Difference between revisions of "CSC111 Why 255?"

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(Created page with "--~~~~ ---- curl -O http://cs.smith.edu/dftwiki/images/redEyes.bmp")
 
(→‎Octal Dump)
 
(6 intermediate revisions by the same user not shown)
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--[[User:Thiebaut|D. Thiebaut]] ([[User talk:Thiebaut|talk]]) 16:14, 13 March 2014 (EDT)
 
--[[User:Thiebaut|D. Thiebaut]] ([[User talk:Thiebaut|talk]]) 16:14, 13 March 2014 (EDT)
 
----
 
----
 +
=Sample JES Program=
 +
<br />
 +
<source lang="python">
 +
# doNotChangeColor( image ).
 +
# Changes the amount of red, green and blue that is in an image
 +
def makeSquares( image ):
 +
  for x in range(0,getWidth(image)):
 +
    for y in range(0,getHeight(image)):
 +
        pixel = getPixel (image, x, y)
 +
        red  = getRed(pixel)
 +
        green = getGreen(pixel)
 +
        blue  = getBlue(pixel)
 +
        if x < getWidth(image)/2 and y < getHeight(image)/2:
 +
          newColor = makeColor( 255, 0, 0 )
 +
        elif x > getWidth(image)/2 and y < getHeight(image)/2:
 +
          newColor = makeColor( 0, 250, 0 )
 +
        elif x < getWidth( image )/2 and y > getHeight( image)/2:
 +
          newColor = makeColor( 0, 0, 240 )
 +
        else:
 +
          newColor = makeColor( 100, 100, 100 )
 +
         
 +
        # the line below replaces the pixel with its original color.  Change
 +
        # the amount of red, green and blue to see some change in the colors
 +
        setColor( pixel, newColor )
 +
  return image
  
−
  curl -O http://cs.smith.edu/dftwiki/images/redEyes.bmp
+
# ================================================================== 
 +
#                            MAIN PROGRAM
 +
# ================================================================== 
 +
file = pickAFile()
 +
image = makePicture( file )
 +
show( image )
 +
 
 +
image = makeSquares( image )
 +
repaint( image )
 +
writePictureTo( image, file )
 +
</source>
 +
<br />
 +
=Sample Image=
 +
<br />
 +
[[Media:square.bmp | square.bmp]]
 +
<br />
 +
identify square.bmp
 +
square.bmp BMP 20x20 20x20+0+0 8-bit sRGB 1.25KB 0.000u 0:00.000
 +
<br />
 +
ls -l square.bmp
 +
  -rw-r--r--  1 thiebaut  wheel  '''1254''' Mar 13 20:48 square.bmp
 +
<br />
 +
=Octal Dump=
 +
<br />
 +
'''od -t u1 square.bmp'''
 +
<source lang="text">
 +
0000000    66  77 230  4  0  0  0  0  0  0  54  0  0  0  40  0
 +
0000020    0  0  20  0  0  0  20  0  0  0  1  0  24  0  0  0
 +
0000040    0  0 176  4  0  0  0  0  0  0  0  0  0  0  0  0
 +
0000060    0  0  0  0  0  0 240  0  0 240  0  0 240  0  0 240
 +
0000100    0  0 240  0  0 240  0  0 240  0  0 240  0  0 240  0
 +
0000120    0 240  0  0 100 100 100 100 100 100 100 100 100 100 100 100
 +
0000140  100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100
 +
0000160  100 100 240  0  0 240  0  0 240  0  0 240  0  0 240  0
 +
...
 +
0002200    0  0 255  0  0 255  0  0 255  0  0 255 100 100 100  0
 +
0002220  250  0  0 250  0  0 250  0  0 250  0  0 250  0  0 250
 +
0002240    0  0 250  0  0 250  0  0 250  0  0  0 255  0  0 255
 +
0002260    0  0 255  0  0 255  0  0 255  0  0 255  0  0 255  0
 +
0002300    0 255  0  0 255  0  0 255 100 100 100  0 250  0  0 250
 +
0002320    0  0 250  0  0 250  0  0 250  0  0 250  0  0 250  0
 +
0002340    0 250  0  0 250  0
 +
</source>
 +
<br />
 +
=Bits=
 +
<br />
 +
<source lang="python">
 +
def toBin( n, noBits ):
 +
    s = bin( n )
 +
    s = "0" * noBits + s[2:]
 +
    return s[-noBits:]
 +
 
 +
noBits = int( input( "Number of bits? " ) )
 +
 
 +
noCombinations = 2**noBits
 +
print( "Number of combinations =", noCombinations )
 +
for i in range( noCombinations ):
 +
    print( "%3d %s" % ( i, toBin( i, noBits ) ) )
 +
 
 +
   
 +
 
 +
</source>
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
<br />
 +
[[Category:Python]][[Category:CSC111]]

Latest revision as of 21:15, 13 March 2014

--D. Thiebaut (talk) 16:14, 13 March 2014 (EDT)

Sample JES Program


# doNotChangeColor( image ).
# Changes the amount of red, green and blue that is in an image
def makeSquares( image ):
  for x in range(0,getWidth(image)):
    for y in range(0,getHeight(image)):
        pixel = getPixel (image, x, y)
        red   = getRed(pixel)
        green = getGreen(pixel)
        blue  = getBlue(pixel)
        if x < getWidth(image)/2 and y < getHeight(image)/2:
          newColor = makeColor( 255, 0, 0 )
        elif x > getWidth(image)/2 and y < getHeight(image)/2:
          newColor = makeColor( 0, 250, 0 )
        elif x < getWidth( image )/2 and y > getHeight( image)/2:
          newColor = makeColor( 0, 0, 240 )
        else:
          newColor = makeColor( 100, 100, 100 )
          
        # the line below replaces the pixel with its original color.  Change
        # the amount of red, green and blue to see some change in the colors
        setColor( pixel, newColor )
  return image

# ==================================================================  
#                             MAIN PROGRAM
# ==================================================================  
file = pickAFile()
image = makePicture( file ) 
show( image )
  
image = makeSquares( image )
repaint( image )
writePictureTo( image, file )


Sample Image


square.bmp 

identify square.bmp
square.bmp BMP 20x20 20x20+0+0 8-bit sRGB 1.25KB 0.000u 0:00.000



ls -l square.bmp 
-rw-r--r--  1 thiebaut  wheel  1254 Mar 13 20:48 square.bmp


Octal Dump


od -t u1 square.bmp

 0000000    66  77 230   4   0   0   0   0   0   0  54   0   0   0  40   0
 0000020     0   0  20   0   0   0  20   0   0   0   1   0  24   0   0   0
 0000040     0   0 176   4   0   0   0   0   0   0   0   0   0   0   0   0
 0000060     0   0   0   0   0   0 240   0   0 240   0   0 240   0   0 240
 0000100     0   0 240   0   0 240   0   0 240   0   0 240   0   0 240   0
 0000120     0 240   0   0 100 100 100 100 100 100 100 100 100 100 100 100
 0000140   100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100
 0000160   100 100 240   0   0 240   0   0 240   0   0 240   0   0 240   0
 ...
 0002200     0   0 255   0   0 255   0   0 255   0   0 255 100 100 100   0
 0002220   250   0   0 250   0   0 250   0   0 250   0   0 250   0   0 250
 0002240     0   0 250   0   0 250   0   0 250   0   0   0 255   0   0 255
 0002260     0   0 255   0   0 255   0   0 255   0   0 255   0   0 255   0
 0002300     0 255   0   0 255   0   0 255 100 100 100   0 250   0   0 250
 0002320     0   0 250   0   0 250   0   0 250   0   0 250   0   0 250   0
 0002340     0 250   0   0 250   0


Bits


def toBin( n, noBits ):
    s = bin( n )
    s = "0" * noBits + s[2:]
    return s[-noBits:]

noBits = int( input( "Number of bits? " ) )

noCombinations = 2**noBits
print( "Number of combinations =", noCombinations )
for i in range( noCombinations ):
    print( "%3d %s" % ( i, toBin( i, noBits ) ) )














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