Transformations and Dragging

Mathematically, moving an object in your sketch transforms that object, and Sketchpad’s dragging behavior is based on three geometric transformations: translation, rotation, and dilation. To allow you to use each of these transformations, Sketchpad actually has three Arrow tools: the Translate Arrow tool, the Rotate Arrow tool, and the Dilate Arrow tool. These three tools behave identically when used to select objects; it’s only their dragging behavior that differs.

The Arrow Tools

With the Arrow tool active, you can also switch transformations by holding down the Shift key and pressing the left or right arrow key on your keyboard.

When Sketchpad starts, the active Selection Arrow tool is the Translate Arrow tool. Choose a different Arrow tool, and a different transformation, by pressing and holding on the Arrow tool icon in the Toolbox. When you press and hold, a menu pops out and you can choose one of the three arrow tools.

· Use the Translate Arrow tool to translate objects by any distance in any direction while maintaining their size, angle, and shape. (This is the default tool.)

· Use the Rotate Arrow tool to rotate objects about a center point, changing their angle while maintaining their size and distance from the center.

· Use the Dilate Arrow tool to dilate objects about a center point, only moving them closer to or farther from the center and making them correspondingly smaller or larger while maintaining their angle and shape.