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Adjust a GIF's Hue/Sat/Lum


This code adjusts the Hue, Saturation and Luminosity of any gif file on the fly! No component needed, it's just asp code.
live demo:
http://www.cwolves.com/testing/coloradj.html
Live site using this:
http://www.cwolves.com/home.asp?hue=0&sat=0&lum=0&con=0&red=true&green=true&blue=true&invert=false
play with all the querystring values in that link.

Original Author: Mark Kahn

Inputs

querystring inputs:
img (image path)
hue (-180 --> 180)
sat (-100 --> 100)
lum (-100 --> 100)

Returns

your new gif

Code

<%
response.contenttype = "image/gif"
src = request.querystring("Img")
Hue = request.querystring("Hue")
Sat = request.querystring("Sat")
Lum = request.querystring("Lum")
function dofix(val)
if val > 239 then
val = val - 239
val = dofix(val)
elseif val < 0 then
val = val + 239
val = dofix(val)
end if
dofix = val
end function
function dofix2(val)
if val > 239 then
dofix2 = 239
elseif val < 0 then
dofix2 = 0
else
dofix2 = val
end if
end function
function hexval(char)
select case char
case "0": hexval = 0
case "1": hexval = 1
case "2": hexval = 2
case "3": hexval = 3
case "4": hexval = 4
case "5": hexval = 5
case "6": hexval = 6
case "7": hexval = 7
case "8": hexval = 8
case "9": hexval = 9
case "A": hexval = 10
case "B": hexval = 11
case "C": hexval = 12
case "D": hexval = 13
case "E": hexval = 14
case "F": hexval = 15
end select
end function
function Ascii(color)
out = ""
for i = 0 to 2
this = mid(color, i*2+1, 2)
tmp = 16*hexval(left(this, 1)) + hexval(right(this, 1))
out = out & chr(tmp)
next
Ascii = out
end function
Function stb(tString)
Dim I, B
For I=1 to len(tString)
B = B & ChrB(Asc(Mid(tString,I,1)))
Next
stb = B
End Function
Function RGBtoHSL(ByVal Red, ByVal Green, ByVal Blue, ByRef Hue, ByRef Sat, ByRef Lum)
pRed = Red / 255
pGreen = Green / 255
pBlue = Blue / 255
If pRed > pGreen Then
If pRed > pBlue Then pMax = pRed Else pMax = pBlue
ElseIf pGreen > pBlue Then
pMax = pGreen
Else
pMax = pBlue
End If
If pRed < pGreen Then
If pRed < pBlue Then pMin = pRed Else pMin = pBlue
ElseIf pGreen < pBlue Then
pMin = pGreen
Else
pMin = pBlue
End If
pLum = (pMax + pMin) / 2
If pMax = pMin Then
pSat = 0
pHue = 0
Else
If pLum < 0.5 Then
pSat = (pMax - pMin) / (pMax + pMin)
Else
pSat = (pMax - pMin) / (2 - pMax - pMin)
End If
Select Case pMax
Case pRed
pHue = (pGreen - pBlue) / (pMax - pMin)
Case pGreen
pHue = 2 + (pBlue - pRed) / (pMax - pMin)
Case pBlue
pHue = 4 + (pRed - pGreen) / (pMax - pMin)
End Select
End If
Hue = pHue * 239 6
If Hue < 0 Then Hue = Hue + 240
Sat = Int(pSat * 239)
Lum = Int(pLum * 239)
End Function
Function HSLtoRGB(ByRef Red, ByRef Green, ByRef Blue, ByVal Hue, ByVal Sat, ByVal Lum)
Dim temp3()
ReDim temp3(3)
pHue = Hue / 239
pSat = Sat / 239
pLum = Lum / 239
If pSat = 0 Then
pRed = pLum
pGreen = pLum
pBlue = pLum
Else
If pLum < 0.5 Then
temp2 = pLum * (1 + pSat)
Else
temp2 = pLum + pSat - pLum * pSat
End If
temp1 = 2 * pLum - temp2
temp3(0) = pHue + 1 / 3
temp3(1) = pHue
temp3(2) = pHue - 1 / 3
For n = 0 To 2
If temp3(n) < 0 Then temp3(n) = temp3(n) + 1
If temp3(n) > 1 Then temp3(n) = temp3(n) - 1
If 6 * temp3(n) < 1 Then
temp3(n) = temp1 + (temp2 - temp1) * 6 * temp3(n)
Else
If 2 * temp3(n) < 1 Then
temp3(n) = temp2
Else
If 3 * temp3(n) < 2 Then temp3(n) = temp1 + (temp2 - temp1) * ((2 / 3) - temp3(n)) * 6 Else temp3(n) = temp1
End If
End If
Next
pRed = temp3(0)
pGreen = temp3(1)
pBlue = temp3(2)
End If
Red = Int(pRed * 255)
Green = Int(pGreen * 255)
Blue = Int(pBlue * 255)
End Function
if not(src = "" or Hue = "") then
set FSO = server.createobject("Scripting.FileSystemObject")
set file = FSO.OpenTextFile(server.mappath(src), 1, false)
StartData = file.read(13)
TableSize = asc(mid(StartData, 11, 1))
tSize  = 1
if (TableSize AND 1) = 1 then tSize = tSize + 1
if (TableSize AND 2) = 2 then tSize = tSize + 2
if (TableSize AND 4) = 4 then tSize = tSize + 4
tSize  = 2^tSize
ColorData = file.read(tSize*3)
EndData = ""
do while not file.atendofstream
EndData = EndData & file.read(100)
loop
file.close: set file = nothing
set FSO = nothing
NewColorData = ""
for i = 1 to len(ColorData)-2 STEP 3
R = asc(mid(colordata, i+0, 1))
G = asc(mid(colordata, i+1, 1))
B = asc(mid(colordata, i+2, 1))
H = 0
L = 0
S = 0
call RGBtoHSL(R, G, B, H, S, L)
H = H + (239/360*Hue)
if Sat < 0 then S = S + Sat * .01 * (S) else S = S + Sat * .01 * (239-S)
if Lum < 0 then L = L + Lum * .01 * (L) else L = L + Lum * .01 * (239-L)
h = dofix(h)
s = dofix2(s)
l = dofix2(l)
call HSLtoRGB(R, G, B, H, S, L)
NewColorData = NewColorData & chr(R) & chr(G) & chr(B)
next
response.binarywrite stb(StartData & NewColorData & EndData)
end if
%>

About this post

Posted: 2002-06-01
By: ArchiveBot
Viewed: 94 times

Categories

ASP/ HTML

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