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Bitmap/Histogram: Difference between revisions
Added BBC BASIC
(Added BBC BASIC) |
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end;
Close (F2);</lang>
=={{header|BBC BASIC}}==
{{works with|BBC BASIC for Windows}}
[[Image:greyscale_bbc.jpg|right]]
[[Image:histogram_bbc.gif|right]]
<lang bbcbasic> INSTALL @lib$+"SORTLIB"
Sort% = FN_sortinit(0,0)
Width% = 200
Height% = 200
VDU 23,22,Width%;Height%;8,16,16,128
*display c:\lena
DIM hist%(255), idx%(255)
FOR i% = 0 TO 255 : idx%(i%) = i% : NEXT
REM Build histogram:
FOR y% = 0 TO Height%-1
FOR x% = 0 TO Width%-1
l% = FNgetpixel(x%,y%) AND &FF
hist%(l%) += 1
NEXT
NEXT y%
REM Sort histogram:
C% = 256
CALL Sort%, hist%(0), idx%(0)
REM Find median:
total% = SUM(hist%())
half% = 0
FOR i% = 0 TO 255
half% += hist%(i%)
IF half% >= total%/2 THEN
median% = idx%(i%)
EXIT FOR
ENDIF
NEXT
REM Display black & white version:
FOR y% = 0 TO Height%-1
FOR x% = 0 TO Width%-1
l% = FNgetpixel(x%,y%) AND &FF
IF l% > median% THEN
PROCsetpixel(x%,y%,255,255,255)
ELSE
PROCsetpixel(x%,y%,0,0,0)
ENDIF
NEXT
NEXT y%
END
DEF PROCsetpixel(x%,y%,r%,g%,b%)
COLOUR 1,r%,g%,b%
GCOL 1
LINE x%*2,y%*2,x%*2,y%*2
ENDPROC
DEF FNgetpixel(x%,y%)
LOCAL col%
col% = TINT(x%*2,y%*2)
SWAP ?^col%,?(^col%+2)
= col%</lang>
=={{header|C}}==
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