# Draw a white circle cv2.circle(img, (W//2, H//2), W//4, (255,255,255), thickness=5)
W, H = 847, 847 # Create an empty BGR image (3 channels) img = np.zeros((H, W, 3), dtype=np.uint8)
const W = 847; const H = 847; const canvas = createCanvas(W, H); const ctx = canvas.getContext('2d'); 847 create an image full
// Write to PNG const out = fs.createWriteStream('node_canvas_full_847.png'); const stream = canvas.createPNGStream(); stream.pipe(out); out.on('finish', () => console.log('✅ Canvas image saved')); – node-canvas uses cairo under the hood; ensure your host has sufficient shared memory ( /dev/shm ) if you scale to > 10 k px. 5.4 C# – SkiaSharp (Cross‑Platform) using SkiaSharp; using System.IO;
If you anticipate images larger than 20 000 × 20 000 px , prefer libraries that expose direct memory mapping (e.g., OpenCV, SkiaSharp) and support streaming/tiled rendering . 5. Step‑by‑Step Workflow Below are concrete recipes for the most common environments. All examples create a full‑size image of 847 × 847 px (the number you supplied) and then fill it with a gradient background, draw a shape, and write it to disk. Why 847 × 847? It demonstrates a non‑power‑of‑two dimension, which can expose alignment bugs that often trigger error 847. 5.1 Python – Pillow from PIL import Image, ImageDraw # Draw a white circle cv2
// Gradient fill (full‑canvas) const gradient = ctx.createLinearGradient(0, 0, W, H); gradient.addColorStop(0, 'rgb(0,128,255)'); gradient.addColorStop(1, 'rgb(255,128,0)'); ctx.fillStyle = gradient; ctx.fillRect(0, 0, W, H);
// Centered white circle ctx.strokeStyle = '#FFF'; ctx.lineWidth = 5; ctx.beginPath(); ctx.arc(W/2, H/2, W/4, 0, Math.PI * 2); ctx.stroke(); Step‑by‑Step Workflow Below are concrete recipes for the
// Encode to PNG (lossless) using var data = bitmap.Encode(SKEncodedImageFormat.Png, 100); File.WriteAllBytes("skia_full_847.png", data.ToArray()); Console.WriteLine("✅ SkiaSharp image saved"); SkiaSharp automatically uses GPU acceleration when available, which can dramatically reduce the time required for rasterizing very large images. 5.5 Photoshop Scripting (ExtendScript) #target photoshop var W = 847; var H = 847;