Image Color Picker

Extract exact pixel colors from uploaded images or pasted clipboard screenshots across HEX, RGB, HSL, HWB, and CMYK formats.

Technical Architecture: Reverse-Engineering In-Browser Pixel Color Sampling​

Extracting precise color values from raster images without blurry interpolation requires low-level canvas coordinate translation and direct pixel buffer access via the HTML5 Canvas API.

1. Viewport-to-Canvas Coordinate Translation & Sampling​

When a user hovers or clicks on a scaled image element, CSS dimensions rarely match the source image's native pixel grid. The sampling engine maps screen coordinates to native image pixels before querying CanvasRenderingContext2D.getImageData():

function samplePixelColor(
  canvas: HTMLCanvasElement,
  clientX: number,
  clientY: number
): { hex: string; rgb: string } {
  const rect = canvas.getBoundingClientRect();
  const scaleX = canvas.width / rect.width;
  const scaleY = canvas.height / rect.height;

  // Compute exact native pixel coordinates
  const x = Math.floor((clientX - rect.left) * scaleX);
  const y = Math.floor((clientY - rect.top) * scaleY);

  const ctx = canvas.getContext('2d', { willReadFrequently: true });
  if (!ctx) throw new Error('Canvas 2D context unavailable');

  // Extract 4-byte RGBA buffer at (x, y)
  const pixel = ctx.getImageData(x, y, 1, 1).data;
  const r = pixel[0];
  const g = pixel[1];
  const b = pixel[2];

  const hex = `#${[r, g, b].map((c) => c.toString(16).padStart(2, '0')).join('')}`;
  return { hex, rgb: `rgb(${r}, ${g}, ${b})` };
}

2. High-Precision Magnifying Loupe & EyeDropper API​

To enable pixel-perfect selection of fine 1px UI borders or icon accents:

• 11×11 Magnifying Loupe: An auxiliary floating canvas extracts a localized $11 \times 11$ pixel neighborhood around the cursor and scales it with image-rendering: pixelated to eliminate antialiasing blur.
• Modern EyeDropper API: In supporting browsers (Chrome, Edge, Opera), the tool can invoke native system-level color sampling across any desktop window or browser element outside the canvas viewport.

Image Sampling Capabilities & Specifications​

Client-Side Security & Zero-Server Data Isolation​

• 100% Client-Side Canvas Processing: All image rendering, scaling, and pixel sampling execute locally in browser memory. Uploaded design mockups, confidential screenshots, or private photos are never uploaded or stored on any server.
• No Telemetry on Media: Images and sampled pixel values are completely isolated from tracking scripts.
• Heap Cleanliness: Object URLs and temporary canvas buffers are revoked when a new file is loaded to prevent browser memory leaks.

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