img-canvas-helper

Stability - 2 Unstable

Helper function to resize or crop jpeg images using node canvas module (requires Cairo)

API

resize(img, maxdim, function(result, data))

Resizes an image where longest dimension is within maxdim
 * imgsrc - string path to image to crop
 * width - integer length of longest width dimension for resized image 
 * height - integer length of longest height dimension for resized image 
 * callback - callback function(
 *     result - boolean true on success
 *     data - canvas object on success, Error on failure

crop(img, maxw, maxh, function(result, data))

Crops an image to bounds specified by maxw and maxh
 * imgsrc - string path to image to crop
 * width - integer width of cropped image
 * height - integer height of cropped image
 * callback - callback function(
 *     result - boolean true on success
 *     data - canvas object on success, Error on failure

writeCanvas(canvas, outfile, function(result, data))

Helper to write canvas to an output jpeg file
 * Useful for writing manipulated image back to a file
 * canvas - canvas to write out to disk
 * outfile - string path to output file
 * callback - function (result, data)
 *    result - boolean result true on successful write
 *    data - bytes written on success, or Error on failure

Convert(options);

Transform stream from input image to modified output image
 * usage:  var Convert = require('img-canvas-helper').Convert;
 *         var imgc = new Convert(options);
 *         imgc.on('data', function (chunk) {
 *            //handle tranformed image data chunk
 *         });
 *         imgc.on('end', function () {
 *            //close any open write streams
 *         });
 *         imgc.on('error', function (err) {
 *            //handle errors
 *         });
 * where:
 *         options = {
 *           img:  <required string path to source image>,
 *           method: <required string conversion method ('resize' | 'crop' currently supported)>,
 *           width: <required integer width of destination image>
 *           height: <required integer height of destination image>
 *         }
 */