Canvas, trim & masks

Use these transforms when the CDN URL needs to produce finished UI assets, not just resized photos.

Image with padding, border, and rounded corners — Padding, border, and radius — `?pad=32&border=8&borderColor=%239100ff&radius=36`.

Logo before ?trim=1.

Logo after ?trim=1 — transparent borders cropped.

Alpha mask — ?w=960&h=540&fit=cover&mask={logoFileId}&maskBg=%23f8f3ff (mask scaled with aspect ratio preserved).

Canvas presentation

Param	Value	Default
`pad`	Equal padding around the image (`0`-`1000`).	`0`
`border`	Equal border (`0`-`400`).	`0`
`borderColor`	Hex border colour with optional alpha.	`#000000`
`radius` (`r`)	Rounded-corner radius in pixels.	`0`
`bg`	Hex background for rotation/padding.	transparent
`rotate` (`rot`)	Rotate by degrees (`-360` to `360`).	`0`
`flip` / `flop`	Vertical / horizontal mirror.	`false`

?w=900&pad=32&bg=%23f8f3ff&border=8&borderColor=%239100ff&radius=36
?w=900&rotate=6&bg=%23ffffff

Trim transparent borders

PNG, WebP, and other alpha images often ship with extra transparent padding. Pass trim=1 to crop away fully transparent pixels before resize and encode:

https://cdn.convertly.sh/{endpointNamespace}/{fileIdOrSlug}?trim=1&w=400&format=webp

Aliases: trimAlpha=1, trim-alpha=1. Trim runs after EXIF auto-orient and before smart crop / resize.

Alpha masks

Apply a mask from a stored file ID or HTTPS URL. The mask is scaled to fit inside the output canvas (aspect ratio preserved, centred). Transparent mask areas reveal maskBg:

?w=900&mask=<file-or-url>&maskBg=%23ffffff00

For overlaying a second image (logo mark on photo), use Watermarks instead.

Getting Started

Image CDN

Media Platform

SDKs & Integrations

Resources

Canvas presentation

Trim transparent borders

Alpha masks

​Canvas presentation

​Trim transparent borders

​Alpha masks

Canvas presentation

Trim transparent borders

Alpha masks