[release/6.0] Move 2 Drawing APIs that are not implemented in netfx to netcoreapp3.1 or later (#60371)

Author: safern

src/libraries/System.Drawing.Common/ref/System.Drawing.Common.cs

@@ -596,12 +596,16 @@ public void Flush(System.Drawing.Drawing2D.FlushIntention intention) { }
         public static System.Drawing.Graphics FromImage(System.Drawing.Image image) { throw null; }
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
         [System.Runtime.Versioning.SupportedOSPlatformAttribute("windows")]
+#if NETCOREAPP3_1_OR_GREATER
         [System.ObsoleteAttribute("Use the Graphics.GetContextInfo overloads that accept arguments for better performance and fewer allocations.", DiagnosticId = "SYSLIB0016", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
+#endif
         public object GetContextInfo() { throw null; }
+#if NETCOREAPP3_1_OR_GREATER
         [System.Runtime.Versioning.SupportedOSPlatformAttribute("windows")]
         public void GetContextInfo(out PointF offset) { throw null; }
         [System.Runtime.Versioning.SupportedOSPlatformAttribute("windows")]
         public void GetContextInfo(out PointF offset, out Region? clip) { throw null; }
+#endif
         public static System.IntPtr GetHalftonePalette() { throw null; }
         public System.IntPtr GetHdc() { throw null; }
         public System.Drawing.Color GetNearestColor(System.Drawing.Color color) { throw null; }

src/libraries/System.Drawing.Common/src/CompatibilitySuppressions.xml

@@ -1,17 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Suppressions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
-  <Suppression>
-    <DiagnosticId>CP0002</DiagnosticId>
-    <Target>M:System.Drawing.Graphics.GetContextInfo(System.Drawing.PointF@)</Target>
-    <Left>lib/netstandard2.0/System.Drawing.Common.dll</Left>
-    <Right>lib/net461/System.Drawing.Common.dll</Right>
-  </Suppression>
-  <Suppression>
-    <DiagnosticId>CP0002</DiagnosticId>
-    <Target>M:System.Drawing.Graphics.GetContextInfo(System.Drawing.PointF@,System.Drawing.Region@)</Target>
-    <Left>lib/netstandard2.0/System.Drawing.Common.dll</Left>
-    <Right>lib/net461/System.Drawing.Common.dll</Right>
-  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:System.Drawing.FontConverter</Target>

src/libraries/System.Drawing.Common/src/System/Drawing/Graphics.Unix.cs

@@ -583,6 +583,7 @@ public object GetContextInfo()
             throw new NotImplementedException();
         }
 
+#if NETCOREAPP3_1_OR_GREATER
         [EditorBrowsable(EditorBrowsableState.Never)]
         [SupportedOSPlatform("windows")]
         public void GetContextInfo(out PointF offset)
@@ -596,6 +597,7 @@ public void GetContextInfo(out PointF offset, out Region? clip)
         {
             throw new PlatformNotSupportedException();
         }
+#endif
 
         private void CheckErrorStatus(int status)
         {

src/libraries/System.Drawing.Common/src/System/Drawing/Graphics.Windows.cs

@@ -684,7 +684,9 @@ public unsafe void EnumerateMetafile(
         /// WARNING: This method is for internal FX support only.
         /// </summary>
         [EditorBrowsable(EditorBrowsableState.Never)]
+#if NETCOREAPP3_1_OR_GREATER
         [Obsolete(Obsoletions.GetContextInfoMessage, DiagnosticId = Obsoletions.GetContextInfoDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
+#endif
         [SupportedOSPlatform("windows")]
         public object GetContextInfo()
         {
@@ -763,6 +765,7 @@ private void GetContextInfo(out Matrix3x2 cumulativeTransform, bool calculateCli
             }
         }
 
+#if NETCOREAPP3_1_OR_GREATER
         /// <summary>
         ///  Gets the cumulative offset.
         /// </summary>
@@ -789,6 +792,7 @@ public void GetContextInfo(out PointF offset, out Region? clip)
             Vector2 translation = cumulativeTransform.Translation;
             offset = new PointF(translation.X, translation.Y);
         }
+#endif
 
         public RectangleF VisibleClipBounds
         {

src/libraries/System.Drawing.Common/src/misc/GDI/WindowsGraphics.cs

@@ -61,6 +61,7 @@ public static WindowsGraphics FromGraphics(Graphics g, ApplyGraphicsProperties p
             {
                 Region? clip = null;
 
+#if NETCOREAPP3_1_OR_GREATER
                 if (properties.HasFlag(ApplyGraphicsProperties.Clipping))
                 {
                     g.GetContextInfo(out offset, out clip);
@@ -69,6 +70,21 @@ public static WindowsGraphics FromGraphics(Graphics g, ApplyGraphicsProperties p
                 {
                     g.GetContextInfo(out offset);
                 }
+#else
+                Matrix? worldTransf = null;
+                if (g.GetContextInfo() is object[] data && data.Length == 2)
+                {
+                    if (properties.HasFlag(ApplyGraphicsProperties.Clipping))
+                    {
+                        clip = data[0] as Region;
+                    }
+                    worldTransf = data[1] as Matrix;
+                    if (worldTransf != null)
+                    {
+                        offset = worldTransf.Offset;
+                    }
+                }
+#endif
 
                 if (clip is not null)
                 {