Canvas size, units & presets

The size of your Canvas decides everything downstream — how your layout breathes, and, for print, the real-world dimensions the press will cut to. It's worth getting right before you commit to a layout, so pick your size first and design into it.

When you start a new document — File ▸ New → "Create new document" — you set most of this up front: choose a job preset (print, publishing or presentation, which seed the right color mode, bleed and page count) or a template, then adjust Width / Height, Units, Resolution (dpi), Color mode, Bleed, Pages and Facing pages before clicking Create. You can still change size and units at any time afterward, as below.

Size presets#

The fastest way to start is a preset. When you add a Canvas or open the size dialog, presets are grouped into five categories along the top:

The category you choose also sets a sensible resolution. Screen categories (Aspect, Social, Product, Screens) author at 72 dpi in pixels — the right choice for anything that lives on a display. Print presets author at 300 dpi in physical units (millimeters, or inches for the US paper sizes), so an A4 lands as a true 210 × 297 mm page rather than a pile of pixels.

Custom size#

Not every job matches a preset. To set an exact size, type your numbers into the Width and Height fields at the bottom of the dialog and click Apply size (or Add canvas when you're creating a new one). The fields read in whatever the document's current unit is, so a label at 60 × 40 mm is as easy to enter as a 1080 px banner.

Units#

Popcorn Editor works in five units:

• Pixels (px)
• Millimeters (mm)
• Centimeters (cm)
• Inches (in)
• Points (pt)

To switch, right-click either ruler (along the top or left edge of the stage) and choose a unit — the current one shows a checkmark. Every measurement in the interface, including the rulers and the Width/Height fields, updates to match. Use px for screen work; use mm, cm, or in for anything headed to print.

Resolution (DPI)#

Below the size fields sits Resolution (DPI). As the in-app hint explains:

Pixels per inch — maps the document to physical sizes (mm, cm, in, pt). Changing it rescales physical measurements; the pixel geometry stays the same.

In other words, DPI is the bridge between pixels and physical size. Raise it and the same pixel canvas describes a smaller physical page; lower it and that page grows. It doesn't add or remove pixels — it just changes how they map to millimeters and inches. The print standard is 300 dpi, which is why print presets set it for you.

Resize an existing Canvas#

Changed your mind after you started? With nothing selected, the Properties panel shows the Active canvas section with W and H fields you can edit directly. For the full preset picker, click Size presets to reopen the Canvas size dialog.

Resizing changes the page, not the objects on it. Your artwork keeps its position and size, so you may need to nudge or rescale a few things to fit the new dimensions.

Add another Canvas#

A single design can hold many Canvases — handy for a multi-page document or a set of related sizes. Click Add canvas in the toolbar (or Menu ▸ Object ▸ Add canvas) and pick a size for the new one. Each Canvas can be a different size and orientation, so a poster and its social cut-downs can live side by side. Working with several Canvases is covered in its own article on multiple canvases.

Document setup & bleed#

Printing means one more step. Open Menu ▸ File ▸ Document setup… and set a Bleed — the margin of artwork that extends past the trim edge so the cut never leaves a white sliver. Bleed shows on the Canvas as a red guide (toggle it with Show bleed) and is included in your PDF exports. Three millimeters is the usual amount; check with your printer. For the full walkthrough, see Document setup & bleed.

Next: put a fresh Canvas to work in Your first design, and when you're headed to print, read up on RGB vs CMYK color modes.