How to resolve the algorithm Color wheel step by step in the VBScript programming language
Published on 12 May 2024 09:40 PM
How to resolve the algorithm Color wheel step by step in the VBScript programming language
Table of Contents
Problem Statement
Write a function to draw a HSV color wheel completely with code. This is strictly for learning purposes only. It's highly recommended that you use an image in an actual application to actually draw the color wheel (as procedurally drawing is super slow). This does help you understand how color wheels work and this can easily be used to determine a color value based on a position within a circle.
Let's start with the solution:
Step by Step solution about How to resolve the algorithm Color wheel step by step in the VBScript programming language
Source code in the vbscript programming language
Option explicit
Class ImgClass
Private ImgL,ImgH,ImgDepth,bkclr,loc,tt
private xmini,xmaxi,ymini,ymaxi,dirx,diry
public ImgArray() 'rgb in 24 bit mode, indexes to palette in 8 bits
private filename
private Palette,szpal
public property get xmin():xmin=xmini:end property
public property get ymin():ymin=ymini:end property
public property get xmax():xmax=xmaxi:end property
public property get ymax():ymax=ymaxi:end property
public property let depth(x)
if x<>8 and x<>32 then err.raise 9
Imgdepth=x
end property
public sub set0 (x0,y0) 'sets the new origin (default tlc). The origin does'nt work if ImgArray is accessed directly
if x0<0 or x0>=imgl or y0<0 or y0>imgh then err.raise 9
xmini=-x0
ymini=-y0
xmaxi=xmini+imgl-1
ymaxi=ymini+imgh-1
end sub
'constructor
Public Default Function Init(name,w,h,orient,dep,bkg,mipal)
'offx, offy posicion de 0,0. si ofx+ , x se incrementa de izq a der, si offy+ y se incrementa de abajo arriba
dim i,j
ImgL=w
ImgH=h
tt=timer
loc=getlocale
' not useful as we are not using SetPixel and accessing ImgArray directly
set0 0,0 'origin blc positive up and right
redim imgArray(ImgL-1,ImgH-1)
bkclr=bkg
if bkg<>0 then
for i=0 to ImgL-1
for j=0 to ImgH-1
imgarray(i,j)=bkg
next
next
end if
Select Case orient
Case 1: dirx=1 : diry=1
Case 2: dirx=-1 : diry=1
Case 3: dirx=-1 : diry=-1
Case 4: dirx=1 : diry=-1
End select
filename=name
ImgDepth =dep
'load user palette if provided
if imgdepth=8 then
loadpal(mipal)
end if
set init=me
end function
private sub loadpal(mipale)
if isarray(mipale) Then
palette=mipale
szpal=UBound(mipale)+1
Else
szpal=256
'Default palette recycled from ATARI
'removed
, not relevant
End if
End Sub
'class termination writes it to a BMP file and displays it
'if an error happens VBS terminates the class before exiting so the BMP is displayed the same
Private Sub Class_Terminate
if err<>0 then wscript.echo "Error " & err.number
wscript.echo "copying image to bmp file"
savebmp
wscript.echo "opening " & filename & " with your default bmp viewer"
CreateObject("Shell.Application").ShellExecute filename
wscript.echo timer-tt & " iseconds"
End Sub
function long2wstr( x) 'falta muy poco!!!
dim k1,k2,x1
k1= (x and &hffff&)' or (&H8000& And ((X And &h8000&)<>0)))
k2=((X And &h7fffffff&) \ &h10000&) Or (&H8000& And (x<0))
long2wstr=chrw(k1) & chrw(k2)
end function
function int2wstr(x)
int2wstr=ChrW((x and &h7fff) or (&H8000 And (X<0)))
End Function
Public Sub SaveBMP
'Save the picture to a bmp file
Dim s,ostream, x,y,loc
const hdrs=54 '14+40
dim bms:bms=ImgH* 4*(((ImgL*imgdepth\8)+3)\4) 'bitmap size including padding
dim palsize:if (imgdepth=8) then palsize=szpal*4 else palsize=0
with CreateObject("ADODB.Stream") 'auxiliary ostream, it creates an UNICODE with bom stream in memory
.Charset = "UTF-16LE" 'o "UTF16-BE"
.Type = 2' adTypeText
.open
'build a header
'bmp header: VBSCript does'nt have records nor writes binary values to files, so we use strings of unicode chars!!
'BMP header
.writetext ChrW(&h4d42) ' 0 "BM" 4d42
.writetext long2wstr(hdrs+palsize+bms) ' 2 fiesize
.writetext long2wstr(0) ' 6 reserved
.writetext long2wstr (hdrs+palsize) '10 image offset
'InfoHeader
.writetext long2wstr(40) '14 infoheader size
.writetext long2wstr(Imgl) '18 image length
.writetext long2wstr(imgh) '22 image width
.writetext int2wstr(1) '26 planes
.writetext int2wstr(imgdepth) '28 clr depth (bpp)
.writetext long2wstr(&H0) '30 compression used 0= NOCOMPR
.writetext long2wstr(bms) '34 imgsize
.writetext long2wstr(&Hc4e) '38 bpp hor
.writetext long2wstr(&hc43) '42 bpp vert
.writetext long2wstr(szpal) '46 colors in palette
.writetext long2wstr(&H0) '50 important clrs 0=all
'write bitmap
'precalc data for orientation
Dim x1,x2,y1,y2
If dirx=-1 Then x1=ImgL-1 :x2=0 Else x1=0:x2=ImgL-1
If diry=-1 Then y1=ImgH-1 :y2=0 Else y1=0:y2=ImgH-1
Select Case imgdepth
Case 32
For y=y1 To y2 step diry
For x=x1 To x2 Step dirx
'writelong fic, Pixel(x,y)
.writetext long2wstr(Imgarray(x,y))
Next
Next
Case 8
'palette
For x=0 to szpal-1
.writetext long2wstr(palette(x)) '52
Next
'image
dim pad:pad=ImgL mod 4
For y=y1 to y2 step diry
For x=x1 To x2 step dirx*2
.writetext chrw((ImgArray(x,y) and 255)+ &h100& *(ImgArray(x+dirx,y) and 255))
Next
'line padding
if pad and 1 then .writetext chrw(ImgArray(x2,y))
if pad >1 then .writetext chrw(0)
Next
Case Else
WScript.Echo "ColorDepth not supported : " & ImgDepth & " bits"
End Select
'use a second stream to save to file starting past the BOM the first ADODB.Stream has added
Dim outf:Set outf= CreateObject("ADODB.Stream")
outf.Type = 1 ' adTypeBinary
outf.Open
.position=2 'remove bom (1 wchar)
.CopyTo outf
.close
outf.savetofile filename,2 'adSaveCreateOverWrite
outf.close
end with
End Sub
end class
function hsv2rgb( Hue, Sat, Value) 'hue 0-360 0-ro 120-ver 240-az ,sat 0-100,value 0-100
dim Angle, Radius,Ur,Vr,Wr,Rdim
dim r,g,b, rgb
Angle = (Hue-150) *0.01745329251994329576923690768489
Ur = Value * 2.55
Radius = Ur * tan(Sat *0.01183199)
Vr = Radius * cos(Angle) *0.70710678 'sqrt(1/2)
Wr = Radius * sin(Angle) *0.40824829 'sqrt(1/6)
r = (Ur - Vr - Wr)
g = (Ur + Vr - Wr)
b = (Ur + Wr + Wr)
'clamp values
if r >255 then
Rdim = (Ur - 255) / (Vr + Wr)
r = 255
g = Ur + (Vr - Wr) * Rdim
b = Ur + 2 * Wr * Rdim
elseif r < 0 then
Rdim = Ur / (Vr + Wr)
r = 0
g = Ur + (Vr - Wr) * Rdim
b = Ur + 2 * Wr * Rdim
end if
if g >255 then
Rdim = (255 - Ur) / (Vr - Wr)
r = Ur - (Vr + Wr) * Rdim
g = 255
b = Ur + 2 * Wr * Rdim
elseif g<0 then
Rdim = -Ur / (Vr - Wr)
r = Ur - (Vr + Wr) * Rdim
g = 0
b = Ur + 2 * Wr * Rdim
end if
if b>255 then
Rdim = (255 - Ur) / (Wr + Wr)
r = Ur - (Vr + Wr) * Rdim
g = Ur + (Vr - Wr) * Rdim
b = 255
elseif b<0 then
Rdim = -Ur / (Wr + Wr)
r = Ur - (Vr + Wr) * Rdim
g = Ur + (Vr - Wr) * Rdim
b = 0
end If
'b lowest byte, red highest byte
hsv2rgb= ((b and &hff)+256*((g and &hff)+256*(r and &hff))and &hffffff)
end function
function ang(col,row)
'if col =0 then if row>0 then ang=0 else ang=180:exit function
if col =0 then
if row<0 then ang=90 else ang=270 end if
else
if col>0 then
ang=atn(-row/col)*57.2957795130
else
ang=(atn(row/-col)*57.2957795130)+180
end if
end if
ang=(ang+360) mod 360
end function
Dim X,row,col,fn,tt,hr,sat,row2
const h=160
const w=160
const rad=159
const r2=25500
tt=timer
fn=CreateObject("Scripting.FileSystemObject").GetSpecialFolder(2)& "\testwchr.bmp"
Set X = (New ImgClass)(fn,w*2,h*2,1,32,0,0)
x.set0 w,h
'wscript.echo x.xmax, x.xmin
for row=x.xmin+1 to x.xmax
row2=row*row
hr=int(Sqr(r2-row2))
For col=hr To 159
Dim a:a=((col\16 +row\16) And 1)* &hffffff
x.imgArray(col+160,row+160)=a
x.imgArray(-col+160,row+160)=a
next
for col=-hr to hr
sat=100-sqr(row2+col*col)/rad *50
' wscript.echo c,r
x.imgArray(col+160,row+160)=hsv2rgb(ang(row,col)+90,100,sat)
next
'script.echo row
next
Set X = Nothing
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