Fix Gray samsonmking#1 not displaying correct

* Port color mapping example from waveshare python examples
* Add simple 4 gray example
* Restore prettier in package.json

README.md

@@ -52,12 +52,12 @@ init();
 **Additional Configuration Options**
 
 ```js
-const {devices, init} = require('epaperjs');
+const { devices, init } = require('epaperjs');
 init(devices.waveshare4in2, {
-    webPort: 3000,                              // WebServer Port
-    websocketPort: 8080,                        // WebSocket API Port
-    staticDirectory: 'static',                  // Directory to serve frontend from
-    url: `http://localhost:3000/index.html`     // Initial URL to load
+    webPort: 3000, // WebServer Port
+    websocketPort: 8080, // WebSocket API Port
+    staticDirectory: 'static', // Directory to serve frontend from
+    url: `http://localhost:3000/index.html`, // Initial URL to load
 });
 ```
 
@@ -132,15 +132,16 @@ sudo apt-get install -y build-essential chromium-browser
 
 **Node.js**\
 Install ePaper.js
-``` bash
+
+```bash
 npm install -S epaperjs
 ```
 
 ## Supported Hardware
 
 | Device                                                             | Supprted Display Modes |
 | ------------------------------------------------------------------ | ---------------------- |
-| [Waveshare 4.2"](https://www.waveshare.com/4.2inch-e-Paper.htm)    | Black / White          |
+| [Waveshare 4.2"](https://www.waveshare.com/4.2inch-e-Paper.htm)    | Black / White, 4 Gray  |
 | [Waveshare 7.5" v2](https://www.waveshare.com/7.5inch-e-Paper.htm) | Black / White          |
 
 ### Adding Support For Additional Displays
@@ -150,9 +151,10 @@ It's easy to extend ePaper.js to support additional Waveshare devices. Displays
 If you would like to request support for another display, please open an issue with the title 'Add support for <Device Make \ Model>'. If you're a developer and have extended support yourself, put up a pull request!
 
 ## Feature Backlog
-- [x] Add support for portrait or landscape display (rotate 90 deg)
-- [ ] Add support for remaining Waveshare SPI ePaper displays
-- [x] Implement 4 Color Grayscale
-- [ ] Implement Red / White / Black Color Mode
-- [ ] Implement Yellow / White / Black Color Mode
-- [ ] Implement Partial Refresh
+
+-   [x] Add support for portrait or landscape display (rotate 90 deg)
+-   [ ] Add support for remaining Waveshare SPI ePaper displays
+-   [x] Implement 4 Color Grayscale
+-   [ ] Implement Red / White / Black Color Mode
+-   [ ] Implement Yellow / White / Black Color Mode
+-   [ ] Implement Partial Refresh

devices.js

@@ -12,7 +12,7 @@ const waveshare4in2Horizontal = {
     },
     init: function () {
         this.driver.init();
-    }
+    },
 };
 
 const waveshare4in2Vertical = {
@@ -21,37 +21,37 @@ const waveshare4in2Vertical = {
     driver: waveshare4In2Driver,
     displayPNG: async function (imgContents) {
         const buffer = await image.convertPNGto1BitBWRotated(imgContents);
-        this.driver.display(buffer)
+        this.driver.display(buffer);
     },
     init: function () {
         this.driver.init();
-    }
+    },
 };
 
 const waveshare4in2HorizontalGray = {
     height: 300,
     width: 400,
     driver: waveshare4In2Driver,
     displayPNG: async function (imgContents) {
-        const buffer = await image.convertPNGto1Bit4Grey(imgContents);
-        this.driver.display_4GrayDisplay(buffer)
+        const buffer = await image.convertPNGto4Grey(imgContents);
+        this.driver.display_4GrayDisplay(buffer);
     },
     init: function () {
         this.driver.init_4Gray();
-    }
+    },
 };
 
 const waveshare4in2VerticalGray = {
     height: 400,
     width: 300,
     driver: waveshare4In2Driver,
     displayPNG: async function (imgContents, color_depth) {
-        const buffer = await image.convertPNGto1Bit4GreyRotated(imgContents);
-        this.driver.display_4GrayDisplay(buffer)
+        const buffer = await image.convertPNGto4GreyRotated(imgContents);
+        this.driver.display_4GrayDisplay(buffer);
     },
     init: function () {
         this.driver.init_4Gray();
-    }
+    },
 };
 
 const waveshare7in5v2Horizontal = {
@@ -64,7 +64,7 @@ const waveshare7in5v2Horizontal = {
     },
     init: function () {
         this.driver.init();
-    }
+    },
 };
 
 const waveshare7in2v2Vertical = {
@@ -77,7 +77,7 @@ const waveshare7in2v2Vertical = {
     },
     init: function () {
         this.driver.init();
-    }
+    },
 };
 
 const devices = {
@@ -90,7 +90,7 @@ const devices = {
     // default waveshare7in5v2 kept for backwards compatibility with releaes 1.1.0
     waveshare7in5v2: waveshare7in5v2Horizontal,
     waveshare7in5v2Horizontal,
-    waveshare7in2v2Vertical
-}
+    waveshare7in2v2Vertical,
+};
 
 module.exports = devices;

examples/4gray/4gray.js

@@ -0,0 +1,3 @@
+const { init, devices } = require('epaperjs');
+
+init(devices.waveshare4in2HorizontalGray);

examples/4gray/README.md

@@ -0,0 +1,15 @@
+# Example 4 Color Gray for ePaper.js
+
+## Colors
+
+| Color          | HEX Code  |
+| -------------- | --------- |
+| Gray 0 (White) | `#FFFFFF` |
+| Gray 1         | `#C0C0C0` |
+| Gray 2         | `#808080` |
+| Gray 3 (Black) | `#000000` |
+
+## Setup
+
+1. `npm install`
+2. `npm run start`