Graphics |
Example -- Using newplot
To illustrate the use of newplot
, this example creates a function that is similar to the built-in plot
function, except it automatically cycles through different line styles instead of using different colors for multiline plots.
function my_plot(x,y) cax = newplot; %newplot returns handle of current axes
LSO = ['-
';'--
';': ';'-
.']; set(cax,'FontName','Times','FontAngle','italic') set(get(cax,'Parent'),'MenuBar','none') % line_handles = line(x,y,'Color','b'); style = 1; for i = 1:length(line_handles) if style > length(LSO), style = 1;end set(line_handles(i),'LineStyle',LSO(style,:)) style = style + 1; end grid on
The function my_plot
uses the high-level line
function syntax to plot the data. This provides the same flexibility in input argument dimension that the built-in plot
function supports. The line
function does not check the value of the figure or axes NextPlot
property. However, because my_plot
calls newplot
, it behaves the same way the high-level plot
function does -- with default values in place, my_plot
clears and resets the axes each time you call it.
my_plot
uses the handle returned by newplot
to access the target figure and axes. This example sets axes font properties and disables the figure's menu bar. Note how the figure handle is obtained via the axes Parent
property.
This picture shows typical output for the my_plot
function.
Basic Plotting M-File Structure
This example illustrates the basic structure of graphics M-files:
newplot
early to conform to the NextPlot
properties and to obtain the handle of the target axes.
newplot
to set any axes properties or to obtain the figure's handle.
The MATLAB default settings for the NextPlot
properties facilitate writing M-files that adhere to the standard behavior: reuse the figure window, but clear and reset the axes with each new graph. Other values for these properties allow you to implement different behaviors.
Replacing Only the Child Objects -- replacechildren
The replacechildren
value for NextPlot
causes newplot
to remove child objects from the figure or axes, but does not reset any property values (except the list of handles contained in the Children
property).
This can be useful after setting properties you want to use for subsequent graphs without having to reset properties. For example, if you type on the command line
set(gca,'ColorOrder',[0 0 1],'LineStyleOrder','-
|--
|:|-
.',... 'NextPlot','replacechildren') plot(x,y)
plot
produces the same output as the M-file my_plot
in the previous section, but only within the current axes. Calling plot
still erases the existing graph (i.e., deletes the axes children), but it does not reset axes properties. The values specified for the ColorOrder
and LineStyleOrder
properties remain in effect.
Targeting Graphics Output with newplot | Testing for Hold State |
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