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After setting the drawing mode to honor transparency and setting the background color to red, the code in Listing 11 causes the three images of the spider along the top of Figure 2 to be displayed each time the render method is called. (Recall that the names of the drawing mode constants appear to be reversed between opaque and transparent.)

The call to the draw method in Listing 11 displays the spider image in the upper-left corner of Figure 2 .

The first call to the drawFlash method calls one of three overloaded versions of the drawFlash method. This version of the method draws a white silhouette of the spider at a location specified by theparameters, 133,0.

The second call to the drawFlash method draws a silhouette of the spider at a location of 266,0, with a width of 131 pixels, a height of128 pixels and a blue color.

Note that none of the code in Listing 11 depends on the logic that is executed in the update method. Therefore, the three images appear to be static despite the fact thatthey are being redrawn about 60 times per second.

The large flashing spider

The call to the drawFlash method in Listing 12 produces the large flashing spider at the bottom of Figure 2 and Figure 3 .

Listing 12 . The large flashing spider.
//Cause an enlarged version of the spider to flash // between white and blue silhouette at a rate// of 1/flashInterval. spider.drawFlash(0f,0f,262f,256f,silohetteColor);}//end render }//end class Slick0160b

This is the same version of the drawFlash method that was called to produce the blue spider in the upper-right corner of Figure 2 . However, in this case, the third and fourth parameters specify that the spider should be drawn with a width of 262pixels and a height of 256 pixels.

More importantly, rather than passing a constant color as the last parameter, Listing 12 passes the reference to the Color object stored in the variable named silohetteColor . Recall that the color represented by that object is periodically switched between white andblue in the update method of Listing 10 . This causes the color of the spider to switch between white and blue.

The end of the program

Listing 12 signals the end of the render method and the end of the class named Slick0160b .

Run the programs

I encourage you to copy the code from Listing 13 and Listing 14 . Compile the code and execute it,making changes, and observing the results of your changes. Make certain that you can explain why your changes behave as they do.


In this module, you learned about using the draw , drawCentered , and drawFlash methods of the Image class.

What's next?

In the next module, you will learn how to use the following methods of the Input class to get user input:

  • isKeyDown
  • isMouseButtonDown
  • getMouseX
  • getMouseY


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Slick0160: Using the draw and drawFlash methods
  • File: Slick0160.htm
  • Published: 02/05/13
  • Revised: 09/03/15

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who doesreceive compensation. If you purchase such a book, please be aware that it is a copy of a module that is freelyavailable on cnx.org and that it was made and published without my prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
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.
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
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
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
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
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.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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what is biological synthesis of nanoparticles
Sanket Reply
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