/a captial J

[Bob Y.]

Does the phrase 'Free Transform' sound like it applies here. This sounds very do'able, but to make it a smooth and robust interface will be tricky.

I mean you would effectively have to re-create a picture editor-esque interface where you could draw a selection rectangle around a portion of trace and give drag handles in either direction and also allow the user to select individual points and move those around. You would have to do some fancy spline interpolation at this point to make sure that the data still had a flow to it and didn't get all jaggy on you.

I think that it would be a .... wait a minute... 'CODING CHALLENGE!!!' This is a great candidate.

Create an interface that would allow a person to intuitively modify the data on a graph interactively.

That aside, are you getting paid enough for this, becasue to do it right is gonna be a Job w/a captial J

Have you looked at the Simulate Arbitrary Signal Express VI? The UI in it does some cursor-drag-to-define-waveform stuff. It's built in. If it did a spline instead of just straightline interpolation (or choice of either) that would be cool.

Maybe you could steal some of it.

Hope that this helps,

Bob Young