Graphics

XData and YData

The XData and YData properties control the coordinate system of the image. For an m-by-n image, the default XData is [1 n] and the default YData is [1 m]. These settings imply the following:

• The left column of the image has an x-coordinate of 1.
• The right column of the image has an x-coordinate of n.
• The top row of the image has a y-coordinate of 1.
• The bottom row of the image has a y-coordinate of m.

For example, the statements

• X = [1 2 3 4; 5 6 7 8; 9 10 11 12];
  h = image(X); colormap(colorcube(12))
  xlabel x; ylabel y
  

produce the following picture.

The XData and YData properties of the resulting image object have the default values shown below.

• get(h,'XData')
  ans =
  
       1     4
  
  get(h,'YData')
  ans =
  
       1     3
  

However, you can override the default settings to specify your own coordinate system. For example, the statements

• X = [1 2 3 4; 5 6 7 8; 9 10 11 12];
  image(X,'XData',[-1 2],'YData',[2 4]); colormap(colorcube(12))
  xlabel x; ylabel y
  

produce the following picture.

Image CDataMapping

EraseMode

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