diff options
Diffstat (limited to 'nx-X11/extras/freetype2/src/autofit/afangles.c')
| -rw-r--r-- | nx-X11/extras/freetype2/src/autofit/afangles.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/nx-X11/extras/freetype2/src/autofit/afangles.c b/nx-X11/extras/freetype2/src/autofit/afangles.c new file mode 100644 index 000000000..e42c962d1 --- /dev/null +++ b/nx-X11/extras/freetype2/src/autofit/afangles.c @@ -0,0 +1,302 @@ +#include "aftypes.h" + +/* + * a python script used to generate the following table + * + +import sys, math + +units = 256 +scale = units/math.pi +comma = "" + +print "" +print "table of arctan( 1/2^n ) for PI = " + repr(units/65536.0) + " units" + +r = [-1] + range(32) + +for n in r: + + if n >= 0: + x = 1.0/(2.0**n) # tangent value + else: + x = 2.0**(-n) + + angle = math.atan(x) # arctangent + angle2 = angle*scale # arctangent in FT_Angle units + + # determine which integer value for angle gives the best tangent + lo = int(angle2) + hi = lo + 1 + tlo = math.tan(lo/scale) + thi = math.tan(hi/scale) + + errlo = abs( tlo - x ) + errhi = abs( thi - x ) + + angle2 = hi + if errlo < errhi: + angle2 = lo + + if angle2 <= 0: + break + + sys.stdout.write( comma + repr( int(angle2) ) ) + comma = ", " + +* +* end of python script +*/ + + + /* this table was generated for AF_ANGLE_PI = 256 */ +#define AF_ANGLE_MAX_ITERS 8 +#define AF_TRIG_MAX_ITERS 8 + + static const FT_Fixed + af_angle_arctan_table[9] = + { + 90, 64, 38, 20, 10, 5, 3, 1, 1 + }; + + + static FT_Int + af_angle_prenorm( FT_Vector* vec ) + { + FT_Fixed x, y, z; + FT_Int shift; + + + x = vec->x; + y = vec->y; + + z = ( ( x >= 0 ) ? x : - x ) | ( (y >= 0) ? y : -y ); + shift = 0; + + if ( z < ( 1L << 27 ) ) + { + do + { + shift++; + z <<= 1; + } while ( z < ( 1L << 27 ) ); + + vec->x = x << shift; + vec->y = y << shift; + } + else if ( z > ( 1L << 28 ) ) + { + do + { + shift++; + z >>= 1; + } while ( z > ( 1L << 28 ) ); + + vec->x = x >> shift; + vec->y = y >> shift; + shift = -shift; + } + return shift; + } + + + static void + af_angle_pseudo_polarize( FT_Vector* vec ) + { + FT_Fixed theta; + FT_Fixed yi, i; + FT_Fixed x, y; + const FT_Fixed *arctanptr; + + + x = vec->x; + y = vec->y; + + /* Get the vector into the right half plane */ + theta = 0; + if ( x < 0 ) + { + x = -x; + y = -y; + theta = AF_ANGLE_PI; + } + + if ( y > 0 ) + theta = - theta; + + arctanptr = af_angle_arctan_table; + + if ( y < 0 ) + { + /* Rotate positive */ + yi = y + ( x << 1 ); + x = x - ( y << 1 ); + y = yi; + theta -= *arctanptr++; /* Subtract angle */ + } + else + { + /* Rotate negative */ + yi = y - ( x << 1 ); + x = x + ( y << 1 ); + y = yi; + theta += *arctanptr++; /* Add angle */ + } + + i = 0; + do + { + if ( y < 0 ) + { + /* Rotate positive */ + yi = y + ( x >> i ); + x = x - ( y >> i ); + y = yi; + theta -= *arctanptr++; + } + else + { + /* Rotate negative */ + yi = y - ( x >> i ); + x = x + ( y >> i ); + y = yi; + theta += *arctanptr++; + } + } while ( ++i < AF_TRIG_MAX_ITERS ); + +#if 0 + /* round theta */ + if ( theta >= 0 ) + theta = FT_PAD_ROUND( theta, 2 ); + else + theta = - FT_PAD_ROUND( -theta, 2 ); +#endif + + vec->x = x; + vec->y = theta; + } + + + /* documentation is in fttrigon.h */ + + FT_LOCAL_DEF( AF_Angle ) + af_angle_atan( FT_Fixed dx, + FT_Fixed dy ) + { + FT_Vector v; + + + if ( dx == 0 && dy == 0 ) + return 0; + + v.x = dx; + v.y = dy; + af_angle_prenorm( &v ); + af_angle_pseudo_polarize( &v ); + + return v.y; + } + + + + FT_LOCAL_DEF( AF_Angle ) + af_angle_diff( AF_Angle angle1, + AF_Angle angle2 ) + { + AF_Angle delta = angle2 - angle1; + + delta %= AF_ANGLE_2PI; + if ( delta < 0 ) + delta += AF_ANGLE_2PI; + + if ( delta > AF_ANGLE_PI ) + delta -= AF_ANGLE_2PI; + + return delta; + } + + + /* well, this needs to be somewhere, right :-) + */ + + 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; + } + } + } + + +#ifdef TEST +#include <stdio.h> +#include <math.h> + +int main( void ) +{ + int angle; + int dist; + + for ( dist = 100; dist < 1000; dist++ ) + { + for ( angle = AF_ANGLE_PI; angle < AF_ANGLE_2PI*4; angle++ ) + { + double a = (angle*3.1415926535)/(1.0*AF_ANGLE_PI); + int dx, dy, angle1, angle2, delta; + + dx = dist * cos(a); + dy = dist * sin(a); + + angle1 = ((atan2(dy,dx)*AF_ANGLE_PI)/3.1415926535); + angle2 = af_angle_atan( dx, dy ); + delta = (angle2 - angle1) % AF_ANGLE_2PI; + if ( delta < 0 ) + delta = -delta; + + if ( delta >= 2 ) + { + printf( "dist:%4d angle:%4d => (%4d,%4d) angle1:%4d angle2:%4d\n", + dist, angle, dx, dy, angle1, angle2 ); + } + } + } + return 0; +} +#endif |