Guide objects for drawing in user interfaces

Systems, methods, and software are disclosed herein that enhance drawing technology in application user interfaces. In an implementation, a guide object is disclosed herein that allows a user to draw against the guide object, position other objects against, and otherwise interact with the guide object as-if it were a stencil. The guide object may be presented as a drawing tool in a user interface to an application that a user may invoke by user input to assist with the creation of content on a canvas. As a line is drawn proximate to the guide object, for example, or as a shape is positioned nearby the guide object, the application obtains guidance information from the guide object that allows the application to render the interaction between line or shape and the guide object as-if it were an actual stencil.