To Blob - iOS | IMG.LY Docs

import Foundation
import IMGLYEngine

@MainActor
func toBlob(engine: Engine) async throws {
  let baseURL = try engine.guidesBaseURL
  try engine.editor.setSettingString("basePath", value: baseURL.absoluteString)
  let sceneURL = baseURL.appendingPathComponent("ly.img.templates/templates/cesdk_business_card_1.scene")
  try await engine.scene.load(from: sceneURL)

  let scene = try engine.scene.get()!
  let page = try engine.scene.getPages().first!

  let pngBlob: Blob = try await engine.block.export(page, mimeType: .png)

  let options = ExportOptions(
    jpegQuality: 0.8,
    targetWidth: 1920,
    targetHeight: 1080,
  )
  let jpegBlob = try await engine.block.export(page, mimeType: .jpeg, options: options)

  let pages = try engine.scene.getPages()
  let stream = try await engine.block.export(pages, mimeType: .png)
  var blobs: [Blob] = []
  for try await blob in stream {
    blobs.append(blob)
  }

  let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent("export.png")
  try pngBlob.write(to: tempURL)
}

Export design blocks to binary Data (aliased as Blob) for saving to disk, uploading to a server, or decoding for on-screen display.

5 mins

estimated time

GitHub

CE.SDK’s engine.block.export() method renders any design block — a page, scene, or individual graphic block — into a Blob. In Swift, Blob is a typealias for Data, so the result integrates directly with Foundation APIs like FileManager and URLSession, and can be decoded straight into an image for display.

Export a Block to PNG#

Call engine.block.export(_:mimeType:) with a block ID and the desired format. The method returns a Blob containing the rendered output.

let pngBlob: Blob = try await engine.block.export(page, mimeType: .png)

Supported image MIME types include .png, .jpeg, .webp, .tga, and .pdf.

Configure Export Options#

Pass an ExportOptions instance to control quality and dimensions. Options vary by format:

Option	Formats	Default	Description
`pngCompressionLevel`	PNG	`5`	0-9, higher = smaller file, same quality
`jpegQuality`	JPEG	`0.9`	0-1, higher = better quality
`webpQuality`	WebP	`1.0`	0-1, higher = better quality
`targetWidth` / `targetHeight`	All image	`0`	Scale to fill target size, keeping aspect ratio

let options = ExportOptions(
  jpegQuality: 0.8,
  targetWidth: 1920,
  targetHeight: 1080,
)
let jpegBlob = try await engine.block.export(page, mimeType: .jpeg, options: options)

When both targetWidth and targetHeight are set, the block scales to fill the target rectangle while preserving its aspect ratio.

Export Multiple Blocks#

To export several blocks efficiently, pass an array of IDs. The method returns an AsyncThrowingStream<Blob, Error> that yields one blob per block in order, reusing a single background engine for all exports.

let pages = try engine.scene.getPages()
let stream = try await engine.block.export(pages, mimeType: .png)
var blobs: [Blob] = []
for try await blob in stream {
  blobs.append(blob)
}

This is more memory-efficient than calling export in a loop because instead of creating an internal worker engine instance for each export only a single instance is created once and reused across all blocks.

Save to Disk#

Since Blob is Data, write it directly to a file URL with Foundation’s write(to:).

let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent("export.png")
try pngBlob.write(to: tempURL)

You can also pass the blob to URLSession for uploading, or decode it as an image for display.

Next Steps#

To PDF — Export scenes as single- or multi-page PDFs with print options.
Conversion Overview — See all supported export formats.