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An object of this class is used to paint a Grayscale plot of a 3D surface ranging from black at the lowest elevation to white at the highestelevation. The various shades of gray vary in a smooth gradient between the two extremes. The leftmost image in Figure 1 is an example of the type of plot produced by an object of this class.

Listing 14. Beginning of the class named CanvasType0surface.
class CanvasType0surface extends Canvas{ CanvasType0surface(){//constructorsetSize(dataWidth * blockSize, dataHeight * blockSize);getCenter(); }//end constructor

The constructor

The constructor for the class is straightforward. It accesses instance variables of the outer enclosing object to set the size of the canvas on thebasis of the size of the surface and the size of the square of pixels that will be used to represent each elevation value on the surface.

The constructor also calls the getCenter method to get the coordinates of the center of the surface in order to be able to draw theoptional red axes in the correct position later.

Overridden paint method for CanvasType0surface class

The real work is done by the overridden paint method, which begins in Listing 15 . Of the three classes used to plot the 3D surface, this is the simplest.

Listing 15. Beginning of overridden paint method.
public void paint(Graphics g){ Color color = null;for(int row = 0;row<dataHeight;row++){ for(int col = 0;col<dataWidth;col++){ //Add in red, green, and blue in// proportion to the value of the // surface height.int red = (int)data[row][col]; int green = red;int blue = red;

Purpose of overridden paint method

The purpose of this overridden paint method is to convert the elevation value of each point on the 3D surface into an appropriate shade ofgray, and to paint a square of pixels on the screen at that elevation value's location where every pixel in the square is the same shade of gray.

In order to produce a gray pixel in a 24-bit color system, you need to set the color values for red, green, and blue to the same value. If all three colorvalues are zero, the pixel color is black. If all three color values are 255, the pixel color is white. If all three color values fall somewhere in betweenzero and 255, the pixel color will be some shade of gray.

Recall that the elevation values were earlier normalized to fall in the range from zero to 255. The code in Listing 15 uses a nested for loop to access every elevation value in the array that describes the 3D surface. Thenit sets the red, green, and blue color values to the normalized surface valuefor each point on the 3D surface.

Instantiate a Color object

Continuing inside the nested for loops, the code in Listing 16 instantiates a new object of type Color based on the current red, green, and blue color values.

Listing 16. Instantiate a Color object.
color = new Color(red,green,blue);

Set colors and draw squares

The code in Listing 17 calls the setColor method of the Graphics class to set the current drawing color to the color described by the Color object referred to by the reference variable named color .

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Cied
what is biological synthesis of nanoparticles
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how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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