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author | Matt A. Tobin <email@mattatobin.com> | 2021-11-19 05:13:01 -0500 |
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committer | Matt A. Tobin <email@mattatobin.com> | 2021-11-19 05:13:01 -0500 |
commit | f8796cf0a4259b4b24b3be8ece0e0c26e2c017d5 (patch) | |
tree | 763b1085175be05e2f3183facb7db9e9494105da /libs/cairo/src/cairo-fixed-private.h | |
parent | e1b02c50457a45eb26108cd318ea833d4608da9b (diff) | |
download | aura-central-f8796cf0a4259b4b24b3be8ece0e0c26e2c017d5.tar.gz |
Issue %3003 - Move cairo up one level
- This also rewrites the moz.build file to be not insane from years of script manipulation
- This also eliminates the remaining mac/uikit quartz shit as well as the BeOS junk.
Diffstat (limited to 'libs/cairo/src/cairo-fixed-private.h')
-rw-r--r-- | libs/cairo/src/cairo-fixed-private.h | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/libs/cairo/src/cairo-fixed-private.h b/libs/cairo/src/cairo-fixed-private.h new file mode 100644 index 000000000..a00e99cf3 --- /dev/null +++ b/libs/cairo/src/cairo-fixed-private.h @@ -0,0 +1,326 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef CAIRO_FIXED_PRIVATE_H +#define CAIRO_FIXED_PRIVATE_H + +#include "cairo-fixed-type-private.h" + +#include "cairo-wideint-private.h" + +/* Implementation */ + +#if (CAIRO_FIXED_BITS != 32) +# error CAIRO_FIXED_BITS must be 32, and the type must be a 32-bit type. +# error To remove this limitation, you will have to fix the tesselator. +#endif + +#define CAIRO_FIXED_ONE ((cairo_fixed_t)(1 << CAIRO_FIXED_FRAC_BITS)) +#define CAIRO_FIXED_ONE_DOUBLE ((double)(1 << CAIRO_FIXED_FRAC_BITS)) +#define CAIRO_FIXED_ONE_FLOAT ((float)(1 << CAIRO_FIXED_FRAC_BITS)) +#define CAIRO_FIXED_EPSILON ((cairo_fixed_t)(1)) + +#define CAIRO_FIXED_FRAC_MASK ((cairo_fixed_t)(((cairo_fixed_unsigned_t)(-1)) >> (CAIRO_FIXED_BITS - CAIRO_FIXED_FRAC_BITS))) +#define CAIRO_FIXED_WHOLE_MASK (~CAIRO_FIXED_FRAC_MASK) + +static inline cairo_fixed_t +_cairo_fixed_from_int (int i) +{ + return i << CAIRO_FIXED_FRAC_BITS; +} + +/* This is the "magic number" approach to converting a double into fixed + * point as described here: + * + * http://www.stereopsis.com/sree/fpu2006.html (an overview) + * http://www.d6.com/users/checker/pdfs/gdmfp.pdf (in detail) + * + * The basic idea is to add a large enough number to the double that the + * literal floating point is moved up to the extent that it forces the + * double's value to be shifted down to the bottom of the mantissa (to make + * room for the large number being added in). Since the mantissa is, at a + * given moment in time, a fixed point integer itself, one can convert a + * float to various fixed point representations by moving around the point + * of a floating point number through arithmetic operations. This behavior + * is reliable on most modern platforms as it is mandated by the IEEE-754 + * standard for floating point arithmetic. + * + * For our purposes, a "magic number" must be carefully selected that is + * both large enough to produce the desired point-shifting effect, and also + * has no lower bits in its representation that would interfere with our + * value at the bottom of the mantissa. The magic number is calculated as + * follows: + * + * (2 ^ (MANTISSA_SIZE - FRACTIONAL_SIZE)) * 1.5 + * + * where in our case: + * - MANTISSA_SIZE for 64-bit doubles is 52 + * - FRACTIONAL_SIZE for 16.16 fixed point is 16 + * + * Although this approach provides a very large speedup of this function + * on a wide-array of systems, it does come with two caveats: + * + * 1) It uses banker's rounding as opposed to arithmetic rounding. + * 2) It doesn't function properly if the FPU is in single-precision + * mode. + */ + +/* The 16.16 number must always be available */ +#define CAIRO_MAGIC_NUMBER_FIXED_16_16 (103079215104.0) + +#if CAIRO_FIXED_BITS <= 32 +#define CAIRO_MAGIC_NUMBER_FIXED ((1LL << (52 - CAIRO_FIXED_FRAC_BITS)) * 1.5) + +/* For 32-bit fixed point numbers */ +static inline cairo_fixed_t +_cairo_fixed_from_double (double d) +{ + union { + double d; + int32_t i[2]; + } u; + + u.d = d + CAIRO_MAGIC_NUMBER_FIXED; +#ifdef FLOAT_WORDS_BIGENDIAN + return u.i[1]; +#else + return u.i[0]; +#endif +} + +#else +# error Please define a magic number for your fixed point type! +# error See cairo-fixed-private.h for details. +#endif + +static inline cairo_fixed_t +_cairo_fixed_from_26_6 (uint32_t i) +{ +#if CAIRO_FIXED_FRAC_BITS > 6 + return i << (CAIRO_FIXED_FRAC_BITS - 6); +#else + return i >> (6 - CAIRO_FIXED_FRAC_BITS); +#endif +} + +static inline cairo_fixed_t +_cairo_fixed_from_16_16 (uint32_t i) +{ +#if CAIRO_FIXED_FRAC_BITS > 16 + return i << (CAIRO_FIXED_FRAC_BITS - 16); +#else + return i >> (16 - CAIRO_FIXED_FRAC_BITS); +#endif +} + +static inline double +_cairo_fixed_to_double (cairo_fixed_t f) +{ + return ((double) f) / CAIRO_FIXED_ONE_DOUBLE; +} + +static inline float +_cairo_fixed_to_float (cairo_fixed_t f) +{ + return ((float) f) / CAIRO_FIXED_ONE_FLOAT; +} + +static inline int +_cairo_fixed_is_integer (cairo_fixed_t f) +{ + return (f & CAIRO_FIXED_FRAC_MASK) == 0; +} + +static inline cairo_fixed_t +_cairo_fixed_floor (cairo_fixed_t f) +{ + return f & ~CAIRO_FIXED_FRAC_MASK; +} + +static inline cairo_fixed_t +_cairo_fixed_round (cairo_fixed_t f) +{ + return _cairo_fixed_floor (f + (CAIRO_FIXED_FRAC_MASK+1)/2); +} + +static inline cairo_fixed_t +_cairo_fixed_round_down (cairo_fixed_t f) +{ + return _cairo_fixed_floor (f + CAIRO_FIXED_FRAC_MASK/2); +} + +static inline int +_cairo_fixed_integer_part (cairo_fixed_t f) +{ + return f >> CAIRO_FIXED_FRAC_BITS; +} + +static inline int +_cairo_fixed_integer_round (cairo_fixed_t f) +{ + return _cairo_fixed_integer_part (f + (CAIRO_FIXED_FRAC_MASK+1)/2); +} + +static inline int +_cairo_fixed_integer_round_down (cairo_fixed_t f) +{ + return _cairo_fixed_integer_part (f + CAIRO_FIXED_FRAC_MASK/2); +} + +static inline int +_cairo_fixed_fractional_part (cairo_fixed_t f) +{ + return f & CAIRO_FIXED_FRAC_MASK; +} + +static inline int +_cairo_fixed_integer_floor (cairo_fixed_t f) +{ + if (f >= 0) + return f >> CAIRO_FIXED_FRAC_BITS; + else + return -((-f - 1) >> CAIRO_FIXED_FRAC_BITS) - 1; +} + +static inline int +_cairo_fixed_integer_ceil (cairo_fixed_t f) +{ + if (f > 0) + return ((f - 1)>>CAIRO_FIXED_FRAC_BITS) + 1; + else + return - (-f >> CAIRO_FIXED_FRAC_BITS); +} + +/* A bunch of explicit 16.16 operators; we need these + * to interface with pixman and other backends that require + * 16.16 fixed point types. + */ +static inline cairo_fixed_16_16_t +_cairo_fixed_to_16_16 (cairo_fixed_t f) +{ +#if (CAIRO_FIXED_FRAC_BITS == 16) && (CAIRO_FIXED_BITS == 32) + return f; +#elif CAIRO_FIXED_FRAC_BITS > 16 + /* We're just dropping the low bits, so we won't ever got over/underflow here */ + return f >> (CAIRO_FIXED_FRAC_BITS - 16); +#else + cairo_fixed_16_16_t x; + + /* Handle overflow/underflow by clamping to the lowest/highest + * value representable as 16.16 + */ + if ((f >> CAIRO_FIXED_FRAC_BITS) < INT16_MIN) { + x = INT32_MIN; + } else if ((f >> CAIRO_FIXED_FRAC_BITS) > INT16_MAX) { + x = INT32_MAX; + } else { + x = f << (16 - CAIRO_FIXED_FRAC_BITS); + } + + return x; +#endif +} + +static inline cairo_fixed_16_16_t +_cairo_fixed_16_16_from_double (double d) +{ + union { + double d; + int32_t i[2]; + } u; + + u.d = d + CAIRO_MAGIC_NUMBER_FIXED_16_16; +#ifdef FLOAT_WORDS_BIGENDIAN + return u.i[1]; +#else + return u.i[0]; +#endif +} + +static inline int +_cairo_fixed_16_16_floor (cairo_fixed_16_16_t f) +{ + if (f >= 0) + return f >> 16; + else + return -((-f - 1) >> 16) - 1; +} + +static inline double +_cairo_fixed_16_16_to_double (cairo_fixed_16_16_t f) +{ + return ((double) f) / (double) (1 << 16); +} + +#if CAIRO_FIXED_BITS == 32 + +static inline cairo_fixed_t +_cairo_fixed_mul (cairo_fixed_t a, cairo_fixed_t b) +{ + cairo_int64_t temp = _cairo_int32x32_64_mul (a, b); + return _cairo_int64_to_int32(_cairo_int64_rsl (temp, CAIRO_FIXED_FRAC_BITS)); +} + +/* computes round (a * b / c) */ +static inline cairo_fixed_t +_cairo_fixed_mul_div (cairo_fixed_t a, cairo_fixed_t b, cairo_fixed_t c) +{ + cairo_int64_t ab = _cairo_int32x32_64_mul (a, b); + cairo_int64_t c64 = _cairo_int32_to_int64 (c); + return _cairo_int64_to_int32 (_cairo_int64_divrem (ab, c64).quo); +} + +/* computes floor (a * b / c) */ +static inline cairo_fixed_t +_cairo_fixed_mul_div_floor (cairo_fixed_t a, cairo_fixed_t b, cairo_fixed_t c) +{ + return _cairo_int64_32_div (_cairo_int32x32_64_mul (a, b), c); +} + + +static inline cairo_fixed_t +_cairo_edge_compute_intersection_y_for_x (const cairo_point_t *p1, + const cairo_point_t *p2, + cairo_fixed_t x) +{ + cairo_fixed_t y, dx; + + if (x == p1->x) + return p1->y; + if (x == p2->x) + return p2->y; + + y = p1->y; + dx = p2->x - p1->x; + if (dx != 0) + y += _cairo_fixed_mul_div_floor (x - p1->x, p2->y - p1->y, dx); + + return y; +} + +static inline cairo_fixed_t +_cairo_edge_compute_intersection_x_for_y (const cairo_point_t *p1, + const cairo_point_t *p2, + cairo_fixed_t y) +{ + cairo_fixed_t x, dy; + + if (y == p1->y) + return p1->x; + if (y == p2->y) + return p2->x; + + x = p1->x; + dy = p2->y - p1->y; + if (dy != 0) + x += _cairo_fixed_mul_div_floor (y - p1->y, p2->x - p1->x, dy); + + return x; +} + +#else +# error Please define multiplication and other operands for your fixed-point type size +#endif + +#endif /* CAIRO_FIXED_PRIVATE_H */ |