Quickstart Guide

Running Fract’ol

Fract’ol supports two fractal types: Mandelbrot and Julia. Each has different command-line requirements.

Basic Usage

./fractol Mandelbrot

The fractal name is case-sensitive. Use Mandelbrot or Julia exactly as shown.

Launch Examples

Launch Mandelbrot Fractal

The Mandelbrot set is the simplest to launch, requiring only the fractal name:

./fractol Mandelbrot

This opens a 2000x1500 pixel window displaying the iconic Mandelbrot set with psychedelic color gradients.

What You'll See

The classic Mandelbrot set centered at origin with:

Resolution: 2000x1500 pixels
Initial zoom: 1.0x
Default iterations: 30
Color scheme: Lime to mint gradient

Launch Julia Fractal

Julia sets require two parameters: the real and imaginary parts of the complex constant c:

./fractol Julia -0.4 0.6

The two parameters represent the complex number c = real + imaginary*i used in the Julia set equation: z = z² + c

Experiment with Parameters

Try different values to discover unique Julia set variations:

# Interesting combinations to try:
./fractol Julia 0.0 0.8
./fractol Julia -0.162 1.04
./fractol Julia -0.54 0.54
./fractol Julia 0.355 0.355

Invalid parameters will result in an error message:

Please enter: 
  "./fractol Mandelbrot"
   or
  "./fractol Julia <value_1> <value_2>"

Interactive Controls

Once the fractal window opens, you can explore and manipulate the visualization in real-time.

Zoom Controls

Zoom In

Mouse Wheel Up or Scroll UpZooms in by 5% (multiplies zoom by 0.95)

Zoom Out

Mouse Wheel Down or Scroll DownZooms out by 5% (multiplies zoom by 1.05)

// From events.c:46-59
if (button == Button4)        // Mouse wheel up
{
    fractol->zoom *= 0.95;    // Zoom in
}
else if (button == Button5)   // Mouse wheel down
{
    fractol->zoom *= 1.05;    // Zoom out
}

Pan/Navigate

Move around the fractal using keyboard controls:

Arrow Keys
WASD Keys

Key	Action
↑ Up	Pan up
↓ Down	Pan down
← Left	Pan left
→ Right	Pan right

Key	Action
W	Pan up
S	Pan down
A	Pan left
D	Pan right

Each pan moves by 0.5 * zoom units, so panning speed adapts to your current zoom level.

// From events.c:30-37
if (keysym == XK_Left || keysym == XK_a)
    fractol->shift_x -= (0.5 * fractol->zoom);
else if (keysym == XK_Right || keysym == XK_d)
    fractol->shift_x += (0.5 * fractol->zoom);
else if (keysym == XK_Up || keysym == XK_w)
    fractol->shift_y += (0.5 * fractol->zoom);
else if (keysym == XK_Down || keysym == XK_s)
    fractol->shift_y -= (0.5 * fractol->zoom);

Iteration Control

Adjust the detail level by changing iteration count:

Increase Detail

+ (Plus Key)Increases iterations by 5 (more detail, slower render)

Decrease Detail

- (Minus Key)Decreases iterations by 5 (less detail, faster render)

Default iteration count is 30. Higher values reveal more detail at deep zoom levels but increase rendering time.

// From events.c:38-41
else if (keysym == XK_plus)
    fractol->iterations_definition += 5;
else if (keysym == XK_minus)
    fractol->iterations_definition -= 5;

Exit Program

Close the fractal viewer:

ESC Key: Exit the program
Window Close Button (X): Exit the program

// From events.c:28-29
if (keysym == XK_Escape)
    close_handler(fractol);

Exploration Workflow

Launch Your Fractal

Start with either Mandelbrot or Julia:

./fractol Mandelbrot

Find an Interesting Region

Use arrow keys or WASD to pan around and locate intricate areas.

Zoom In

Scroll up to zoom into the region. The fractal will re-render automatically after each zoom.

Increase Detail

If the zoomed region looks blocky, press + to increase iterations for more detail:

Iterations: 30 → 35 → 40 → 45...

Continue Exploring

Repeat the zoom and pan process to discover infinite complexity:

Mandelbrot set borders contain infinite detail
Julia sets vary dramatically based on the c parameter
Try zooming into “seahorse valley” or “elephant valley” regions

Understanding the Rendering

Window Dimensions

The fractal renders at a fixed resolution defined in the header file:

// From fractol.h:24-25
#define WIDTH   2000
#define HEIGHT  1500

Color Scheme

Pixels are colored based on iteration escape time:

White: Points inside the set (reached max iterations)
Gradient (Lime to Mint): Points outside the set, colored by escape speed

// From fractol_render.c:53-54
color = map(i, PSYCHEDELIC_LIME, PSYCHEDELIC_MINT,
            fractol->iterations_definition);

The color interpolates between:

PSYCHEDELIC_LIME (#00FF00)
PSYCHEDELIC_MINT (#98FF98)

based on how quickly the point escapes to infinity.

Fractal Mathematics

Both fractals iterate the equation z = z² + c:

Mandelbrot: c is the pixel coordinate, z starts at 0
Julia: c is the command-line parameter, z starts at the pixel coordinate

// From fractol_render.c:48-58
while (i < fractol->iterations_definition)
{
    z = sum_complex(sqare_complex(z), c);
    if ((z.x * z.x) + (z.y * z.y) > fractol->escape_value)
    {
        color = map(i, PSYCHEDELIC_LIME, PSYCHEDELIC_MINT,
                fractol->iterations_definition);
        my_pixel_put(x, y, &fractol->img, color);
        return;
    }
    i++;
}

Tips for Best Results

Performance

Lower iterations for faster exploration
Increase iterations only when zooming deep
Smaller zoom values render faster

Aesthetics

Try Julia parameters between -1 and 1
Zoom into boundary regions for detail
Experiment with iteration counts (30-100)

Exploration

Start wide, then zoom progressively
Pan slowly to find interesting regions
Save interesting Julia parameters

Technical

Default escape value: 4
Coordinate mapping: -2 to +2 (real), +2 to -2 (imaginary)
Window must support X11 events

Command Reference

Keyboard Controls Summary

Key	Action
ESC	Exit program
↑ / W	Pan up
↓ / S	Pan down
← / A	Pan left
→ / D	Pan right
+	Increase iterations (+5)
-	Decrease iterations (-5)

Mouse Controls Summary

Action	Effect
Scroll Up	Zoom in (×0.95)
Scroll Down	Zoom out (×1.05)

Next Steps

Now that you know how to use Fract’ol, explore more advanced topics:

Learn about the fractal mathematics behind the visualizations
Understand the rendering algorithm and optimization techniques
Explore customization options for colors and parameters

Getting Started

User Guide

Technical Reference

Advanced

Running Fract’ol

Basic Usage

Launch Examples

What You'll See

Interactive Controls

Zoom Controls

Zoom In

Zoom Out

Pan/Navigate

Iteration Control

Increase Detail

Decrease Detail

Exit Program

Exploration Workflow

Understanding the Rendering

Window Dimensions

Color Scheme

Fractal Mathematics

Tips for Best Results

Performance

Aesthetics

Exploration

Technical

Command Reference

Keyboard Controls Summary

Mouse Controls Summary

Next Steps

Build docs developers (and LLMs) love

Getting Started

User Guide

Technical Reference

Advanced

​Running Fract’ol

​Basic Usage

​Launch Examples

What You'll See

​Interactive Controls

​Zoom Controls

Zoom In

Zoom Out

​Pan/Navigate

​Iteration Control

Increase Detail

Decrease Detail

​Exit Program

​Exploration Workflow

​Understanding the Rendering

​Window Dimensions

​Color Scheme

​Fractal Mathematics

​Tips for Best Results

Performance

Aesthetics

Exploration

Technical

​Command Reference

​Keyboard Controls Summary

​Mouse Controls Summary

​Next Steps

Build docs developers (and LLMs) love

Running Fract’ol

Basic Usage

Launch Examples

Interactive Controls

Zoom Controls

Pan/Navigate

Iteration Control

Exit Program

Exploration Workflow

Understanding the Rendering

Window Dimensions

Color Scheme

Fractal Mathematics

Tips for Best Results

Command Reference

Keyboard Controls Summary

Mouse Controls Summary

Next Steps