Adding new slides on a canvas in a zooming user interface

A computer system configured by computer program code to perform operations comprising:

• during creation of a slide presentation on a canvas, following addition of a plurality of slides, receiving a user request to add a new slide to the canvas;
• determining a reference window for placement of the new slide;
• determining whether placements of prior slides on the canvas within the reference window follow a pattern in at least one of location, zoom level, or orientation;
• in response to determining that the prior slides within the reference window follow a pattern, determining a next location, zoom level, or orientation for placement of the new slide in accordance with the pattern and determining whether placement of the new slide is blocked by previously created display elements;
• and
• in response to determining that the prior slides within the reference window do not follow a pattern or in response to determining that placement of the new slide in accordance with the pattern is blocked, determining a placement of the new slide in accordance with default rules based on one or more of the prior slides;
• and
• adding the new slide to the canvas.