Affine 2D-Transformations

The programme „Affine 2D-Transformations“ for Android offers the graphical representation of the affine transformations with points, vectors and polygons.

The following transformations (maps) are available:

1) Translation

2) Rotation

3) Reflection with respect to a line

4) Reflection with respect to a point

5) Scaling

6) Shear

7) General affine transformation

At first you create a point or a polygon using the main menu. Then you select a transformation from the list in the main menu, which leads you to an input dialog, where you specify the necessary data. In the case of point related transformations, the point will be created in the scene. The same holds for line related transformations, where the straight line will be created in the scene.

To map a polygon you tap on the surrounding line segments, which brings up a local menu. In this menu you select „Map by“. This shows a submenu with all transformations previously defined. After the selection the programme calculates the image and adds the corresponding polygon to the graphic.

Every inverse image can be moved in the coordinate system and all images will be adapted to the new situation.

You can show the location of the vertices in the text area by using the local object‘s menu.

There are 4 lines available, where you can place describing text. This may be helpful, if you intend to export the graphic as png-file on a SD-card using the corresponding entry in the main menu.

The whole graphic can also be saved in the programme‘s local memory in order to load it later.