3.1 Java1489-plotting 3d surfaces using java  (Page 9/24)

Preview

The purpose of the program that I will present and explain in this module is to display a 3D surface using color (or shades of gray) to represent theelevation of each point on a 3D surface.

Constructor

The constructor for this class receives a 3D surface defined as a rectangular 2D array of values of type double . Each double value represents a sample point on the 3D surface. The surface values may bepositive, negative, or both.

When an object of the class is constructed, it plots the 3D surface using one of six possible formats representing the elevation of each point on the surfacewith a color or a shade of gray.

Parameters

The constructor requires four parameters:

• double[][]dataIn
• int blockSize
• boolean axis
• int display

The purpose of each parameter is as follows:

Datain

The parameter named dataIn is a reference to the 2D array of type double containing the data that describes the 3D surface.

Blocksize

The value of the parameter named blockSize defines the size of a colored square in the final display that represents a single input surfaceelevation value. For example, if blockSize is 1, each input surface value is represented by a single pixel in the display. If blockSize is 5, each input surface value is represented by a colored square having 5 pixels on each side (25 pixels in a square) .

The test code in the main method displays a surface having 59 values along the horizontal axis and 59 values along the vertical axis. Eachelevation value on the surface is represented in the final display by a colored square that is 2 pixels on each side.

Axis

The parameter named axis specifies whether optional red axes will be drawn on the display with the origin at the center as shown in Figure 1 .

Display

The parameter named display specifies one of six possible display formats. The value of display must be between 0 and 5 inclusive.

Values of 0, 1, and 2 specify the following formats:

Display = 0

This value for the display parameter specifies a Grayscale plot with a smooth gradient from black at the minimum to white at the maximum.

Display = 1

This value for the display parameter specifies a Color Shift plot with a smooth gradient from blue at the low end through aqua, green, and yellow to redat the high end. The minimum elevation is colored black. The maximum elevation is colored white.

Display = 2

This value for the display parameter specifies a Color Contour plot. The surface is subdivided into 23 levels and each of the 23 levels is represented byone of the following colors in order from lowest to highest elevation:

• Color.BLACK
• Color.GRAY
• Color.LIGHT_GRAY
• Color.BLUE
• new Color(100,100,255)
• new Color(140,140,255)
• new Color(175,175,255)
• Color.CYAN
• new Color(140,255,255)
• Color.GREEN
• new Color(140,255,140)
• new Color(200,255,200)
• Color.PINK
• new Color(255,140,255)
• Color.MAGENTA
• new Color(255,0,140)
• Color.RED
• new Color(255,100,0)
• Color.ORANGE
• new Color(255,225,0)
• Color.YELLOW
• new Color(255,255,150)
• Color.WHITE

Note that some of the colors in the above list refer to named color constants in the Color class. Others refer to new Color objects constructed by mixing the specified levels of red, green, and blue.