This panel provides the ability to annotate Regions of Interest (ROIs) and save them as masks.

While drawing, you can switch across the image volumes loaded in CaPTk, by pressing the numbers 1-9 on your keyboard.

Toggle between non-zero (taken from the opacity box) and zero opacity of the entire annotated mask by using the keyboard key "m".

Visualize a single label using "Control + <label number>" and add labels to the visualization using "Alt + <label number>". To reset, press "Control/Alt + 0".

There are the following controls underneath the Drawing tab:

Button/Box	Description
View Mode	Switch from drawing mode (which is enabled when either Near or Far ROI drawing is selected) to normal viewing mode.
Line	Draw a line of selected label color and size.
Rectangle	Draw a rectangle of selected label color and size.
Circle	Draw a circle of selected label color and size.
Free-Hand	Draw selected label using brush of specified size using mouse left button drag.
Fill	Fill a closed boundary with selected label - uses ITK's connected component filter.
Eraser	Erases all labels using brush of specified size.
Label Selector	Label selector between 1-9.
Marker Size	A square marker of specific voxel size.
Marker Opacity	Sets the opacity of the marker between 0.0 (transparent) and 1.0 (opaque).
Clear Selected Label	Remove selected label completely from the mask.
Clear All Labels	Remove all labels completely from the mask.
Undo	Undo last drawing action.
Change Values	By providing the same number of old and new values in the format AxBxC, the values of the annotated region can be quickly changed.

---