bkjs-wand

ImageMagick wand module for node and backendjs

Requirements

Installing dependencies on CentOS:

yum -y install libpng-devel libjpeg-turbo-devel

Installing dependencies on Mac OS X using macports:

port install libpng jpeg

Usage

• resizeImage(source, options, callback) - resize image using ImageMagick
  • source can be a Buffer or file name
  • options can have the following properties:
    • width - output image width, if negative and the original image width is smaller than the specified, nothing happens
    • height - output image height, if negative and the original image height is smaller this the specified, nothing happens
    • quality - 0 - 99
    • out - output file name
    • ext - image extention
    • outfile - a filename where to save scaled image, if not given the binary image data is passed to the callback
    • frame - which frame to resize for animated GIFs, 0 is default, -1 to convert all frames
    • no_animation - if set to 1 it will convert GIF animation, otherwise animated GIF is simply returned as is
    • posterize - levels, 2,3,4
    • dither - 1 to dither
    • normalize - 1 to normalize image
    • quantize - number of colors
    • treedepth - 0 or 1 for quantize
    • flip - 1 to flip image
    • flop - 1 1 to flop image
    • blur_radius - radius in pixels
    • blur_sigma - std deviation in pixels
    • sharpen_radius - radius in pixels
    • sharpen_sigma - std deviation in pixels
    • brightness - -100 - 100
    • contrast - -100 - 100
    • rotate - degrees
    • opacity - 0 - 1.0
    • crop_width - crop coordinates
    • crop_height
    • crop_x
    • crop_y
    • bgcolor - RGB for background
    • filter - box, triangle, hermite, hanning, hamming, blackman, gaussian, quadratic, cubic, catrom, mitchell, lanczos, kaiser, welsh, parzen, bohman, barlett, lagrange, jinc, sinc, sincfast, lanczossharp, lanzos2, lanzos2sharp, robidoux, robidouxsharp, cosine, spline, lanczosradius
    • colorspace - rgb, gray, transparent, ohta, xyz, ycbcr, ycc, yiq, ypbpr, yuv, cmylk, srgb, hls, hwb
    • gravity - northwest, north, northeast, west, center, east, southwest, south, southeast

On return the callback will receive the image data if no outfile was specified or null, and the third argument if an object with the result image information: file, ext, height, width, orientation, rotation.

The original image dimentions are returned as _width and _height.

The file where the image is sved will have the actual extention, if the outfile parameter contains invalid extention it will be replaced with the actual resulting image type.

  require("bkjs-wand").resizeImage("a.png", { width: 120, height: 120 }, function(err, data, info) {
     if (!err) fs.writeFile("b.png", data);
     console.log(err, info);
  })

Author

Vlad Seryakov