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Annotate

Draw on an image: arrows, rectangles, ellipses, lines and text. Drawing is raster, implemented in the core — there is no GUI and no external editor involved, so the same annotations render identically in every language.

Function

Section titled “Function”
annotate_image(input, &[Annotation]) -> Vec<u8>
Language Name
Rust annotate_image
JavaScript annotateImage
Python annotate_image
CLI dusrelimage annotate <input> --annotations annotations.json -o out.jpg

Annotation ops

Section titled “Annotation ops”

Coordinates are absolute pixels (not percentages). Colours are hex strings ("#ff0000") or { r, g, b } objects.

Op Fields
Arrow from: [x, y], to: [x, y], colour, width
Rect x, y, w, h, colour, width, fill (optional fill colour)
Ellipse x, y, w, h (bounding box), colour, width, fill (optional)
Line from: [x, y], to: [x, y], colour, width
Text x, y, text, size, colour

Ops draw in the order given — later ops paint over earlier ones. Text uses the bundled DejaVu Sans font.

Examples

Section titled “Examples”
import { annotateImage } from 'dusrelimage';


const out = annotateImage(input, [
  { type: 'Arrow', from: [50, 50], to: [300, 200], colour: '#ff0000', width: 4 },
  { type: 'Rect', x: 300, y: 100, w: 200, h: 120, colour: '#00ff00', width: 3 },
  { type: 'Text', x: 300, y: 90, text: 'Look here', size: 28, colour: '#00ff00' },
]);
from dusrelimage import annotate_image


out = annotate_image(data, [
    {"type": "Ellipse", "x": 100, "y": 100, "w": 150, "h": 150,
     "colour": "#0000ff", "width": 3, "fill": "#0000ff22"},
    {"type": "Line", "from": [0, 0], "to": [400, 400],
     "colour": "#ff0000", "width": 2},
])
Terminal window
# annotations.json: [{ "type": "Arrow", "from": [50, 50], "to": [300, 200], "colour": "#ff0000", "width": 4 }]
dusrelimage annotate photo.jpg --annotations annotations.json -o annotated.jpg

Errors

Section titled “Errors”
Code When
INVALID_IMAGE Input is not a decodable image.
INVALID_ARGUMENT Bad annotation (unknown op type, negative size, bad colour).
INVALID_TYPE A wrong value type reached the bindings layer.
IMAGE_TOO_LARGE Over max_pixels (default 120,000,000).
EMPTY_INPUT Empty input bytes.