patch 9.2.0321: MS-Windows: No OpenType font support

Problem:  MS-Windows: No OpenType font support
Solution: Allow specifying OpenType font features directly in 'guifont'
          (Yasuhiro Matsumoto).

Allow specifying OpenType font features directly in 'guifont' using
the ':f' option (e.g., :set guifont=Cascadia_Code:h14:fss19=1:fcalt=0).
Each ':fXXXX=N' sets a single OpenType feature tag with a parameter
value.  Multiple features can be specified by repeating the ':f' option.

This only takes effect when 'renderoptions' is set to use DirectWrite
(type:directx).  Default features (calt, liga, clig, rlig, kern) are
preserved unless explicitly overridden.

closes: #19857

Signed-off-by: Yasuhiro Matsumoto <mattn.jp@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/gui.txt

@@ -1,4 +1,4 @@
-*gui.txt*	For Vim version 9.2.  Last change: 2026 Feb 14
+*gui.txt*	For Vim version 9.2.  Last change: 2026 Apr 07
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -1150,11 +1150,22 @@ For the Win32 GUI					*E244* *E245*
 	      NONANTIALIASED, CLEARTYPE and DEFAULT.  Normally you would use
 	      "qDEFAULT".
 	      Some quality values are not supported in legacy OSs.
+	fXX - OpenType font feature.  Specify a single feature as
+	      tag=value, where tag is a 4-character OpenType feature
+	      tag and value is the parameter (0 to disable, 1 or
+	      higher to enable/select variant).  Multiple features
+	      can be specified by repeating the ":f" option.
+	      This only takes effect when 'renderoptions' is set to use
+	      DirectWrite (type:directx).  Default features (calt, liga,
+	      etc.) are preserved unless explicitly overridden.
+	      Example: ":fss19=1:fcalt=0" enables Stylistic Set 19
+	      and disables Contextual Alternates.
 - A '_' can be used in the place of a space, so you don't need to use
   backslashes to escape the spaces.
 Examples: >
     :set guifont=courier_new:h12:w5:b:cRUSSIAN
     :set guifont=Andale_Mono:h7.5:w4.5
+    :set guifont=Cascadia_Code:h14:fss19=1:fcalt=1:fliga=1
 
 See also |font-sizes|.
 

runtime/doc/version9.txt

@@ -52614,12 +52614,16 @@ Other ~
 - |system()| and |systemlist()| functions accept a list as first argument,
   bypassing the shell completely.
 
+Platform specific ~
+-----------------
+- support OpenType font features in 'guifont' for DirectWrite (Win32)
+
 xxd ~
 ---
 Add "-t" option to append a terminating NUL byte to C include output (-i).
 
 							*changed-9.3*
-Changed~
+Changed ~
 -------
 - Support for NeXTStep was dropped with patch v9.2.0122
 - |json_decode()| is stricter: keywords must be lowercase, lone surrogates are

src/gui_dwrite.cpp

@@ -313,6 +313,9 @@ struct DWriteContext {
 
     D2D1_TEXT_ANTIALIAS_MODE mTextAntialiasMode;
 
+    DWriteFontFeature mFontFeatures[DWRITE_MAX_FONT_FEATURES];
+    int mFontFeatureCount;
+
     // METHODS
 
     DWriteContext();
@@ -357,6 +360,8 @@ struct DWriteContext {
 
     DWriteRenderingParams *GetRenderingParams(
 	    DWriteRenderingParams *params);
+
+    void SetFontFeatures(const DWriteFontFeature *features, int count);
 };
 
 class AdjustedGlyphRun : public DWRITE_GLYPH_RUN
@@ -648,8 +653,10 @@ DWriteContext::DWriteContext() :
     mFontStyle(DWRITE_FONT_STYLE_NORMAL),
     mFontSize(0.0f),
     mFontAscent(0.0f),
-    mTextAntialiasMode(D2D1_TEXT_ANTIALIAS_MODE_DEFAULT)
+    mTextAntialiasMode(D2D1_TEXT_ANTIALIAS_MODE_DEFAULT),
+    mFontFeatureCount(0)
 {
+    ZeroMemory(mFontFeatures, sizeof(mFontFeatures));
     HRESULT hr;
 
     hr = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,
@@ -1086,6 +1093,56 @@ DWriteContext::DrawText(const WCHAR *text, int len,
 	textLayout->SetFontWeight(mFontWeight, textRange);
 	textLayout->SetFontStyle(mFontStyle, textRange);
 
+	if (mFontFeatureCount > 0)
+	{
+	    // Default OpenType features that DirectWrite normally enables.
+	    // SetTypography() overrides all defaults, so we must
+	    // re-add them here explicitly.
+	    static const DWRITE_FONT_FEATURE defaultFeatures[] = {
+		{ DWRITE_FONT_FEATURE_TAG_CONTEXTUAL_ALTERNATES, 1 },
+		{ DWRITE_FONT_FEATURE_TAG_STANDARD_LIGATURES, 1 },
+		{ DWRITE_FONT_FEATURE_TAG_CONTEXTUAL_LIGATURES, 1 },
+		{ DWRITE_FONT_FEATURE_TAG_REQUIRED_LIGATURES, 1 },
+		{ DWRITE_FONT_FEATURE_TAG_KERNING, 1 },
+	    };
+	    static const int numDefaults = sizeof(defaultFeatures)
+		/ sizeof(defaultFeatures[0]);
+
+	    IDWriteTypography *typography = NULL;
+	    hr = mDWriteFactory->CreateTypography(&typography);
+	    if (SUCCEEDED(hr))
+	    {
+		// Add default features, skipping any that the user
+		// has explicitly specified (either + or -).
+		for (int d = 0; d < numDefaults; ++d)
+		{
+		    int overridden = 0;
+		    for (int u = 0; u < mFontFeatureCount; ++u)
+		    {
+			if ((DWRITE_FONT_FEATURE_TAG)mFontFeatures[u].tag
+				== defaultFeatures[d].nameTag)
+			{
+			    overridden = 1;
+			    break;
+			}
+		    }
+		    if (!overridden)
+			typography->AddFontFeature(defaultFeatures[d]);
+		}
+		// Add user-specified features.
+		for (int i = 0; i < mFontFeatureCount; ++i)
+		{
+		    DWRITE_FONT_FEATURE ff = {
+			(DWRITE_FONT_FEATURE_TAG)mFontFeatures[i].tag,
+			mFontFeatures[i].parameter
+		    };
+		    typography->AddFontFeature(ff);
+		}
+		textLayout->SetTypography(typography, textRange);
+		SafeRelease(&typography);
+	    }
+	}
+
 	// Calculate baseline using font ascent from font metrics.
 	// Do NOT use GetLineMetrics() because it returns different values
 	// depending on text content (e.g., when CJK characters trigger
@@ -1413,3 +1470,24 @@ DWriteContext_GetRenderingParams(
     else
 	return NULL;
 }
+
+    void
+DWriteContext::SetFontFeatures(
+	const DWriteFontFeature *features, int count)
+{
+    if (count > DWRITE_MAX_FONT_FEATURES)
+	count = DWRITE_MAX_FONT_FEATURES;
+    mFontFeatureCount = count;
+    if (count > 0 && features != NULL)
+	memcpy(mFontFeatures, features, sizeof(DWriteFontFeature) * count);
+}
+
+    void
+DWriteContext_SetFontFeatures(
+	DWriteContext *ctx,
+	const DWriteFontFeature *features,
+	int count)
+{
+    if (ctx != NULL)
+	ctx->SetFontFeatures(features, count);
+}

src/gui_dwrite.h

@@ -51,6 +51,13 @@ typedef struct DWriteRenderingParams {
     int textAntialiasMode;
 } DWriteRenderingParams;
 
+#define DWRITE_MAX_FONT_FEATURES 32
+
+typedef struct DWriteFontFeature {
+    unsigned int tag;	    // OpenType feature tag (4 bytes)
+    unsigned int parameter; // Feature parameter (0 = disable, 1 = enable)
+} DWriteFontFeature;
+
 void DWrite_Init(void);
 void DWrite_Final(void);
 
@@ -86,6 +93,11 @@ DWriteRenderingParams *DWriteContext_GetRenderingParams(
 	DWriteContext *ctx,
 	DWriteRenderingParams *params);
 
+void DWriteContext_SetFontFeatures(
+	DWriteContext *ctx,
+	const DWriteFontFeature *features,
+	int count);
+
 #ifdef __cplusplus
 }
 #endif

src/gui_w32.c

@@ -145,7 +145,6 @@ gui_mch_set_rendering_options(char_u *s)
     int	    dx_geom = 0;
     int	    dx_renmode = 0;
     int	    dx_taamode = 0;
-
     // parse string as rendering options.
     for (p = s; p != NULL && *p != NUL; )
     {
@@ -3956,6 +3955,60 @@ gui_mch_init_font(char_u *font_name, int fontset UNUSED)
     if (font == NOFONT)
 	return FAIL;
 
+#if defined(FEAT_DIRECTX)
+    // Parse font features from guifont (e.g., ":fss19=1:fcalt=0:fliga=1").
+    {
+	DWriteFontFeature features[DWRITE_MAX_FONT_FEATURES];
+	int		    feat_count = 0;
+	char_u		    *fp;
+
+	if (font_name != NULL)
+	{
+	    // Find each ":f" option in font_name.
+	    for (fp = font_name; *fp != NUL; fp++)
+	    {
+		if (*fp == ':' && *(fp + 1) == 'f')
+		{
+		    char_u tag[5];
+		    int    ti = 0;
+		    unsigned int param = 1;
+
+		    fp += 2;  // skip ":f"
+		    while (*fp != NUL && *fp != '=' && *fp != ':'
+			    && ti < 4)
+			tag[ti++] = *fp++;
+		    tag[ti] = NUL;
+
+		    if (ti != 4)
+			continue;  // invalid tag length
+
+		    if (*fp == '=')
+		    {
+			fp++;
+			param = (unsigned int)atoi((char *)fp);
+			while (*fp >= '0' && *fp <= '9')
+			    fp++;
+		    }
+
+		    if (feat_count < DWRITE_MAX_FONT_FEATURES)
+		    {
+			features[feat_count].tag =
+			    ((unsigned int)tag[0])
+			    | ((unsigned int)tag[1] << 8)
+			    | ((unsigned int)tag[2] << 16)
+			    | ((unsigned int)tag[3] << 24);
+			features[feat_count].parameter = param;
+			feat_count++;
+		    }
+
+		    fp--;  // adjust for loop increment
+		}
+	    }
+	}
+	DWriteContext_SetFontFeatures(s_dwc, features, feat_count);
+    }
+#endif
+
     if (font_name == NULL)
 	font_name = (char_u *)"";
 #ifdef FEAT_MBYTE_IME

src/os_mswin.c

@@ -3210,6 +3210,12 @@ get_logfont(
 		    }
 		}
 		break;
+	    case L'f':
+		// Font features (e.g., "fss19=1").
+		// Parsed separately by gui_mch_init_font(); skip here.
+		while (*p && *p != L':')
+		    p++;
+		break;
 	    case L'q':
 		for (i = 0; i < (int)ARRAY_LENGTH(quality_pairs); ++i)
 		{

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    321,
 /**/
     320,
 /**/