| /* |
| * Copyright 2010 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <algorithm> |
| |
| #include "SkTouchGesture.h" |
| #include "SkMatrix.h" |
| #include "SkTime.h" |
| |
| #define DISCRETIZE_TRANSLATE_TO_AVOID_FLICKER true |
| |
| static const SkScalar MAX_FLING_SPEED = SkIntToScalar(1500); |
| |
| static SkScalar pin_max_fling(SkScalar speed) { |
| if (speed > MAX_FLING_SPEED) { |
| speed = MAX_FLING_SPEED; |
| } |
| return speed; |
| } |
| |
| static double getseconds() { |
| return SkTime::GetMSecs() * 0.001; |
| } |
| |
| // returns +1 or -1, depending on the sign of x |
| // returns +1 if z is zero |
| static SkScalar SkScalarSignNonZero(SkScalar x) { |
| SkScalar sign = SK_Scalar1; |
| if (x < 0) { |
| sign = -sign; |
| } |
| return sign; |
| } |
| |
| static void unit_axis_align(SkVector* unit) { |
| const SkScalar TOLERANCE = SkDoubleToScalar(0.15); |
| if (SkScalarAbs(unit->fX) < TOLERANCE) { |
| unit->fX = 0; |
| unit->fY = SkScalarSignNonZero(unit->fY); |
| } else if (SkScalarAbs(unit->fY) < TOLERANCE) { |
| unit->fX = SkScalarSignNonZero(unit->fX); |
| unit->fY = 0; |
| } |
| } |
| |
| void SkFlingState::reset(float sx, float sy) { |
| fActive = true; |
| fDirection.set(sx, sy); |
| fSpeed0 = SkPoint::Normalize(&fDirection); |
| fSpeed0 = pin_max_fling(fSpeed0); |
| fTime0 = getseconds(); |
| |
| unit_axis_align(&fDirection); |
| // printf("---- speed %g dir %g %g\n", fSpeed0, fDirection.fX, fDirection.fY); |
| } |
| |
| bool SkFlingState::evaluateMatrix(SkMatrix* matrix) { |
| if (!fActive) { |
| return false; |
| } |
| |
| const float t = (float)(getseconds() - fTime0); |
| const float MIN_SPEED = 2; |
| const float K0 = 5; |
| const float K1 = 0.02f; |
| const float speed = fSpeed0 * (sk_float_exp(- K0 * t) - K1); |
| if (speed <= MIN_SPEED) { |
| fActive = false; |
| return false; |
| } |
| float dist = (fSpeed0 - speed) / K0; |
| |
| // printf("---- time %g speed %g dist %g\n", t, speed, dist); |
| float tx = fDirection.fX * dist; |
| float ty = fDirection.fY * dist; |
| if (DISCRETIZE_TRANSLATE_TO_AVOID_FLICKER) { |
| tx = (float)sk_float_round2int(tx); |
| ty = (float)sk_float_round2int(ty); |
| } |
| matrix->setTranslate(tx, ty); |
| // printf("---- evaluate (%g %g)\n", tx, ty); |
| |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static const SkMSec MAX_DBL_TAP_INTERVAL = 300; |
| static const float MAX_DBL_TAP_DISTANCE = 100; |
| static const float MAX_JITTER_RADIUS = 2; |
| |
| // if true, then ignore the touch-move, 'cause its probably just jitter |
| static bool close_enough_for_jitter(float x0, float y0, float x1, float y1) { |
| return sk_float_abs(x0 - x1) <= MAX_JITTER_RADIUS && |
| sk_float_abs(y0 - y1) <= MAX_JITTER_RADIUS; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| SkTouchGesture::SkTouchGesture() { |
| this->reset(); |
| } |
| |
| SkTouchGesture::~SkTouchGesture() { |
| } |
| |
| void SkTouchGesture::reset() { |
| fIsTransLimited = false; |
| fTouches.reset(); |
| fState = kEmpty_State; |
| fLocalM.reset(); |
| fGlobalM.reset(); |
| |
| fLastUpMillis = SkTime::GetMSecs() - 2*MAX_DBL_TAP_INTERVAL; |
| fLastUpP.set(0, 0); |
| } |
| |
| void SkTouchGesture::flushLocalM() { |
| fGlobalM.postConcat(fLocalM); |
| fLocalM.reset(); |
| } |
| |
| const SkMatrix& SkTouchGesture::localM() { |
| if (fFlinger.isActive()) { |
| if (!fFlinger.evaluateMatrix(&fLocalM)) { |
| this->flushLocalM(); |
| } |
| } |
| return fLocalM; |
| } |
| |
| void SkTouchGesture::appendNewRec(void* owner, float x, float y) { |
| Rec* rec = fTouches.append(); |
| rec->fOwner = owner; |
| rec->fStartX = rec->fPrevX = rec->fLastX = x; |
| rec->fStartY = rec->fPrevY = rec->fLastY = y; |
| rec->fLastT = rec->fPrevT = static_cast<float>(SkTime::GetSecs()); |
| } |
| |
| void SkTouchGesture::touchBegin(void* owner, float x, float y) { |
| // SkDebugf("--- %d touchBegin %p %g %g\n", fTouches.count(), owner, x, y); |
| |
| int index = this->findRec(owner); |
| if (index >= 0) { |
| this->flushLocalM(); |
| fTouches.removeShuffle(index); |
| SkDebugf("---- already exists, removing\n"); |
| } |
| |
| if (fTouches.count() == 2) { |
| return; |
| } |
| |
| this->flushLocalM(); |
| fFlinger.stop(); |
| |
| this->appendNewRec(owner, x, y); |
| |
| switch (fTouches.count()) { |
| case 1: |
| fState = kTranslate_State; |
| break; |
| case 2: |
| fState = kZoom_State; |
| break; |
| default: |
| break; |
| } |
| } |
| |
| int SkTouchGesture::findRec(void* owner) const { |
| for (int i = 0; i < fTouches.count(); i++) { |
| if (owner == fTouches[i].fOwner) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| static SkScalar center(float pos0, float pos1) { |
| return (pos0 + pos1) * 0.5f; |
| } |
| |
| static const float MAX_ZOOM_SCALE = 4; |
| static const float MIN_ZOOM_SCALE = 0.25f; |
| |
| float SkTouchGesture::limitTotalZoom(float scale) const { |
| // this query works 'cause we know that we're square-scale w/ no skew/rotation |
| const float curr = SkScalarToFloat(fGlobalM[0]); |
| |
| if (scale > 1 && curr * scale > MAX_ZOOM_SCALE) { |
| scale = MAX_ZOOM_SCALE / curr; |
| } else if (scale < 1 && curr * scale < MIN_ZOOM_SCALE) { |
| scale = MIN_ZOOM_SCALE / curr; |
| } |
| return scale; |
| } |
| |
| void SkTouchGesture::touchMoved(void* owner, float x, float y) { |
| // SkDebugf("--- %d touchMoved %p %g %g\n", fTouches.count(), owner, x, y); |
| |
| if (kEmpty_State == fState) { |
| return; |
| } |
| |
| int index = this->findRec(owner); |
| if (index < 0) { |
| // not found, so I guess we should add it... |
| SkDebugf("---- add missing begin\n"); |
| this->appendNewRec(owner, x, y); |
| index = fTouches.count() - 1; |
| } |
| |
| Rec& rec = fTouches[index]; |
| |
| // not sure how valuable this is |
| if (fTouches.count() == 2) { |
| if (close_enough_for_jitter(rec.fLastX, rec.fLastY, x, y)) { |
| // SkDebugf("--- drop touchMove, withing jitter tolerance %g %g\n", rec.fLastX - x, rec.fLastY - y); |
| return; |
| } |
| } |
| |
| rec.fPrevX = rec.fLastX; rec.fLastX = x; |
| rec.fPrevY = rec.fLastY; rec.fLastY = y; |
| rec.fPrevT = rec.fLastT; |
| rec.fLastT = static_cast<float>(SkTime::GetSecs()); |
| |
| switch (fTouches.count()) { |
| case 1: { |
| float dx = rec.fLastX - rec.fStartX; |
| float dy = rec.fLastY - rec.fStartY; |
| dx = (float)sk_float_round2int(dx); |
| dy = (float)sk_float_round2int(dy); |
| fLocalM.setTranslate(dx, dy); |
| } break; |
| case 2: { |
| SkASSERT(kZoom_State == fState); |
| const Rec& rec0 = fTouches[0]; |
| const Rec& rec1 = fTouches[1]; |
| |
| float scale = this->computePinch(rec0, rec1); |
| scale = this->limitTotalZoom(scale); |
| |
| fLocalM.setTranslate(-center(rec0.fStartX, rec1.fStartX), |
| -center(rec0.fStartY, rec1.fStartY)); |
| fLocalM.postScale(scale, scale); |
| fLocalM.postTranslate(center(rec0.fLastX, rec1.fLastX), |
| center(rec0.fLastY, rec1.fLastY)); |
| } break; |
| default: |
| break; |
| } |
| } |
| |
| void SkTouchGesture::touchEnd(void* owner) { |
| // SkDebugf("--- %d touchEnd %p\n", fTouches.count(), owner); |
| |
| int index = this->findRec(owner); |
| if (index < 0) { |
| SkDebugf("--- not found\n"); |
| return; |
| } |
| |
| const Rec& rec = fTouches[index]; |
| if (this->handleDblTap(rec.fLastX, rec.fLastY)) { |
| return; |
| } |
| |
| // count() reflects the number before we removed the owner |
| switch (fTouches.count()) { |
| case 1: { |
| this->flushLocalM(); |
| float dx = rec.fLastX - rec.fPrevX; |
| float dy = rec.fLastY - rec.fPrevY; |
| float dur = rec.fLastT - rec.fPrevT; |
| if (dur > 0) { |
| fFlinger.reset(dx / dur, dy / dur); |
| } |
| fState = kEmpty_State; |
| } break; |
| case 2: |
| this->flushLocalM(); |
| SkASSERT(kZoom_State == fState); |
| fState = kEmpty_State; |
| break; |
| default: |
| SkASSERT(kZoom_State == fState); |
| break; |
| } |
| |
| fTouches.removeShuffle(index); |
| |
| limitTrans(); |
| } |
| |
| float SkTouchGesture::computePinch(const Rec& rec0, const Rec& rec1) { |
| double dx = rec0.fStartX - rec1.fStartX; |
| double dy = rec0.fStartY - rec1.fStartY; |
| double dist0 = sqrt(dx*dx + dy*dy); |
| |
| dx = rec0.fLastX - rec1.fLastX; |
| dy = rec0.fLastY - rec1.fLastY; |
| double dist1 = sqrt(dx*dx + dy*dy); |
| |
| double scale = dist1 / dist0; |
| return (float)scale; |
| } |
| |
| bool SkTouchGesture::handleDblTap(float x, float y) { |
| bool found = false; |
| double now = SkTime::GetMSecs(); |
| if (now - fLastUpMillis <= MAX_DBL_TAP_INTERVAL) { |
| if (SkPoint::Length(fLastUpP.fX - x, |
| fLastUpP.fY - y) <= MAX_DBL_TAP_DISTANCE) { |
| fFlinger.stop(); |
| fLocalM.reset(); |
| fGlobalM.reset(); |
| fTouches.reset(); |
| fState = kEmpty_State; |
| found = true; |
| } |
| } |
| |
| fLastUpMillis = now; |
| fLastUpP.set(x, y); |
| return found; |
| } |
| |
| void SkTouchGesture::setTransLimit(const SkRect& contentRect, const SkRect& windowRect) { |
| fIsTransLimited = true; |
| fContentRect = contentRect; |
| fWindowRect = windowRect; |
| } |
| |
| void SkTouchGesture::limitTrans() { |
| if (!fIsTransLimited) { |
| return; |
| } |
| |
| SkRect scaledContent = fContentRect; |
| fGlobalM.mapRect(&scaledContent); |
| const SkScalar ZERO = 0; |
| |
| fGlobalM.postTranslate(ZERO, std::min(ZERO, fWindowRect.fBottom - scaledContent.fTop)); |
| fGlobalM.postTranslate(ZERO, std::max(ZERO, fWindowRect.fTop - scaledContent.fBottom)); |
| fGlobalM.postTranslate(std::min(ZERO, fWindowRect.fRight - scaledContent.fLeft), ZERO); |
| fGlobalM.postTranslate(std::max(ZERO, fWindowRect.fLeft - scaledContent.fRight), ZERO); |
| } |