How do I implement zooming using key presses while user is selecting points using GINPUT in MATLAB 7.4 (R2007a)?

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MathWorks Support Team am 21 Jan. 2010

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Akzeptierte Antwort: MathWorks Support Team

I have an application where the user needs to select several points from the figure. I am implementing this using the function GINPUT.

However, while selecting points using the mouse during the execution of GINPUT, I want to be able to zoom/pan the figure using key presses.

The KEYPRESSFCN callback does not fire while GINPUT is being executed. I am wondering how to implement this functionality.

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Answer 1

MathWorks Support Team am 21 Jan. 2010

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https://de.mathworks.com/matlabcentral/answers/99166-how-do-i-implement-zooming-using-key-presses-while-user-is-selecting-points-using-ginput-in-matlab-7#answer_108513

my_ginput.m

It is possible to modify the function GINPUT so that while selecting points using mouse one can also use key presses to have more functionality like zoom/pan the figure.

GINPUT uses the function WAITFORBUTTONPRESS to wait until the user clicks the mouse or hits a key. As soon as these events occur the pointer locations are stored. This code can be modified by implementing a while loop which keeps on scanning for points until the user clicks the mouse, hits Ctrl+C, or hits Enter. The code can contain IF conditions to take appropriate keypress actions when the user hits other keys.

Please refer to the attached 'my_ginput' function which can zoom in/out when the user presses r/v while selecting points on the figure.

You can extend the WFBP subfunction in the file in a similar manner to implement panning functionality.