<< Chapter < Page Chapter >> Page >

Transparency or opacity

For those not familiar with the concepts surrounding screen color and transparency, the value of alphaspecifies a transparency or opacity level. When an attempt is made to draw a pixel in the same screen location as an existing pixel, the colorof the last pixel drawn will be completely opaque and will dominate if it has an alpha value of 1.0. In that case, the first pixel drawn will no longer bevisible.

If the last pixel drawn has an alpha value of 0, it will be totally transparent and the first pixel drawn will continue to be totally visible.

For values between 0.0 and 1.0, the first pixel drawn will show through to some extent and the final color of the pixel will be a mix of the original colorand the new color.

Four runs with different alpha values

For this example, the Flex 3 application was modified, compiled, and run four times in succession by substituting four different values of backgroundAlpha into the code in Listing 2. The results are shown in Figure 3.

Application window background for alpha values of 0.0, 0.33, 0.66, and 1.0.

Missing image.
Application window background for alpha values of 0.0, 0.33, 0.66, and 1.0.

Four output images

The four images shown in Figure 3, going from left to right, top to bottom, represent alpha values of 0.0, 0.33, 0.66, and 1.0 respectively.

An alpha value of 0.0

For an alpha value of 0.0, the output color is pure red as shown by the top-left image in Figure 3. In this case, the gradient color scheme istotally transparent.

An alpha value of 1.0

For an alpha value of 1.0, the output colors range from pure green at the top to pure blue at the bottom as shown in the bottom-right image in Figure 3.In this case, the gradient color scheme is totally opaque and the red background color doesn't show through at all.

Alpha values of 0.33 and 0.66

For alpha values of 0.33 and 0.66, the output is a mix of the red background and the green/blue gradient as shown by the top-right and bottom-left images inFigure 3.

(The image in the bottom-left corner of Figure 3 corresponds to what you should see if you run the online version of this application.)

Conclusion regarding the Flex 3 version

These results suggest that the alpha value specified by backgroundAlpha in Flex 3 applies to the colors specified by backgroundGradientColors and does not apply to the color specified by backgroundColor . .

In other words, the gradient colors can be made more or less transparent by changing the value of backgroundAlpha allowing the red backgroundColor to show through the gradient colors. However, the value of alpha doesn't appear to affect the background color.

If you modify the code in Listing 2 by removing the backgroundColor attribute, and then compile and run it for different values of alpha, you willsee a similar result. In that case, however, the resulting colors will be a mixture of the default gray background color shown in Figure 1 and thegreen/blue gradient shown in the bottom right corner of Figure 3.

The Flex 4 version

The Flex 4 program named AppBackground03 replicates the behavior of the Flex 3 version named AppBackground01 . By necessity, this version of the program is significantly more complicated thanthe Flex 3 version.

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
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, Introduction to xml. OpenStax CNX. Dec 02, 2014 Download for free at https://legacy.cnx.org/content/col11207/1.18
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Introduction to xml' conversation and receive update notifications?

Ask