API Reference

<template>
  <ImageCropper
    :aspect-ratio="aspectRatio"
    :output-format="format"
    :quality="quality"
    @crop-complete="handleCropComplete"
  />
</template>

interface CropResult {
  url: string; // Blob URL of cropped image
  blob: Blob; // Image blob data
  canvas: HTMLCanvasElement; // Canvas element
  info: {
    width: number; // Output width in pixels
    height: number; // Output height in pixels
    size: number; // File size in bytes
    format: string; // Output format
  };
}

interface ImageInfo {
  width: number; // Original width
  height: number; // Original height
  size: number; // File size in bytes
  type: string; // MIME type
  name: string; // Original filename
}

interface CropSettings {
  aspectRatio: number | 'free';
  outputFormat: 'png' | 'jpeg' | 'webp';
  quality: number;
  outputWidth?: number;
  outputHeight?: number;
}

const cropperOptions = {
  aspectRatio: NaN, // Free aspect ratio
  viewMode: 1, // Restrict crop box to canvas
  responsive: true, // Responsive cropper
  restore: false, // Don't restore after resize
  guides: true, // Show dashed lines
  center: true, // Show center indicator
  highlight: false, // Don't highlight crop area
  cropBoxMovable: true, // Allow moving crop box
  cropBoxResizable: true, // Allow resizing crop box
  toggleDragModeOnDblclick: false, // Disable double-click
};

// Load image from file
function loadImageFromFile(file: File): Promise<string> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = (e) => resolve(e.target?.result as string);
    reader.onerror = reject;
    reader.readAsDataURL(file);
  });
}

// Download blob as file
function downloadBlob(blob: Blob, filename: string): void {
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(url);
}

// Convert canvas to blob
function canvasToBlob(canvas: HTMLCanvasElement, format: string, quality?: number): Promise<Blob> {
  return new Promise((resolve) => {
    canvas.toBlob(resolve, `image/${format}`, quality);
  });
}

// Get image dimensions
function getImageDimensions(src: string): Promise<{ width: number; height: number }> {
  return new Promise((resolve) => {
    const img = new Image();
    img.onload = () =>
      resolve({
        width: img.naturalWidth,
        height: img.naturalHeight,
      });
    img.src = src;
  });
}

// Format file size for display
function formatFileSize(bytes: number): string {
  const sizes = ['Bytes', 'KB', 'MB', 'GB'];
  if (bytes === 0) return '0 Bytes';
  const i = Math.floor(Math.log(bytes) / Math.log(1024));
  return Math.round((bytes / Math.pow(1024, i)) * 100) / 100 + ' ' + sizes[i];
}

// Validate image file
function isValidImageFile(file: File): boolean {
  return file.type.startsWith('image/');
}

// File validation errors
class InvalidFileTypeError extends Error {
  constructor() {
    super('Invalid file type. Please select an image file.');
  }
}

// Memory errors
class ImageTooLargeError extends Error {
  constructor() {
    super('Image is too large to process in this browser.');
  }
}

// Processing errors
class CropProcessingError extends Error {
  constructor(message: string) {
    super(`Crop processing failed: ${message}`);
  }
}

// Graceful error handling
function handleCropError(error: Error): void {
  if (error instanceof InvalidFileTypeError) {
    // Show file type error message
    showErrorMessage('Please select a valid image file');
  } else if (error instanceof ImageTooLargeError) {
    // Suggest image size reduction
    showErrorMessage('Image too large. Please use a smaller image');
  } else {
    // Generic error handling
    showErrorMessage('An error occurred. Please try again');
  }
}

// Clean up resources
function cleanup(): void {
  // Revoke blob URLs
  blobUrls.forEach((url) => URL.revokeObjectURL(url));

  // Destroy cropper instance
  if (cropper) {
    cropper.destroy();
    cropper = null;
  }

  // Clear canvas references
  canvasRefs.length = 0;
}

// Process large images efficiently
function processLargeImage(canvas: HTMLCanvasElement): HTMLCanvasElement {
  const maxDimension = 4096; // Browser limit
  const scale = Math.min(maxDimension / canvas.width, maxDimension / canvas.height, 1);

  if (scale < 1) {
    const scaledCanvas = document.createElement('canvas');
    scaledCanvas.width = canvas.width * scale;
    scaledCanvas.height = canvas.height * scale;

    const ctx = scaledCanvas.getContext('2d');
    ctx.drawImage(canvas, 0, 0, scaledCanvas.width, scaledCanvas.height);

    return scaledCanvas;
  }

  return canvas;
}