Update README.md

lab#3/README.md

@@ -39,6 +39,8 @@ Also, I found myself consulting the documentation on the [MSDN](http://msdn.micr
 
 First of all, I made wireframe models of the application's window and dialogbox, with general layout and functionality, using the [MockFlow](http://mockflow.com/) tool. 
 
+NOTE: In the mockup it was specified the hotkeys for zooming, but this feature was not implemented, and I do not claim points for this.
+
 ![Window Mockup](https://raw.github.com/TUM-FAF/WP-FAF-111-Roibu-Roman/master/lab%233/screens/mockup.png)
 
 Result Application
@@ -47,6 +49,23 @@ This is a screen shot of the application's window in my native Mac OS X envirome
 
 ![Window screenshot](https://raw.github.com/TUM-FAF/WP-FAF-111-Roibu-Roman/master/lab%233/screens/screenshot.png)
 
+Using the app
+-------------
+The user specifies the tool he wants to use, selecting it from the `Tools` group. How to draw: 
+
+- `Pen` tool will draw a continuous line with the stroke weight equal to 1, and the selectable stroke color, by selecting this tool, and **left-clicking** on the drawing area. 
+- `Line` tool will draw a straight line between two points, with the selectable stroke weight and color, by **left-clicking** on the drawing area (start point), and **draging & releasing** the mouse botton (end point). 
+- `Polygon` tool will draw a rectangle, with selectable stroke weight and color, filled with a selectable color, or not, by **left-clicking** on the drawing area (top left corner), and **draging & releasing** the mouse botton (bottom right corner). 
+- `Ellipse` tool will draw an ellipse, with selectable stroke weight and color, filled with a selectable color, or not, by **left-clicking** on the drawing area (top left corner), and **draging & releasing** the mouse botton (bottom right corner). 
+- `Bezier` tool will draw a Bezier curve, with selectable stroke weight and color. It is done in the following manner:
+   - **Left-clicking**  - start point.
+   - **Drag & Releas**  - 1st control point.
+   - **Right-clicking** - 2st control point.
+   - **Drag & Releas**  - end point.
+- `Eraser` tool will erase the drawing area, with a selectable weight, leaving the drawing area clean. 
+
+By **Ctrl + Shift + Left Click**ing, the last **polygon** or **ellipse** will be erased from the drawing area.
+
 Conclusions
 -----------
 This laboratory work was an interesting one. I had the opportunity to buid an applications will a lot of basic drawing features, somewhat resembling the MS Paint application.