What is Doodleback?

A lot of drawing apps let you construct a circle but usually in only one way. They let you copy an object but in only one way or erase but in only one way. But what if you wanted to erase with a star or copy something by rotation? Doodleback’s philosophy is that how you’re able to construct things is almost as important as what you can construct. Being able to precisely place objects at the moment of their creation simplifies many drawings that would otherwise be difficult or almost impossible. You can get it here on Google Play.

Zoom Mode

The Zoom Button in the upper left hand corner toggles the Paper between Drawing Mode and Zoom Mode. Here is Doodleback in Drawing Mode. And here is Doodleback in Zoom Mode after the Zoom Button has been pressed. Besides the label at the top of the screen, you can immediately recognize Zoom Mode by the fact that all Paths are now drawn in outline. [Read More]

Path Construction Mode

Most tools have a main Construction Mode button in the side Option Buttons. This button controls how the touch events are interpreted during the construction of the Path and usually looks like a miniature version of the path under construction. In the example below, the button has a circular icon because the Path under construction is a Circle. In the first screenshot the initial touch is interpreted as the center of the circle and the current location of your finger is interpreted as a point on the circumference. [Read More]

Option Buttons

Option Buttons are buttons that control aspects of a Path while it is being constructed such as the number of points on a Star, the increment used when rotating a Path, or how the initial touch point and current touch point are interpreted (the Path Construction Mode. The buttons or their meanings can change during different steps in the Path’s construction. Here’s an example using the Star Tool: IMPORTANT NOTE: Options buttons are used during LIVE construction. [Read More]

Header Option Buttons

The Header Option Buttons are the buttons that are available at the top of screen during all Path constructions. They are more general than the side Option Buttons which differ from tool to tool. The first is the Lock Button. Lock Button The Lock Button freezes motion input. When the path is locked, no future touch events will change it until it’s unlocked again. This is useful, for instance, if you’re trying to precisely place a path, set an angle, position a bezier point or vertex, etc. [Read More]

Mark Button

Many paths use a Mark Button (the cross-hair looking button) during their construction. Tapping this button tells the path that the current position of your finger should be used to define an important point or attribute of the path. Here’s an example using the Circular Ring Sector tool. First the Mark Button is used to define the inner radius. When you’ve dragged to the desired radius, hit the mark button. [Read More]


Snapping is one of the most important concepts in Doodleback, but if you don’t understand how it works, it can sometimes be frustrating. When Snapping is turned on, the important points (described below) of the Path you’re constructing will automatically snap to other important points on the Paper. For example, take this septagon (7-sided Polygon). Using Snapping and the Line Segment tool I can quickly create spokes from its center to its vertices. [Read More]


The Radar overlay helps you find Snapping Point. Many tools, such as the Transformation tools, require you to touch a Snapping Point in order to use the tool. For example, to move a Triangle you need to grab one of its corners or its center. For a triangle, this is easy to locate, but for some other paths the Snapping Points may not be obvious. If you attempt to grab a path and “miss”, a Radar like image will appear which will show you all the snapping points in the vicinity of your touch. [Read More]

Drag Constraints

Many tools offer a Drag Constraints button during construction. It looks like this. In the setting displayed above, there are no restrictions on motion. Other settings of the Drag Constraints button allow you to restrict the motion of an operation (such as a Move) horizontally, vertically, along a vector, etc. For example, with the setting below I can move the Circle only up and down. And this setting allows me to move it only left and right. [Read More]


Z-Level is a fairly easy concept to grasp. The z-level of a Path is simply its height above the page. If Path A has a z-level higher than Path B, then Path A is above Path B. Every time you create a Path, it will have a z-level higher than the other Paths on the page, that is, new Paths will appear on top of existing Paths. In this example, the Rectangle has a higher z-level than the Circle. [Read More]


A Vertex is just a corner of a Polygon (Triangle, Rectangle, Trapezoid, etc.) or the end of a Line Segment or Arrow. The Octagon below has 8 vertices. Conventionally, in mathematics, the ends of a Line Segment wouldn’t be considered vertices, but in Doodleback they are. It’s important to know what’s considered a Vertex and what isn’t for purposes of applying Vertex Tools to them. The Vertex Tools allow you to move vertices. [Read More]