diff options
Diffstat (limited to 'fitz/base_geometry.c')
| -rw-r--r-- | fitz/base_geometry.c | 155 |
1 files changed, 39 insertions, 116 deletions
diff --git a/fitz/base_geometry.c b/fitz/base_geometry.c index ef22a6fa..1486279f 100644 --- a/fitz/base_geometry.c +++ b/fitz/base_geometry.c @@ -3,24 +3,6 @@ #define MAX4(a,b,c,d) fz_max(fz_max(a,b), fz_max(c,d)) #define MIN4(a,b,c,d) fz_min(fz_min(a,b), fz_min(c,d)) -/* A useful macro to add with overflow detection and clamping. - - We want to do "b = a + x", but to allow for overflow. Consider the - top bits, and the cases in which overflow occurs: - - overflow a x b ~a^x a^b (~a^x)&(a^b) - no 0 0 0 1 0 0 - yes 0 0 1 1 1 1 - no 0 1 0 0 0 0 - no 0 1 1 0 1 0 - no 1 0 0 0 1 0 - no 1 0 1 0 0 0 - yes 1 1 0 1 1 1 - no 1 1 1 1 0 0 -*/ -#define ADD_WITH_SAT(b,a,x) \ - ((b) = (a) + (x), (b) = (((~(a)^(x))&((a)^(b))) < 0 ? ((x) < 0 ? INT_MIN : INT_MAX) : (b))) - /* Matrices, points and affine transformations */ const fz_matrix fz_identity = { 1, 0, 0, 1, 0, 0 }; @@ -180,43 +162,44 @@ fz_transform_vector(fz_matrix m, fz_point p) /* Rectangles and bounding boxes */ +/* biggest and smallest integers that a float can represent perfectly (i.e. 24 bits) */ +#define MAX_SAFE_INT 16777216 +#define MIN_SAFE_INT -16777216 + const fz_rect fz_infinite_rect = { 1, 1, -1, -1 }; const fz_rect fz_empty_rect = { 0, 0, 0, 0 }; const fz_rect fz_unit_rect = { 0, 0, 1, 1 }; -const fz_bbox fz_infinite_bbox = { 1, 1, -1, -1 }; -const fz_bbox fz_empty_bbox = { 0, 0, 0, 0 }; -const fz_bbox fz_unit_bbox = { 0, 0, 1, 1 }; - -#define SAFE_INT(f) ((f > INT_MAX) ? INT_MAX : ((f < INT_MIN) ? INT_MIN : (int)f)) -fz_bbox -fz_bbox_covering_rect(fz_rect f) +fz_rect +fz_rect_covering_rect(fz_rect f) { - fz_bbox i; f.x0 = floorf(f.x0); f.y0 = floorf(f.y0); f.x1 = ceilf(f.x1); f.y1 = ceilf(f.y1); - i.x0 = SAFE_INT(f.x0); - i.y0 = SAFE_INT(f.y0); - i.x1 = SAFE_INT(f.x1); - i.y1 = SAFE_INT(f.y1); - return i; + + /* check for integer overflow */ + f.x0 = fz_clamp(f.x0, MIN_SAFE_INT, MAX_SAFE_INT); + f.y0 = fz_clamp(f.y0, MIN_SAFE_INT, MAX_SAFE_INT); + f.x1 = fz_clamp(f.x1, MIN_SAFE_INT, MAX_SAFE_INT); + f.y1 = fz_clamp(f.y1, MIN_SAFE_INT, MAX_SAFE_INT); + return f; } -fz_bbox +fz_rect fz_round_rect(fz_rect f) { - fz_bbox i; f.x0 = floorf(f.x0 + 0.001); f.y0 = floorf(f.y0 + 0.001); f.x1 = ceilf(f.x1 - 0.001); f.y1 = ceilf(f.y1 - 0.001); - i.x0 = SAFE_INT(f.x0); - i.y0 = SAFE_INT(f.y0); - i.x1 = SAFE_INT(f.x1); - i.y1 = SAFE_INT(f.y1); - return i; + + /* check for integer overflow */ + f.x0 = fz_clamp(f.x0, MIN_SAFE_INT, MAX_SAFE_INT); + f.y0 = fz_clamp(f.y0, MIN_SAFE_INT, MAX_SAFE_INT); + f.x1 = fz_clamp(f.x1, MIN_SAFE_INT, MAX_SAFE_INT); + f.y1 = fz_clamp(f.y1, MIN_SAFE_INT, MAX_SAFE_INT); + return f; } fz_rect @@ -251,52 +234,6 @@ fz_union_rect(fz_rect a, fz_rect b) return r; } -fz_bbox -fz_intersect_bbox(fz_bbox a, fz_bbox b) -{ - fz_bbox r; - /* Check for empty box before infinite box */ - if (fz_is_empty_rect(a)) return fz_empty_bbox; - if (fz_is_empty_rect(b)) return fz_empty_bbox; - if (fz_is_infinite_rect(a)) return b; - if (fz_is_infinite_rect(b)) return a; - r.x0 = fz_maxi(a.x0, b.x0); - r.y0 = fz_maxi(a.y0, b.y0); - r.x1 = fz_mini(a.x1, b.x1); - r.y1 = fz_mini(a.y1, b.y1); - return (r.x1 < r.x0 || r.y1 < r.y0) ? fz_empty_bbox : r; -} - -fz_bbox -fz_translate_bbox(fz_bbox a, int xoff, int yoff) -{ - fz_bbox b; - - if (fz_is_empty_rect(a)) return a; - if (fz_is_infinite_rect(a)) return a; - ADD_WITH_SAT(b.x0, a.x0, xoff); - ADD_WITH_SAT(b.y0, a.y0, yoff); - ADD_WITH_SAT(b.x1, a.x1, xoff); - ADD_WITH_SAT(b.y1, a.y1, yoff); - return b; -} - -fz_bbox -fz_union_bbox(fz_bbox a, fz_bbox b) -{ - fz_bbox r; - /* Check for empty box before infinite box */ - if (fz_is_empty_rect(a)) return b; - if (fz_is_empty_rect(b)) return a; - if (fz_is_infinite_rect(a)) return a; - if (fz_is_infinite_rect(b)) return b; - r.x0 = fz_mini(a.x0, b.x0); - r.y0 = fz_mini(a.y0, b.y0); - r.x1 = fz_maxi(a.x1, b.x1); - r.y1 = fz_maxi(a.y1, b.y1); - return r; -} - fz_rect fz_transform_rect(fz_matrix m, fz_rect r) { @@ -320,42 +257,28 @@ fz_transform_rect(fz_matrix m, fz_rect r) return r; } -fz_bbox -fz_transform_bbox(fz_matrix m, fz_bbox b) +fz_rect +fz_translate_rect(fz_rect a, float xoff, float yoff) { - fz_point s, t, u, v; - - if (fz_is_infinite_bbox(b)) - return b; - - s.x = b.x0; s.y = b.y0; - t.x = b.x0; t.y = b.y1; - u.x = b.x1; u.y = b.y1; - v.x = b.x1; v.y = b.y0; - s = fz_transform_point(m, s); - t = fz_transform_point(m, t); - u = fz_transform_point(m, u); - v = fz_transform_point(m, v); - b.x0 = MIN4(s.x, t.x, u.x, v.x); - b.y0 = MIN4(s.y, t.y, u.y, v.y); - b.x1 = MAX4(s.x, t.x, u.x, v.x); - b.y1 = MAX4(s.y, t.y, u.y, v.y); + fz_rect b; + if (fz_is_empty_rect(a)) return a; + if (fz_is_infinite_rect(a)) return a; + b.x0 = a.x0 + xoff; + b.y0 = a.y0 + yoff; + b.x1 = a.x1 + xoff; + b.y1 = a.y1 + yoff; return b; - } -fz_bbox -fz_expand_bbox(fz_bbox a, int expand) +fz_rect +fz_expand_rect(fz_rect a, float expand) { - fz_bbox b; - - if (fz_is_infinite_bbox(a)) - return a; - - ADD_WITH_SAT(b.x0, a.x0, -expand); - ADD_WITH_SAT(b.y0, a.y0, -expand); - ADD_WITH_SAT(b.x1, a.x1, expand); - ADD_WITH_SAT(b.y1, a.y1, expand); + fz_rect b; + if (fz_is_empty_rect(a)) return a; + if (fz_is_infinite_rect(a)) return a; + b.x0 = a.x0 - expand; + b.y0 = a.y0 - expand; + b.x1 = a.x1 + expand; + b.y1 = a.y1 + expand; return b; - } |