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Saving Jpeg/Exif info Please Help.I'm trying to write up a simple image stamper application that stamps the Exif date information from the jpegs that I've taken from my digital camera and saves the new file with the date stamped on the lower right part of the picture. (I'm not an advanced programmer so my code may not be 100% efficient - sorry, I'm still learning) Everything works fine until the saving part. I've been able to read the file into a picturebox, transform it into bitmap to write the text on it, Then save the file under a new filename. But when I save the file all Exif information is lost. How can I preserve this information? I'm thinking that when I transform the image to a bitmap this loss happens, but When I work on the image itself using the image.fromfile property the file is locked until the application exits so I have to read the file as a filestream and convert it into a bitmap to write text on it and save it without locking the file. Otherwise I cannot overwrite the file. I'm doing something along these lines: (I have 2 pictureboxes pb_orig and pb_final, the Pictext is the Exif date that is returned from another function) Dim fs As New System.IO.FileStream(PicName, IO.FileMode.Open) Dim bm As New Bitmap(fs) Dim g As Graphics = Graphics.FromImage(bm) Dim ph As Integer = pb_Orig.Image.Height Dim pw As Integer = pb_Orig.Image.Width Dim StrWidth = g.MeasureString(PicText.ToString, New Font (TS_CB_Font.SelectedText, (pw * 0.05), FontStyle.Regular, GraphicsUnit.Pixel)).Width Dim StrHeight = g.MeasureString(PicText.ToString, New Font (TS_CB_Font.SelectedText, (ph * 0.05), FontStyle.Regular, GraphicsUnit.Pixel)).Height g.DrawString(PicText, New Font(TS_CB_Font.Text, (ph * 0.05), FontStyle.Regular, GraphicsUnit.Pixel), New SolidBrush(CD1.Color), pb_Orig.Image.Width - StrWidth, pb_Orig.Image.Height - StrHeight) pb_Final.Image = DirectCast(bm.Clone, Image) fs.Close() bm.Dispose() The save goes like this: Dim SaveBitmap As New Bitmap(pb_Final.Image) SaveBitmap.Save(SaveFileDialog1.FileName, Imaging.ImageFormat.Jpeg) SaveBitmap.Dispose() If I dont use the Imaging.ImageFormat.Jpeg somehow my pictures end up being saved as PNG files... Any help will be greatly appreciated... I'm guessing here, but I'm thinking when you convert it to bitmap, you
lose all of the EXIF data which is specific to JPG format files. Check out this link: http://www.bobpowell.net/modifyImage.htm
The code sample is written in C# but, can be converted to VB pretty easy (sample below): Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim imageName As String = "c:\\Test.jpg" ' substitute your own image name here 'NOTE Don't use this test code to draw on images that you want to keep! Dim i As Image = Image.FromFile(imageName) Dim g As Graphics = Graphics.FromImage(i) g.FillRectangle(Brushes.White, 5, 5, 170, 40) 'g.DrawRectangle(Pens.DarkBlue, 5, 5, 150, 30) Dim sf As StringFormat = CType(StringFormat.GenericTypographic.Clone(), StringFormat) sf.Alignment = StringAlignment.Center sf.LineAlignment = StringAlignment.Center g.DrawString(DateTime.Now.ToShortDateString(), New Font("Arial", 14, GraphicsUnit.Point), Brushes.Black, 5, 5) ', New RectangleF(7, 7, 94, 25), sf) g.Dispose() i.Save("C:\test2.jpg") i.Dispose() '---------------------------------------------------------------- ' Converted from C# to VB .NET using CSharpToVBConverter(1.2). ' Developed by: Kamal Patel (http://www.KamalPatel.net) '---------------------------------------------------------------- End Sub What I'm trying to say is you can draw on a jpg image and should save the image data. The reason you are loosing the EXIF data is because you are drawing to a Bitmap and then saving back to jpg. The conversion between the two is causing the loss of info. By just drawing on the jpg image like I did using Bob's code ( converted from C# to VB.NET) I was able to draw the ShortDate info on the image and save the image (with another name) without loosing the EXIF data. james Show quoteHide quote "TheGanjaMan" <theganjaman@somplace.invalid> wrote in message news:Xns97A2A1DE580E4TheGanjaMan@207.46.248.16... > Hi everyone, > > I'm trying to write up a simple image stamper application that stamps the > Exif date information from the jpegs that I've taken from my digital > camera and saves the new file with the date stamped on the lower right > part of the picture. (I'm not an advanced programmer so my code may not > be 100% efficient - sorry, I'm still learning) > > Everything works fine until the saving part. I've been able to read the > file into a picturebox, transform it into bitmap to write the text on it, > Then save the file under a new filename. > > But when I save the file all Exif information is lost. How can I > preserve this information? I'm thinking that when I transform the image > to a bitmap this loss happens, but When I work on the image itself using > the image.fromfile property the file is locked until the application > exits so I have to read the file as a filestream and convert it into a > bitmap to write text on it and save it without locking the file. > Otherwise I cannot overwrite the file. > > I'm doing something along these lines: > (I have 2 pictureboxes pb_orig and pb_final, the Pictext is the Exif date > that is returned from another function) > > Dim fs As New System.IO.FileStream(PicName, IO.FileMode.Open) > Dim bm As New Bitmap(fs) > Dim g As Graphics = Graphics.FromImage(bm) > Dim ph As Integer = pb_Orig.Image.Height > Dim pw As Integer = pb_Orig.Image.Width > Dim StrWidth = g.MeasureString(PicText.ToString, New Font > (TS_CB_Font.SelectedText, (pw * 0.05), FontStyle.Regular, > GraphicsUnit.Pixel)).Width > Dim StrHeight = g.MeasureString(PicText.ToString, New Font > (TS_CB_Font.SelectedText, (ph * 0.05), FontStyle.Regular, > GraphicsUnit.Pixel)).Height > g.DrawString(PicText, New Font(TS_CB_Font.Text, (ph * 0.05), > FontStyle.Regular, GraphicsUnit.Pixel), New SolidBrush(CD1.Color), > pb_Orig.Image.Width - StrWidth, pb_Orig.Image.Height - StrHeight) > pb_Final.Image = DirectCast(bm.Clone, Image) > fs.Close() > bm.Dispose() > > > The save goes like this: > Dim SaveBitmap As New Bitmap(pb_Final.Image) > SaveBitmap.Save(SaveFileDialog1.FileName, Imaging.ImageFormat.Jpeg) > SaveBitmap.Dispose() > > If I dont use the Imaging.ImageFormat.Jpeg somehow my pictures end up > being saved as PNG files... > > Any help will be greatly appreciated... Hi James,
Thank you for the link and the code sample... It seems to have solved my problems for now and pointed me in the right direction. Cheers... TheGanjaMan Show quoteHide quote "james" <jjames700REMOV***@earthlink.net> wrote in news:erO#3kZXGHA.2268@TK2MSFTNGP02.phx.gbl: > Check out this link: http://www.bobpowell.net/modifyImage.htm > > The code sample is written in C# but, can be converted to VB pretty > easy (sample below): > > Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As > System.EventArgs) Handles Button1.Click > > Dim imageName As String = "c:\\Test.jpg" ' substitute your own image > name here > > 'NOTE Don't use this test code to draw on images that you want to > keep! > > > What I'm trying to say is you can draw on a jpg image and should save > the image data. The reason you are loosing the EXIF data is because > you are drawing to a Bitmap and then saving back to jpg. The > conversion between the two is causing the loss of info. By just > drawing on the jpg image like I did using Bob's code ( converted from > C# to VB.NET) I was able to draw the ShortDate info on the image and > save the image (with another name) without loosing the EXIF data. > > james On Tue, 11 Apr 2006 05:53:44 -0700, TheGanjaMan
<theganjaman@somplace.invalid> wrote: Show quoteHide quote >Hi everyone, Concerning the EXIF tags:> >I'm trying to write up a simple image stamper application that stamps the >Exif date information from the jpegs that I've taken from my digital >camera and saves the new file with the date stamped on the lower right >part of the picture. (I'm not an advanced programmer so my code may not >be 100% efficient - sorry, I'm still learning) > >Everything works fine until the saving part. I've been able to read the >file into a picturebox, transform it into bitmap to write the text on it, >Then save the file under a new filename. > >But when I save the file all Exif information is lost. How can I >preserve this information? I'm thinking that when I transform the image >to a bitmap this loss happens, but When I work on the image itself using >the image.fromfile property the file is locked until the application >exits so I have to read the file as a filestream and convert it into a >bitmap to write text on it and save it without locking the file. >Otherwise I cannot overwrite the file. > >I'm doing something along these lines: >(I have 2 pictureboxes pb_orig and pb_final, the Pictext is the Exif date >that is returned from another function) > >Dim fs As New System.IO.FileStream(PicName, IO.FileMode.Open) >Dim bm As New Bitmap(fs) >Dim g As Graphics = Graphics.FromImage(bm) >Dim ph As Integer = pb_Orig.Image.Height >Dim pw As Integer = pb_Orig.Image.Width >Dim StrWidth = g.MeasureString(PicText.ToString, New Font >(TS_CB_Font.SelectedText, (pw * 0.05), FontStyle.Regular, >GraphicsUnit.Pixel)).Width >Dim StrHeight = g.MeasureString(PicText.ToString, New Font >(TS_CB_Font.SelectedText, (ph * 0.05), FontStyle.Regular, >GraphicsUnit.Pixel)).Height >g.DrawString(PicText, New Font(TS_CB_Font.Text, (ph * 0.05), >FontStyle.Regular, GraphicsUnit.Pixel), New SolidBrush(CD1.Color), >pb_Orig.Image.Width - StrWidth, pb_Orig.Image.Height - StrHeight) >pb_Final.Image = DirectCast(bm.Clone, Image) >fs.Close() >bm.Dispose() > > >The save goes like this: >Dim SaveBitmap As New Bitmap(pb_Final.Image) >SaveBitmap.Save(SaveFileDialog1.FileName, Imaging.ImageFormat.Jpeg) >SaveBitmap.Dispose() > >If I dont use the Imaging.ImageFormat.Jpeg somehow my pictures end up >being saved as PNG files... > >Any help will be greatly appreciated... You would need to read and temporarily store the EXIF tags when loading the original and then write back the tags when resaving the altered file (not a trivial matter). If you happen to have VB6, you could look at this example: http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=48293&lngWId=1 Or, try a Google seach for a similar example in .Net. Gene Hi Gene,
Thanks for the link. I am able to extract and store all the required exif tags in memory when working with the picture. I just didn't know how to write them back into the file. Thanks for helping out... Cheers... TheGanjaMan gene kelley <o***@by.me> wrote in Show quoteHide quote news:g1go32dqb0a9300q275qqqbl8goqcqpmnm@4ax.com: > Concerning the EXIF tags: > You would need to read and temporarily store the EXIF tags when > loading the original and then write back the tags when resaving the > altered file (not a trivial matter). > > If you happen to have VB6, you could look at this example: > http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=482 > 93&lngWId=1 > > Or, try a Google seach for a similar example in .Net. > > Gene 
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