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The paint method for this class begins by setting up a pair of nested for loops that will be used to process each elevation point on the surface, and by initializing the color values for red, green, andblue to 0 in the innermost loop.

Set white and black for max and min values

If the elevation value is equal to 255, color values are set to cause that elevation to be painted white. If the elevation value is equal to 0, color values are set to cause that elevation to be painted black.

Listing 23 sets the color values to cause the extreme values of 0 and 255 to be painted black and white. Note that the code in Listing 23 is the beginning of a series of if-else constructs.

Listing 23. Set white and black for max and min values.
if((int)data[row][col]== 255){ red = green = blue = 255;//white}else if((int)data[row][col]== 0 ){ red = green = blue = 0;//black

Elevations other than the extreme ends

If the elevation is not one of the extreme values of 0 or 255, control passes to code that subdivides the total elevation range from 1 to 254 into thefollowing four ranges and then sets the color values for each range separately:

  • 0 less than elevation less than or equal 63
  • 63 less than elevation less than or equal 127
  • 127 less than elevation less than or equal 191
  • 191 less than elevation less than or equal 254

Processing the lowest range

Listing 24 shows the code that is used to process the lowest range of elevations between 1 and 63.

Listing 24. Process elevations from 1 to 63 inclusive.
}else if(((int)data[row][col]>0)&&((int)data[row][col]<= 63)){ int temp = 4 * ((int)data[row][col]- 0); blue = 255;green = temp;

What we are shooting for here is to produce color values that will result in a smooth gradient of color from blue at the low end to aqua at the high end ofthe range.

(See the leftmost one-fourth of the calibration scale for the middle image in Figure 1 .)

Scale the elevation values

Listing 24 begins by multiplying the elevation value by a factor of 4 to put it into the range from 4 to 252. This makes the elevation values compatible withallowable color values that range from 0 to 255.

The color aqua

The color aqua is produced by mixing equal amounts of blue and green. Listing 24 holds the value of blue constant at 255 and increases the value of green in proportion to the elevation value. Thus, at the lower end of the range, blue hasa value of 255 and green has a value of 4. (This is almost pure blue.) At the upper end of the range, blue still has a value of 255 and green has avalue of 252. (This is almost the pure secondary color aqua.)

In all cases, the value of red is 0 within this range. These color values (blue and temp) will be used later to instantiate a Color object, which will be used to control the plotting color for that portion of thedisplay.

Processing the other three ranges

Now that you know the basic scheme, you shouldn't have any difficulty understanding the code for processing the other three ranges shown in Listing 25 .

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
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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
what is the stm
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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
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How we are making nano material?
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LITNING
scanning tunneling microscope
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how nano science is used for hydrophobicity
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Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
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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 .
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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 ?
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biomolecules are e building blocks of every organics and inorganic materials.
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research.net
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Introduction about quantum dots in nanotechnology
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Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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