Angle Dividing Segment

The Angle Dividing Segment tool allows you to create a segment that divides an angle that you define by either 1⁄2, 1⁄3, 1⁄4, 1⁄5, 1⁄6,1⁄7, 1⁄8, 1⁄9,1⁄10, 1⁄11, or 1⁄12. You create the angle using the mark button by marking first one side endpoint of the angle, then the vertex of the angle, and finally the second side endpoint. The line segment will be drawn from the vertex of the angle along a dividing angle equal to the fraction that you selected. [Read More]


The Arrow tool lets you draw a single or double headed arrow. The head or heads of the arrow are defined before construction using the Arrow Settings which are located at the bottom of the Lines tool tab and visible when the Arrow tool is selected: Use the drop down boxes to select the arrow styles (including None) and use the seekbars to set the angles and sizes of the ends. [Read More]

Change Arrow

The Change Arrow tool lets you change the endpoints of an existing Arrow. It can only be applied to Arrows. Select the tool on the Lines tool tab. The Arrow Settings will then be visible at the bottom of the tab.

Modify the settings, return to the canvas, and then simply tap an existing Arrow to apply the new settings. Here’s an example:

Free Draw

The Free Draw tool is like the typical “pen” tool that you’ve seen in other apps. In Doodleback, it has two modes two modes though: Free Line Blob Free Line mode will draw a line that follows your finger as you move it around the page. Blob mode will do the same, but it will also connect the start and end points of the line to form a connected shape. [Read More]


The Kaleidoscope tool allows you to easily create things like this. This was made using the Standard Construction method Essentially, all it does is duplicate and reflect a Free Draw path around a central point. There are several different options available for construction. Standard Contruction begins drawing from the first point you touch and uses that point as the center. Mark Radius Construction also uses the first touch point as the center of the path but the drawing doesn’t begin until you mark the radius. [Read More]

Line Segment

The Line Segment tool lets you draw a line segment in several different ways. During construction, you can specify the orientation (free, horizontal, vertical, or along a vector), the number of Bezier points on the segment (either one or two, and this can be changed later with the Change Number of Bezier Points tool), and also where along the segment the initial touch point is located. The default location of the initial touch point is the end point, but you can also start the segment at ¼, ⅓, ½, ⅔, or ¾ of the way along the length of the segment. [Read More]

Null Tool

The Null tool does nothing. This may not sound very useful, but it is if you just want to point out features of the canvas to someone without changing it. A small transparent circle is displayed at the point you’re touching. This might be useful if you’re displaying the device screen on a separate screen. Think of it like a laser pointer for presentation.

Null Free Draw

The Null Free Draw tool lets you draw a transitory line on the screen. The line is immediately removed when you lift your finger. Like the Null Segment tool and the Null tool, the Null Free Draw tool is just for presentation purposes. It lets you interact with the page without changing it.

Null Segment

The Null Segment tool allows you to draw a temporary segment on the screen. The segment is immediately removed as soon as you lift your finger. This is only for presentation purposes. It allows you to interact with the page without changing it, similar to the Null tool. One thing to note is that the Null Segment honors Snapping. If you don’t want this, simply turn Snapping off using the Header Option Button for snapping. [Read More]

Perpendicular Segment

The Perpendicular Segment tool creates a segment that is perpendicular to another segment, real or imaginary. We say “real or imaginary” because really all you’re doing is select two points and then drawing a new segment perpendicular to the line passing through those points. If there happens to be another segment or a side of a rectangle or triangle lying along that line, then the new segment will be perpendicular to it too. [Read More]