png metadata

Hi guys,

I want to use the png tEXT metadata, can some help with some code sample
of some link to web resources about this topic.



Best regards,
Stefan

Hi Stefan,

The query string to get to Png Metadata (tEXT) is: “/text/comment�. You can replace “comment� with any of the tEXT fields, like Author or Keywords.

From a PngBitmapDecoder or from a BitmapFrame, try this:

System.Windows.Media.Imaging.BitmapMetadata metadata = decoder.Metadata;

if ( metadata != null )
{
foreach ( string query in metadata )
{
object o = metadata.GetQuery ( query );
}
}

Alternatively if you know what metadata you’re looking for, you can look for it using .GetQuery(“/text/comment�) [for example]. In order to set Metadata on the BitmapFrame, use the .SetQuery(…) method.

Thanks,

Robert.

-----Original Message-----
From: stefan_tabaranu
Posted At: Monday, February 27, 2006 10:36 PM
Posted To: microsoft.public.windows.developer.winfx.avalon
Conversation: png metadata
Subject: png metadata


Hi guys,

I want to use the png tEXT metadata, can some help with some code sample
of some link to web resources about this topic.



Best regards,
Stefan

Hi Robert,

Thx a lot for your response, I try to render some simple text on an image
like this:

RenderTargetBitmap rtb = new RenderTargetBitmap(500, 500, 30, 30,
PixelFormats.Pbgra32);
DrawingVisual dv = new DrawingVisual();
DrawingContext dc = dv.RenderOpen();

dc.DrawText(
new FormattedText("Test .... drawing some text",
CultureInfo.CurrentUICulture,
FlowDirection.LeftToRight,
new Typeface("Verdana"),
36, Brushes.Black),
new Point(200, 116));
dc.Close();

rtb.Render(dv);

PngBitmapEncoder png = new PngBitmapEncoder();

png.Metadata = new BitmapMetadata("/tEXT/"); //error - Property
could not be found

png.Frames.Add(BitmapFrame.Create(rtb));
using (Stream stm = File.Create("c:/foo.png"))
{
png.Save(stm);
}

When I try to create a new instance of the metadata object I get an error
message "Property could not be found".
I make something wrong ? I have a Beta 1 version of winfx sdk, shall I try
with another version ?

Best regards,
Stefan

"robertwl@nospam.microsoft.com" wrote:

> Hi Stefan,
>
> The query string to get to Png Metadata (tEXT) is: “/text/comment�. You can replace “comment� with any of the tEXT fields, like Author or Keywords.
>
> From a PngBitmapDecoder or from a BitmapFrame, try this:
>
> System.Windows.Media.Imaging.BitmapMetadata metadata = decoder.Metadata;
>
> if ( metadata != null )
> {
> foreach ( string query in metadata )
> {
> object o = metadata.GetQuery ( query );
> }
> }
>
> Alternatively if you know what metadata you’re looking for, you can look for it using .GetQuery(“/text/comment�) [for example]. In order to set Metadata on the BitmapFrame, use the .SetQuery(…) method.
>
> Thanks,
>
> Robert.
>
> -----Original Message-----
> From: stefan_tabaranu
> Posted At: Monday, February 27, 2006 10:36 PM
> Posted To: microsoft.public.windows.developer.winfx.avalon
> Conversation: png metadata
> Subject: png metadata
>
>
> Hi guys,
>
> I want to use the png tEXT metadata, can some help with some code sample
> of some link to web resources about this topic.
>
>
>
> Best regards,
> Stefan
>

The PNG text chunk is "tEXt" not "tEXT"

Glenn