Update documentation

README.md

@@ -44,13 +44,74 @@ bitmap.drawText(font, "Hello World!", 10, 100);
 let bitmapData = bitmap.data();  // Return a Node.js Buffer
 ```
 
+## Image formats
+
+With release 2.0.0, drawing and pixel storage are separated. This way, 
+different image formats (e.g. RGB with interleaved or planar storage) can be used
+by providing a `Canvas` implementantion to the `Bitmap` constructor.
+
+The following canvas implementations are included in the distribution:
+
+|Class name               |Description                                           |
+|-------------------------|------------------------------------------------------|
+|canvas.Grayscale         |Grayscale pixel values                                |
+|canvas.RGB               |RGB pixel values, interleaved storage (R-G-B-R-G-B)   |
+|canvas.PlanarRGB         |RGB pixel values, planar storage (R-R-G-G-B-B)        |
+|canvas.InterleavedStorage|Interleaved storage of values with multiple components|
+|canvas.PlanarStorage     |Planar storage of values with multiple components     |
+|canvas.Base              |Base class, use this for custom implementations       |
+
+Note that drawing gradients using `drawGradientRect()` only produces sensible results on a grayscale canvas.
+
+### Example: RGB image with 8 bits per pixel per color channel 
+
+```javascript
+const bitmapManipulation = require("bitmap-manipulation");
+
+// Create a canvas that stores interleaved RGB pixels 
+let canvas = new bitmapManipulation.canvas.RGB(400, 300, 1);
+
+// Create a bitmap that uses this canvas for pixel storage
+let bitmap = new bitmapManipulation.Bitmap(canvas);
+
+// Draw a rectangle filled with cyan and a purple border.
+// Note that the RGB canvas requires pixel values to be RGB arrays
+bitmap.drawFilledRect(10, 10, 100, 50, [255, 0, 255], [0, 255, 255]);
+
+// Get bytes of the image
+let imageData = bitmap.data();
+```
+
+### Example: RGBA image with 16 bits per pixel per color channel
+
+```javascript
+const bitmapManipulation = require("bitmap-manipulation");
+
+// Create a canvas that stores interleaved RGBA pixels 
+let canvas = new bitmapManipulation.canvas.Interleaved(400, 300, 4, 2);
+
+// Create a bitmap that uses this canvas for pixel storage
+let bitmap = new bitmapManipulation.Bitmap(canvas);
+
+// Draw a rectangle filled with half-opaque cyan and a solid purple border.
+let halfOpaqueCyan = [0, 65535, 65535, 32767];
+let solidPurple = [65535, 0, 65535, 65535];
+bitmap.drawFilledRect(10, 10, 100, 50, halfOpaqueCyan, solidPurple);
+
+// Get bytes of the image
+let imageData = bitmap.data();
+```
+
+## BMP file support
+
+Loading from and writing to BMP files is supported using the subclass `BMPBitmap`.
+See `examples/Drawing` for details.
+
 ## Documentation
 
-The documentation can be generated from the source code by:
+The documentation can be [generated](http://usejsdoc.org/) from the source code by:
 
-<pre>
-[jsdoc](http://usejsdoc.org/) index.js
-</pre>
+    jsdoc index.js
 
 ## License