Using csImageFile to Join Images - A Simple Counter
This demonstration application shows how the image merging features of csImageFile can be used to display a page counter. You will need the csImageFile component installed on your server as well as the sample files, which can be downloaded below.
Download the sample scripts - countdemo.zip (40 KB)
Download the trial csImageFile component - csift.zip (4.5 MB)
The files in countdemo.zip include 10 digits as bitmaps, a fairly simple web page to hold the counter and the main asp script - "counter.asp". There is also a text file containing the count total and a PDF document for explanation.
Most graphical page counters work by calling the script inside an image tag, something like this...
<img src="counter.asp">
The work is done by the counter.asp script which reads the count, increments it, produces an image of it and then streams this image to the <img> tag, making the browser think it is an image file. This script is listed below with some notes.
<%
'These 3 lines prevent the page being cached
'and make the server finish processing it before streaming it.
'Use this method when asp output is an image rather than html.
Response.Expires = 0
Response.Buffer = true
Response.Clear
'Create a csImageFile object
'Adjust this for the full version or 64 bit version.
'Create it now because we will use the CurrentDir property
Set Obj = Server.CreateObject("csImageFileTrial.Manage")
'The counter total is stored in count.txt
'so open the file and read the value into a variable called count
Set FileStreamObj = CreateObject("Scripting.FileSystemObject")
Set TextFile = FileStreamObj.OpenTextFile(Obj.CurrentDir & "\count.txt")
Count = TextFile.Readline
TextFile.Close
'Increment the counter
Count = Count + 1
If Count > 9999 Then
Count = 0
End If
'Overwrite count.txt with a new file containing the new total
Set NewFile = FileStreamObj.CreateTextFile(Obj.CurrentDir & "\count.txt")
NewFile.WriteLine(Count)
NewFile.Close
'Extract a single character for each digit
Count = CStr(Count)
While Len(Count) < 4
Count = "0" & Count
Wend
Units = Mid(Count, 4, 1)
Tens = Mid(Count, 3, 1)
Hundreds = Mid(Count, 2, 1)
Thousands = Mid(Count, 1, 1)
'Create the background image in memory.
'This sets the size of the combined image.
Obj.NewImage 120, 40, "ffffff"
'Use the MergeBack method once for each digit.
'The path to the second image file is specified
'and the coordinates are to position the top left of the second image.
Obj.MergeBack Obj.CurrentDir + "\" & Thousands & ".bmp", 0, 0
Obj.MergeBack Obj.CurrentDir + "\" & Hundreds & ".bmp", 30, 0
Obj.MergeBack Obj.CurrentDir + "\" & Tens & ".bmp", 60, 0
Obj.MergeBack Obj.CurrentDir + "\" & Units & ".bmp", 90, 0
'Specify the MIME type and send the data out as binary
Response.ContentType = "image/gif"
Response.BinaryWrite Obj.GIFData
%>
Note that the script must have permission to create and modify files in its own directory. This means that the Internet Guest Account must have Modify permission for that directory.
The counter can be seen working here.
- Other ASP examples using csImageFile:
- Simple Resize - code for resizing an image to fit a box and for displaying thumbnails from a directory.
- Upload to Database and Resize - example of using csASPUpload and MS Access.
- Upload to File and Resize - example of using csASPUpload and saving to disk.
- File Info - an example of reading and editing JPEG meta data.
- Multipage TIFFs - an example showing how to view pages in a multipage TIFF.