From e294200dac3d7cd41a02e0753f63acfbb5e24820 Mon Sep 17 00:00:00 2001
From: Khaled Hosny <khaled@aliftype.com>
Date: Fri, 15 Jul 2022 21:36:50 +0200
Subject: [PATCH] [ft] Check for FT_Get_Transform at build time

---
 configure.ac |  2 +-
 meson.build  |  1 +
 src/hb-ft.cc | 22 ++++++++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 8873907de..aec960090 100644
--- a/configure.ac
+++ b/configure.ac
@@ -308,7 +308,7 @@ if $have_freetype; then
 	AC_DEFINE(HAVE_FREETYPE, 1, [Have FreeType 2 library])
 	save_libs=$LIBS
 	LIBS="$LIBS $FREETYPE_LIBS"
-	AC_CHECK_FUNCS(FT_Get_Var_Blend_Coordinates FT_Set_Var_Blend_Coordinates FT_Done_MM_Var)
+	AC_CHECK_FUNCS(FT_Get_Var_Blend_Coordinates FT_Set_Var_Blend_Coordinates FT_Done_MM_Var FT_Get_Transform)
 	LIBS=$save_libs
 fi
 AM_CONDITIONAL(HAVE_FREETYPE, $have_freetype)
diff --git a/meson.build b/meson.build
index 8039efdc2..d6a206e25 100644
--- a/meson.build
+++ b/meson.build
@@ -198,6 +198,7 @@ if freetype_dep.found()
     ['FT_Get_Var_Blend_Coordinates', {'deps': freetype_dep}],
     ['FT_Set_Var_Blend_Coordinates', {'deps': freetype_dep}],
     ['FT_Done_MM_Var', {'deps': freetype_dep}],
+    ['FT_Get_Transform', {'deps': freetype_dep}],
   ]
 
   if freetype_dep.type_name() == 'internal'
diff --git a/src/hb-ft.cc b/src/hb-ft.cc
index 8b1128bea..dd2cbbc44 100644
--- a/src/hb-ft.cc
+++ b/src/hb-ft.cc
@@ -422,9 +422,13 @@ hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
   hb_lock_t lock (ft_font->lock);
   FT_Face ft_face = ft_font->ft_face;
   int load_flags = ft_font->load_flags;
+#ifdef HAVE_FT_GET_TRANSFORM
   FT_Matrix matrix;
   FT_Get_Transform (ft_face, &matrix, nullptr);
   float mult = matrix.xx / 65536.f;
+#else
+  float mult = font->x_scale < 0 ? -1 : +1;
+#endif
 
   for (unsigned int i = 0; i < count; i++)
   {
@@ -456,9 +460,13 @@ hb_ft_get_glyph_v_advance (hb_font_t *font,
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
   hb_lock_t lock (ft_font->lock);
   FT_Fixed v;
+#ifdef HAVE_FT_GET_TRANSFORM
   FT_Matrix matrix;
   FT_Get_Transform (ft_font->ft_face, &matrix, nullptr);
   float y_mult = matrix.yy / 65536.f;
+#else
+  float y_mult = font->y_scale < 0 ? -1 : +1;
+#endif
 
   if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v)))
     return 0;
@@ -484,10 +492,15 @@ hb_ft_get_glyph_v_origin (hb_font_t *font,
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
   hb_lock_t lock (ft_font->lock);
   FT_Face ft_face = ft_font->ft_face;
+#ifdef HAVE_FT_GET_TRANSFORM
   FT_Matrix matrix;
   FT_Get_Transform (ft_face, &matrix, nullptr);
   float x_mult = matrix.xx / 65536.f;
   float y_mult = matrix.yy / 65536.f;
+#else
+  float x_mult = font->x_scale < 0 ? -1 : +1;
+  float y_mult = font->y_scale < 0 ? -1 : +1;
+#endif
 
   if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
     return false;
@@ -534,10 +547,15 @@ hb_ft_get_glyph_extents (hb_font_t *font,
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
   hb_lock_t lock (ft_font->lock);
   FT_Face ft_face = ft_font->ft_face;
+#ifdef HAVE_FT_GET_TRANSFORM
   FT_Matrix matrix;
   FT_Get_Transform (ft_face, &matrix, nullptr);
   float x_mult = matrix.xx / 65536.f;
   float y_mult = matrix.yy / 65536.f;
+#else
+  float x_mult = font->x_scale < 0 ? -1 : +1;
+  float y_mult = font->y_scale < 0 ? -1 : +1;
+#endif
 
   if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
     return false;
@@ -639,9 +657,13 @@ hb_ft_get_font_h_extents (hb_font_t *font HB_UNUSED,
   const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
   hb_lock_t lock (ft_font->lock);
   FT_Face ft_face = ft_font->ft_face;
+#ifdef HAVE_FT_GET_TRANSFORM
   FT_Matrix matrix;
   FT_Get_Transform (ft_face, &matrix, nullptr);
   float y_mult = matrix.yy / 65536.f;
+#else
+  float y_mult = font->y_scale < 0 ? -1 : +1;
+#endif
 
   metrics->ascender = FT_MulFix(ft_face->ascender, ft_face->size->metrics.y_scale);
   metrics->descender = FT_MulFix(ft_face->descender, ft_face->size->metrics.y_scale);