misc/libfreetype/src/autofit/afangles.c
changeset 5172 88f2e05288ba
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libfreetype/src/autofit/afangles.c	Mon Apr 25 01:46:54 2011 +0200
@@ -0,0 +1,292 @@
+/***************************************************************************/
+/*                                                                         */
+/*  afangles.c                                                             */
+/*                                                                         */
+/*    Routines used to compute vector angles with limited accuracy         */
+/*    and very high speed.  It also contains sorting routines (body).      */
+/*                                                                         */
+/*  Copyright 2003-2006, 2011 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 "aftypes.h"
+
+
+#if 0
+
+  FT_LOCAL_DEF( FT_Int )
+  af_corner_is_flat( FT_Pos  x_in,
+                     FT_Pos  y_in,
+                     FT_Pos  x_out,
+                     FT_Pos  y_out )
+  {
+    FT_Pos  ax = x_in;
+    FT_Pos  ay = y_in;
+
+    FT_Pos  d_in, d_out, d_corner;
+
+
+    if ( ax < 0 )
+      ax = -ax;
+    if ( ay < 0 )
+      ay = -ay;
+    d_in = ax + ay;
+
+    ax = x_out;
+    if ( ax < 0 )
+      ax = -ax;
+    ay = y_out;
+    if ( ay < 0 )
+      ay = -ay;
+    d_out = ax + ay;
+
+    ax = x_out + x_in;
+    if ( ax < 0 )
+      ax = -ax;
+    ay = y_out + y_in;
+    if ( ay < 0 )
+      ay = -ay;
+    d_corner = ax + ay;
+
+    return ( d_in + d_out - d_corner ) < ( d_corner >> 4 );
+  }
+
+
+  FT_LOCAL_DEF( FT_Int )
+  af_corner_orientation( FT_Pos  x_in,
+                         FT_Pos  y_in,
+                         FT_Pos  x_out,
+                         FT_Pos  y_out )
+  {
+    FT_Pos  delta;
+
+
+    delta = x_in * y_out - y_in * x_out;
+
+    if ( delta == 0 )
+      return 0;
+    else
+      return 1 - 2 * ( delta < 0 );
+  }
+
+#endif /* 0 */
+
+
+  /*
+   *  We are not using `af_angle_atan' anymore, but we keep the source
+   *  code below just in case...
+   */
+
+
+#if 0
+
+
+  /*
+   *  The trick here is to realize that we don't need a very accurate angle
+   *  approximation.  We are going to use the result of `af_angle_atan' to
+   *  only compare the sign of angle differences, or check whether its
+   *  magnitude is very small.
+   *
+   *  The approximation
+   *
+   *    dy * PI / (|dx|+|dy|)
+   *
+   *  should be enough, and much faster to compute.
+   */
+  FT_LOCAL_DEF( AF_Angle )
+  af_angle_atan( FT_Fixed  dx,
+                 FT_Fixed  dy )
+  {
+    AF_Angle  angle;
+    FT_Fixed  ax = dx;
+    FT_Fixed  ay = dy;
+
+
+    if ( ax < 0 )
+      ax = -ax;
+    if ( ay < 0 )
+      ay = -ay;
+
+    ax += ay;
+
+    if ( ax == 0 )
+      angle = 0;
+    else
+    {
+      angle = ( AF_ANGLE_PI2 * dy ) / ( ax + ay );
+      if ( dx < 0 )
+      {
+        if ( angle >= 0 )
+          angle = AF_ANGLE_PI - angle;
+        else
+          angle = -AF_ANGLE_PI - angle;
+      }
+    }
+
+    return angle;
+  }
+
+
+#elif 0
+
+
+  /* the following table has been automatically generated with */
+  /* the `mather.py' Python script                             */
+
+#define AF_ATAN_BITS  8
+
+  static const FT_Byte  af_arctan[1L << AF_ATAN_BITS] =
+  {
+     0,  0,  1,  1,  1,  2,  2,  2,
+     3,  3,  3,  3,  4,  4,  4,  5,
+     5,  5,  6,  6,  6,  7,  7,  7,
+     8,  8,  8,  9,  9,  9, 10, 10,
+    10, 10, 11, 11, 11, 12, 12, 12,
+    13, 13, 13, 14, 14, 14, 14, 15,
+    15, 15, 16, 16, 16, 17, 17, 17,
+    18, 18, 18, 18, 19, 19, 19, 20,
+    20, 20, 21, 21, 21, 21, 22, 22,
+    22, 23, 23, 23, 24, 24, 24, 24,
+    25, 25, 25, 26, 26, 26, 26, 27,
+    27, 27, 28, 28, 28, 28, 29, 29,
+    29, 30, 30, 30, 30, 31, 31, 31,
+    31, 32, 32, 32, 33, 33, 33, 33,
+    34, 34, 34, 34, 35, 35, 35, 35,
+    36, 36, 36, 36, 37, 37, 37, 38,
+    38, 38, 38, 39, 39, 39, 39, 40,
+    40, 40, 40, 41, 41, 41, 41, 42,
+    42, 42, 42, 42, 43, 43, 43, 43,
+    44, 44, 44, 44, 45, 45, 45, 45,
+    46, 46, 46, 46, 46, 47, 47, 47,
+    47, 48, 48, 48, 48, 48, 49, 49,
+    49, 49, 50, 50, 50, 50, 50, 51,
+    51, 51, 51, 51, 52, 52, 52, 52,
+    52, 53, 53, 53, 53, 53, 54, 54,
+    54, 54, 54, 55, 55, 55, 55, 55,
+    56, 56, 56, 56, 56, 57, 57, 57,
+    57, 57, 57, 58, 58, 58, 58, 58,
+    59, 59, 59, 59, 59, 59, 60, 60,
+    60, 60, 60, 61, 61, 61, 61, 61,
+    61, 62, 62, 62, 62, 62, 62, 63,
+    63, 63, 63, 63, 63, 64, 64, 64
+  };
+
+
+  FT_LOCAL_DEF( AF_Angle )
+  af_angle_atan( FT_Fixed  dx,
+                 FT_Fixed  dy )
+  {
+    AF_Angle  angle;
+
+
+    /* check trivial cases */
+    if ( dy == 0 )
+    {
+      angle = 0;
+      if ( dx < 0 )
+        angle = AF_ANGLE_PI;
+      return angle;
+    }
+    else if ( dx == 0 )
+    {
+      angle = AF_ANGLE_PI2;
+      if ( dy < 0 )
+        angle = -AF_ANGLE_PI2;
+      return angle;
+    }
+
+    angle = 0;
+    if ( dx < 0 )
+    {
+      dx = -dx;
+      dy = -dy;
+      angle = AF_ANGLE_PI;
+    }
+
+    if ( dy < 0 )
+    {
+      FT_Pos  tmp;
+
+
+      tmp = dx;
+      dx  = -dy;
+      dy  = tmp;
+      angle -= AF_ANGLE_PI2;
+    }
+
+    if ( dx == 0 && dy == 0 )
+      return 0;
+
+    if ( dx == dy )
+      angle += AF_ANGLE_PI4;
+    else if ( dx > dy )
+      angle += af_arctan[FT_DivFix( dy, dx ) >> ( 16 - AF_ATAN_BITS )];
+    else
+      angle += AF_ANGLE_PI2 -
+               af_arctan[FT_DivFix( dx, dy ) >> ( 16 - AF_ATAN_BITS )];
+
+    if ( angle > AF_ANGLE_PI )
+      angle -= AF_ANGLE_2PI;
+
+    return angle;
+  }
+
+
+#endif /* 0 */
+
+
+  FT_LOCAL_DEF( void )
+  af_sort_pos( FT_UInt  count,
+               FT_Pos*  table )
+  {
+    FT_UInt  i, j;
+    FT_Pos   swap;
+
+
+    for ( i = 1; i < count; i++ )
+    {
+      for ( j = i; j > 0; j-- )
+      {
+        if ( table[j] > table[j - 1] )
+          break;
+
+        swap         = table[j];
+        table[j]     = table[j - 1];
+        table[j - 1] = swap;
+      }
+    }
+  }
+
+
+  FT_LOCAL_DEF( void )
+  af_sort_widths( FT_UInt   count,
+                  AF_Width  table )
+  {
+    FT_UInt      i, j;
+    AF_WidthRec  swap;
+
+
+    for ( i = 1; i < count; i++ )
+    {
+      for ( j = i; j > 0; j-- )
+      {
+        if ( table[j].org > table[j - 1].org )
+          break;
+
+        swap         = table[j];
+        table[j]     = table[j - 1];
+        table[j - 1] = swap;
+      }
+    }
+  }
+
+
+/* END */