1. Find all objects and the corrensponding function of each object.
2. Extract the classes from the above objects.
2.1 List multiple objects of a same class,and find out their common characteristics and behaviors.
2.1.1 Canvas
2.1.2 Geometry
2.1.3 Style
Painter
3. not yet
4. Situation test
situation 1: Draw a line

1. Find all objects and the corrensponding function of each object.

1. Canvas
2. Geometry
3. Style
4. Painter

2. Extract the classes from the above objects.

2.1 List multiple objects of a same class,and find out their common characteristics and behaviors.

2.1.1 Canvas

1. Multiple objects of Canvas:

• screen (include pdf) – using graphics card.
• wall
• paper

  we just need to care ‘screen’.

1. common characteristics and behaviors

• width
• height
• backgroundColor

2.1.2 Geometry

1. Multiple objects of Geometry

• triangle
• rectangle
• circle
• point

1. Common characteristics and behaviors

• perimeter
• area

2.1.3 Style

1. Multiple objects of Style

• lineStyle – Pen
• regionStyle – Brush

1. Common characteristics and behaviors

• color
• width

Painter

1. Multiple objects of Style

• projector
• printer
• painter

1. Common characteristics and behaviors

• DrawPolygon
• DrawLine
• DrawPoint
• FillPolygon

You can view the results of this phase now.

3. not yet

4. Situation test

situation 1: Draw a line

1. new Canvas(width,height,bgcolor);
2. new LineStyle(lineType,width);
3. List points = new List(new Point(),new Point());
4. Geometry geo = new Polygon(points);
5. Painter.Draw(canvas,style,geo);

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