Doodl is a generative application that transforms photographs into drawings by means of a semi-autonomous process where you can control many variables – or just relax and watch it develop.

The Swarm

The drawings are generated by a population of automomous particles. They are computational agents that follow some simple rules. As they move around the screen, they leave a visible trace. The accumulation of those paths forms the ever-changing drawing we can see.

Color to movement

The movement of the particles is guided by the colors in the source image. That's why the resulting drawing usually keeps some kind of resemblance with it. The source image is a sort of virtual terrain for the particles, a force field that guides the speed and direction of their movement.

The essential mechanism behind Doodl is the translation from color into movement. In other words, the transformation of the numeric values that represent colors in the source image, into a direction and velocity for each of the particles, according to their current position.

Drawings from photos

There is an infinite number of ways to perform that translation. You can experiment with many of them, and tweak many other parameters to produce an unlimited variety of drawings from any photo. We can imagine all those drawings were already there, hidden in the correlations between color values in an image. Doodl is the tool that lets you release them, a creative application to turn any photo (or set of photos) in a source of endless artistic possibilities.

Dynamic Variables



Average velocity of the particles. Select low values for a finer level of detail, high values for a bolder look and faster changes.


Base direction of the particles' movement. It will be further modified by other factors. Different angles yield different drawings from the same source image.


Tendency of each particle to keep moving in the same direction it was moving before. Drag towards "rough" for more detail, or towards "smooth" for smoother lines and faster movement.


How transparent the strokes are, from invisible on the left end to completely opaque on the right.


How many particles are on screen. Choose few to modify the drawing slowly and improve control of the process, or a lot to increment the rate of change. Lower the amount of particles if the application is running slowly on your computer.

Stroke Weight

Level of variation of the stroke width. A higher value results in a higher maximum stroke thickness. It doesn't affect Stroke Type a.

Direction Formula

Choose from 16 available formulas to translate the source image's color data into a force field that controls the movement of the particles. Each formula represents a different drawing style.

A recommendation: choose Stroke Type a (hairline) if you want to appreciate the differences between these options most clearly.

Velocity source

Select which value from the source image's color data will control the speed of the particles. The effect of this parameter can be subtle in some situations. Increase the value of the Speed slider to see the differencees more clearly. Your choices are:

+r  ⇒  red, proportional. Steps will be longer on zones with a higher red value.
-r  ⇒  red, inverse. Steps will be longer on zones with a lower red value.
+g  ⇒  green, proportional. Steps will be longer on zones with a higher green value.
-g  ⇒  green, inverse. Steps will be longer on zones with a lower green value.
+b  ⇒  blue, proportional. Steps will be longer on zones with a higher blue value.
-b  ⇒  blue, inverse. Steps will be longer on zones with a lower blue value.
+v  ⇒  brightness, proportional. Steps will be longer on brighter regions.
-v  ⇒  brightness, inverse. Steps will be longer on darker regions.

Stroke Type

Choose a brush style for tracing the particles' trajectory. Here's an illustrative description of each option:

a  ⇒  Hairline (not affected by Stroke Weight value)
b  ⇒  Worms
c  ⇒  Ribbons
d  ⇒  Strings
e  ⇒  Splatter
f  ⇒  Stars
g  ⇒  Bubbles
h  ⇒  Stairs


Check to draw with colors taken from the source image. Uncheck to make a monochrome drawing.

Play / Pause

Pause and resume the drawing process. You can pause and make adjustments to your settings that will be applied when you press Play again.

Action Buttons



Clears the drawing canvas.


Load new source images from Flickr or from your computer.

Loading from your computer: A system dialogue will open to browse your local drive. You can select many images at once. Only JPEG format is allowed.

Loading from Flickr: You have the option of getting images from Flickr by user screen name, by tag(s), or both. If you fill in both the 'user' and 'tags' field, Doodl will load photos with the given tag(s) from that particular user's stream, if there are any. A maximum of 10 photos will be loaded on each request.



Save a high resolution snapshot of the current drawing to your computer.


Change all dynamic variables at random to generate a new style for your drawing.

Print T-shirt

Print the current drawing on apparel and other products at Zazzle.

Source image controls


Image Strip

Images you load from Flickr or from your computer are stored in the image strip, where you can select any of them to feed the generative process and remove the ones you don't need any more.

When Doodl loads for the first time, some images are loaded from Flickr. They will be automatically removed from the strip as soon as you load your own.

Focused Image

The image at the center of the strip, inside the green box, is the one currently used as a base for the generative drawing on the main screen.

Click on on any other image to focus it, or let them rotate automatically by checking Auto Change Image (see below).

Remove an image

Whenever you move your mouse over a source image, a red cross button will appear in the right top corner. Click it to remove the image from the strip. Clicking on the image itself will focus it instead.

Next and Previous

You can also move forwards and backwards through the image strip by clicking the Next and Previous arrows at the right and left ends of the strip.

Auto Change Image

Enable or disable the automatic rotation of source images ("slideshow mode").

Image Rotation Speed

Set the interval between source image changes, from very quick to very slow. Only available when automatic rotation is enabled.