'This script produces resized and thumbnail images out of a given
'directory on the fly by using imagemagic

Option Explicit

On Error Resume Next
Const ERROR_SUCCESS = 0

Dim img
Dim info
Dim rs
Dim elem
Dim sMsgs
Dim inputdir
Dim inputfld
Dim outputdir
Dim outputfld
Dim fso
Dim str
Dim f
Dim tnSize
Dim maxSize

inputdir = "C:\temp\input\"
outputdir = "C:\temp\output\"
'define how big the thumbnail should be
tnSize = "20%"
'define the max dimensions for the resized images
maxSize = "320x200"

Set img = CreateObject("ImageMagickObject.MagickImage.1")
Set fso = CreateObject("Scripting.FileSystemObject")
Set inputfld = fso.GetFolder(inputdir).Files
Set outputfld = fso.GetFolder(outputdir).Files

str = ""
'reads all files in input dir, resizes them, creates thumbnails and copies them into output dir
'OPTIONS FOR CONVERT FUNCTION (taken from http://imagemagick.org/script/command-line-options.php):
'
'-resize width{%}{@} {!} {<} {>}
'resize an image.
'By default, the width and height are maximum values. That is, the image is expanded or contracted to fit the width and height value while maintaining the aspect ratio of the image. Append an exclamation point to the geometry to force the image size to exactly the size you specify. For example, if you specify 640x480! the image width is set to 640 pixels and height to 480.
'If only the width is specified, the width assumes the value and the height is chosen to maintain the aspect ratio of the image. Similarly, if only the height is specified (e.g., -resize x256, the width is chosen to maintain the aspect ratio.
'To specify a percentage width or height instead, append %. The image size is multiplied by the width and height percentages to obtain the final image dimensions. To increase the size of an image, use a value greater than 100 (e.g. 125%). To decrease an image's size, use a percentage less than 100.
'Use @ to specify the maximum area in pixels of an image.
'Use < to change the dimensions of the image only if its width or height exceeds the geometry specification. > resizes the image only if both of its dimensions are less than the geometry specification. For example, if you specify 640x480 and the image size is 256x256, the image size does not change. However, if the image is 512x512 or 1024x1024, it is resized to 480x480. Enclose the geometry specification in quotation marks to prevent the < or > from being interpreted by your shell as a file redirection.
'if the -filter option precedes the -resize option, the image is resized with the specified filter.
'If the -support option precedes the -resize option, the image is resized with the specified support.

For Each f In inputfld
	If Not fso.fileexists(outputdir & "tn_" & f.Name) Then
		rs = img.Convert("-thumbnail",tnSize,inputdir & f.Name,outputdir & "tn_" & f.Name)
	End If
	If Not fso.fileexists(outputdir & f.Name) Then
		rs = img.Convert("-resize",maxSize,inputdir & f.Name,outputdir & f.Name)
	End If 
Next

If Err.Number <> ERROR_SUCCESS Then ShowError: WScript.Quit
MsgBox "info: " & msgs
Set img=Nothing
WScript.Quit(0)

Sub ShowError
  sMsgs = ""
  If BasicError(Err.Number) > 5000 Then
    sMsgs = " ImageMagickObject" & vbCrLf
  End If
  WScript.Echo Err.Number & ": " & Err.Description & vbCrLf & sMsgs
End Sub

Function BasicError(e)
  BasicError = e And &HFFFF&
End Function