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A simple constructor

The code in Listing 29 also defines the constructor, whose only purpose is to save an integer identifying the position of this object in the vertical stack of MyCanvas objects.

Beginning of the overridden paint method

The beginning of the overridden paint method for the MyCanvas class is shown in Listing 30 .

Listing 30. Beginning of the overridden paint method.
public void paint(Graphics g){ //Calculate the scale factorsxScale = width/(xMax-xMin); yScale = height/(yMax-yMin);//Set the origin based on the // minimum values in x and yg.translate((int)((0-xMin)*xScale), (int)((0-yMin)*yScale));drawAxes(g);//Draw the axes g.setColor(Color.BLACK);

The code in Listing 30 :

  • Calculates and saves the scale factors for converting from double coordinate values to integer values inpixels.
  • Moves the plotting origin to the correct location.
  • Calls a method to draw the axes (in red) on the MyCanvas object.
  • Sets the color to black for the remainder of the plotting activity on the object.

Get old coordinate values

The plotting process consists of drawing straight line segment between pairs ofpoints. For each line segment, one of the points is defined by a pair of old coordinate values. The other point is defined by a pair of new coordinate values.

The code in Listing 31 initializes the beginning point for the plot. The initial value for the x-coordinate is the left edge of the plotting area.

Listing 31. Get old coordinate values.
//Get initial data values double xVal = xMin;int oldX = getTheX(xVal); int oldY = 0;//Use the Canvas obj number to // determine which method to// call to get the value for y. switch(cnt){case 0 : oldY = getTheY(data.f1(xVal));break; case 1 :oldY = getTheY(data.f2(xVal)); break;case 2 : oldY = getTheY(data.f3(xVal));break; case 3 :oldY = getTheY(data.f4(xVal)); break;case 4 : oldY = getTheY(data.f5(xVal));}//end switch

The initial y-coordinate value

The initial value for the y-coordinate depends on which function is being plotted on the MyCanvas object. Recall that each MyCanvas object contains an instance variable that identifies its position in the vertical stack of MyCanvas objects. The switch statement in Listing 31 uses that information to call one of the five methods named f1 through f5 . This gets the correct value for the y-coordinate based on the value of the x-coordinatefor each MyCanvas object.

The methods named getTheX and getTheY called by the code in Listing 31 convert the coordinate values from type double to integer values in pixels.

The method named getTheY also changes the sign on the data so that positive y-values go up the screen rather than down the screen.

(By default, positive vertical coordinate values go down the screen from top to bottom in Java.)

Plot the points

The remainder of the overridden paint method is shown in Listing 32 .

Plot the points.
//Now loop and plot the points while(xVal<xMax){ int yVal = 0;//Get next data value. Use the // Canvas obj number to// determine which method to // invoke to get the value for y.switch(cnt){ case 0 :yVal = getTheY(data.f1(xVal));break; case 1 :yVal = getTheY(data.f2(xVal));break; case 2 :yVal = getTheY(data.f3(xVal));break; case 3 :yVal = getTheY(data.f4(xVal));break; case 4 :yVal = getTheY(data.f5(xVal));}//end switch1 //Convert the x-value to an int// and draw the next line segment int x = getTheX(xVal);g.drawLine(oldX,oldY,x,yVal); //Increment along the x-axisxVal += xCalcInc; //Save end point to use as start// point for next line segment. oldX = x;oldY = yVal; }//end while loop}//end overridden paint method

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
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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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