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-rw-r--r--src/3rdparty/freetype/src/base/ftbbox.c512
1 files changed, 178 insertions, 334 deletions
diff --git a/src/3rdparty/freetype/src/base/ftbbox.c b/src/3rdparty/freetype/src/base/ftbbox.c
index 4b8e9112fe..f9a17517ec 100644
--- a/src/3rdparty/freetype/src/base/ftbbox.c
+++ b/src/3rdparty/freetype/src/base/ftbbox.c
@@ -4,7 +4,7 @@
/* */
/* FreeType bbox computation (body). */
/* */
-/* Copyright 1996-2001, 2002, 2004, 2006, 2010 by */
+/* Copyright 1996-2002, 2004, 2006, 2010, 2013, 2014 by */
/* David Turner, Robert Wilhelm, and Werner Lemberg. */
/* */
/* This file is part of the FreeType project, and may only be used */
@@ -25,6 +25,8 @@
#include <ft2build.h>
+#include FT_INTERNAL_DEBUG_H
+
#include FT_BBOX_H
#include FT_IMAGE_H
#include FT_OUTLINE_H
@@ -40,16 +42,35 @@
} TBBox_Rec;
+#define FT_UPDATE_BBOX( p, bbox ) \
+ FT_BEGIN_STMNT \
+ if ( p->x < bbox.xMin ) \
+ bbox.xMin = p->x; \
+ if ( p->x > bbox.xMax ) \
+ bbox.xMax = p->x; \
+ if ( p->y < bbox.yMin ) \
+ bbox.yMin = p->y; \
+ if ( p->y > bbox.yMax ) \
+ bbox.yMax = p->y; \
+ FT_END_STMNT
+
+#define CHECK_X( p, bbox ) \
+ ( p->x < bbox.xMin || p->x > bbox.xMax )
+
+#define CHECK_Y( p, bbox ) \
+ ( p->y < bbox.yMin || p->y > bbox.yMax )
+
+
/*************************************************************************/
/* */
/* <Function> */
/* BBox_Move_To */
/* */
/* <Description> */
- /* This function is used as a `move_to' and `line_to' emitter during */
+ /* This function is used as a `move_to' emitter during */
/* FT_Outline_Decompose(). It simply records the destination point */
- /* in `user->last'; no further computations are necessary since we */
- /* use the cbox as the starting bbox which must be refined. */
+ /* in `user->last'. We also update bbox in case contour starts with */
+ /* an implicit `on' point. */
/* */
/* <Input> */
/* to :: A pointer to the destination vector. */
@@ -64,17 +85,42 @@
BBox_Move_To( FT_Vector* to,
TBBox_Rec* user )
{
+ FT_UPDATE_BBOX( to, user->bbox );
+
user->last = *to;
return 0;
}
-#define CHECK_X( p, bbox ) \
- ( p->x < bbox.xMin || p->x > bbox.xMax )
+ /*************************************************************************/
+ /* */
+ /* <Function> */
+ /* BBox_Line_To */
+ /* */
+ /* <Description> */
+ /* This function is used as a `line_to' emitter during */
+ /* FT_Outline_Decompose(). It simply records the destination point */
+ /* in `user->last'; no further computations are necessary because */
+ /* bbox already contains both explicit ends of the line segment. */
+ /* */
+ /* <Input> */
+ /* to :: A pointer to the destination vector. */
+ /* */
+ /* <InOut> */
+ /* user :: A pointer to the current walk context. */
+ /* */
+ /* <Return> */
+ /* Always 0. Needed for the interface only. */
+ /* */
+ static int
+ BBox_Line_To( FT_Vector* to,
+ TBBox_Rec* user )
+ {
+ user->last = *to;
-#define CHECK_Y( p, bbox ) \
- ( p->y < bbox.yMin || p->y > bbox.yMax )
+ return 0;
+ }
/*************************************************************************/
@@ -83,7 +129,7 @@
/* BBox_Conic_Check */
/* */
/* <Description> */
- /* Finds the extrema of a 1-dimensional conic Bezier curve and update */
+ /* Find the extrema of a 1-dimensional conic Bezier curve and update */
/* a bounding range. This version uses direct computation, as it */
/* doesn't need square roots. */
/* */
@@ -106,30 +152,19 @@
FT_Pos* min,
FT_Pos* max )
{
- if ( y1 <= y3 && y2 == y1 ) /* flat arc */
- goto Suite;
-
- if ( y1 < y3 )
- {
- if ( y2 >= y1 && y2 <= y3 ) /* ascending arc */
- goto Suite;
- }
- else
- {
- if ( y2 >= y3 && y2 <= y1 ) /* descending arc */
- {
- y2 = y1;
- y1 = y3;
- y3 = y2;
- goto Suite;
- }
- }
-
- y1 = y3 = y1 - FT_MulDiv( y2 - y1, y2 - y1, y1 - 2*y2 + y3 );
-
- Suite:
- if ( y1 < *min ) *min = y1;
- if ( y3 > *max ) *max = y3;
+ /* This function is only called when a control off-point is outside */
+ /* the bbox that contains all on-points. It finds a local extremum */
+ /* within the segment, equal to (y1*y3 - y2*y2)/(y1 - 2*y2 + y3). */
+ /* Or, offsetting from y2, we get */
+
+ y1 -= y2;
+ y3 -= y2;
+ y2 += FT_MulDiv( y1, y3, y1 + y3 );
+
+ if ( y2 < *min )
+ *min = y2;
+ if ( y2 > *max )
+ *max = y2;
}
@@ -164,8 +199,8 @@
FT_Vector* to,
TBBox_Rec* user )
{
- /* we don't need to check `to' since it is always an `on' point, thus */
- /* within the bbox */
+ /* in case `to' is implicit and not included in bbox yet */
+ FT_UPDATE_BBOX( to, user->bbox );
if ( CHECK_X( control, user->bbox ) )
BBox_Conic_Check( user->last.x,
@@ -193,9 +228,9 @@
/* BBox_Cubic_Check */
/* */
/* <Description> */
- /* Finds the extrema of a 1-dimensional cubic Bezier curve and */
- /* updates a bounding range. This version uses splitting because we */
- /* don't want to use square roots and extra accuracy. */
+ /* Find the extrema of a 1-dimensional cubic Bezier curve and */
+ /* update a bounding range. This version uses iterative splitting */
+ /* because it is faster than the exact solution with square roots. */
/* */
/* <Input> */
/* p1 :: The start coordinate. */
@@ -211,294 +246,117 @@
/* */
/* max :: The address of the current maximum. */
/* */
-
-#if 0
-
- static void
- BBox_Cubic_Check( FT_Pos p1,
- FT_Pos p2,
- FT_Pos p3,
- FT_Pos p4,
- FT_Pos* min,
- FT_Pos* max )
+ static FT_Pos
+ cubic_peak( FT_Pos q1,
+ FT_Pos q2,
+ FT_Pos q3,
+ FT_Pos q4 )
{
- FT_Pos stack[32*3 + 1], *arc;
-
-
- arc = stack;
-
- arc[0] = p1;
- arc[1] = p2;
- arc[2] = p3;
- arc[3] = p4;
-
- do
+ FT_Pos peak = 0;
+ FT_Int shift;
+
+ /* This function finds a peak of a cubic segment if it is above 0 */
+ /* using iterative bisection of the segment, or returns 0. */
+ /* The fixed-point arithmetic of bisection is inherently stable */
+ /* but may loose accuracy in the two lowest bits. To compensate, */
+ /* we upscale the segment if there is room. Large values may need */
+ /* to be downscaled to avoid overflows during bisection. */
+ /* It is called with either q2 or q3 positive, which is necessary */
+ /* for the peak to exist and avoids undefined FT_MSB. */
+
+ shift = 27 -
+ FT_MSB( FT_ABS( q1 ) | FT_ABS( q2 ) | FT_ABS( q3 ) | FT_ABS( q4 ) );
+
+ if ( shift > 0 )
{
- FT_Pos y1 = arc[0];
- FT_Pos y2 = arc[1];
- FT_Pos y3 = arc[2];
- FT_Pos y4 = arc[3];
-
+ /* upscaling too much just wastes time */
+ if ( shift > 2 )
+ shift = 2;
+
+ q1 <<= shift;
+ q2 <<= shift;
+ q3 <<= shift;
+ q4 <<= shift;
+ }
+ else
+ {
+ q1 >>= -shift;
+ q2 >>= -shift;
+ q3 >>= -shift;
+ q4 >>= -shift;
+ }
- if ( y1 == y4 )
+ /* for a peak to exist above 0, the cubic segment must have */
+ /* at least one of its control off-points above 0. */
+ while ( q2 > 0 || q3 > 0 )
+ {
+ /* determine which half contains the maximum and split */
+ if ( q1 + q2 > q3 + q4 ) /* first half */
{
- if ( y1 == y2 && y1 == y3 ) /* flat */
- goto Test;
+ q4 = q4 + q3;
+ q3 = q3 + q2;
+ q2 = q2 + q1;
+ q4 = q4 + q3;
+ q3 = q3 + q2;
+ q4 = ( q4 + q3 ) / 8;
+ q3 = q3 / 4;
+ q2 = q2 / 2;
}
- else if ( y1 < y4 )
+ else /* second half */
{
- if ( y2 >= y1 && y2 <= y4 && y3 >= y1 && y3 <= y4 ) /* ascending */
- goto Test;
+ q1 = q1 + q2;
+ q2 = q2 + q3;
+ q3 = q3 + q4;
+ q1 = q1 + q2;
+ q2 = q2 + q3;
+ q1 = ( q1 + q2 ) / 8;
+ q2 = q2 / 4;
+ q3 = q3 / 2;
}
- else
+
+ /* check whether either end reached the maximum */
+ if ( q1 == q2 && q1 >= q3 )
{
- if ( y2 >= y4 && y2 <= y1 && y3 >= y4 && y3 <= y1 ) /* descending */
- {
- y2 = y1;
- y1 = y4;
- y4 = y2;
- goto Test;
- }
+ peak = q1;
+ break;
}
+ if ( q3 == q4 && q2 <= q4 )
+ {
+ peak = q4;
+ break;
+ }
+ }
- /* unknown direction -- split the arc in two */
- arc[6] = y4;
- arc[1] = y1 = ( y1 + y2 ) / 2;
- arc[5] = y4 = ( y4 + y3 ) / 2;
- y2 = ( y2 + y3 ) / 2;
- arc[2] = y1 = ( y1 + y2 ) / 2;
- arc[4] = y4 = ( y4 + y2 ) / 2;
- arc[3] = ( y1 + y4 ) / 2;
-
- arc += 3;
- goto Suite;
-
- Test:
- if ( y1 < *min ) *min = y1;
- if ( y4 > *max ) *max = y4;
- arc -= 3;
-
- Suite:
- ;
- } while ( arc >= stack );
- }
-
-#else
-
- static void
- test_cubic_extrema( FT_Pos y1,
- FT_Pos y2,
- FT_Pos y3,
- FT_Pos y4,
- FT_Fixed u,
- FT_Pos* min,
- FT_Pos* max )
- {
- /* FT_Pos a = y4 - 3*y3 + 3*y2 - y1; */
- FT_Pos b = y3 - 2*y2 + y1;
- FT_Pos c = y2 - y1;
- FT_Pos d = y1;
- FT_Pos y;
- FT_Fixed uu;
-
- FT_UNUSED ( y4 );
-
-
- /* The polynomial is */
- /* */
- /* P(x) = a*x^3 + 3b*x^2 + 3c*x + d , */
- /* */
- /* dP/dx = 3a*x^2 + 6b*x + 3c . */
- /* */
- /* However, we also have */
- /* */
- /* dP/dx(u) = 0 , */
- /* */
- /* which implies by subtraction that */
- /* */
- /* P(u) = b*u^2 + 2c*u + d . */
-
- if ( u > 0 && u < 0x10000L )
- {
- uu = FT_MulFix( u, u );
- y = d + FT_MulFix( c, 2*u ) + FT_MulFix( b, uu );
+ if ( shift > 0 )
+ peak >>= shift;
+ else
+ peak <<= -shift;
- if ( y < *min ) *min = y;
- if ( y > *max ) *max = y;
- }
+ return peak;
}
static void
- BBox_Cubic_Check( FT_Pos y1,
- FT_Pos y2,
- FT_Pos y3,
- FT_Pos y4,
+ BBox_Cubic_Check( FT_Pos p1,
+ FT_Pos p2,
+ FT_Pos p3,
+ FT_Pos p4,
FT_Pos* min,
FT_Pos* max )
{
- /* always compare first and last points */
- if ( y1 < *min ) *min = y1;
- else if ( y1 > *max ) *max = y1;
+ /* This function is only called when a control off-point is outside */
+ /* the bbox that contains all on-points. So at least one of the */
+ /* conditions below holds and cubic_peak is called with at least one */
+ /* non-zero argument. */
- if ( y4 < *min ) *min = y4;
- else if ( y4 > *max ) *max = y4;
+ if ( p2 > *max || p3 > *max )
+ *max += cubic_peak( p1 - *max, p2 - *max, p3 - *max, p4 - *max );
- /* now, try to see if there are split points here */
- if ( y1 <= y4 )
- {
- /* flat or ascending arc test */
- if ( y1 <= y2 && y2 <= y4 && y1 <= y3 && y3 <= y4 )
- return;
- }
- else /* y1 > y4 */
- {
- /* descending arc test */
- if ( y1 >= y2 && y2 >= y4 && y1 >= y3 && y3 >= y4 )
- return;
- }
-
- /* There are some split points. Find them. */
- {
- FT_Pos a = y4 - 3*y3 + 3*y2 - y1;
- FT_Pos b = y3 - 2*y2 + y1;
- FT_Pos c = y2 - y1;
- FT_Pos d;
- FT_Fixed t;
-
-
- /* We need to solve `ax^2+2bx+c' here, without floating points! */
- /* The trick is to normalize to a different representation in order */
- /* to use our 16.16 fixed point routines. */
- /* */
- /* We compute FT_MulFix(b,b) and FT_MulFix(a,c) after normalization. */
- /* These values must fit into a single 16.16 value. */
- /* */
- /* We normalize a, b, and c to `8.16' fixed float values to ensure */
- /* that its product is held in a `16.16' value. */
-
- {
- FT_ULong t1, t2;
- int shift = 0;
-
-
- /* The following computation is based on the fact that for */
- /* any value `y', if `n' is the position of the most */
- /* significant bit of `abs(y)' (starting from 0 for the */
- /* least significant bit), then `y' is in the range */
- /* */
- /* -2^n..2^n-1 */
- /* */
- /* We want to shift `a', `b', and `c' concurrently in order */
- /* to ensure that they all fit in 8.16 values, which maps */
- /* to the integer range `-2^23..2^23-1'. */
- /* */
- /* Necessarily, we need to shift `a', `b', and `c' so that */
- /* the most significant bit of its absolute values is at */
- /* _most_ at position 23. */
- /* */
- /* We begin by computing `t1' as the bitwise `OR' of the */
- /* absolute values of `a', `b', `c'. */
-
- t1 = (FT_ULong)( ( a >= 0 ) ? a : -a );
- t2 = (FT_ULong)( ( b >= 0 ) ? b : -b );
- t1 |= t2;
- t2 = (FT_ULong)( ( c >= 0 ) ? c : -c );
- t1 |= t2;
-
- /* Now we can be sure that the most significant bit of `t1' */
- /* is the most significant bit of either `a', `b', or `c', */
- /* depending on the greatest integer range of the particular */
- /* variable. */
- /* */
- /* Next, we compute the `shift', by shifting `t1' as many */
- /* times as necessary to move its MSB to position 23. This */
- /* corresponds to a value of `t1' that is in the range */
- /* 0x40_0000..0x7F_FFFF. */
- /* */
- /* Finally, we shift `a', `b', and `c' by the same amount. */
- /* This ensures that all values are now in the range */
- /* -2^23..2^23, i.e., they are now expressed as 8.16 */
- /* fixed-float numbers. This also means that we are using */
- /* 24 bits of precision to compute the zeros, independently */
- /* of the range of the original polynomial coefficients. */
- /* */
- /* This algorithm should ensure reasonably accurate values */
- /* for the zeros. Note that they are only expressed with */
- /* 16 bits when computing the extrema (the zeros need to */
- /* be in 0..1 exclusive to be considered part of the arc). */
-
- if ( t1 == 0 ) /* all coefficients are 0! */
- return;
-
- if ( t1 > 0x7FFFFFUL )
- {
- do
- {
- shift++;
- t1 >>= 1;
-
- } while ( t1 > 0x7FFFFFUL );
-
- /* this loses some bits of precision, but we use 24 of them */
- /* for the computation anyway */
- a >>= shift;
- b >>= shift;
- c >>= shift;
- }
- else if ( t1 < 0x400000UL )
- {
- do
- {
- shift++;
- t1 <<= 1;
-
- } while ( t1 < 0x400000UL );
-
- a <<= shift;
- b <<= shift;
- c <<= shift;
- }
- }
-
- /* handle a == 0 */
- if ( a == 0 )
- {
- if ( b != 0 )
- {
- t = - FT_DivFix( c, b ) / 2;
- test_cubic_extrema( y1, y2, y3, y4, t, min, max );
- }
- }
- else
- {
- /* solve the equation now */
- d = FT_MulFix( b, b ) - FT_MulFix( a, c );
- if ( d < 0 )
- return;
-
- if ( d == 0 )
- {
- /* there is a single split point at -b/a */
- t = - FT_DivFix( b, a );
- test_cubic_extrema( y1, y2, y3, y4, t, min, max );
- }
- else
- {
- /* there are two solutions; we need to filter them */
- d = FT_SqrtFixed( (FT_Int32)d );
- t = - FT_DivFix( b - d, a );
- test_cubic_extrema( y1, y2, y3, y4, t, min, max );
-
- t = - FT_DivFix( b + d, a );
- test_cubic_extrema( y1, y2, y3, y4, t, min, max );
- }
- }
- }
+ /* now flip the signs to update the minimum */
+ if ( p2 < *min || p3 < *min )
+ *min -= cubic_peak( *min - p1, *min - p2, *min - p3, *min - p4 );
}
-#endif
-
/*************************************************************************/
/* */
@@ -534,8 +392,9 @@
FT_Vector* to,
TBBox_Rec* user )
{
- /* we don't need to check `to' since it is always an `on' point, thus */
- /* within the bbox */
+ /* We don't need to check `to' since it is always an on-point, */
+ /* thus within the bbox. Only segments with an off-point outside */
+ /* the bbox can possibly reach new extreme values. */
if ( CHECK_X( control1, user->bbox ) ||
CHECK_X( control2, user->bbox ) )
@@ -560,31 +419,35 @@
return 0;
}
-FT_DEFINE_OUTLINE_FUNCS(bbox_interface,
+
+ FT_DEFINE_OUTLINE_FUNCS(bbox_interface,
(FT_Outline_MoveTo_Func) BBox_Move_To,
- (FT_Outline_LineTo_Func) BBox_Move_To,
+ (FT_Outline_LineTo_Func) BBox_Line_To,
(FT_Outline_ConicTo_Func)BBox_Conic_To,
(FT_Outline_CubicTo_Func)BBox_Cubic_To,
0, 0
)
+
/* documentation is in ftbbox.h */
FT_EXPORT_DEF( FT_Error )
FT_Outline_Get_BBox( FT_Outline* outline,
FT_BBox *abbox )
{
- FT_BBox cbox;
- FT_BBox bbox;
+ FT_BBox cbox = { 0x7FFFFFFFL, 0x7FFFFFFFL,
+ -0x7FFFFFFFL, -0x7FFFFFFFL };
+ FT_BBox bbox = { 0x7FFFFFFFL, 0x7FFFFFFFL,
+ -0x7FFFFFFFL, -0x7FFFFFFFL };
FT_Vector* vec;
FT_UShort n;
if ( !abbox )
- return FT_Err_Invalid_Argument;
+ return FT_THROW( Invalid_Argument );
if ( !outline )
- return FT_Err_Invalid_Outline;
+ return FT_THROW( Invalid_Outline );
/* if outline is empty, return (0,0,0,0) */
if ( outline->n_points == 0 || outline->n_contours <= 0 )
@@ -599,32 +462,13 @@ FT_DEFINE_OUTLINE_FUNCS(bbox_interface,
/* coincide, we exit immediately. */
vec = outline->points;
- bbox.xMin = bbox.xMax = cbox.xMin = cbox.xMax = vec->x;
- bbox.yMin = bbox.yMax = cbox.yMin = cbox.yMax = vec->y;
- vec++;
- for ( n = 1; n < outline->n_points; n++ )
+ for ( n = 0; n < outline->n_points; n++ )
{
- FT_Pos x = vec->x;
- FT_Pos y = vec->y;
-
-
- /* update control box */
- if ( x < cbox.xMin ) cbox.xMin = x;
- if ( x > cbox.xMax ) cbox.xMax = x;
-
- if ( y < cbox.yMin ) cbox.yMin = y;
- if ( y > cbox.yMax ) cbox.yMax = y;
+ FT_UPDATE_BBOX( vec, cbox);
if ( FT_CURVE_TAG( outline->tags[n] ) == FT_CURVE_TAG_ON )
- {
- /* update bbox for `on' points only */
- if ( x < bbox.xMin ) bbox.xMin = x;
- if ( x > bbox.xMax ) bbox.xMax = x;
-
- if ( y < bbox.yMin ) bbox.yMin = y;
- if ( y > bbox.yMax ) bbox.yMax = y;
- }
+ FT_UPDATE_BBOX( vec, bbox);
vec++;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-04 23:07:47 +0000