<< Chapter < Page
  Digital signal processing - dsp     Page 20 / 25
Chapter >> Page >

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

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Digital signal processing - dsp' conversation and receive update notifications?

Ask