misc/libfreetype/src/base/ftadvanc.c
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/base/ftadvanc.c	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,163 @@
+/***************************************************************************/
+/*                                                                         */
+/*  ftadvanc.c                                                             */
+/*                                                                         */
+/*    Quick computation of advance widths (body).                          */
+/*                                                                         */
+/*  Copyright 2008, 2009 by                                                */
+/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
+/*                                                                         */
+/*  This file is part of the FreeType project, and may only be used,       */
+/*  modified, and distributed under the terms of the FreeType project      */
+/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
+/*  this file you indicate that you have read the license and              */
+/*  understand and accept it fully.                                        */
+/*                                                                         */
+/***************************************************************************/
+
+
+#include <ft2build.h>
+#include FT_ADVANCES_H
+#include FT_INTERNAL_OBJECTS_H
+
+
+  static FT_Error
+  _ft_face_scale_advances( FT_Face    face,
+                           FT_Fixed*  advances,
+                           FT_UInt    count,
+                           FT_Int32   flags )
+  {
+    FT_Fixed  scale;
+    FT_UInt   nn;
+
+
+    if ( flags & FT_LOAD_NO_SCALE )
+      return FT_Err_Ok;
+
+    if ( face->size == NULL )
+      return FT_Err_Invalid_Size_Handle;
+
+    if ( flags & FT_LOAD_VERTICAL_LAYOUT )
+      scale = face->size->metrics.y_scale;
+    else
+      scale = face->size->metrics.x_scale;
+
+    /* this must be the same scaling as to get linear{Hori,Vert}Advance */
+    /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c)        */
+
+    for ( nn = 0; nn < count; nn++ )
+      advances[nn] = FT_MulDiv( advances[nn], scale, 64 );
+
+    return FT_Err_Ok;
+  }
+
+
+   /* at the moment, we can perform fast advance retrieval only in */
+   /* the following cases:                                         */
+   /*                                                              */
+   /*  - unscaled load                                             */
+   /*  - unhinted load                                             */
+   /*  - light-hinted load                                         */
+
+#define LOAD_ADVANCE_FAST_CHECK( flags )                            \
+          ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING )    || \
+            FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT )
+
+
+  /* documentation is in ftadvanc.h */
+
+  FT_EXPORT_DEF( FT_Error )
+  FT_Get_Advance( FT_Face    face,
+                  FT_UInt    gindex,
+                  FT_Int32   flags,
+                  FT_Fixed  *padvance )
+  {
+    FT_Face_GetAdvancesFunc  func;
+
+
+    if ( !face )
+      return FT_Err_Invalid_Face_Handle;
+
+    if ( gindex >= (FT_UInt)face->num_glyphs )
+      return FT_Err_Invalid_Glyph_Index;
+
+    func = face->driver->clazz->get_advances;
+    if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) )
+    {
+      FT_Error  error;
+
+
+      error = func( face, gindex, 1, flags, padvance );
+      if ( !error )
+        return _ft_face_scale_advances( face, padvance, 1, flags );
+
+      if ( error != FT_ERROR_BASE( FT_Err_Unimplemented_Feature ) )
+        return error;
+    }
+
+    return FT_Get_Advances( face, gindex, 1, flags, padvance );
+  }
+
+
+  /* documentation is in ftadvanc.h */
+
+  FT_EXPORT_DEF( FT_Error )
+  FT_Get_Advances( FT_Face    face,
+                   FT_UInt    start,
+                   FT_UInt    count,
+                   FT_Int32   flags,
+                   FT_Fixed  *padvances )
+  {
+    FT_Face_GetAdvancesFunc  func;
+    FT_UInt                  num, end, nn;
+    FT_Error                 error = FT_Err_Ok;
+
+
+    if ( !face )
+      return FT_Err_Invalid_Face_Handle;
+
+    num = (FT_UInt)face->num_glyphs;
+    end = start + count;
+    if ( start >= num || end < start || end > num )
+      return FT_Err_Invalid_Glyph_Index;
+
+    if ( count == 0 )
+      return FT_Err_Ok;
+
+    func = face->driver->clazz->get_advances;
+    if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) )
+    {
+      error = func( face, start, count, flags, padvances );
+      if ( !error )
+        goto Exit;
+
+      if ( error != FT_ERROR_BASE( FT_Err_Unimplemented_Feature ) )
+        return error;
+    }
+
+    error = FT_Err_Ok;
+
+    if ( flags & FT_ADVANCE_FLAG_FAST_ONLY )
+      return FT_Err_Unimplemented_Feature;
+
+    flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY;
+    for ( nn = 0; nn < count; nn++ )
+    {
+      error = FT_Load_Glyph( face, start + nn, flags );
+      if ( error )
+        break;
+
+      padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT )
+                      ? face->glyph->advance.y
+                      : face->glyph->advance.x;
+    }
+
+    if ( error )
+      return error;
+
+  Exit:
+    return _ft_face_scale_advances( face, padvances, count, flags );
+  }
+
+
+/* END */