Force LTR / logical order for text in GdiEngine (microsoft#12722)

Some applications like `vim -H` implement their own BiDi reordering.
Previously we used `PolyTextOutW` which supported such arrangements,
but with a0527a1 and the switch to `ExtTextOutW` we broke such applications.
This commit restores the old behavior by reimplementing the basics
of `ExtTextOutW`'s internal workings while enforcing LTR ordering.

## Validation Steps Performed
* Create a text file with "ץחסק פחופפסנ חס קוח ז׳חסש ץקקטק פחטסץ"
  Viewing the text file with `vim -H` presents the contents as expected ✅
* Printing enwik8 is as fast as before ✅
* Font fallback for various eastern scripts in enwik8 works as expected ✅
* `DECDWL` double-width sequences ✅
* Horizontal scrolling (apart from producing expected artifacts) ✅

Closes microsoft#12294

(cherry picked from commit d97d9f0)

.github/actions/spelling/expect/expect.txt

@@ -239,6 +239,7 @@ CHARSETINFO
 chcp
 checkbox
 checkboxes
+Checkin
 chh
 Childitem
 chk
@@ -915,6 +916,7 @@ getwriter
 GFEh
 Gfun
 gfx
+GGI
 GHIJK
 GHIJKL
 GHIJKLM
@@ -1092,6 +1094,7 @@ ifndef
 IFont
 ifstream
 IGNOREEND
+IGNORELANGUAGE
 IHigh
 IHosted
 iid
@@ -1458,6 +1461,7 @@ mscorlib
 msctf
 msctls
 msdata
+MSDL
 msdn
 msft
 MSGCMDLINEF
@@ -2229,6 +2233,7 @@ srect
 srv
 srvinit
 srvpipe
+ssa
 ssh
 sstream
 stackoverflow
@@ -2554,6 +2559,7 @@ USESHOWWINDOW
 USESIZE
 USESTDHANDLES
 ushort
+usp
 USRDLL
 utf
 utils

src/renderer/gdi/gdirenderer.hpp

@@ -91,6 +91,8 @@ namespace Microsoft::Console::Render
                                                             const int nIndex,
                                                             const LONG dwNewLong) noexcept;
 
+        static bool FontHasWesternScript(HDC hdc);
+
         bool _fPaintStarted;
 
         til::rect _invalidCharacters;
@@ -138,13 +140,15 @@ namespace Microsoft::Console::Render
         COLORREF _lastFg;
         COLORREF _lastBg;
 
-        enum class FontType : size_t
+        enum class FontType : uint8_t
         {
+            Undefined,
             Default,
             Italic,
             Soft
         };
         FontType _lastFontType;
+        bool _fontHasWesternScript = false;
 
         XFORM _currentLineTransform;
         LineRendition _currentLineRendition;

src/renderer/gdi/lib/gdi.vcxproj

@@ -6,7 +6,7 @@
     <RootNamespace>gdi</RootNamespace>
     <ProjectName>RendererGdi</ProjectName>
     <TargetName>ConRenderGdi</TargetName>
-    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <ConfigurationType>StaticLibrary</ConfigurationType>
   </PropertyGroup>
   <Import Project="$(SolutionDir)src\common.build.pre.props" />
   <ItemGroup>
@@ -22,6 +22,11 @@
     <ClInclude Include="..\gdirenderer.hpp" />
     <ClInclude Include="..\precomp.h" />
   </ItemGroup>
+  <ItemDefinitionGroup>
+    <Lib>
+      <AdditionalDependencies>usp10.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Lib>
+  </ItemDefinitionGroup>
   <!-- Careful reordering these. Some default props (contained in these files) are order sensitive. -->
   <Import Project="$(SolutionDir)src\common.build.post.props" />
 </Project>

src/renderer/gdi/paint.cpp

@@ -11,6 +11,15 @@
 
 using namespace Microsoft::Console::Render;
 
+// This is an excerpt of GDI's FontHasWesternScript() as
+// used by InternalTextOut() which is part of ExtTextOutW().
+bool GdiEngine::FontHasWesternScript(HDC hdc)
+{
+    WORD glyphs[4];
+    return (GetGlyphIndicesW(hdc, L"dMr\"", 4, glyphs, GGI_MARK_NONEXISTING_GLYPHS) == 4) &&
+           (glyphs[0] != 0xFFFF && glyphs[1] != 0xFFFF && glyphs[2] != 0xFFFF && glyphs[3] != 0xFFFF);
+}
+
 // Routine Description:
 // - Prepares internal structures for a painting operation.
 // Arguments:
@@ -54,6 +63,8 @@ using namespace Microsoft::Console::Render;
     _debugContext = GetDC(_debugWindow);
 #endif
 
+    _lastFontType = FontType::Undefined;
+
     return S_OK;
 }
 
@@ -445,10 +456,42 @@ using namespace Microsoft::Console::Render;
         for (size_t i = 0; i != _cPolyText; ++i)
         {
             const auto& t = _pPolyText[i];
-            if (!ExtTextOutW(_hdcMemoryContext, t.x, t.y, t.uiFlags, &t.rcl, t.lpstr, t.n, t.pdx))
+
+            // The following if/else replicates the essentials of how ExtTextOutW() without ETO_IGNORELANGUAGE works.
+            // See InternalTextOut().
+            //
+            // Unlike the original, we don't check for `GetTextCharacterExtra(hdc) != 0`,
+            // because we don't ever call SetTextCharacterExtra() anyways.
+            //
+            // GH#12294:
+            // Additionally we set ss.fOverrideDirection to TRUE, because we need to present RTL
+            // text in logical order in order to be compatible with applications like `vim -H`.
+            if (_fontHasWesternScript && ScriptIsComplex(t.lpstr, t.n, SIC_COMPLEX) == S_FALSE)
             {
-                hr = E_FAIL;
-                break;
+                if (!ExtTextOutW(_hdcMemoryContext, t.x, t.y, t.uiFlags | ETO_IGNORELANGUAGE, &t.rcl, t.lpstr, t.n, t.pdx))
+                {
+                    hr = E_FAIL;
+                    break;
+                }
+            }
+            else
+            {
+                SCRIPT_STATE ss{};
+                ss.fOverrideDirection = TRUE;
+
+                SCRIPT_STRING_ANALYSIS ssa;
+                hr = ScriptStringAnalyse(_hdcMemoryContext, t.lpstr, t.n, 0, -1, SSA_GLYPHS | SSA_FALLBACK, 0, nullptr, &ss, t.pdx, nullptr, nullptr, &ssa);
+                if (FAILED(hr))
+                {
+                    break;
+                }
+
+                hr = ScriptStringOut(ssa, t.x, t.y, t.uiFlags, &t.rcl, 0, 0, FALSE);
+                std::ignore = ScriptStringFree(&ssa);
+                if (FAILED(hr))
+                {
+                    break;
+                }
             }
         }
 

src/renderer/gdi/precomp.h

@@ -16,8 +16,9 @@ Module Name:
 // This includes support libraries from the CRT, STL, WIL, and GSL
 #include "LibraryIncludes.h"
 
-#include <windows.h>
+#include <Windows.h>
 #include <windowsx.h>
+#include <usp10.h>
 
 #ifndef _NTSTATUS_DEFINED
 #define _NTSTATUS_DEFINED

src/renderer/gdi/state.cpp

@@ -29,7 +29,7 @@ GdiEngine::GdiEngine() :
     _fInvalidRectUsed(false),
     _lastFg(INVALID_COLOR),
     _lastBg(INVALID_COLOR),
-    _lastFontType(FontType::Default),
+    _lastFontType(FontType::Undefined),
     _currentLineTransform(IDENTITY_XFORM),
     _currentLineRendition(LineRendition::SingleWidth),
     _fPaintStarted(false),
@@ -142,15 +142,6 @@ GdiEngine::~GdiEngine()
     _hwndTargetWindow = hwnd;
     _hdcMemoryContext = hdcNewMemoryContext;
 
-    // If we have a font, apply it to the context.
-    if (nullptr != _hfont)
-    {
-        LOG_HR_IF_NULL(E_FAIL, SelectFont(_hdcMemoryContext, _hfont));
-    }
-
-    // Record the fact that the selected font is the default.
-    _lastFontType = FontType::Default;
-
     if (nullptr != hdcRealWindow)
     {
         LOG_HR_IF(E_FAIL, !(ReleaseDC(_hwndTargetWindow, hdcRealWindow)));
@@ -327,6 +318,7 @@ GdiEngine::~GdiEngine()
             break;
         }
         _lastFontType = fontType;
+        _fontHasWesternScript = FontHasWesternScript(_hdcMemoryContext);
     }
 
     return S_OK;
@@ -348,9 +340,6 @@ GdiEngine::~GdiEngine()
     // Select into DC
     RETURN_HR_IF_NULL(E_FAIL, SelectFont(_hdcMemoryContext, hFont.get()));
 
-    // Record the fact that the selected font is the default.
-    _lastFontType = FontType::Default;
-
     // Save off the font metrics for various other calculations
     RETURN_HR_IF(E_FAIL, !(GetTextMetricsW(_hdcMemoryContext, &_tmFontMetrics)));
 
@@ -456,7 +445,9 @@ GdiEngine::~GdiEngine()
                                                 const SIZE cellSize,
                                                 const size_t centeringHint) noexcept
 {
-    // If the soft font is currently selected, replace it with the default font.
+    // If we previously called SelectFont(_hdcMemoryContext, _softFont), it will
+    // still hold a reference to the _softFont object we're planning to overwrite.
+    // --> First revert back to the standard _hfont, lest we have dangling pointers.
     if (_lastFontType == FontType::Soft)
     {
         RETURN_HR_IF_NULL(E_FAIL, SelectFont(_hdcMemoryContext, _hfont));