Properly apply translation and clipping in TextRenderer (#4525)

Translation and clipping should only be applied from Graphics objects when they are explicitly asked for in the TextFormatFlags.

Adds regression tests.

Fixes #4524

src/System.Windows.Forms.Primitives/src/Interop/Gdi32/Interop.HENHMETAFILE.cs

@@ -17,6 +17,7 @@ internal static partial class Gdi32
             public bool IsNull => Handle == IntPtr.Zero;
 
             public static explicit operator IntPtr(HENHMETAFILE hmetafile) => hmetafile.Handle;
+            public static explicit operator HENHMETAFILE(IntPtr hmetafile) => new HENHMETAFILE(hmetafile);
         }
     }
 }

src/System.Windows.Forms.Primitives/tests/TestUtilities/Metafiles/EmfScope.cs

@@ -14,7 +14,7 @@ namespace System.Windows.Forms.Metafiles
     internal class EmfScope : DisposalTracking.Tracker, IDisposable
     {
         public Gdi32.HDC HDC { get; }
-        private Gdi32.HENHMETAFILE _hmf;
+        private Gdi32.HENHMETAFILE _hemf;
 
         public unsafe EmfScope()
             : this (Gdi32.CreateEnhMetaFileW(hdc: default, lpFilename: null, lprc: null, lpDesc: null))
@@ -24,7 +24,12 @@ public unsafe EmfScope()
         public EmfScope(Gdi32.HDC hdc)
         {
             HDC = hdc;
-            _hmf = default;
+            _hemf = default;
+        }
+
+        public EmfScope(Gdi32.HENHMETAFILE hemf)
+        {
+            _hemf = hemf;
         }
 
         public unsafe static EmfScope Create() => new EmfScope();
@@ -33,17 +38,17 @@ public Gdi32.HENHMETAFILE HENHMETAFILE
         {
             get
             {
-                if (HDC.IsNull)
+                if (_hemf.IsNull)
                 {
-                    return default;
-                }
+                    if (HDC.IsNull)
+                    {
+                        return default;
+                    }
 
-                if (_hmf.IsNull)
-                {
-                    _hmf = Gdi32.CloseEnhMetaFile(HDC);
+                    _hemf = Gdi32.CloseEnhMetaFile(HDC);
                 }
 
-                return _hmf;
+                return _hemf;
             }
         }
 

src/System.Windows.Forms/src/System/Windows/Forms/TextRenderer.cs

@@ -4,7 +4,6 @@
 
 using System.Drawing;
 using System.Drawing.Text;
-using System.Windows.Forms.Internal;
 using static Interop;
 
 namespace System.Windows.Forms
@@ -301,7 +300,7 @@ public static void DrawText(IDeviceContext dc, string? text, Font? font, Rectang
             // This MUST come before retreiving the HDC, which locks the Graphics object
             Gdi32.QUALITY quality = FontQualityFromTextRenderingHint(dc);
 
-            using var hdc = new DeviceContextHdcScope(dc);
+            using var hdc = new DeviceContextHdcScope(dc, GetApplyStateFlags(dc, flags));
 
             DrawTextInternal(hdc, text, font, bounds, foreColor, quality, backColor, flags);
         }
@@ -534,7 +533,9 @@ public static Size MeasureText(IDeviceContext dc, ReadOnlySpan<char> text, Font?
             // This MUST come before retreiving the HDC, which locks the Graphics object
             Gdi32.QUALITY quality = FontQualityFromTextRenderingHint(dc);
 
-            using var hdc = new DeviceContextHdcScope(dc);
+            // Applying state may not impact text size measurements. Rather than risk missing some
+            // case we'll apply as we have historically to avoid suprise regressions.
+            using var hdc = new DeviceContextHdcScope(dc, GetApplyStateFlags(dc, flags));
             using var hfont = GdiCache.GetHFONT(font, quality, hdc);
             return hdc.HDC.MeasureText(text, hfont, proposedSize, flags);
         }
@@ -596,5 +597,29 @@ private static Gdi32.QUALITY GetDefaultFontQuality()
             return SystemInformation.FontSmoothingType == 0x0002
                 ? Gdi32.QUALITY.CLEARTYPE : Gdi32.QUALITY.ANTIALIASED;
         }
+
+        /// <summary>
+        ///  Gets the proper <see cref="ApplyGraphicsProperties"/> flags for the given <paramref name="textFormatFlags"/>.
+        /// </summary>
+        private static ApplyGraphicsProperties GetApplyStateFlags(IDeviceContext deviceContext, TextFormatFlags textFormatFlags)
+        {
+            if (deviceContext is not Graphics)
+            {
+                return ApplyGraphicsProperties.None;
+            }
+
+            var apply = ApplyGraphicsProperties.None;
+            if (textFormatFlags.HasFlag(TextFormatFlags.PreserveGraphicsClipping))
+            {
+                apply |= ApplyGraphicsProperties.Clipping;
+            }
+
+            if (textFormatFlags.HasFlag(TextFormatFlags.PreserveGraphicsTranslateTransform))
+            {
+                apply |= ApplyGraphicsProperties.TranslateTransform;
+            }
+
+            return apply;
+        }
     }
 }

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/TextRendererTests.cs

@@ -4,7 +4,10 @@
 
 using System.Collections.Generic;
 using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Drawing.Imaging;
 using System.Drawing.Text;
+using System.IO;
 using System.Windows.Forms.Metafiles;
 using Moq;
 using WinForms.Common.Tests;
@@ -829,5 +832,87 @@ public void TextRenderer_MeasureText_Padding(TextFormatFlags flags, Size expecte
                 { TextFormatFlags.LeftAndRightPadding, new Size(82, 13) },
                 { TextFormatFlags.NoPadding, new Size(71, 13) }
             };
+
+        [WinFormsTheory]
+        [MemberData(nameof(TextRenderer_DrawText_ApplyState_TestData))]
+        public void TextRenderer_DrawText_ApplyState(TextFormatFlags flags, Rectangle expectedBounds)
+        {
+            using var hdc = new Interop.Gdi32.CreateDcScope(default);
+            DeviceContextState state = new DeviceContextState(hdc);
+
+            using MemoryStream stream = new MemoryStream(1024);
+            using (Metafile metafileRecorder = new Metafile(stream, hdc.HDC.Handle, EmfType.EmfOnly))
+            using (Graphics graphics = Graphics.FromImage(metafileRecorder))
+            {
+                using Matrix matrix = new Matrix();
+                matrix.Translate(5, 10);
+                graphics.Transform = matrix;
+                using Region region = new(new Rectangle(1, 2, 6, 8));
+                graphics.Clip = region;
+
+                TextRenderer.DrawText(
+                    graphics,
+                    "Landshark",
+                    SystemFonts.DefaultFont,
+                    new Rectangle(0, 0, int.MaxValue, int.MaxValue),
+                    Color.Red,
+                    flags);
+            }
+
+            // Need to queue the stream back to the beginning for the reader
+            stream.Position = 0;
+            using Metafile metafile = new Metafile(stream);
+            using var emf = new EmfScope((Interop.Gdi32.HENHMETAFILE)metafile.GetHenhmetafile());
+
+            emf.Validate(
+                state,
+                Validate.TextOut(
+                    "Landshark",
+                    expectedBounds,
+                    State.FontFace(SystemFonts.DefaultFont.Name),
+                    State.TextColor(Color.Red)));
+        }
+
+        public static TheoryData<TextFormatFlags, Rectangle> TextRenderer_DrawText_ApplyState_TestData
+            => new TheoryData<TextFormatFlags, Rectangle>
+            {
+                { TextFormatFlags.Default, new Rectangle(3, 0, 49, 12) },
+                { TextFormatFlags.PreserveGraphicsTranslateTransform, new Rectangle(8, 10, 49, 12) },
+                { TextFormatFlags.PreserveGraphicsClipping, new Rectangle(6, 12, 5, 0) },
+                { TextFormatFlags.PreserveGraphicsClipping | TextFormatFlags.PreserveGraphicsTranslateTransform, new Rectangle(8, 12, 3, 7) },
+            };
+
+        [WinFormsTheory]
+        [MemberData(nameof(TextRenderer_MeasureText_ApplyState_TestData))]
+        public void TextRenderer_MeasureText_ApplyState(TextFormatFlags flags, Size expectedSize)
+        {
+            using var image = new Bitmap(200, 50);
+            using Graphics graphics = Graphics.FromImage(image);
+            using Matrix matrix = new Matrix();
+            matrix.Translate(5, 10);
+            graphics.Transform = matrix;
+            using Region region = new(new Rectangle(1, 2, 6, 8));
+            graphics.Clip = region;
+
+            Size size = TextRenderer.MeasureText(
+                graphics,
+                "Landshark",
+                SystemFonts.DefaultFont,
+                new Size(int.MaxValue, int.MaxValue),
+                flags);
+
+            Assert.Equal(expectedSize, size);
+        }
+
+        public static TheoryData<TextFormatFlags, Size> TextRenderer_MeasureText_ApplyState_TestData
+            => new TheoryData<TextFormatFlags, Size>
+            {
+                // State application doesn't practially impact size measurements, but we still want to have a regession test
+                // here in case something sneaks in.
+                { TextFormatFlags.Default, new Size(57, 13) },
+                { TextFormatFlags.PreserveGraphicsTranslateTransform, new Size(57, 13) },
+                { TextFormatFlags.PreserveGraphicsClipping, new Size(57, 13) },
+                { TextFormatFlags.PreserveGraphicsClipping | TextFormatFlags.PreserveGraphicsTranslateTransform, new Size(57, 13) },
+            };
     }
 }