Lossless Compression
Lossless Compression (Reversible Data Reduction)
Lossless compression reduces file size without discarding any image data. The original image can be perfectly reconstructed from the compressed file. PNG, TIFF (with LZW), and WebP lossless use this approach.
技術的詳細
Lossless algorithms exploit statistical redundancy: PNG uses DEFLATE (LZ77 + Huffman coding) with row-level prediction filters. Typical compression ratios range from 2:1 to 10:1 depending on image complexity.
例
```javascript
// Image compression via Canvas
canvas.toBlob(
blob => console.log(`Size: ${(blob.size/1024).toFixed(0)} KB`),
'image/jpeg',
0.8 // quality: 0.0 (smallest) to 1.0 (best)
);
// WebP output (25-34% smaller than JPEG)
canvas.toBlob(cb, 'image/webp', 0.8);
```
関連フォーマット
関連ツール
C
Compress Image
R
Resize Image
C
Crop Image
R
Rotate Image
F
Flip Image
C
Convert Image
W
Watermark Image
S
SVG to PNG
I
Image to Base64
R
Round Corners
A
Add Border
I
Image Filters
A
Adjust Image
B
Blur Image
S
Sharpen Image
M
Make Square
G
Grayscale Image
S
Sepia Image
P
Pixelate Image
S
Strip Image Metadata