Set stream copy position to beginning (#12971)

Tanya-Solyanik · web-flow · commit 1c2a83a930b2 · 2025-03-10T17:13:56.000-07:00
This is a manual port of #12953. The code was refactored in .NET 9 so the fix needs manually applied. ###### Microsoft Reviewers: [Open in CodeFlow](https://microsoft.github.io/open-pr/?codeflow=https://github.com/dotnet/winforms/pull/12971)
diff --git a/src/System.Drawing.Common/src/System/Drawing/Internal/GPStream.cs b/src/System.Drawing.Common/src/System/Drawing/Internal/GPStream.cs
@@ -20,6 +20,7 @@ internal GPStream(Stream stream, bool makeSeekable = true)
             // Copy to a memory stream so we can seek
             MemoryStream memoryStream = new MemoryStream();
             stream.CopyTo(memoryStream);
+            memoryStream.Position = 0;
             _dataStream = memoryStream;
         }
         else

Original file line number	Diff line number	Diff line change
`@@ -20,6 +20,7 @@ internal GPStream(Stream stream, bool makeSeekable = true)`
`20`	`20`	`// Copy to a memory stream so we can seek`
`21`	`21`	`MemoryStream memoryStream = new MemoryStream();`
`22`	`22`	`stream.CopyTo(memoryStream);`
	`23`	`+ memoryStream.Position = 0;`
`23`	`24`	`_dataStream = memoryStream;`
`24`	`25`	`}`
`25`	`26`	`else`