How to make LEGEND adapt when a plot is zoomed?

I have quite a 'busy' plot with potentially up to 50 or more curves on it. I made a (large :-) legend box that allows the user to identify which curve is which.

The 'problem' is that when zooming into this figure, many of the curves become invisible. However, the number of items in the legend box does not adapt. Is it possible to show the label in the legend box only for these lines that are actually visible, or turn off labels for those lines that have become invisible because of the zooming? This would greatly enhance the clarity of the plot.

-marcel

[dpb]

You could do it, but the only way AFAIK is to do so in a callback function. You could compute those that are outside the existing bounds of the axes and set the legend only for those. But, I don't know there's a visible property in legend on element-by-element basis that would automagically remove those labels only.

Would take quite a lot of experimenting I suspect.

[Walter Roberson]

IconDisplayStyle can control whether a particular handle is included in the legend

[dpb]

Where's that prroperty, Walter? I can't seem to track it down anywhere, "search" in doc doesn't return any hits...

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/406-how-do-i-skip-items-in-a-legend#answer_562

[marcel hendrix]

I had seen this when initially browsing for answered questions to comparable problems. This Iconstuff is perfect to toggle distracting legend lines off, but is there a property that tells that an object is in the visible area of the window?

[dpb]

You might be able to adapt some of the Image Processing TB functions? (I think there are some tools there about intersection spaces altho I don't have it to know for certain.) Then there's rectint in base product that could possibly be helpful. In that case would depend greatly on the form of the data lines methinks as the bounding rectangle could enclose but there still a section being shown in part...

[Walter Roberson]

If all x is less than plot lower x or all x is greater than plot upper x or likewise for y, then the object is off screen.

There is no built-in for this, you will need to iterate over all of the graphics objects in your zoom callback.

Be careful not to test for

 all(x in range) and all(y in range)

If you do that then you incorrectly exclude objects that cross from side to side.