add a lib for rendering text in sdl2 and rules to make in makefile

SDL2_ttf/external/harfbuzz/util/helper-cairo-ft.hh

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+/*
+ * Copyright © 2022  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HELPER_CAIRO_FT_HH
+#define HELPER_CAIRO_FT_HH
+
+#include "font-options.hh"
+
+#include <cairo-ft.h>
+#include <hb-ft.h>
+#include FT_MULTIPLE_MASTERS_H
+
+static FT_Library ft_library;
+
+#ifdef HAVE_ATEXIT
+static inline
+void free_ft_library ()
+{
+  FT_Done_FreeType (ft_library);
+}
+#endif
+
+static void
+_release_blob (void *arg)
+{
+  FT_Face ft_face = (FT_Face) arg;
+  hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
+}
+
+static inline cairo_font_face_t *
+helper_cairo_create_ft_font_face (const font_options_t *font_opts)
+{
+  cairo_font_face_t *cairo_face;
+  /* We cannot use the FT_Face from hb_font_t, as doing so will confuse hb_font_t because
+   * cairo will reset the face size.  As such, create new face...
+   * TODO Perhaps add API to hb-ft to encapsulate this code. */
+  FT_Face ft_face = nullptr;//hb_ft_font_get_face (font);
+  if (!ft_face)
+  {
+    if (!ft_library)
+    {
+      FT_Init_FreeType (&ft_library);
+#ifdef HAVE_ATEXIT
+      atexit (free_ft_library);
+#endif
+    }
+
+    unsigned int blob_length;
+    const char *blob_data = hb_blob_get_data (font_opts->blob, &blob_length);
+
+    if (FT_New_Memory_Face (ft_library,
+			    (const FT_Byte *) blob_data,
+			    blob_length,
+			    font_opts->face_index,
+			    &ft_face))
+      fail (false, "FT_New_Memory_Face fail");
+  }
+  if (!ft_face)
+  {
+    /* This allows us to get some boxes at least... */
+    cairo_face = cairo_toy_font_face_create ("@cairo:sans",
+					     CAIRO_FONT_SLANT_NORMAL,
+					     CAIRO_FONT_WEIGHT_NORMAL);
+  }
+  else
+  {
+    ft_face->generic.data = hb_blob_reference (font_opts->blob);
+    ft_face->generic.finalizer = _release_blob;
+
+#if !defined(HB_NO_VAR) && defined(HAVE_FT_SET_VAR_BLEND_COORDINATES)
+    unsigned int num_coords;
+    const float *coords = hb_font_get_var_coords_design (font_opts->font, &num_coords);
+    if (num_coords)
+    {
+      FT_Fixed *ft_coords = (FT_Fixed *) calloc (num_coords, sizeof (FT_Fixed));
+      if (ft_coords)
+      {
+	for (unsigned int i = 0; i < num_coords; i++)
+	  ft_coords[i] = coords[i] * 65536.f;
+	FT_Set_Var_Design_Coordinates (ft_face, num_coords, ft_coords);
+	free (ft_coords);
+      }
+    }
+#endif
+
+    cairo_face = cairo_ft_font_face_create_for_ft_face (ft_face, font_opts->ft_load_flags);
+  }
+  return cairo_face;
+}
+
+static inline bool
+helper_cairo_ft_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
+{
+  bool ret = false;
+#ifdef FT_HAS_COLOR
+  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);
+  if (ft_face)
+  {
+    if (FT_HAS_COLOR (ft_face))
+      ret = true;
+    cairo_ft_scaled_font_unlock_face (scaled_font);
+  }
+#endif
+  return ret;
+}
+
+#endif