Split CLI from main code (#3)

* Flesh out the package.json a little * Split out CLI from main code
scotchfield · Feb 14, 2018 · 6ca55e1 · 6ca55e1
1 parent 627dac4
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diff --git a/README.md b/README.md
@@ -9,16 +9,26 @@ However, it might be jealous of all those parrots and their parties. Let's help
 
 ![Party Smiling Emoji](./party-smile.gif "Party Smiling Emoji")
 
-## Usage
-`node index.js smile.png party.gif`
-
 Note: If you'd like to create emojis for Slack, make sure your input image is 128x128 (or less).
 
-### Radius
+## Usage
+### CLI
+`bin/ppp smile.png party.gif`
+
+#### Radius
 If you want to tune the radius of the animating circle, you can use the `--radius=<n>` option. The default for this is `10`.
 
-For example, `node index.js --radius=0 smile.png party.gif` will create a party version of `smile.png` where the image has an ounce or two less party.
+For example, `bin/ppp --radius=0 smile.png party.gif` will create a party version of `smile.png` where the image has an ounce or two less party.
 
 ![Still Party Smile Emoji](./still-party-smile.gif "Still Party Smile Emoji")
 
+### Node
+```
+const fs = require("fs");
+const PartyPartyParty = require("party-party-party");
+
+const outputFileStream = fs.createWriteStream("my-output-file.gif");
+PartyPartyParty("my-input.png", outputFileStream, 10);
+```
+
 ![Party Heart Emoji](./heart.gif "Party Heart Emoji")
diff --git a/bin/ppp b/bin/ppp
@@ -0,0 +1,3 @@
+#!/usr/bin/env node
+
+require('../lib/cli').run(__filename);
diff --git a/index.js b/index.js
@@ -1,33 +1,6 @@
-const fs = require("fs");
-const minimist = require("minimist");
 const getPixels = require("get-pixels");
 const gifEncoder = require("gif-encoder");
-
-// Process the arguments we're launched with and get rid of anything we won't be using.
-args = minimist(process.argv, {
-    default: {
-        "radius": 10, // 0 = regular stationary party
-    },
-    unknown: arg => {
-        // Filter out node and our index.js.
-        // This ensures that the args._ array will just be the files we process
-        if (arg === process.execPath) return false;
-        if (arg === __filename) return false;
-        return true;
-    }
-});
-
-//TODO(somewhatabstract): Make this code an importable module and then provide a simple wrapper for direct CLI usage
-//TODO(somewhatabstract): Consider adding some scaling or a --fitslack option?
-//TODO(somewhatabstract): Add ability to specify lots of different files at once.
-//TODO(somewhatabstract): Add error checks and useful help text.
-if (args._.length !== 2) {
-    console.log("Usage: " + __filename + " input.png output.gif");
-    process.exit(-1);
-}
-
-const inputFilename = args._[0];
-const outputFilename = args._[1];
+const toGreyscale = require("./lib/grayscale");
 
 // The party palette. Party on, Sirocco!
 const colours = [
@@ -43,100 +16,88 @@ const colours = [
     [255, 105, 104]
 ];
 
-//TODO(somewhatabstract): Add other variations to radius, like tilt (for bobbling side to side)
-const partyOffset = [];
-const partyRadius = parseInt(args.radius);
-colours.forEach((c, colourIndex) => {
-    const x =
-        partyRadius * Math.sin(2 * Math.PI * (-colourIndex / colours.length));
-    const y =
-        partyRadius * Math.cos(2 * Math.PI * (-colourIndex / colours.length));
-    partyOffset.push([Math.round(x), Math.round(y)]);
-});
-
-function toGreyscale(pixels) {
-    const greyscale = [];
-
-    for (var i = 0; i < pixels.data.length / 4; i += 1) {
-        const idx = i * 4;
-        if (pixels.data[idx + 3] < 64) {
-            greyscale.push(-1);
-        } else {
-            const avg =
-                (pixels.data[idx] +
-                    pixels.data[idx + 1] +
-                    pixels.data[idx + 2]) /
-                3;
-            greyscale.push(avg);
-        }
-    }
-    return greyscale;
-}
-
-function imageData(err, pixels) {
-    if (err) {
-        console.log("Invalid image path..");
-        console.log(err);
-        return;
-    }
-
-    const { shape } = pixels;
-    const greyscale = toGreyscale(pixels);
-
-    const gif = new gifEncoder(shape[0], shape[1]);
-    const outputFile = fs.createWriteStream(outputFilename);
-    gif.pipe(outputFile);
-
-    gif.setDelay(50);
-    gif.setRepeat(0);
-    gif.setTransparent("0x00FF00");
-    gif.writeHeader();
-    gif.on("readable", function() {
-        gif.read();
+/**
+ * Writes a party version of the given input image to the specified output stream.
+ * @param {string} inputFilename A GIF image file to be partified
+ * @param {stream.Writable} outputStream The stream where the partified image is to be written
+ * @param {number} partyRadius The radius used to animate movement in the output image
+ */
+function createPartyImage(inputFilename, outputStream, partyRadius) {
+    //TODO(somewhatabstract): Add other variations to radius, like tilt (for bobbling side to side)
+    const partyOffset = [];
+    colours.forEach((c, colourIndex) => {
+        const x =
+            partyRadius * Math.sin(2 * Math.PI * (-colourIndex / colours.length));
+        const y =
+            partyRadius * Math.cos(2 * Math.PI * (-colourIndex / colours.length));
+        partyOffset.push([Math.round(x), Math.round(y)]);
     });
 
-    function getPixelValue(arr, shape, x, y) {
-        if (x < 0 || x >= shape[0] || y < 0 || y >= shape[1]) {
-            return -1;
+    function processImage(err, pixels) {
+        if (err) {
+            console.log("Invalid image path..");
+            console.log(err);
+            return;
         }
 
-        return (result = arr[x + y * shape[0]]);
-    }
+        const { shape } = pixels;
+        const greyscale = toGreyscale(pixels);
 
-    colours.forEach(function(c, colourIndex) {
-        const offset = partyOffset[colourIndex];
-        const p = [];
+        const gif = new gifEncoder(shape[0], shape[1]);
+        gif.pipe(outputStream);
 
-        for (var y = 0; y < shape[1]; y += 1) {
-            for (var x = 0; x < shape[0]; x += 1) {
-                let g = getPixelValue(
-                    greyscale,
-                    shape,
-                    x + offset[0],
-                    y + offset[1]
-                );
+        gif.setDelay(50);
+        gif.setRepeat(0);
+        gif.setTransparent("0x00FF00");
+        gif.writeHeader();
+        gif.on("readable", function() {
+            gif.read();
+        });
 
-                if (g === -1) {
-                    p.push(0);
-                    p.push(255);
-                    p.push(0);
-                    p.push(0);
-                } else {
-                    g = g < 32 ? 32 : g;
+        function getPixelValue(arr, shape, x, y) {
+            if (x < 0 || x >= shape[0] || y < 0 || y >= shape[1]) {
+                return -1;
+            }
+            return arr[x + y * shape[0]];
+        }
 
-                    p.push(g * c[0] / 255);
-                    p.push(g * c[1] / 255);
-                    p.push(g * c[2] / 255);
-                    p.push(255);
+        colours.forEach(function(c, colourIndex) {
+            const offset = partyOffset[colourIndex];
+            const p = [];
+
+            for (let y = 0; y < shape[1]; y += 1) {
+                for (let x = 0; x < shape[0]; x += 1) {
+                    let g = getPixelValue(
+                        greyscale,
+                        shape,
+                        x + offset[0],
+                        y + offset[1]
+                    );
+
+                    if (g === -1) {
+                        p.push(0);
+                        p.push(255);
+                        p.push(0);
+                        p.push(0);
+                    } else {
+                        g = g < 32 ? 32 : g;
+
+                        p.push(g * c[0] / 255);
+                        p.push(g * c[1] / 255);
+                        p.push(g * c[2] / 255);
+                        p.push(255);
+                    }
                 }
             }
-        }
 
-        gif.addFrame(p);
-        gif.flushData();
-    });
+            gif.addFrame(p);
+            gif.flushData();
+        });
+
+        gif.finish();
+    }
 
-    gif.finish();
+    getPixels(inputFilename, processImage);
 }
 
-const input = getPixels(inputFilename, imageData);
+module.exports = createPartyImage;
diff --git a/lib/cli.js b/lib/cli.js
@@ -0,0 +1,37 @@
+const fs = require("fs");
+const minimist = require("minimist");
+const PartyPartyParty = require("../index");
+
+function run(launchFilePath) {
+    // Process the arguments we're launched with and get rid of anything we won't be using.
+    args = minimist(process.argv, {
+        default: {
+            "radius": 10, // 0 = regular stationary party
+        },
+        unknown: arg => {
+            // Filter out node and our index.js.
+            // This ensures that the args._ array will just be the files we process
+            if (arg === process.execPath) return false;
+            if (arg === (launchFilePath || __filename)) return false;
+            return true;
+        }
+    });
+
+    //TODO(somewhatabstract): Consider adding some scaling or a --fitslack option?
+    //TODO(somewhatabstract): Add ability to specify lots of different files at once.
+    //TODO(somewhatabstract): Add error checks and useful help text.
+    if (args._.length !== 2) {
+        console.log("Usage: " + (launchFilePath || __filename) + " input.png output.gif");
+        process.exit(-1);
+    }
+
+    const inputFilename = args._[0];
+    const outputFilename = args._[1];
+
+    const outputFileStream = fs.createWriteStream(outputFilename);
+    PartyPartyParty(inputFilename, outputFileStream, parseInt(args.radius));
+}
+
+module.exports = {
+    run
+}
diff --git a/lib/grayscale.js b/lib/grayscale.js
@@ -0,0 +1,20 @@
+function toGreyscale(pixels) {
+    const greyscale = [];
+
+    for (var i = 0; i < pixels.data.length / 4; i += 1) {
+        const idx = i * 4;
+        if (pixels.data[idx + 3] < 64) {
+            greyscale.push(-1);
+        } else {
+            const avg =
+                (pixels.data[idx] +
+                    pixels.data[idx + 1] +
+                    pixels.data[idx + 2]) /
+                3;
+            greyscale.push(avg);
+        }
+    }
+    return greyscale;
+}
+
+module.exports = toGreyscale;
diff --git a/package.json b/package.json
@@ -2,12 +2,32 @@
   "name": "party-party-party",
   "version": "1.0.0",
   "description": "Turn a source image into an animated party emoji",
-  "main": "index.js",
-  "scripts": {
-    "test": "test"
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/scotchfield/party-party-party.git"
+  },
+  "bugs": {
+    "url": "https://github.com/scotchfield/party-party-party/issues"
   },
   "author": "scotchfield",
   "license": "MIT",
+  "contributors": [
+    "Scott Grant <swrittenb@gmail.com>",
+    "Jeff Yates <jeff@somewhatabstract.com>"
+  ],
+  "keywords": [
+    "party",
+    "emoji",
+    "emoticon",
+    "images",
+    "animation"
+  ],
+  "main": "index.js",
+  "bin": {
+    "ppp": "./bin/ppp"
+  },
+  "scripts": {
+  },
   "dependencies": {
     "get-pixels": "^3.3.0",
     "gif-encoder": "^0.6.1",