Is it possible to detect a broken image?

The reason being - I render graphs like so:

<IMG SRC="barCausalGraph.asp ....> (using the third party csDrawGraph.dll component )

On the page I am currently employing this tactic:

1.on page A I run query to get a two dimentional array for my graph
2.check is not EOF
3.if not EOF, run the <IMG SRC="barCausalGraph.asp ...> code (which of course is on page B) and graph dispalys on page A fine

However if at step 2 it is EOF of course I display a message saying 'no data found...' therefore no graph is shown on page A

Is there a way to skip step 1 go strait to step 2 then detect is the Image is broken? If it is then display my 'no data found mssge'?

I want to do this becase there is no need to run the query on page A. It is run only to detect if I should go to step 2. As Im sure you are aware, the query on page A is a duplicate of the query run on page B. If I could detect if the image is broken (therefore no graph will be shown) I can make my page less resource hungry. The query is conditionaly very long as the end user uses a wizard to get the exact graph they want. There is 20 or 30 possible categories/conditions they may choose from.

Sorry for the long winded post. I attempted to make my process/ question as clear as possible.

TYIA



Wind is your friend
Matt
www.elitemarquees.com.au

__________________
Wind is your friend
Matt

Hmm. I am unfamiliar with the component but couldn't you do something like this on page B:

if rs.eof
'Send a place holder image that says 'No Data Found'
else
'Send graph
end if

or is this not an option?

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Hi Doug

Its from http://www.chestysoft.com/drawgraph/default.asp I have found it to be a great component. very worth $50. I have email them about changes EG including a liniar regretion type trend line. The guy updated and sent me a new dll within days. Good bloke.

I not sure how I would send a place holder given page B is called within the image tag. I have exclude the query however here is the code that draws the chart (also gives other users a snap shot of some of tyhe chart properties):

     do while not values.eof
        Chart.AddData values(0), values(1), colours(count)
        values.moveNext
        count = count + 1
     loop
     if runSecondConRS = true then
        if not seconConRS.Eof then
           do until seconConRS.Eof
              Chart.AddData seconConRS(0), seconConRS(1), colours(count)
              seconConRS.moveNext
              count = count + 1
           loop
        end if
     end if
     Chart.Width = request.queryString("width")
     Chart.Height = request.queryString("height")
     Chart.LegendX = request.queryString("width") -135
     Chart.MaxX = request.queryString("width")-180
     Chart.MaxY = request.queryString("height")-210
     Chart.LegendTextSize = 7
     Chart.BarWidth = 15
     Chart.GridColor = "#cccccc"
     Chart.XAxisText = session("xAxisName")
     Chart.YAxisText = "Number of Incidents"
        'Chart.Title = session("osirTypeName")
     Chart.LabelVertical = true
     Chart.ShowBarTotal = true
     Chart.AxisTextBold = true
     Chart.ShowGrid = true
     Chart.ShowTrendLine = trendLine
     Chart.TrendLineColor = request.queryString("trendColor")
     Chart.TrendLineWidth = 1
     Response.ContentType = "Image/Gif"
     Response.BinaryWrite Chart.GIFBar
     Response.End
     set chart=nothing
     set values=nothing
     if isobject(runSecondConRS) then set runSecondConRS = nothing end if
     conn.close
     set conn = nothing

Wind is your friend
Matt
www.elitemarquees.com.au

Hi Matt,
Essentially you are going to do the same thing: create a stream and then write that stream (or byte array) to the response stream.

I have never served an image from the file system through a stream in classic, it was always in a database so I am not of much help there. The second code sample on this page should help you though: http://www.rodsdot.com/ee/dynamicImage.asp

If you want to stream from a database you can use a form of this code:
http://authors.aspalliance.com/steve...imagequery.asp

hth.

================================================== =========
Read this if you want to know how to get a correct reply for your question:
http://www.catb.org/~esr/faqs/smart-questions.html
================================================== =========
.: Wrox Technical Editor / Author :.
Wrox Books 24 x 7
================================================== =========

Cheers mate. As always I appriciate your time. I will have a good read through your links.

Wind is your friend
Matt
www.elitemarquees.com.au

No problem. I hope one of the links provide you with a solution. =]
-Doug

================================================== =========
Read this if you want to know how to get a correct reply for your question:
http://www.catb.org/~esr/faqs/smart-questions.html
================================================== =========
.: Wrox Technical Editor / Author :.
Wrox Books 24 x 7
================================================== =========