From 653fc8d97fc3e7c8f45008155bf8d253d5e8b383 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fridrich=20=C5=A0trba?= <fridrich.strba@bluewin.ch>
Date: Thu, 9 May 2013 23:28:51 +0200
Subject: [PATCH] Fix Uniscribe backend on Windows XP

Call the OpenType functions (that are Vista+ only) over function
pointers and if they are not present in usp10.dll, fall back to
the ScriptItemize, ScriptShape and ScriptPlace that are present on
Windows XP too.
---
 src/hb-uniscribe.cc | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 62 insertions(+), 3 deletions(-)

diff --git a/src/hb-uniscribe.cc b/src/hb-uniscribe.cc
index 2f01c28..b4fafb3 100644
--- a/src/hb-uniscribe.cc
+++ b/src/hb-uniscribe.cc
@@ -44,6 +44,10 @@
 #endif
 
 
+typedef HRESULT WINAPI (*SIOT)(const WCHAR*,int,int,const SCRIPT_CONTROL*,const SCRIPT_STATE*,SCRIPT_ITEM*,OPENTYPE_TAG*,int*);
+typedef HRESULT WINAPI (*SSOT)(HDC,SCRIPT_CACHE*,SCRIPT_ANALYSIS*,OPENTYPE_TAG,OPENTYPE_TAG,int*,TEXTRANGE_PROPERTIES**,int,const WCHAR*,int,int,WORD*,SCRIPT_CHARPROP*,WORD*,SCRIPT_GLYPHPROP*,int*);
+typedef HRESULT WINAPI (*SPOT)(HDC,SCRIPT_CACHE*,SCRIPT_ANALYSIS*,OPENTYPE_TAG,OPENTYPE_TAG,int*,TEXTRANGE_PROPERTIES**,int,const WCHAR*,const WORD*,const SCRIPT_CHARPROP*,int,const WORD*,const SCRIPT_GLYPHPROP*,int,int*,GOFFSET*,ABC*);
+
 /*
 DWORD GetFontData(
   __in   HDC hdc,
@@ -240,6 +244,11 @@ _hb_uniscribe_shape (hb_shape_plan_t    *shape_plan,
   hb_face_t *face = font->face;
   hb_uniscribe_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
   hb_uniscribe_shaper_font_data_t *font_data = HB_SHAPER_DATA_GET (font);
+  SIOT siot = NULL;
+  SSOT ssot = NULL;
+  SPOT spot = NULL;
+  HMODULE hinstLib = GetModuleHandle("usp10.dll");
+    
 
 #define FAIL(...) \
   HB_STMT_START { \
@@ -249,6 +258,15 @@ _hb_uniscribe_shape (hb_shape_plan_t    *shape_plan,
 
   HRESULT hr;
 
+  if (hinstLib)
+  {
+    siot = (SIOT)GetProcAddress(hinstLib, "ScriptItemizeOpenType");
+  
+    ssot = (SSOT)GetProcAddress(hinstLib, "ScriptShapeOpenType");
+  
+    spot = (SPOT)GetProcAddress(hinstLib, "ScriptPlaceOpenType");
+  }
+  
 retry:
 
   unsigned int scratch_size;
@@ -291,6 +309,7 @@ retry:
 
   ALLOCATE_ARRAY (WORD, glyphs, glyphs_size);
   ALLOCATE_ARRAY (SCRIPT_GLYPHPROP, glyph_props, glyphs_size);
+  ALLOCATE_ARRAY (SCRIPT_VISATTR, vis_attr, glyphs_size);
   ALLOCATE_ARRAY (int, advances, glyphs_size);
   ALLOCATE_ARRAY (GOFFSET, offsets, glyphs_size);
   ALLOCATE_ARRAY (uint32_t, vis_clusters, glyphs_size);
@@ -312,7 +331,8 @@ retry:
   bidi_state.uBidiLevel = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;
   bidi_state.fOverrideDirection = 1;
 
-  hr = ScriptItemizeOpenType (wchars,
+  if (siot && ssot && spot) {
+    hr = siot (wchars,
 			      chars_len,
 			      MAX_ITEMS,
 			      &bidi_control,
@@ -320,6 +340,16 @@ retry:
 			      items,
 			      script_tags,
 			      &item_count);
+  }
+  else {
+    hr = ScriptItemize(wchars,
+			        chars_len,
+			        MAX_ITEMS,
+			        &bidi_control,
+			        &bidi_state,
+			        items,
+			        &item_count);
+  }
   if (unlikely (FAILED (hr)))
     FAIL ("ScriptItemizeOpenType() failed: 0x%08xL", hr);
 
@@ -344,7 +374,8 @@ retry:
     unsigned int item_chars_len = items[i + 1].iCharPos - chars_offset;
 
   retry_shape:
-    hr = ScriptShapeOpenType (font_data->hdc,
+    if (siot && ssot && spot) {
+      hr = ssot (font_data->hdc,
 			      &font_data->script_cache,
 			      &items[i].a,
 			      script_tags[i],
@@ -361,6 +392,20 @@ retry:
 			      glyphs + glyphs_offset,
 			      glyph_props + glyphs_offset,
 			      (int *) &glyphs_len);
+    }
+	else {
+      hr = ScriptShape (font_data->hdc,
+			        &font_data->script_cache,
+			        wchars + chars_offset,
+			        item_chars_len,
+			        glyphs_size - glyphs_offset,
+			        &items[i].a,
+			        /* out */
+			        glyphs + glyphs_offset,
+			        log_clusters + chars_offset,
+			        vis_attr + glyphs_offset,
+			        (int *) &glyphs_len);
+	}
 
     if (unlikely (items[i].a.fNoGlyphIndex))
       FAIL ("ScriptShapeOpenType() set fNoGlyphIndex");
@@ -386,7 +431,8 @@ retry:
     for (unsigned int j = chars_offset; j < chars_offset + item_chars_len; j++)
       log_clusters[j] += glyphs_offset;
 
-    hr = ScriptPlaceOpenType (font_data->hdc,
+    if (siot && ssot && spot) {
+      hr = spot (font_data->hdc,
 			      &font_data->script_cache,
 			      &items[i].a,
 			      script_tags[i],
@@ -405,6 +451,19 @@ retry:
 			      advances + glyphs_offset,
 			      offsets + glyphs_offset,
 			      NULL);
+    }
+	else {
+      hr = ScriptPlace (font_data->hdc,
+			        &font_data->script_cache,
+			        glyphs + glyphs_offset,
+			        glyphs_len,
+			        vis_attr + glyphs_offset,
+			        &items[i].a,
+			        /* out */
+			        advances + glyphs_offset,
+			        offsets + glyphs_offset,
+			        NULL);
+    }
     if (unlikely (FAILED (hr)))
       FAIL ("ScriptPlaceOpenType() failed: 0x%08xL", hr);
 
-- 
1.8.2.2