1 2/* 3 * Copyright 2010 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 11#include "SkTouchGesture.h" 12#include "SkMatrix.h" 13#include "SkTime.h" 14 15#define DISCRETIZE_TRANSLATE_TO_AVOID_FLICKER true 16 17static const SkScalar MAX_FLING_SPEED = SkIntToScalar(1500); 18 19static SkScalar pin_max_fling(SkScalar speed) { 20 if (speed > MAX_FLING_SPEED) { 21 speed = MAX_FLING_SPEED; 22 } 23 return speed; 24} 25 26static double getseconds() { 27 return SkTime::GetMSecs() * 0.001; 28} 29 30// returns +1 or -1, depending on the sign of x 31// returns +1 if z is zero 32static SkScalar SkScalarSignNonZero(SkScalar x) { 33 SkScalar sign = SK_Scalar1; 34 if (x < 0) { 35 sign = -sign; 36 } 37 return sign; 38} 39 40static void unit_axis_align(SkVector* unit) { 41 const SkScalar TOLERANCE = SkDoubleToScalar(0.15); 42 if (SkScalarAbs(unit->fX) < TOLERANCE) { 43 unit->fX = 0; 44 unit->fY = SkScalarSignNonZero(unit->fY); 45 } else if (SkScalarAbs(unit->fY) < TOLERANCE) { 46 unit->fX = SkScalarSignNonZero(unit->fX); 47 unit->fY = 0; 48 } 49} 50 51void SkFlingState::reset(float sx, float sy) { 52 fActive = true; 53 fDirection.set(sx, sy); 54 fSpeed0 = SkPoint::Normalize(&fDirection); 55 fSpeed0 = pin_max_fling(fSpeed0); 56 fTime0 = getseconds(); 57 58 unit_axis_align(&fDirection); 59// printf("---- speed %g dir %g %g\n", fSpeed0, fDirection.fX, fDirection.fY); 60} 61 62bool SkFlingState::evaluateMatrix(SkMatrix* matrix) { 63 if (!fActive) { 64 return false; 65 } 66 67 const float t = (float)(getseconds() - fTime0); 68 const float MIN_SPEED = 2; 69 const float K0 = 5; 70 const float K1 = 0.02f; 71 const float speed = fSpeed0 * (sk_float_exp(- K0 * t) - K1); 72 if (speed <= MIN_SPEED) { 73 fActive = false; 74 return false; 75 } 76 float dist = (fSpeed0 - speed) / K0; 77 78// printf("---- time %g speed %g dist %g\n", t, speed, dist); 79 float tx = fDirection.fX * dist; 80 float ty = fDirection.fY * dist; 81 if (DISCRETIZE_TRANSLATE_TO_AVOID_FLICKER) { 82 tx = (float)sk_float_round2int(tx); 83 ty = (float)sk_float_round2int(ty); 84 } 85 matrix->setTranslate(tx, ty); 86// printf("---- evaluate (%g %g)\n", tx, ty); 87 88 return true; 89} 90 91/////////////////////////////////////////////////////////////////////////////// 92 93static const SkMSec MAX_DBL_TAP_INTERVAL = 300; 94static const float MAX_DBL_TAP_DISTANCE = 100; 95static const float MAX_JITTER_RADIUS = 2; 96 97// if true, then ignore the touch-move, 'cause its probably just jitter 98static bool close_enough_for_jitter(float x0, float y0, float x1, float y1) { 99 return sk_float_abs(x0 - x1) <= MAX_JITTER_RADIUS && 100 sk_float_abs(y0 - y1) <= MAX_JITTER_RADIUS; 101} 102 103/////////////////////////////////////////////////////////////////////////////// 104 105SkTouchGesture::SkTouchGesture() { 106 this->reset(); 107} 108 109SkTouchGesture::~SkTouchGesture() { 110} 111 112void SkTouchGesture::reset() { 113 fTouches.reset(); 114 fState = kEmpty_State; 115 fLocalM.reset(); 116 fGlobalM.reset(); 117 118 fLastUpT = SkTime::GetMSecs() - 2*MAX_DBL_TAP_INTERVAL; 119 fLastUpP.set(0, 0); 120} 121 122void SkTouchGesture::flushLocalM() { 123 fGlobalM.postConcat(fLocalM); 124 fLocalM.reset(); 125} 126 127const SkMatrix& SkTouchGesture::localM() { 128 if (fFlinger.isActive()) { 129 if (!fFlinger.evaluateMatrix(&fLocalM)) { 130 this->flushLocalM(); 131 } 132 } 133 return fLocalM; 134} 135 136void SkTouchGesture::appendNewRec(void* owner, float x, float y) { 137 Rec* rec = fTouches.append(); 138 rec->fOwner = owner; 139 rec->fStartX = rec->fPrevX = rec->fLastX = x; 140 rec->fStartY = rec->fPrevY = rec->fLastY = y; 141 rec->fLastT = rec->fPrevT = SkTime::GetMSecs(); 142} 143 144void SkTouchGesture::touchBegin(void* owner, float x, float y) { 145// SkDebugf("--- %d touchBegin %p %g %g\n", fTouches.count(), owner, x, y); 146 147 int index = this->findRec(owner); 148 if (index >= 0) { 149 this->flushLocalM(); 150 fTouches.removeShuffle(index); 151 SkDebugf("---- already exists, removing\n"); 152 } 153 154 if (fTouches.count() == 2) { 155 return; 156 } 157 158 this->flushLocalM(); 159 fFlinger.stop(); 160 161 this->appendNewRec(owner, x, y); 162 163 switch (fTouches.count()) { 164 case 1: 165 fState = kTranslate_State; 166 break; 167 case 2: 168 fState = kZoom_State; 169 break; 170 default: 171 break; 172 } 173} 174 175int SkTouchGesture::findRec(void* owner) const { 176 for (int i = 0; i < fTouches.count(); i++) { 177 if (owner == fTouches[i].fOwner) { 178 return i; 179 } 180 } 181 return -1; 182} 183 184static SkScalar center(float pos0, float pos1) { 185 return (pos0 + pos1) * 0.5f; 186} 187 188static const float MAX_ZOOM_SCALE = 4; 189static const float MIN_ZOOM_SCALE = 0.25f; 190 191float SkTouchGesture::limitTotalZoom(float scale) const { 192 // this query works 'cause we know that we're square-scale w/ no skew/rotation 193 const float curr = SkScalarToFloat(fGlobalM[0]); 194 195 if (scale > 1 && curr * scale > MAX_ZOOM_SCALE) { 196 scale = MAX_ZOOM_SCALE / curr; 197 } else if (scale < 1 && curr * scale < MIN_ZOOM_SCALE) { 198 scale = MIN_ZOOM_SCALE / curr; 199 } 200 return scale; 201} 202 203void SkTouchGesture::touchMoved(void* owner, float x, float y) { 204// SkDebugf("--- %d touchMoved %p %g %g\n", fTouches.count(), owner, x, y); 205 206 if (kEmpty_State == fState) { 207 return; 208 } 209 210 int index = this->findRec(owner); 211 if (index < 0) { 212 // not found, so I guess we should add it... 213 SkDebugf("---- add missing begin\n"); 214 this->appendNewRec(owner, x, y); 215 index = fTouches.count() - 1; 216 } 217 218 Rec& rec = fTouches[index]; 219 220 // not sure how valuable this is 221 if (fTouches.count() == 2) { 222 if (close_enough_for_jitter(rec.fLastX, rec.fLastY, x, y)) { 223// SkDebugf("--- drop touchMove, withing jitter tolerance %g %g\n", rec.fLastX - x, rec.fLastY - y); 224 return; 225 } 226 } 227 228 rec.fPrevX = rec.fLastX; rec.fLastX = x; 229 rec.fPrevY = rec.fLastY; rec.fLastY = y; 230 rec.fPrevT = rec.fLastT; rec.fLastT = SkTime::GetMSecs(); 231 232 switch (fTouches.count()) { 233 case 1: { 234 float dx = rec.fLastX - rec.fStartX; 235 float dy = rec.fLastY - rec.fStartY; 236 dx = (float)sk_float_round2int(dx); 237 dy = (float)sk_float_round2int(dy); 238 fLocalM.setTranslate(dx, dy); 239 } break; 240 case 2: { 241 SkASSERT(kZoom_State == fState); 242 const Rec& rec0 = fTouches[0]; 243 const Rec& rec1 = fTouches[1]; 244 245 float scale = this->computePinch(rec0, rec1); 246 scale = this->limitTotalZoom(scale); 247 248 fLocalM.setTranslate(-center(rec0.fStartX, rec1.fStartX), 249 -center(rec0.fStartY, rec1.fStartY)); 250 fLocalM.postScale(scale, scale); 251 fLocalM.postTranslate(center(rec0.fLastX, rec1.fLastX), 252 center(rec0.fLastY, rec1.fLastY)); 253 } break; 254 default: 255 break; 256 } 257} 258 259void SkTouchGesture::touchEnd(void* owner) { 260// SkDebugf("--- %d touchEnd %p\n", fTouches.count(), owner); 261 262 int index = this->findRec(owner); 263 if (index < 0) { 264 SkDebugf("--- not found\n"); 265 return; 266 } 267 268 const Rec& rec = fTouches[index]; 269 if (this->handleDblTap(rec.fLastX, rec.fLastY)) { 270 return; 271 } 272 273 // count() reflects the number before we removed the owner 274 switch (fTouches.count()) { 275 case 1: { 276 this->flushLocalM(); 277 float dx = rec.fLastX - rec.fPrevX; 278 float dy = rec.fLastY - rec.fPrevY; 279 float dur = (rec.fLastT - rec.fPrevT) * 0.001f; 280 if (dur > 0) { 281 fFlinger.reset(dx / dur, dy / dur); 282 } 283 fState = kEmpty_State; 284 } break; 285 case 2: 286 this->flushLocalM(); 287 SkASSERT(kZoom_State == fState); 288 fState = kEmpty_State; 289 break; 290 default: 291 SkASSERT(kZoom_State == fState); 292 break; 293 } 294 295 fTouches.removeShuffle(index); 296} 297 298float SkTouchGesture::computePinch(const Rec& rec0, const Rec& rec1) { 299 double dx = rec0.fStartX - rec1.fStartX; 300 double dy = rec0.fStartY - rec1.fStartY; 301 double dist0 = sqrt(dx*dx + dy*dy); 302 303 dx = rec0.fLastX - rec1.fLastX; 304 dy = rec0.fLastY - rec1.fLastY; 305 double dist1 = sqrt(dx*dx + dy*dy); 306 307 double scale = dist1 / dist0; 308 return (float)scale; 309} 310 311bool SkTouchGesture::handleDblTap(float x, float y) { 312 bool found = false; 313 SkMSec now = SkTime::GetMSecs(); 314 if (now - fLastUpT <= MAX_DBL_TAP_INTERVAL) { 315 if (SkPoint::Length(fLastUpP.fX - x, 316 fLastUpP.fY - y) <= MAX_DBL_TAP_DISTANCE) { 317 fFlinger.stop(); 318 fLocalM.reset(); 319 fGlobalM.reset(); 320 fTouches.reset(); 321 fState = kEmpty_State; 322 found = true; 323 } 324 } 325 326 fLastUpT = now; 327 fLastUpP.set(x, y); 328 return found; 329} 330