Bitmap/Histogram: Difference between revisions

=={{header|FBSL}}==

FBSL volatiles and function call concatenation used for brevity.

'''24-bpp P.O.T.-size BMP solution:'''

[[File:FBSLHistogram.PNG|right]]

<lang qbasic>#DEFINE WM_CLOSE 16

DIM colored = ".\LenaClr.bmp", grayscale = ".\LenaGry.bmp", blackwhite = ".\LenaBnw.bmp"

DIM head, tail, r, g, b, l, m, ptr, blobsize = 54 ' sizeof BMP headers

FILEGET(FILEOPEN(colored, BINARY), FILELEN(colored)): FILECLOSE(FILEOPEN) ' fill buffer

head = @FILEGET + blobsize: tail = @FILEGET + FILELEN ' get buffer bounds

ToGrayScale() ' derive grayscale image and save it to disk

ToBlackAndWhite() ' ditto, black-and-white image

FBSLSETTEXT(ME, "Clr") ' display colored image

FBSLTILE(ME, FBSLLOADIMAGE(colored))

RESIZE(ME, 0, 0, 136, 162): CENTER(ME): SHOW(ME)

FBSLTILE(FBSLFORM("Gry"), FBSLLOADIMAGE(grayscale)) ' ditto, grayscale

RESIZE(FBSLFORM, 0, 0, 136, 162): CENTER(FBSLFORM): SHOW(FBSLFORM)

FBSLTILE(FBSLFORM("B/w"), FBSLLOADIMAGE(blackwhite)) ' ditto, black-and-white

RESIZE(FBSLFORM, 0, 0, 136, 162): CENTER(FBSLFORM): SHOW(FBSLFORM)

BEGIN EVENTS ' main message loop

IF CBMSG = WM_CLOSE THEN DESTROY(ME) ' click any [X] button to quit

END EVENTS

SUB ToGrayScale()

FOR ptr = head TO tail STEP 3

b = PEEK(ptr + 0, 1) ' Windows stores colors in BGR order

g = PEEK(ptr + 1, 1)

r = PEEK(ptr + 2, 1)

l = 0.2126 * r + 0.7152 * g + 0.0722 * b ' derive luminance

POKE(ptr + 0, CHR(l))(ptr + 1, CHR)(ptr + 2, CHR) ' set pixel to shade of gray

m = m + l

NEXT

FILEPUT(FILEOPEN(grayscale, BINARY_NEW), FILEGET): FILECLOSE(FILEOPEN) ' save grayscale image

END SUB

SUB ToBlackAndWhite()

STATIC b = CHR(0), w = CHR(255) ' initialize once

m = m / (tail - head) * 3 ' derive median

FOR ptr = head TO tail STEP 3

IF PEEK(ptr + 0, 1) < m THEN ' set pixel black

POKE(ptr + 0, b)(ptr + 1, b)(ptr + 2, b)

ELSE ' set pixel white

POKE(ptr + 0, w)(ptr + 1, w)(ptr + 2, w)

END IF

NEXT

FILEPUT(FILEOPEN(blackwhite, BINARY_NEW), FILEGET): FILECLOSE(FILEOPEN) ' save b/w image

END SUB</lang>