Copy Plot with Copyobj: A Step-by-Step Guide on How to Duplicate Plots Using MATLAB’s copyobj Function

Introduction:

Copying plots in MATLAB using the copyobj function is a straightforward process that allows you to duplicate graphics objects and their children. This is particularly useful for creating multiple similar plots without having to recreate them from scratch.

Overview of the Process:

1. Identify the Object: Determine the graphics object you want to copy.
2. Specify the New Parent: Define the new parent object where the copied plot will reside.
3. Use copyobj: Execute the copyobj function with the object and new parent as arguments.

newObj = copyobj(oldObj, newParent);

Importance and Common Use Cases:

• Efficiency: Saves time by avoiding the need to recreate plots.
• Consistency: Ensures uniformity across multiple plots.
• Customization: Allows for easy modifications and comparisons between similar plots.

Common use cases include duplicating figures for different datasets, creating templates for recurring reports, and maintaining consistency in visual presentations.

Understanding copyobj

The copyobj function in MATLAB creates copies of graphics objects. When you use copyobj(obj, parent), it duplicates the specified graphics object (obj) and assigns it to a new parent (parent). The new object is identical to the original but has a different parent and a new handle. If the original object has children, copyobj copies them as well.

For example, you can copy a plot from one figure to another by specifying the plot handle and the target figure handle.

Step-by-Step Guide

Sure, here is the step-by-step process to copy a plot using copyobj in MATLAB:

1. Create the original figure and plot:

   f1 = figure;
   ax1 = axes(f1);
   plot(ax1, rand(10, 1));
   

2. Create a new figure to copy the plot into:

   f2 = figure;
   

3. Copy the axes from the original figure to the new figure:

   ax2 = copyobj(ax1, f2);
   

4. Adjust the position of the copied axes if necessary:

   ax2.Position = ax1.Position;
   

This will copy the entire plot, including all its properties, from the original figure to the new figure.

Common Issues and Solutions

Here are some common issues encountered when using copyobj to copy a plot, along with their solutions:

1. Properties Not Updating:

   • Issue: After copying, changes to the properties of the copied plot do not take effect.
   • Solution: Ensure that you are modifying the properties of the copied object, not the original. Use the handle of the new object returned by copyobj to make changes.

2. Position and Size Issues:

   • Issue: The copied plot appears in the wrong position or with an incorrect size.
   • Solution: Manually set the Position property of the copied plot to match your desired layout. For example:

     newPlot = copyobj(originalPlot, newParent);
     set(newPlot, 'Position', [left, bottom, width, height]);
     

3. Axes Limits and Labels Not Copied:

   • Issue: Axes limits, labels, and other properties are not copied over.
   • Solution: Manually copy these properties from the original axes to the new axes. For example:

     newAxes = copyobj(originalAxes, newParent);
     set(newAxes, 'XLim', get(originalAxes, 'XLim'), 'YLim', get(originalAxes, 'YLim'));
     xlabel(newAxes, get(get(originalAxes, 'XLabel'), 'String'));
     ylabel(newAxes, get(get(originalAxes, 'YLabel'), 'String'));
     

4. Children Objects Not Copied:

   • Issue: Child objects (like lines, text, etc.) are not copied.
   • Solution: Ensure that copyobj is called on the parent object that contains all the children. If necessary, recursively copy child objects.

5. Graphics Rendering Issues:

   • Issue: The copied plot does not render correctly or appears distorted.
   • Solution: Check for any rendering-specific properties that need to be set or adjusted. Sometimes, re-rendering the figure or refreshing the display can help:

     drawnow;
     

6. Event Listeners and Callbacks Not Copied:

   • Issue: Event listeners and callbacks are not copied to the new plot.
   • Solution: Manually reassign event listeners and callbacks to the copied plot. For example:

     newPlot = copyobj(originalPlot, newParent);
     set(newPlot, 'ButtonDownFcn', @yourCallbackFunction);
     

These solutions should help you address the common issues encountered when using copyobj to copy plots in MATLAB.

Practical Examples

Here are some practical examples demonstrating how to use copyobj in different scenarios:

Example 1: Copying a Plot to a New Figure

% Create original plot
figure1 = figure;
ax1 = axes('Parent', figure1);
plot(ax1, rand(10, 1));

% Copy the plot to a new figure
figure2 = figure;
ax2 = axes('Parent', figure2);
copyobj(allchild(ax1), ax2);

Example 2: Copying a Plot to a Specific Subplot

% Create original plot
figure1 = figure;
ax1 = axes('Parent', figure1);
plot(ax1, rand(10, 1));

% Create a new figure with subplots
figure2 = figure;
subplot(2, 1, 1);
ax2 = subplot(2, 1, 2);

% Copy the plot to the second subplot
copyobj(allchild(ax1), ax2);

Example 3: Copying a Plot to a UIPanel

% Create original plot
figure1 = figure;
ax1 = axes('Parent', figure1);
plot(ax1, rand(10, 1));

% Create a new figure with a UIPanel
figure2 = figure;
panel = uipanel('Parent', figure2);
ax2 = axes('Parent', panel);

% Copy the plot to the UIPanel
copyobj(allchild(ax1), ax2);

Example 4: Copying Multiple Plots

% Create original plots
figure1 = figure;
ax1 = axes('Parent', figure1);
plot(ax1, rand(10, 1));
hold on;
plot(ax1, rand(10, 1) * 2);

% Copy the plots to a new figure
figure2 = figure;
ax2 = axes('Parent', figure2);
copyobj(allchild(ax1), ax2);

These examples should help you understand how to use copyobj in various scenarios.

The `copyobj` Function in MATLAB

The `copyobj` function in MATLAB is used to copy objects from one figure to another, allowing for easy duplication of plots, axes, and other graphical elements.

Using `copyobj`

• The original plot must be in the same figure as the object being copied.
• The destination axes or panel must have the same type (e.g., axes, uipanel) and properties as the source object.
• If you want to copy multiple plots, hold on to the current plot before creating new ones.

Benefits of Using `copyobj`

• Easy duplication of complex plots with multiple elements
• Preservation of original object’s properties and layout
• Flexibility in copying objects between different figures and subplots

By following these guidelines and examples, you can effectively use `copyobj` to copy plots and other graphical elements in MATLAB.