Package Exports

cwebp-bin

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (cwebp-bin) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

node-cwebp-bin

Examples


8bit converted png (14,225 bytes)	WebP converted (14,924 bytes)

This case, 8-bit converted PNG image is smaller than WebP one,
Of course, WebP images are smaller than 24-bit PNG images.
But if PNG (event though 8-bit converted!) contains many colors, it depends.


JPEGMini optimized jpg (39,335 bytes)	WebP converted (24,300 bytes)

In most cases, WebP images are smaller than JPEG images.

Dependencies on Linux

WebP requires following libraries on Linux. See detail.

$ sudo apt-get install libjpeg-dev libpng-dev libtiff-dev libgif-dev

Install

$ npm install --save cwebp-bin

Usage

Command Line

$ cwebp input.png -o output.webp

From source file

var execFile = require('child_process').execFile;
var cwebp = require('cwebp-bin').path;

execFile(cwebp, ['input.png', '-o', 'output.webp'], function (error) {
  if (error) {
    throw error;
  }

  console.log('Image was converted');
});

Options

Usage:
 cwebp [-preset <...>] [options] in_file [-o out_file]

If input size (-s) for an image is not specified, it is assumed to be a PNG, JPEG or TIFF file.
options:
  -h / -help  ............ short help
  -H / -longhelp  ........ long help
  -q <float> ............. quality factor (0:small..100:big)
  -alpha_q <int> ......... Transparency-compression quality (0..100).
  -preset <string> ....... Preset setting, one of:
                            default, photo, picture,
                            drawing, icon, text
     -preset must come first, as it overwrites other parameters.  -z <int> ............... Activates lossless preset with given                            level in [0:fast, ..., 9:slowest]

  -m <int> ............... compression method (0=fast, 6=slowest)
  -segments <int> ........ number of segments to use (1..4)
  -size <int> ............ Target size (in bytes)
  -psnr <float> .......... Target PSNR (in dB. typically: 42)

  -s <int> <int> ......... Input size (width x height) for YUV
  -sns <int> ............. Spatial Noise Shaping (0:off, 100:max)
  -f <int> ............... filter strength (0=off..100)
  -sharpness <int> ....... filter sharpness (0:most .. 7:least sharp)
  -strong ................ use strong filter instead of simple (default).
  -nostrong .............. use simple filter instead of strong.
  -partition_limit <int> . limit quality to fit the 512k limit on
                           the first partition (0=no degradation ... 100=full)
  -pass <int> ............ analysis pass number (1..10)
  -crop <x> <y> <w> <h> .. crop picture with the given rectangle
  -resize <w> <h> ........ resize picture (after any cropping)
  -mt .................... use multi-threading if available
  -low_memory ............ reduce memory usage (slower encoding)
  -map <int> ............. print map of extra info.
  -print_psnr ............ prints averaged PSNR distortion.
  -print_ssim ............ prints averaged SSIM distortion.
  -print_lsim ............ prints local-similarity distortion.
  -d <file.pgm> .......... dump the compressed output (PGM file).
  -alpha_method <int> .... Transparency-compression method (0..1)
  -alpha_filter <string> . predictive filtering for alpha plane.
                           One of: none, fast (default) or best.
  -alpha_cleanup ......... Clean RGB values in transparent area.
  -blend_alpha <hex> ..... Blend colors against background color
                           expressed as RGB values written in
                           hexadecimal, e.g. 0xc0e0d0 for red=0xc0
                           green=0xe0 and blue=0xd0.
  -noalpha ............... discard any transparency information.
  -lossless .............. Encode image losslessly.
  -hint <string> ......... Specify image characteristics hint.
                           One of: photo, picture or graph

  -metadata <string> ..... comma separated list of metadata to
                           copy from the input to the output if present.
                           Valid values: all, none (default), exif, icc, xmp

  -short ................. condense printed message
  -quiet ................. don't print anything.
  -version ............... print version number and exit.
  -noasm ................. disable all assembly optimizations.
  -v ..................... verbose, e.g. print encoding/decoding times
  -progress .............. report encoding progress

Experimental Options:
  -jpeg_like ............. Roughly match expected JPEG size.
  -af .................... auto-adjust filter strength.
  -pre <int> ............. pre-processing filter

License

This is licensed under BSD.

WebP is licensed under Creative Commons Attribution 3.0 License.