generation of PNG in asp.net failed

<%@ Page Language = "VB" ContentType="image/Png" %>
<%@ Import Namespace = "System.Drawing"%>
<%@ Import Namespace = "System.Drawing.Imaging"%>
<%@ Import Namespace = "System.Drawing.Drawing2D"%>

<%
Response.Clear()
Dim height As integer = 100
Dim width As integer = 200

Dim bmp As New Bitmap(width, height, PixelFormat.Format24bppRgb)
Dim g As Graphics = Graphics.FromImage(bmp)

g.SmoothingMode = SmoothingMode.AntiAlias
g.Clear(Color.White)
g.FillRectangle(New SolidBrush(Color.LightGray), 1, 1, 150, 50)
g.DrawString("Zone", New Font("Verdana", 10), SystemBrushes.WindowText, New
PointF(10, 15))

bmp.Save(Response.OutputStream, ImageFormat.Png)
g.Dispose()
bmp.Dispose()
Response.End()

%>

Error Msg
Exception Details: System.Runtime.InteropServices.ExternalException: A
generic error occurred in GDI+.

I wonder if i could generate png in asp.net by using "Dim bmp As New
Bitmap(width, height, PixelFormat.Format24bppRgb)" that?

If not so, what i should use?

Thank you.

Regards,
Angus

angus

What if you "g.dispose" before saving ?

Patrice


"angus" <> a écrit dans le message de
news:...
> <%@ Page Language = "VB" ContentType="image/Png" %>
> <%@ Import Namespace = "System.Drawing"%>
> <%@ Import Namespace = "System.Drawing.Imaging"%>
> <%@ Import Namespace = "System.Drawing.Drawing2D"%>
>
> <%
> Response.Clear()
> Dim height As integer = 100
> Dim width As integer = 200
>
> Dim bmp As New Bitmap(width, height, PixelFormat.Format24bppRgb)
> Dim g As Graphics = Graphics.FromImage(bmp)
>
> g.SmoothingMode = SmoothingMode.AntiAlias
> g.Clear(Color.White)
> g.FillRectangle(New SolidBrush(Color.LightGray), 1, 1, 150, 50)
> g.DrawString("Zone", New Font("Verdana", 10), SystemBrushes.WindowText,
New
> PointF(10, 15))
>
> bmp.Save(Response.OutputStream, ImageFormat.Png)
> g.Dispose()
> bmp.Dispose()
> Response.End()
>
> %>
>
> Error Msg
> Exception Details: System.Runtime.InteropServices.ExternalException: A
> generic error occurred in GDI+.
>
> I wonder if i could generate png in asp.net by using "Dim bmp As New
> Bitmap(width, height, PixelFormat.Format24bppRgb)" that?
>
> If not so, what i should use?
>
> Thank you.
>
> Regards,
> Angus
>
>

Patrice

the same error happened also.

by the way, if i changed

> > bmp.Save(Response.OutputStream, ImageFormat.Png)

to

bmp.Save(Response.OutputStream, ImageFormat.Jpeg)
as well as change the contenttype to "contenttype='image/jpeg'

every thing works fine.


"Patrice" <> wrote in message
news:...
> What if you "g.dispose" before saving ?
>
> Patrice
>
>
> "angus" <> a écrit dans le message de
> news:...
> > <%@ Page Language = "VB" ContentType="image/Png" %>
> > <%@ Import Namespace = "System.Drawing"%>
> > <%@ Import Namespace = "System.Drawing.Imaging"%>
> > <%@ Import Namespace = "System.Drawing.Drawing2D"%>
> >
> > <%
> > Response.Clear()
> > Dim height As integer = 100
> > Dim width As integer = 200
> >
> > Dim bmp As New Bitmap(width, height, PixelFormat.Format24bppRgb)
> > Dim g As Graphics = Graphics.FromImage(bmp)
> >
> > g.SmoothingMode = SmoothingMode.AntiAlias
> > g.Clear(Color.White)
> > g.FillRectangle(New SolidBrush(Color.LightGray), 1, 1, 150, 50)
> > g.DrawString("Zone", New Font("Verdana", 10), SystemBrushes.WindowText,
> New
> > PointF(10, 15))
> >
> > bmp.Save(Response.OutputStream, ImageFormat.Png)
> > g.Dispose()
> > bmp.Dispose()
> > Response.End()
> >
> > %>
> >
> > Error Msg
> > Exception Details: System.Runtime.InteropServices.ExternalException: A
> > generic error occurred in GDI+.
> >
> > I wonder if i could generate png in asp.net by using "Dim bmp As New
> > Bitmap(width, height, PixelFormat.Format24bppRgb)" that?
> >
> > If not so, what i should use?
> >
> > Thank you.
> >
> > Regards,
> > Angus
> >
> >
>
>

angus

I made a search about this weird issue and found that according to
http://www.c-sharpcorner.com/Code/20...orkWithPNG.asp the PNG file
format requires a seekable stream...


"angus" <> a écrit dans le message de
news:...
> the same error happened also.
>
> by the way, if i changed
>
> > > bmp.Save(Response.OutputStream, ImageFormat.Png)
>
> to
>
> bmp.Save(Response.OutputStream, ImageFormat.Jpeg)
> as well as change the contenttype to "contenttype='image/jpeg'
>
> every thing works fine.
>
>
> "Patrice" <> wrote in message
> news:...
> > What if you "g.dispose" before saving ?
> >
> > Patrice
> >
> >
> > "angus" <> a écrit dans le message de
> > news:...
> > > <%@ Page Language = "VB" ContentType="image/Png" %>
> > > <%@ Import Namespace = "System.Drawing"%>
> > > <%@ Import Namespace = "System.Drawing.Imaging"%>
> > > <%@ Import Namespace = "System.Drawing.Drawing2D"%>
> > >
> > > <%
> > > Response.Clear()
> > > Dim height As integer = 100
> > > Dim width As integer = 200
> > >
> > > Dim bmp As New Bitmap(width, height, PixelFormat.Format24bppRgb)
> > > Dim g As Graphics = Graphics.FromImage(bmp)
> > >
> > > g.SmoothingMode = SmoothingMode.AntiAlias
> > > g.Clear(Color.White)
> > > g.FillRectangle(New SolidBrush(Color.LightGray), 1, 1, 150, 50)
> > > g.DrawString("Zone", New Font("Verdana", 10),
SystemBrushes.WindowText,
> > New
> > > PointF(10, 15))
> > >
> > > bmp.Save(Response.OutputStream, ImageFormat.Png)
> > > g.Dispose()
> > > bmp.Dispose()
> > > Response.End()
> > >
> > > %>
> > >
> > > Error Msg
> > > Exception Details: System.Runtime.InteropServices.ExternalException: A
> > > generic error occurred in GDI+.
> > >
> > > I wonder if i could generate png in asp.net by using "Dim bmp As New
> > > Bitmap(width, height, PixelFormat.Format24bppRgb)" that?
> > >
> > > If not so, what i should use?
> > >
> > > Thank you.
> > >
> > > Regards,
> > > Angus
> > >
> > >
> >
> >
>
>

Patrice

MemoryStream io = new MemoryStream();
bmp.Save(io, ImageFormat.Png);
Response.BinaryWrite( io.GetBuffer() );


"Patrice" <> wrote in message news:...
> I made a search about this weird issue and found that according to
> http://www.c-sharpcorner.com/Code/20...orkWithPNG.asp the PNG file
> format requires a seekable stream...
>
>
> "angus" <> a écrit dans le message de
> news:...
> > the same error happened also.
> >
> > by the way, if i changed
> >
> > > > bmp.Save(Response.OutputStream, ImageFormat.Png)
> >
> > to
> >
> > bmp.Save(Response.OutputStream, ImageFormat.Jpeg)
> > as well as change the contenttype to "contenttype='image/jpeg'
> >
> > every thing works fine.
> >
> >
> > "Patrice" <> wrote in message
> > news:...
> > > What if you "g.dispose" before saving ?
> > >
> > > Patrice
> > >
> > >
> > > "angus" <> a écrit dans le message de
> > > news:...
> > > > <%@ Page Language = "VB" ContentType="image/Png" %>
> > > > <%@ Import Namespace = "System.Drawing"%>
> > > > <%@ Import Namespace = "System.Drawing.Imaging"%>
> > > > <%@ Import Namespace = "System.Drawing.Drawing2D"%>
> > > >
> > > > <%
> > > > Response.Clear()
> > > > Dim height As integer = 100
> > > > Dim width As integer = 200
> > > >
> > > > Dim bmp As New Bitmap(width, height, PixelFormat.Format24bppRgb)
> > > > Dim g As Graphics = Graphics.FromImage(bmp)
> > > >
> > > > g.SmoothingMode = SmoothingMode.AntiAlias
> > > > g.Clear(Color.White)
> > > > g.FillRectangle(New SolidBrush(Color.LightGray), 1, 1, 150, 50)
> > > > g.DrawString("Zone", New Font("Verdana", 10),
> SystemBrushes.WindowText,
> > > New
> > > > PointF(10, 15))
> > > >
> > > > bmp.Save(Response.OutputStream, ImageFormat.Png)
> > > > g.Dispose()
> > > > bmp.Dispose()
> > > > Response.End()
> > > >
> > > > %>
> > > >
> > > > Error Msg
> > > > Exception Details: System.Runtime.InteropServices.ExternalException: A
> > > > generic error occurred in GDI+.
> > > >
> > > > I wonder if i could generate png in asp.net by using "Dim bmp As New
> > > > Bitmap(width, height, PixelFormat.Format24bppRgb)" that?
> > > >
> > > > If not so, what i should use?
> > > >
> > > > Thank you.
> > > >
> > > > Regards,
> > > > Angus
> > > >
> > > >
> > >
> > >
> >
> >
>
>

Hans Kesting