Error codes

Every public function returns a Result and never panics on bad input. On failure you get a DusrelError with three things:

• code — a stable, machine-readable string. Branch on this, never on the message text.
• message_en — a human-readable message in English.
• message_hi — the same message in Hindi (Roman-script Hinglish, as written in crates/dusrelimage/src/error.rs — not Devanagari). The wordings in the table below match the code exactly; {detail} / {format} / {w} / {h} / {pixels} / {max_pixels} / {max_dimension} / {target} / {smallest} / {x} / {y} / {q} / {what} are filled in per failure.

In Rust the error is returned as a DusrelError; in JavaScript it is thrown as a DusrelError (an Error subclass with .code, .messageEn and .messageHi); in Python it is raised as a DusrelError (with .code, .message_en and .message_hi). The codes are identical in every language. (The raw WASM exports throw the same failure as a JSON string — the JavaScript and Python wrappers convert it into the typed error.)

The codes

Code	When it happens	message_en	message_hi
INVALID_IMAGE	Input bytes are not an image, are truncated, or cannot be decoded.	Invalid image: {detail}	Galat image hai: {detail}
UNSUPPORTED_FORMAT	The image format is recognised but not supported for this operation (e.g. AVIF input, or an encode target the encoder cannot write).	Unsupported image format: {format}.	Ye image format support nahi hai: {format}.
IMAGE_TOO_LARGE	The image has more pixels than CommonOptions.max_pixels (default 120,000,000), or a side longer than max_dimension (default 16000).	Image is too large: {w}x{h} ({pixels} pixels) exceeds the limit of {max_pixels} pixels / {max_dimension} px per side.	Image bahut badi hai: {w}x{h} ({pixels} pixels) limit se zyada hai — {max_pixels} pixels / {max_dimension} px per side.
TARGET_SIZE_UNREACHABLE	compress_to_size could not reach the target — even the lowest quality still exceeds it.	Target size of {target} bytes cannot be reached: even the lowest quality produces {smallest} bytes.	Target size {target} bytes tak nahi pahunch sakte: sabse low quality par bhi {smallest} bytes bante hain.
CROP_OUT_OF_BOUNDS	The crop rectangle sticks out of the image.	Crop rectangle ({x}, {y}, {w}x{h}) is outside the image ({iw}x{ih}).	Crop rectangle ({x}, {y}, {w}x{h}) image ({iw}x{ih}) se bahar hai.
PIXEL_OUT_OF_BOUNDS	The picked pixel is outside the image.	Pixel ({x}, {y}) is outside the image ({w}x{h}).	Pixel ({x}, {y}) image ({w}x{h}) se bahar hai.
INVALID_QUALITY	Quality is outside 1–100. (A WebP effort outside 0–6 is INVALID_ARGUMENT, not this code; there is no user-facing PNG level option.)	Quality {q} is invalid. Quality must be between 1 and 100.	Quality {q} galat hai. Quality 1 se 100 ke beech honi chahiye.
INVALID_DIMENSIONS	A width/height is zero or missing where required. (A side longer than max_dimension is IMAGE_TOO_LARGE, not this code.)	Invalid dimensions: {detail}	Galat dimensions hain: {detail}
INVALID_ARGUMENT	A bad argument: opacity outside 0–1, block size outside 2–100, effort outside 0–6, watermark with neither text nor logo, a bad collage layout, an unreadable input file (CLI). Text and logo may be combined — only “neither” is an error.	Varies by call	Varies by call
EMPTY_INPUT	An input list or byte buffer is empty where at least one item is required (no collage inputs, empty image bytes).	{what} is empty.	{what} khaali hai.
INVALID_TYPE	A wrong value type reached a typed API (bindings layer).	Invalid type: {detail}	Galat type hai: {detail}

Branch on code, never on text

The message_en / message_hi wording may gain detail in a later release; the code values are stable. bulk_process never fails the whole batch — a per-item failure is reported with its own code (see Info & bulk).

Examples

use dusrelimage::{crop_image, CropOptions};

match crop_image(&img, &CropOptions { x: 900, y: 0, width: 200, height: 200, ..Default::default() }) {
    Ok(out) => std::fs::write("cropped.png", out)?,
    Err(e) => {
        // e.code == "CROP_OUT_OF_BOUNDS"
        // e.message_en == "Crop rectangle (900, 0, 200x200) is outside the image (800x600)."
        eprintln!("{e}");
    }
}

import { compressToSize, DusrelError } from 'dusrelimage';

try {
  compressToSize(img, 10 * 1024); // 10 KB — probably unreachable for a photo
} catch (e) {
  if (e instanceof DusrelError && e.code === 'TARGET_SIZE_UNREACHABLE') {
    console.log(e.messageEn); // English
    console.log(e.messageHi); // Hindi
  }
}

from dusrelimage import pick_colour, DusrelError

try:
    pick_colour(img, 9999, 0)
except DusrelError as e:
    assert e.code == "PIXEL_OUT_OF_BOUNDS"
    print(e.message_en)
    print(e.message_hi)