report.md

JDrawpad

JDrawpad is an application for designing vector graphics.

It lets the user interactively draw simple vector shapes on a rectangular canvas using a pointing device. It provides facilities for saving an artwork and opening an existing artwork, as well for saving an artwork to a universal graphic file format (Scalable Vector Graphic or SVG). It uses the JavaFX GUI framework.

Structure

Classes

The main JavaFX application class:

• Main (extends javafx.application.Application)

Helper classes:

• Classes for helper objects
  • DrawingHelper
  • CanvasHistory
• Classes defining event handlers
  • UIHandlers
  • DrawingHandlers
• Classes defining utility functions
  • FileUtils
  • CsvGenerator
  • CsvParser
  • SvgGenerator

Relationships between the top-level classes

Descriptions of the classes

Class: Main

Every JavaFX program must have a class that extends javafx.application.Application and overrides its start(Stage primaryStage) method. primaryStage represents the primary window in the application. When a JavaFX application starts up, it creates a root Stage (GUI window) object which is passed to the start(Stage primaryStage) method of the root class (that extends Application) in the JavaFX application. In our program, Main serves the purpose of the root class. We are also using it to perform the primary UI-related operations.

Inner class: ToolButton. Represents a tool button. It’s a subclass of JavaFX’s ToggleButton, so that if it’s included in a ToggleGroup, only one of the buttons in that ToggleGroup can be selected at a time at most. The ToggleGroup for our toolbar buttons is the field toolbarGroup.

Class: UIHandlers

This class defines event handlers for some UI elements.

Class: DrawingHandlers

This class defines the event-handler objects that are triggered when user interacts with the canvas using a pointing device while a tool is selected.

Class: DrawingHelper

This class defines functions that perform the actual drawing commands as well as the related (inner) classes.

Class: CsvGenerator

This class defines methods that produce a comma-separated representation from a shape object to be written to the JDP file (a CSV format).

Class: SvgGenerator

This class defines methods that produce SVG code from a shape.

Class: CsvParser

This class defines methods that produce shape objects from a each line from the JDP file (CSV format).

Class: FileUtils

This class defines the utility methods for reading and writing files.

Class: CanvasHistory

The CanvasHistory class represents the timeline of the canvas. JDrawpad uses a CanvasHistory for its undo-redo functionality.

How the classes work together