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CDB-3686 Adds support for per mil tolerance when comparing images as in Mac OS X some results from ImageMagick are a bit odd

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This commit is contained in:
Raul Ochoa
2014-08-04 01:30:24 +02:00
parent 9b5921e8e1
commit 73d1db3bd2
3 changed files with 61 additions and 38 deletions
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67
test/support/assert.js
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@@ -1,10 +1,11 @@
// Cribbed from the ever prolific Konstantin Kaefer
// https://github.com/mapbox/tilelive-mapnik/blob/master/test/support/assert.js
var fs = require('fs');
var http = require('http');
var path = require('path');
var exec = require('child_process').exec;
var exec = require('child_process').exec,
fs = require('fs'),
http = require('http'),
path = require('path'),
util = require('util');
var assert = module.exports = exports = require('assert');
@@ -66,35 +67,51 @@ assert.utfgridEqualsFile = function(buffer, file_b, tolerance, callback) {
callback(err);
};
//
// @param tol tolerated color distance as a percent over max channel value
// by default this is zero. For meaningful values, see
// http://www.imagemagick.org/script/command-line-options.php#metric
//
assert.imageEqualsFile = function(buffer, file_b, tol, callback) {
/**
* Takes an image data as an input and an image path and compare them using ImageMagick fuzz algorithm, if case the
* similarity is not within the tolerance limit it will callback with an error.
*
* @param buffer The image data to compare from
* @param {string} referenceImageRelativeFilePath The relative file to compare against
* @param {number} tolerance tolerated mean color distance, as a per mil (‰)
* @param {function} callback Will call to home with null in case there is no error, otherwise with the error itself
* @see FUZZY in http://www.imagemagick.org/script/command-line-options.php#metric
*/
assert.imageEqualsFile = function(buffer, referenceImageRelativeFilePath, tolerance, callback) {
if (!callback) callback = function(err) { if (err) throw err; };
file_b = path.resolve(file_b);
var file_a = '/tmp/windshaft-test-image-test.png'; // + (Math.random() * 1e16); // TODO: make predictable
var err = fs.writeFileSync(file_a, buffer, 'binary');
var referenceImageFilePath = path.resolve(referenceImageRelativeFilePath),
testImageFilePath = '/tmp/windshaft-test-image-' + (Math.random() * 1e16); // TODO: make predictable
var err = fs.writeFileSync(testImageFilePath, buffer, 'binary');
if (err) throw err;
var fuzz = tol + '%';
exec('compare -fuzz ' + fuzz + ' -metric AE "' + file_a + '" "' +
file_b + '" /dev/null', function(err, stdout, stderr) {
var imageMagickCmd = util.format(
'compare -metric fuzz "%s" "%s" /dev/null',
testImageFilePath, referenceImageFilePath
);
exec(imageMagickCmd, function(err, stdout, stderr) {
if (err) {
fs.unlinkSync(file_a);
fs.unlinkSync(testImageFilePath);
callback(err);
} else {
stderr = stderr.trim();
var similarity = parseFloat(stderr);
if ( similarity > 0 ) {
var err = new Error('Images not equal(' + similarity + '): ' +
file_a + ' ' + file_b);
err.similarity = similarity;
callback(err);
var metrics = stderr.match(/([0-9]*) \((.*)\)/);
if ( ! metrics ) {
callback(new Error("No match for " + stderr));
return;
}
var similarity = parseFloat(metrics[2]),
tolerancePerMil = (tolerance / 1000);
if (similarity > tolerancePerMil) {
err = new Error(util.format(
'Images %s and %s are not equal (got %d similarity, expected %d)',
testImageFilePath, referenceImageFilePath, similarity, tolerancePerMil)
);
err.similarity = similarity;
callback(err);
} else {
fs.unlinkSync(file_a);
callback(null);
fs.unlinkSync(testImageFilePath);
callback(null);
}
}
});