Database Search

match allmatch any Look in all areasLook in current areas Check all datesPrevious dayPrevious 3 daysPrevious weekPrevious fortnightPrevious monthPrevious 2 monthsPrevious 3 monthsPrevious half-yearPrevious year

TechHome

Samples from Users

• !!NEWSFLASH!!
• Change Image DPI
• Convert 24 Bit Bitmaps to Greyscale
• Convert to Grayscale
• Create Thumbnail Images and Display in HTML
• Pixie and Compression
• Pixie Photo Print Sample
• PNG Files Not Supported

Can't find the information you are looking for here? Then leave a message over on our WinBatch Tech Support Forum.

Convert to Grayscale

 Keywords: greyscale black and white B&W colour

Question:

How can an color image be converted to black and white

Answer:

Use the Pixie Extender.

AddExtender("wwimg34i.dll")
Bright= 100 ;no adjustment
Sat= 0 ;grayscale 
Hue= 100 ;no adjustment
BSH=StrCat(Bright,",",Sat,",",Hue)

infile="color.jpg"
outfile="BlackandWhite.jpg"

ImgModulate(infile,outfile,BSH) ;Brightness, Saturation, Hue

User Reply:

I tried the pixie extender and it does a nice job but it doesn't convert 24 bit to 8 bit.

Answer:

I think it does if you're converting JPG's or GIF's to black and white. I'm guessing you're converting a BMP, though? To make it an 8-bit black and white BMP, try this code:

AddExtender("WWIMG44I.DLL")

Bright= 100 ;no adjustment
Sat= 0 ;grayscale
Hue= 100 ;no adjustment
BSH=StrCat(Bright,",",Sat,",",Hue)
infile ="color.bmp"
outfile="blackandwhite.bmp"

ImgModulate(infile,outfile,BSH) ;Convert to black-and-white

  ;this will convert it to 8-bit (256 colors)
ext = StrUpper(FileExtension(outfile))
If ext!="JPG" && ext!="GIF"  ;if we didn't already convert to a JPG or GIF, then do so now
  outfile_8bit=StrCat(FileRoot(outfile),".gif") ;GIF looks better than a JPG
  ImgConvert(outfile,outfile_8bit) ;convert to a black-and-white GIF...should be 256 colors now
  ImgConvert(outfile_8bit,outfile) ;convert it back to its original format...should stay 256 colors
  FileDelete(outfile_8bit)  ;remove temporary GIF
EndIf

or, even cleaner (ImgModulate can convert at the same time...this way only requires one call to ImgConvert):

AddExtender("WWIMG44I.DLL")

Bright= 100 ;no adjustment
Sat= 0 ;grayscale
Hue= 100 ;no adjustment
BSH=StrCat(Bright,",",Sat,",",Hue)
infile ="color.bmp"
outfile="blackandwhite.gif"  ;make the outfile a GIF

ImgModulate(infile,outfile,BSH) ;convert to black and white GIF...should be 8-bits now (256 colors)
ImgConvert(outfile,StrCat(FileRoot(outfile),".bmp")) ;convert it back to BMP...should stay 256 colors
FileDelete(outfile)  ;remove temporary GIF

---

Article ID:   W16843

File Created: 2014:01:29:15:34:52

Last Updated: 2014:01:29:15:34:52