Image.Blank

Examples below assume this module is imported with an imports: entry under alias Image. Kind references follow that alias — substitute your own if you import it under a different name.

Produces a solid-color canvas as PNG bytes — the seed of an image pipeline (compose with Image.Overlay) or a hermetic test fixture that replaces embedded base64 images.

An unrecognized CSS color is rejected with ERR_INVALID_INPUT rather than silently producing a default-colored canvas (the underlying canvas API keeps its previous fill color on invalid assignment).

---

Example

kind: Image.Blank
metadata: { name: Canvas }

- name: board
  inputs: { width: 800, height: 600, color: "#003366" }
  invoke: !ref Canvas
- name: marked
  inputs:
    image: "${{ steps.board.result.image }}"
    shapes:
      - { x: 40, y: 40, width: 200, height: 120, label: "header" }
  invoke: !ref DrawBoxes

---

Configuration

Field	Type	Required	Description
color	string	no (default #FFFFFF)	CSS fill color. A per-invocation color takes precedence.
format	png | jpeg | webp	no (default png)	Output image format. A per-invocation format takes precedence.
quality	integer	no (default 80)	Encoder quality (1–100) for the lossy formats; ignored for png.

Invocation inputs

Input	Type	Required	Description
width	integer	yes	Canvas width in pixels, 1–16384.
height	integer	yes	Canvas height in pixels, 1–16384.
color	string	no	CSS fill color. Takes precedence over the resource-level color.
format	png | jpeg | webp	no	Output image format. Takes precedence over the resource-level format.
quality	integer	no	Encoder quality (1–100) for the lossy formats; ignored for png.

Output

Field	Type	Description
image	Uint8Array	Solid-color canvas as buffered image bytes in the chosen format.
width	integer	Canvas width in pixels (echoed back).
height	integer	Canvas height in pixels (echoed back).
mediaType	string	MIME type of the encoded image (image/png, image/jpeg, or image/webp).

Errors

Code	When
ERR_INVALID_INPUT	width/height is not an integer between 1 and 16384, color is not a recognized CSS color, format is not png/jpeg/webp, or quality is not an integer between 1 and 100.