If the fractal currently loaded in Fred's Fractal Viewer is a Mandelbrot, then you can generally activate Julia Set Preview mode. In this mode, the cursor in the client area of the Viewer becomes a crosshair cursor(). If you left click the mouse in the Viewer when the cursor is a crosshair, that will launch the Julia Set Preview window. The Julia Set Preview window calculates and displays the Julia set for the values of (Cx,Cy) that correspond to the location in Mandelbrot space where you clicked the mouse. If you left click the crosshair cursor at a new location in the main Viewer, the Julia set in the Preview window will immediately update to show the Julia Set for the new value of (Cx,Cy).


The (x,y) range in Julia space defaults to a range around the origin (0,0). Clicking on the zoom in and out buttons on the Preview toolbar decreases and increases the range in Julia space. Because calculating the Julia set can be computationally expensive(and slow), the toolbar zoom buttons do not force a recalculation of the Julia set. To force recalculation, press the recalc toolbar button().


If you would like to save this Julia set permanently, you can launch Fred's Fractal Factory by clicking on the Factory button in the Julia Set Preview toolbar().


Note that the Julia Set Preview feature is only enabled if a GPU is currently available and selected for Fred's Fractal Viewer. Fred's Fractal Viewer will usually default to using a GPU if it can find one.