How to make new tools

The best is to derive from existing tools, and redefine only what you don't like. The tools often function within a group of tools. They share a common way of using mouse buttons, and it is oke to push a tool unto the stack, and returning to the parent tool after stopping itself. Like tools based on a2dStTool use all as controller a2dStToolContr.

Changing State

A tool is used to manipulate what is in a drawing. User input combined with selected objects and mouse hit objects, brings a tool from one state into another. Down here some examples of what can bring a tool into a different state.

mouse event

key state

object hit

object selected

action

LeftDown

true

1

Select object hit

RightDown

true

1

depends on drag or not

LeftDown

Ctrl Down

true

1

deselect all & add hit object

LeftDown + drag

Ctrl Down

true

0

deselect all & add selected objects

LeftDown + drag

Shift Down

true

0

add selected objects in rect

LeftDown + drag

Alt Down

true

n >= 1

move selected objects

RightDown + drag

Ctrl Down

true

1

drag canvas area

LeftDown + LeftUp at xy

Alt Down

true

1

select

RightDown + RightUp at xy

Alt Down

true

0

popup menu

LeftUp

true

1

depending on keys, treat dragged rect

non

Space bar

false

0

zoom out

Tool push and pop

A tool controller, is designed to be able to push and pop tools from a tool stack. This makes it possible to draw a polygon, and while doing push a zooming tool onto the stack, continue drawing, and zoom out again. And that way it easy to draw a polygon very accurate even it is all over the drawing.

Zoom Tool

Diagram1.png

wxArt2D: ToolDevelopment (last edited 2008-08-16 18:20:10 by KlaasHolwerda)