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Bitmap/Histogram: Difference between revisions
Added solution for Action!
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(Added solution for Action!) |
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Line 11:
* Replace each pixel of luminance lesser than the median to black, and others to white.
Use [[read ppm file | read]]/[[write ppm file]], and [[grayscale image]] solutions.
=={{header|Action!}}==
{{libheader|Action! Bitmap tools}}
<lang Action!>INCLUDE "H6:LOADPPM5.ACT"
DEFINE HISTSIZE="256"
PROC PutBigPixel(INT x,y BYTE col)
IF x>=0 AND x<=79 AND y>=0 AND y<=47 THEN
y==LSH 2
col==RSH 4
IF col<0 THEN col=0
ELSEIF col>15 THEN col=15 FI
Color=col
Plot(x,y)
DrawTo(x,y+3)
FI
RETURN
PROC DrawImage(GrayImage POINTER image INT x,y)
INT i,j
BYTE c
FOR j=0 TO image.gh-1
DO
FOR i=0 TO image.gw-1
DO
c=GetGrayPixel(image,i,j)
PutBigPixel(x+i,y+j,c)
OD
OD
RETURN
PROC CalcHistogram(GrayImage POINTER image INT ARRAY hist)
INT i,j
BYTE c
Zero(hist,HISTSIZE*2)
FOR j=0 TO image.gh-1
DO
FOR i=0 TO image.gw-1
DO
c=GetGrayPixel(image,i,j)
hist(c)==+1
OD
OD
RETURN
BYTE FUNC CalcThresholdValue(INT width,height INT ARRAY hist)
INT i,sum,total,curr
total=width*height
sum=0
FOR i=0 TO HISTSIZE-1
DO
curr=hist(i)
IF sum>=(total-curr)/2 THEN
RETURN (i)
FI
sum==+curr
OD
RETURN (HISTSIZE-1)
PROC Binarize(GrayImage POINTER src,dst BYTE threshold)
INT i,j
BYTE c
FOR j=0 TO src.gh-1
DO
FOR i=0 TO src.gw-1
DO
c=GetGrayPixel(src,i,j)
IF c<threshold THEN
c=0
ELSE
c=255
FI
SetGrayPixel(dst,i,j,c)
OD
OD
RETURN
PROC Main()
BYTE CH=$02FC ;Internal hardware value for last key pressed
BYTE ARRAY dataIn(900),dataOut(900)
GrayImage in,out
INT ARRAY hist(HISTSIZE)
BYTE threshold
INT size=[30],x,y
Put(125) PutE() ;clear the screen
InitGrayImage(in,size,size,dataIn)
InitGrayImage(out,size,size,dataOut)
PrintE("Loading source image...")
LoadPPM5(in,"H6:LENA30G.PPM")
PrintE("Calc histogram...")
CalcHistogram(in,hist)
PrintE("Calc threshold value...")
threshold=CalcThresholdValue(in.gw,in.gh,hist)
PrintE("Binarization...")
Binarize(in,out,threshold)
Graphics(9)
x=(40-size)/2
y=(48-size)/2
DrawImage(in,x,y)
DrawImage(out,x+40,y)
DO UNTIL CH#$FF OD
CH=$FF
RETURN</lang>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Bitmap_Histogram.png Screenshot from Atari 8-bit computer]
=={{header|Ada}}==
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