CPSC 170 Post Lab 2
Drawing
Due Before Lab on Tuesday, February 1^st

For this assignment you will create a simple vector graphics drawing program like Adobe Illustrator or the open source Inkscape. A vector graphics program is different from a raster graphics program in that all objects that are drawn to a scene are stored parametrically instead of in a raster image, like in Adobe photoshop or Microsoft Paint. Storing objects this way allows the user of the program to zoom without losing detail and to more easily edit objects that have already been added. However, it also requires that the scene be re-rendered to a raster image for display every time a change is made.

Details

Begin by creating classes to store the objects that are drawn by the user. Create an abstract class that will be extended for each of the different shapes that can be drawn (an oval and a line are sufficient for this assignment, but you can add others if you wish). The abstract class should have instance variables that define the bounding region for an object to be drawn. Four floating point numbers representing the two points that define opposite corners of the object's bounding rectangle are sufficient. Also add a constructor that specifies the instance data and a paint method that takes a graphics object as a parameter, but does nothing. Next, define classes for the oval and the line that do define the contents of the paint method.

The last class you will need is a class that contains the main method and displays the window for the program. The window's main panel should contain two sub-panels. The Left sub-panel should contain radio buttons, aligned vertically, that represent the current tool that is selected by the user (oval, pencil, or zoom). You can use the images in the tar file DrawIcons.tar.gz for the radio buttons. The right sub-panel should be the panel that extends JPanel so that it can override paintComponent and be where the user can draw. This class should have an initially empty list of drawable objects as an instance variable. Every time the user draws something to the window the list should be updated with the new object. The paintComponent method should simply iterate over the entire list and draw every object.

Finally you will need to implement each of the different tools that the user selects.

• The oval tool should allow the user to click and drag an oval. When the oval tool is selected and a mouse pressed event occurs, an oval of size 0 should be added to the list of objects. Each time a drag event occurs the oval that was added should be updated to reflect its current size and location.
• The pencil tool should allow the user to click and drag a series of connected lines. When the pencil tool is selected and a mouse pressed event occurs, a line of length 0 should be added to the list of objects. Each time a drag event occurs the line that was added last should be updated to have its endpoint at the drag location and a new line of length 0 should be added.
• The zoom tool should allow the user to click to zoom the view in. The panel should store the bounding rectangle of the area that is currently being displayed (and the object paint methods should draw based on this bounding rectangle). When the zoom tool is selected and a mouse clicked event occurs, the bounding rectangle should be updated to be half the size and centerd on the location of the click.

Submission: Tar and submit your code on the course Inquire site.