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Graphics Object Handles

What You Can Do with Handles

A handle refers to a specific instance of a graphics object. Use the object handle to set and query the values of the object properties.

When you create graphics objects, you can save the handle to the object in a variable. For example:

x = 1:10;
y = x.^2;
plot(x,y);
h = text(5,25,'*(5,25)');

The variable h refers to this particular text object '*(5,25)', which is located at the point 5,25. Use the handle h to query and set the properties of this text object.

Set font size

h.FontSize = 12;

Get font size

h.FontSize
ans =

     12

Make a copy of the variable h. The copy refers to the same object. For example, the following statements create a copy of the handle, but not the object:

hNew = h;
hNew.FontAngle = 'italic';
h.FontAngle
ans =

italic

What You Cannot Do with Handles

Handles variables are objects. Do not attempt to perform operations involving handles that convert the handles to a numeric, character, or any other type. For example, you cannot:

  • Perform arithmetic operations on handles.

  • Use handles directly in logical statements without converting to a logical value.

  • Rely on the numeric values of figure handles (integers) in logical statements.

  • Combine handles with data in numeric arrays.

  • Convert handles to character vectors or use handles in character vector operations.

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