Tool Bar

The Alchemy tool bar is used to control how shapes look when they are created. For example, you can change the style of the shape, the transparency, the line width and so on. When it is attached to the main window, the tool bar can be toggled on and off by pressing the space bar.

Let's go through the controls on the tool bar one by one.

Style

Toggle between drawing with a line or solid fill.
Keyboard Shortcut: S

Over/Under

Toggle between drawing over other shapes on the canvas or under them.
Keyboard Shortcut: D

Line Weight

Increase/Decrease the line weight.
Keyboard Shortcut: [ ]

Colour

The colour button is used to control colours. Click on the arrows in the top right to change between foreground and background colour or use the keyboard shortcut X.

Click on either the foreground or background colour swatch to bring up the colour picker and select a colour:

Click on an area inside the colour picker to choose a colour. The area at the top of the colour has black,  grey (50%), and white.

In addition you can click on the eye dropper icon to select a colour from the desktop. Use the button with three dots (...) to open a more precise colour selection window as shown below.

Transparency

Adjust the transparency of the active colour. When the foreground colour is active, the transparency is applied to the foreground, and when the background colour is active, the transparency is applied to the background.

Create & Affect

These two buttons control the currently selected Alchemy 'module', and also the controls that appear in the bottom part of the tool bar.

Clear

Clear the entire Alchemy canvas.
Keyboard Shortcut OS X: Command + Backspace
Keyboard Shortcut Windows: Ctrl + Backspace