Performance Considerations when Setting up Plots

Collaboration diagram for Performance Considerations when Setting up Plots:

Many of the function in JKQTPlotter case an immediate redraw of the widget. Examples are JKQTPlott::setX(), JKQTPlotter::setY(), JKQTPlotter::setAbsoluteX(), JKQTPlotter::setAbsoluteY(), JKQTPlotter::addGraph() ... so if you use a combination of these while setting up your plot, it is possible to cause several (rather expensive) redraws of the plot widget. Therefore you can disable this redrawing, using JKQTPlotter::setPlotUpdateEnabled() and you can explicitly cause a redraw with JKQTPlotter::redrawPlot(). To make this process even easier to use, there is a guard helper class for this: JKQTPlotterUpdateGuard.

Here is a code example:

{
  JKQTPlotterUpdateGuard guard(plotter);
 
  // set up plot here, e.g.
  plotter->setX();
  plotter->setY(); ...
} // Block ends and immediate plot updates are reenabled. Also JKQTPlotter::redrawPlot() is called.

This code has the same effect as the long version without the guard class shown below:

const bool wasReplotEnabled=plotter->isPlotUpdateEnabled();
plotter->setPlotUpdateEnabled(false);
 
  // set up plot here, e.g.
  plotter->setX();
  plotter->setY(); ...
 
// Setup ends and immediate plot updates are reenabled. Also JKQTPlotter::redrawPlot() is called.        
plotter->setPlotUpdateEnabled(false);
if (wasReplotEnabled) plotter->redrawPlot();

See also

JKQTPlotter::setPlotUpdateEnabled(), JKQTPlotter::redrawPlot(), JKQTPlotterUpdateGuard