Improved performance benchmarks and usage docs

README.md

@@ -11,7 +11,9 @@ The typical use case for this high performance Node.js module is to convert a la
 
 It is somewhat opinionated in that it only deals with JPEG images, always obeys the requested dimensions by either cropping or embedding and insists on a mild sharpen of the resulting image.
 
-Under the hood you'll find the blazingly fast [libvips](https://github.com/jcupitt/libvips) image processing library, originally created in 1989 at Birkbeck College and currently maintained by the University of Southampton. Speed is typically 25-30% faster than the imagemagick equivalent.
+Under the hood you'll find the blazingly fast [libvips](https://github.com/jcupitt/libvips) image processing library, originally created in 1989 at Birkbeck College and currently maintained by the University of Southampton.
+
+Speed is typically 4x faster than the imagemagick equivalent.
 
 ## Prerequisites
 
@@ -26,7 +28,7 @@ Ubuntu 12.04 LTS:
 
 	sudo ln -s /usr/lib/pkgconfig/vips-7.26.pc /usr/lib/pkgconfig/vips.pc
 
-Ubuntu 13.04:
+Ubuntu 13.04 (64-bit):
 
 	sudo ln -s /usr/lib/x86_64-linux-gnu/pkgconfig/vips-7.28.pc /usr/lib/pkgconfig/vips.pc
 
@@ -36,28 +38,59 @@ Ubuntu 13.04:
 
 ## Usage
 
-```javascript
   var sharp = require("sharp");
+
+### crop(inputPath, outputPath, width, height, callback)
+
+Scale and crop JPEG `inputPath` to `width` x `height` and write JPEG to `outputPath` calling `callback` when complete.
+
+Example:
+
+```javascript
 sharp.crop("input.jpg", "output.jpg", 300, 200, function(err) {
   if (err) {
     throw err;
   }
-  // output.jpg is cropped input.jpg
+  // output.jpg is a 300 pixels wide and 200 pixels high image
+  // containing a scaled and cropped version of input.jpg
 });
+```
+
+### embedWhite(inputPath, outputPath, width, height, callback)
+
+Scale and embed JPEG `inputPath` to `width` x `height` using a white canvas and write JPEG to `outputPath` calling `callback` when complete.
+
+```javascript
 sharp.embedWhite("input.jpg", "output.jpg", 200, 300, function(err) {
   if (err) {
     throw err;
   }
-  // output.jpg contains input.jpg embedded with a white border
+  // output.jpg is a 300 pixels wide and 200 pixels high image
+  // containing a scaled version of input.jpg embedded on a white canvas
 });
+```
+
+### embedBlack(inputPath, outputPath, width, height, callback)
+
+Scale and embed JPEG `inputPath` to `width` x `height` using a black canvas and write JPEG to `outputPath` calling `callback` when complete.
+
+```javascript
 sharp.embedBlack("input.jpg", "output.jpg", 200, 300, function(err) {
   if (err) {
     throw err;
   }
-  // output.jpg contains input.jpg embedded with a black border
+  // output.jpg is a 300 pixels wide and 200 pixels high image
+  // containing a scaled version of input.jpg embedded on a black canvas
 });
 ```
 
 ## Testing [![Build Status](https://travis-ci.org/lovell/sharp.png?branch=master)](https://travis-ci.org/lovell/sharp)
 
 	npm test
+
+## Performance
+
+Using an AMD Athlon quad core CPU with 512KB L2 cache clocked at 3.3GHz with 8GB RAM:
+
+* imagemagick x 5.55 ops/sec ±0.68% (31 runs sampled)
+* sharp x 24.49 ops/sec ±6.85% (64 runs sampled)

package.json

@@ -1,14 +1,15 @@
 {
   "name": "sharp",
-  "version": "0.0.1",
-  "main": "./build/Release/sharp",
+  "version": "0.0.2",
+  "main": "index.js",
   "description": "High performance Node.js module to resize JPEG images using the libvips image processing library",
   "repository": {
     "type": "git",
     "url": "git://github.com/lovell/sharp"
   },
   "devDependencies": {
-    "imagemagick": "*"
+    "imagemagick": "*",
+    "benchmark": "*"
   },
   "scripts": {
     "test": "node tests/perf.js"

tests/perf.js

@@ -1,16 +1,17 @@
 var sharp = require("../index");
 var imagemagick = require("imagemagick");
 var assert = require("assert");
+var Benchmark = require("benchmark");
 
-// http://www.flickr.com/photos/grizdave/2569067123/
-var input = __dirname + "/2569067123_aca715a2ee_o.jpg";
+var input = __dirname + "/2569067123_aca715a2ee_o.jpg"; // http://www.flickr.com/photos/grizdave/2569067123/
 var output = __dirname + "/output.jpg";
-
 var width = 640;
 var height = 480;
 
-// imagemagick
-var time = process.hrtime();
+var suite = new Benchmark.Suite;
+suite.add("imagemagick", {
+  "defer": true,
+  "fn": function(deferred) {
     imagemagick.resize({
       srcPath: input,
       dstPath: output,
@@ -20,23 +21,24 @@ imagemagick.resize({
     }, function(err) {
       if (err) {
         throw err;
+      } else {
+        deferred.resolve();
       }
-  var diff = process.hrtime(time);
-  imagemagickTime = diff[0] * 1e9 + diff[1];
-  console.log("imagemagick took %d nanoseconds", imagemagickTime);
-
-  // sharp
-  time = process.hrtime();
+    });
+  }
+}).add("sharp", {
+  "defer": true,
+  "fn": function(deferred) {
     sharp.crop(input, output, width, height, function(err) {
       if (err) {
         throw err;
+      } else {
+        deferred.resolve();
       }
-    diff = process.hrtime(time);
-	var sharpTime = diff[0] * 1e9 + diff[1];
-    console.log("sharp took %d nanoseconds", sharpTime);
-
-	// diff
-	assert(sharpTime < imagemagickTime, "sharp was blunt");
-	console.log("sharp was %d%% faster", (imagemagickTime - sharpTime) / imagemagickTime * 100);
-  });
     });
+  }
+}).on("cycle", function(event) {
+  console.log(String(event.target));
+}).on("complete", function() {
+  assert(this.filter("fastest").pluck("name") == "sharp");
+}).run();