These videos demonstrate most of the DrGeo features: basic manipulations, simple construction, use of the advanced integrated programming tools.
Note: In some video, halo are used, to show a halo surrounding graphic elements of the user interface, depending on your platform you need to press the right mouse button, or combination of key like Alt+clic. See Squeak, un Smalltalk libre multimédia.
Starting with Dr. Geo II
In the following video, I show basic operations with DrGeo.
- Free point, point on curve
- Intersection point
- Middle of two points
- Middle of a segment
- Point define by coordinates
- Circle defined by two points
- Circle defined by center and radius
- Parallel line
- Perpendicular line
- Central symmetry
- Axial symmetry
- Rotation with geometric angle in degree
- Rotation with oriented angle in degree
- Distance : distance between two points, a point and a line, segment length, vector norm, arc length, circle perimeter, line slope
- Geometric angle
- Oriented angle
- Free value you can change at will
- Undo/redo commands
- Style on object: change aspect, edit object name, edit value. Demonstrated for the various item categories
Smalltalk programmed figure
It is a progressive collection of screencasts. You should view all once in the listed order bellow.
- Demonstration of Smalltalk programmed figure
- Write a programmed triangle
- Write a programmed triangle with randomized summit
- Write programmed recursive triangles
- Point defined with a block of code to update its coordinates, here compute the closest point on a polygon to another point.
- Write and use a script without any argument
- Write and use a script with one argument
- Write and use a script with two arguments
- Write and use a script returning a Point instance
- A funny example using Smalltalk script and the homothety transformation
Several misc examples of use can be view at ftp://ftp.ofset.org/squeak/drgeo. Beware these screencasts are based on earlier version of DrGeoII and the video quality may not be as good as the previous ones.
If you want to collaborate on that page, just write to firstname.lastname@example.org, I create an account for you.
The video are encoded with the maximum quality, at a screen resolution not higher to the PAL DVD format (720x576). However it can be at a lower screen resolution.
To produce the screencast, I use recordmydesktop with the maximum video quality at 8 fps and no sound:
recordmydesktop --no-sound --windowid 0x3800002 --fps 8 -o 003-advanced-record-in-menu
With some of these screencasts we produced a video clip presenting Dr. Geo II.