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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

find the 15th term of the geometric sequince whose first is 18 and last term of 387
Jerwin Reply
I know this work
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
virgelyn Reply
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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
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I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
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Commplementary angles
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what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
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a perfect square v²+2v+_
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Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
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
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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
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how do you translate this in Algebraic Expressions
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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?
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what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
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I start with an easy one. carbon nanotubes woven into a long filament like a string
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what is nanomaterials​ and their applications of sensors.
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what is nano technology
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what is system testing?
preparation of nanomaterial
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
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
anybody can imagine what will be happen after 100 years from now in nano tech world
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
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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?
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Source:  OpenStax, Introduction to xml. OpenStax CNX. Dec 02, 2014 Download for free at https://legacy.cnx.org/content/col11207/1.18
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