langgenius/dify · error · Error

Could not create a canvas context

Error message

Could not create a canvas context

What it means

Error "Could not create a canvas context" thrown in langgenius/dify.

Source

Thrown at web/app/components/base/app-icon-picker/utils.ts:58

  }
}

/**
 * This function was adapted from the one in the ReadMe of https://github.com/DominicTobias/react-image-crop
 */
export default async function getCroppedImg(
  imageSrc: string,
  pixelCrop: { x: number; y: number; width: number; height: number },
  fileName: string,
  rotation = 0,
  flip = { horizontal: false, vertical: false },
): Promise<Blob> {
  const image = await createImage(imageSrc)
  const canvas = document.createElement('canvas')
  const ctx = canvas.getContext('2d')
  const mimeType = getMimeType(fileName)

  if (!ctx) throw new Error('Could not create a canvas context')

  const rotRad = getRadianAngle(rotation)

  // calculate bounding box of the rotated image
  const { width: bBoxWidth, height: bBoxHeight } = rotateSize(image.width, image.height, rotation)

  // set canvas size to match the bounding box
  canvas.width = bBoxWidth
  canvas.height = bBoxHeight

  // translate canvas context to a central location to allow rotating and flipping around the center
  ctx.translate(bBoxWidth / 2, bBoxHeight / 2)
  ctx.rotate(rotRad)
  ctx.scale(flip.horizontal ? -1 : 1, flip.vertical ? -1 : 1)
  ctx.translate(-image.width / 2, -image.height / 2)

  // draw rotated image
  ctx.drawImage(image, 0, 0)

View on GitHub (pinned to ef8544b173)

When it happens

Trigger: Thrown at web/app/components/base/app-icon-picker/utils.ts:58 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langgenius/dify@ef8544b173 (2026-08-12). Data as JSON: /api/errors/3bfe0d61531b3782. Report an issue: GitHub.