1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SkPoint_DEFINED 18 #define SkPoint_DEFINED 19 20 #include "SkMath.h" 21 #include "SkScalar.h" 22 23 /** \struct SkIPoint 24 25 SkIPoint holds two 32 bit integer coordinates 26 */ 27 struct SkIPoint { 28 int32_t fX, fY; 29 30 static SkIPoint Make(int32_t x, int32_t y) { 31 SkIPoint pt; 32 pt.set(x, y); 33 return pt; 34 } 35 36 int32_t x() const { return fX; } 37 int32_t y() const { return fY; } 38 void setX(int32_t x) { fX = x; } 39 void setY(int32_t y) { fY = y; } 40 41 /** 42 * Returns true iff fX and fY are both zero. 43 */ 44 bool isZero() const { return (fX | fY) == 0; } 45 46 /** 47 * Set both fX and fY to zero. Same as set(0, 0) 48 */ 49 void setZero() { fX = fY = 0; } 50 51 /** Set the x and y values of the point. */ 52 void set(int32_t x, int32_t y) { fX = x; fY = y; } 53 54 /** Rotate the point clockwise, writing the new point into dst 55 It is legal for dst == this 56 */ 57 void rotateCW(SkIPoint* dst) const; 58 59 /** Rotate the point clockwise, writing the new point back into the point 60 */ 61 62 void rotateCW() { this->rotateCW(this); } 63 64 /** Rotate the point counter-clockwise, writing the new point into dst. 65 It is legal for dst == this 66 */ 67 void rotateCCW(SkIPoint* dst) const; 68 69 /** Rotate the point counter-clockwise, writing the new point back into 70 the point 71 */ 72 void rotateCCW() { this->rotateCCW(this); } 73 74 /** Negate the X and Y coordinates of the point. 75 */ 76 void negate() { fX = -fX; fY = -fY; } 77 78 /** Return a new point whose X and Y coordinates are the negative of the 79 original point's 80 */ 81 SkIPoint operator-() const { 82 SkIPoint neg; 83 neg.fX = -fX; 84 neg.fY = -fY; 85 return neg; 86 } 87 88 /** Add v's coordinates to this point's */ 89 void operator+=(const SkIPoint& v) { 90 fX += v.fX; 91 fY += v.fY; 92 } 93 94 /** Subtract v's coordinates from this point's */ 95 void operator-=(const SkIPoint& v) { 96 fX -= v.fX; 97 fY -= v.fY; 98 } 99 100 /** Returns true if the point's coordinates equal (x,y) */ 101 bool equals(int32_t x, int32_t y) const { 102 return fX == x && fY == y; 103 } 104 105 friend bool operator==(const SkIPoint& a, const SkIPoint& b) { 106 return a.fX == b.fX && a.fY == b.fY; 107 } 108 109 friend bool operator!=(const SkIPoint& a, const SkIPoint& b) { 110 return a.fX != b.fX || a.fY != b.fY; 111 } 112 113 /** Returns a new point whose coordinates are the difference between 114 a and b (i.e. a - b) 115 */ 116 friend SkIPoint operator-(const SkIPoint& a, const SkIPoint& b) { 117 SkIPoint v; 118 v.set(a.fX - b.fX, a.fY - b.fY); 119 return v; 120 } 121 122 /** Returns a new point whose coordinates are the sum of a and b (a + b) 123 */ 124 friend SkIPoint operator+(const SkIPoint& a, const SkIPoint& b) { 125 SkIPoint v; 126 v.set(a.fX + b.fX, a.fY + b.fY); 127 return v; 128 } 129 130 /** Returns the dot product of a and b, treating them as 2D vectors 131 */ 132 static int32_t DotProduct(const SkIPoint& a, const SkIPoint& b) { 133 return a.fX * b.fX + a.fY * b.fY; 134 } 135 136 /** Returns the cross product of a and b, treating them as 2D vectors 137 */ 138 static int32_t CrossProduct(const SkIPoint& a, const SkIPoint& b) { 139 return a.fX * b.fY - a.fY * b.fX; 140 } 141 }; 142 143 struct SK_API SkPoint { 144 SkScalar fX, fY; 145 146 static SkPoint Make(SkScalar x, SkScalar y) { 147 SkPoint pt; 148 pt.set(x, y); 149 return pt; 150 } 151 152 SkScalar x() const { return fX; } 153 SkScalar y() const { return fY; } 154 155 /** Set the point's X and Y coordinates */ 156 void set(SkScalar x, SkScalar y) { fX = x; fY = y; } 157 158 /** Set the point's X and Y coordinates by automatically promoting (x,y) to 159 SkScalar values. 160 */ 161 void iset(int32_t x, int32_t y) { 162 fX = SkIntToScalar(x); 163 fY = SkIntToScalar(y); 164 } 165 166 /** Set the point's X and Y coordinates by automatically promoting p's 167 coordinates to SkScalar values. 168 */ 169 void iset(const SkIPoint& p) { 170 fX = SkIntToScalar(p.fX); 171 fY = SkIntToScalar(p.fY); 172 } 173 174 void setAbs(const SkPoint& pt) { 175 fX = SkScalarAbs(pt.fX); 176 fY = SkScalarAbs(pt.fY); 177 } 178 179 // counter-clockwise fan 180 void setIRectFan(int l, int t, int r, int b) { 181 SkPoint* v = this; 182 v[0].set(SkIntToScalar(l), SkIntToScalar(t)); 183 v[1].set(SkIntToScalar(l), SkIntToScalar(b)); 184 v[2].set(SkIntToScalar(r), SkIntToScalar(b)); 185 v[3].set(SkIntToScalar(r), SkIntToScalar(t)); 186 } 187 void setIRectFan(int l, int t, int r, int b, size_t stride); 188 189 // counter-clockwise fan 190 void setRectFan(SkScalar l, SkScalar t, SkScalar r, SkScalar b) { 191 SkPoint* v = this; 192 v[0].set(l, t); 193 v[1].set(l, b); 194 v[2].set(r, b); 195 v[3].set(r, t); 196 } 197 void setRectFan(SkScalar l, SkScalar t, SkScalar r, SkScalar b, size_t stride); 198 199 void offset(SkScalar dx, SkScalar dy) { 200 fX += dx; 201 fY += dy; 202 } 203 204 /** Return the euclidian distance from (0,0) to the point 205 */ 206 SkScalar length() const { return SkPoint::Length(fX, fY); } 207 SkScalar distanceToOrigin() const { return this->length(); } 208 209 /** Set the point (vector) to be unit-length in the same direction as it 210 currently is, and return its old length. If the old length is 211 degenerately small (nearly zero), do nothing and return false, otherwise 212 return true. 213 */ 214 bool normalize(); 215 216 /** Set the point (vector) to be unit-length in the same direction as the 217 x,y params. If the vector (x,y) has a degenerate length (i.e. nearly 0) 218 then return false and do nothing, otherwise return true. 219 */ 220 bool setNormalize(SkScalar x, SkScalar y); 221 222 /** Scale the point (vector) to have the specified length, and return that 223 length. If the original length is degenerately small (nearly zero), 224 do nothing and return false, otherwise return true. 225 */ 226 bool setLength(SkScalar length); 227 228 /** Set the point (vector) to have the specified length in the same 229 direction as (x,y). If the vector (x,y) has a degenerate length 230 (i.e. nearly 0) then return false and do nothing, otherwise return true. 231 */ 232 bool setLength(SkScalar x, SkScalar y, SkScalar length); 233 234 /** Scale the point's coordinates by scale, writing the answer into dst. 235 It is legal for dst == this. 236 */ 237 void scale(SkScalar scale, SkPoint* dst) const; 238 239 /** Scale the point's coordinates by scale, writing the answer back into 240 the point. 241 */ 242 void scale(SkScalar value) { this->scale(value, this); } 243 244 /** Rotate the point clockwise by 90 degrees, writing the answer into dst. 245 It is legal for dst == this. 246 */ 247 void rotateCW(SkPoint* dst) const; 248 249 /** Rotate the point clockwise by 90 degrees, writing the answer back into 250 the point. 251 */ 252 void rotateCW() { this->rotateCW(this); } 253 254 /** Rotate the point counter-clockwise by 90 degrees, writing the answer 255 into dst. It is legal for dst == this. 256 */ 257 void rotateCCW(SkPoint* dst) const; 258 259 /** Rotate the point counter-clockwise by 90 degrees, writing the answer 260 back into the point. 261 */ 262 void rotateCCW() { this->rotateCCW(this); } 263 264 /** Negate the point's coordinates 265 */ 266 void negate() { 267 fX = -fX; 268 fY = -fY; 269 } 270 271 /** Returns a new point whose coordinates are the negative of the point's 272 */ 273 SkPoint operator-() const { 274 SkPoint neg; 275 neg.fX = -fX; 276 neg.fY = -fY; 277 return neg; 278 } 279 280 /** Add v's coordinates to the point's 281 */ 282 void operator+=(const SkPoint& v) { 283 fX += v.fX; 284 fY += v.fY; 285 } 286 287 /** Subtract v's coordinates from the point's 288 */ 289 void operator-=(const SkPoint& v) { 290 fX -= v.fX; 291 fY -= v.fY; 292 } 293 294 /** Returns true if the point's coordinates equal (x,y) 295 */ 296 bool equals(SkScalar x, SkScalar y) const { return fX == x && fY == y; } 297 298 friend bool operator==(const SkPoint& a, const SkPoint& b) { 299 return a.fX == b.fX && a.fY == b.fY; 300 } 301 302 friend bool operator!=(const SkPoint& a, const SkPoint& b) { 303 return a.fX != b.fX || a.fY != b.fY; 304 } 305 306 /** Returns a new point whose coordinates are the difference between 307 a's and b's (a - b) 308 */ 309 friend SkPoint operator-(const SkPoint& a, const SkPoint& b) { 310 SkPoint v; 311 v.set(a.fX - b.fX, a.fY - b.fY); 312 return v; 313 } 314 315 /** Returns a new point whose coordinates are the sum of a's and b's (a + b) 316 */ 317 friend SkPoint operator+(const SkPoint& a, const SkPoint& b) { 318 SkPoint v; 319 v.set(a.fX + b.fX, a.fY + b.fY); 320 return v; 321 } 322 323 /** Returns the euclidian distance from (0,0) to (x,y) 324 */ 325 static SkScalar Length(SkScalar x, SkScalar y); 326 327 /** Normalize pt, returning its previous length. If the prev length is too 328 small (degenerate), return 0 and leave pt unchanged. 329 */ 330 static SkScalar Normalize(SkPoint* pt); 331 332 /** Returns the euclidian distance between a and b 333 */ 334 static SkScalar Distance(const SkPoint& a, const SkPoint& b) { 335 return Length(a.fX - b.fX, a.fY - b.fY); 336 } 337 338 /** Returns the dot product of a and b, treating them as 2D vectors 339 */ 340 static SkScalar DotProduct(const SkPoint& a, const SkPoint& b) { 341 return SkScalarMul(a.fX, b.fX) + SkScalarMul(a.fY, b.fY); 342 } 343 344 /** Returns the cross product of a and b, treating them as 2D vectors 345 */ 346 static SkScalar CrossProduct(const SkPoint& a, const SkPoint& b) { 347 return SkScalarMul(a.fX, b.fY) - SkScalarMul(a.fY, b.fX); 348 } 349 350 SkScalar cross(const SkPoint& vec) const { 351 return CrossProduct(*this, vec); 352 } 353 354 SkScalar dot(const SkPoint& vec) const { 355 return DotProduct(*this, vec); 356 } 357 358 SkScalar lengthSqd() const { 359 return DotProduct(*this, *this); 360 } 361 362 SkScalar distanceToSqd(const SkPoint& pt) const { 363 SkScalar dx = fX - pt.fX; 364 SkScalar dy = fY - pt.fY; 365 return SkScalarMul(dx, dx) + SkScalarMul(dy, dy); 366 } 367 368 SkScalar distanceToLineSegmentBetweenSqd(const SkPoint& a, 369 const SkPoint& b) const; 370 371 SkScalar distanceToLineSegmentBetween(const SkPoint& a, 372 const SkPoint& b) const { 373 return SkScalarSqrt(this->distanceToLineSegmentBetweenSqd(a, b)); 374 } 375 }; 376 377 typedef SkPoint SkVector; 378 379 #endif 380 381
