diff --git a/lib/screenshotHandler.js b/lib/screenshotHandler.js index 5b82cd3..b803ed9 100644 --- a/lib/screenshotHandler.js +++ b/lib/screenshotHandler.js @@ -48,6 +48,8 @@ var screenshotHandler = function() { }) + .then(this.addWhiteBackground) + .then(this.toBuffer); }; @@ -92,6 +94,39 @@ var screenshotHandler = function() { return deferred.promise; }; + // If the page doesn't set a bg color, the default PhantomJS one is transparent + // When transforming PNG to JPG, transparent pixels become black. + // This is why we need to add a transparent background. + this.addWhiteBackground = function(image) { + var deferred = Q.defer(); + + // Create a canvas with the same dimensions as your image: + lwip.create(image.width(), image.height(), 'white', function(err, canvas){ + if (err) { + debug('Could not create a white canvas'); + debug(err); + + deferred.reject(err); + } else { + // Paste original image on top of the canvas + canvas.paste(0, 0, image, function(err, image){ + if (err) { + debug('Could not paste image on the white canvas'); + debug(err); + + deferred.reject(err); + } else { + // Now image has a white background... + debug('White background correctly added'); + deferred.resolve(image); + } + }); + } + }); + + return deferred.promise; + }; + this.toBuffer = function(image) { var deferred = Q.defer();