VectorPaint canvas sizes: distinguish px, pt, mm and exported pixels

English translation of the Chinese original, translated on 2026-10-23. The article body uses automated translation; app descriptions, historical reading notes and video subtitles receive separate editorial checks. Original publication dates, attribution, code and version notes are retained.

Use a square icon and a small printed card to separate canvas proportions, document units, editor zoom and final PNG pixels, avoiding repeated setup changes.

Set the delivery target before entering dimensions

Before creating a document, note where the work will be used, whether it is landscape or portrait, and the final file type. The first exercise is a square web icon; the second is a portrait event card with room for text above and below. Both can use vector paths, but their aspect ratios differ. Stretching a square design into a rectangle turns circles into ellipses. These values are exercise suggestions, not app capacity limits or universal platform upload specifications.

Understand four easily confused kinds of size

Canvas dimensions define the document's working area; object dimensions define a shape's geometry; zoom changes only your viewing distance on screen; PNG pixel dimensions determine how many samples the exported raster image contains. Zooming in does not add image pixels. For example, a circle spanning half the canvas width occupies more screen space when zoomed in, but its proportion relative to the canvas stays unchanged.

Create your first square canvas

From the gallery, create a canvas with a purpose-specific name such as “Mountain Icon_Practice.” Open custom dimensions, choose px, enter 512 for both width and height, and verify the units and values before creating it. Draw a rectangle occupying about two-thirds of the canvas and check that space remains on all sides. Here, 512 is a document-creation example. A later 1024-pixel PNG still needs to be checked in the export interface rather than assuming automatic double-size output.

Use millimeters for a defined physical size

For a printed card, create a separate document 100 mm wide and 150 mm tall, then mark an inner margin of about 8 mm with a rectangle as a composition guide. Millimeters describe physical size; print clarity also depends on the file's content and the printing process. Do not equate 100 mm with 100 px. When changing units, watch whether the dimensions convert and recheck the aspect ratio rather than changing numbers while overlooking their units.

Organize content with margins and proportions

For the square exercise, leave roughly 48 canvas units on all sides and keep the main shape in the central area. For a portrait card, first divide the layout into title, subject, and explanatory text areas. Address proportions before details. Focusing too early on tiny coordinate errors can obscure larger problems such as an oversized title or a subject too close to the edge. Near a boundary, inspect the actual contour and outer stroke edge, not only the path centerline.

Check pixel dimensions again during export

Choose PNG in Export and Share and confirm the final dimensions and preview. A 512×512 file and a 1024×1024 file are different raster deliverables. The latter has four times as many pixels, but file size and processing cost do not necessarily scale by exactly four. If the design contains a photo, increasing output pixels does not create detail missing from the original. For PDF, check page dimensions and whether the recipient prints at original size.

An easy calculation to get wrong: physical dimensions and pixels

Suppose you are delivering a card 100 mm wide to a workflow that accepts only images and requires a specific pixel width. Confirm the recipient's specification first, then prepare the pixel file during export. Do not simply switch canvas units from millimeters to pixels and reuse the original numbers. Physical width, image pixels, and print scaling must work together. Write the requirement as a complete sentence: “What is the finished width in millimeters, what is the delivered image width in pixels, and is scaling allowed when printing?” This is clearer than merely asking for high resolution.

Another common issue is a mismatch between the canvas ratio and the target container. A 100×150 portrait image placed in a square cover usually requires padding, cropping, or a new layout; stretching changes the shapes. Mark the target ratio in a copy and check what might be cropped, especially titles and fine lines near the edges. If one design must serve both a banner and a square avatar, reuse the graphic elements but arrange them separately, with clear names for both versions.

Finally, inspect source images. A photo with few pixels retains that limitation even on a very large vector canvas. If you need a sharper photo, replace the source with a sufficiently detailed one rather than merely raising canvas or export numbers.

Final checks and revision order

Check the aspect ratio first, then margins and any overflowing title, and finally the actual pixel dimensions in the PNG's file information. If width and height are reversed, correct the document orientation or rearrange the layout instead of arbitrarily squashing every object. Save, exit, and reopen the original to confirm that its name and canvas contents are recognizable. This is a recommended check for you to perform on your own device.

Further exercise: export one icon at two sizes

Export the same original as 512×512 and 1024×1024 PNGs. Include the pixel dimensions in each filename so you can compare them without overwriting either.
Open both images at the same displayed width and see whether their compositions match. Then inspect their file properties to distinguish displayed size from actual pixels.
Add a thick stroke near the canvas edge and check whether it is clipped. If it is, increase the composition's margins and export again.

Frequently asked questions

Will zooming to 400% improve export quality?

No. Zoom helps you inspect nodes and edges; PNG quality depends on final pixels and source quality. Review the result at its normal usage size first, then zoom in to locate problems instead of editing only at extreme magnification.

Why are the canvas and export different sizes when both say 512?

Check the unit beside every number, the export area, and the pixel dimensions first. Document units and export pixels serve different purposes; equal numbers do not necessarily mean equal sizes.

Can I use it directly for professional printing?

You can prepare vector or PDF files, but confirm bleed, color requirements, font handling, and finished dimensions with the printer. This exercise does not replace print proofing or promise a particular printing color standard.

Sources and scope

This article is based on VectorPaint App Store description and the available feature entry points; Apple’s public release information Checked on October 22, 2026, for version 1.0.7, requiring iOS / iPadOS 17.0 or later. The interface may vary by device and version. Dimensions, colours and wording are exercise suggestions; confirm the requirements for your actual use.