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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.

Summary

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

Miscellaneous

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
Disclaimers:

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

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
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Sherica
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Sherica
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Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
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Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Anatomy of a game engine. OpenStax CNX. Feb 07, 2013 Download for free at https://legacy.cnx.org/content/col11489/1.13
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