Creating Graphical User Interfaces

Example: Displaying an Image File

This example shows how to display an image file on a GUI. The example

• Displays an image file on an axes.
• Resizes the axes to fit the image.
• Resizes the GUI so that its width and height are 100 pixels larger than the image file.

To build the example:

1. Open a blank template in the Layout Editor.
2. Drag an axes into the layout area.
3. Select M-file editor from the View menu.
4. Add the following code to the opening function:

• set(hObject, 'Units', 'pixels');
  handles.banner = imread([matlabroot filesep 'demos' filesep 
  'banner.jpg']); % Read the image file banner.jpg
  info = imfinfo([matlabroot filesep 'demos' filesep 
  'banner.jpg']); % Determine the size of the image file
  position = get(hObject, 'Position');
  set(hObject, 'Position', [position(1:2) info.Width + 100 
  info.Height + 100]);
  axes(handles.axes1);
  image(handles.banner)
  set(handles.axes1, ...
      'Visible', 'off', ...
      'Units', 'pixels', ...
      'Position', [50 50 info.Width info.Height]);
  

When you run the GUI, it appears as in the following figure.

The preceding code performs the following operations:

• Reads the image file banner.jpg using the command imread.
• Determines the size of the image file in pixels using the command imfinfo.
• Sets the width and height of the GUI to be 100 pixels greater than the corresponding dimensions of the image file, which are stored as info.Width and info.Height, respectively. The width and height of the GUI are the third and fourth entries of the vector position.
• Displays the image in the axes using the command image(handles.banner).
• Makes the following changes to the axes properties:
• Sets 'Visible' to 'off' so that the axes are invisible
• Sets 'Units' to 'pixels' to match the units of the vector position
• Sets 'Position' to [50, 50, info.Width info.Height] to set the size of the axes equal to that of the image file, and center the image file on the GUI.

How the GUI and Dialog Work

Selecting GUI Options