/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkDashPathEffect.h"
#include "SkDashPathPriv.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#include "SkStrokeRec.h"
SkDashPathEffect::SkDashPathEffect(const SkScalar intervals[], int count, SkScalar phase)
: fPhase(0)
, fInitialDashLength(-1)
, fInitialDashIndex(0)
, fIntervalLength(0) {
SkASSERT(intervals);
SkASSERT(count > 1 && SkIsAlign2(count));
fIntervals = (SkScalar*)sk_malloc_throw(sizeof(SkScalar) * count);
fCount = count;
for (int i = 0; i < count; i++) {
fIntervals[i] = intervals[i];
}
// set the internal data members
SkDashPath::CalcDashParameters(phase, fIntervals, fCount,
&fInitialDashLength, &fInitialDashIndex, &fIntervalLength, &fPhase);
}
SkDashPathEffect::~SkDashPathEffect() {
sk_free(fIntervals);
}
bool SkDashPathEffect::filterPath(SkPath* dst, const SkPath& src,
SkStrokeRec* rec, const SkRect* cullRect) const {
return SkDashPath::InternalFilter(dst, src, rec, cullRect, fIntervals, fCount,
fInitialDashLength, fInitialDashIndex, fIntervalLength);
}
static void outset_for_stroke(SkRect* rect, const SkStrokeRec& rec) {
SkScalar radius = SkScalarHalf(rec.getWidth());
if (0 == radius) {
radius = SK_Scalar1; // hairlines
}
if (SkPaint::kMiter_Join == rec.getJoin()) {
radius *= rec.getMiter();
}
rect->outset(radius, radius);
}
// Attempt to trim the line to minimally cover the cull rect (currently
// only works for horizontal and vertical lines).
// Return true if processing should continue; false otherwise.
static bool cull_line(SkPoint* pts, const SkStrokeRec& rec,
const SkMatrix& ctm, const SkRect* cullRect,
const SkScalar intervalLength) {
if (nullptr == cullRect) {
SkASSERT(false); // Shouldn't ever occur in practice
return false;
}
SkScalar dx = pts[1].x() - pts[0].x();
SkScalar dy = pts[1].y() - pts[0].y();
if ((dx && dy) || (!dx && !dy)) {
return false;
}
SkRect bounds = *cullRect;
outset_for_stroke(&bounds, rec);
// cullRect is in device space while pts are in the local coordinate system
// defined by the ctm. We want our answer in the local coordinate system.
SkASSERT(ctm.rectStaysRect());
SkMatrix inv;
if (!ctm.invert(&inv)) {
return false;
}
inv.mapRect(&bounds);
if (dx) {
SkASSERT(dx && !dy);
SkScalar minX = pts[0].fX;
SkScalar maxX = pts[1].fX;
if (dx < 0) {
SkTSwap(minX, maxX);
}
SkASSERT(minX < maxX);
if (maxX <= bounds.fLeft || minX >= bounds.fRight) {
return false;
}
// Now we actually perform the chop, removing the excess to the left and
// right of the bounds (keeping our new line "in phase" with the dash,
// hence the (mod intervalLength).
if (minX < bounds.fLeft) {
minX = bounds.fLeft - SkScalarMod(bounds.fLeft - minX, intervalLength);
}
if (maxX > bounds.fRight) {
maxX = bounds.fRight + SkScalarMod(maxX - bounds.fRight, intervalLength);
}
SkASSERT(maxX > minX);
if (dx < 0) {
SkTSwap(minX, maxX);
}
pts[0].fX = minX;
pts[1].fX = maxX;
} else {
SkASSERT(dy && !dx);
SkScalar minY = pts[0].fY;
SkScalar maxY = pts[1].fY;
if (dy < 0) {
SkTSwap(minY, maxY);
}
SkASSERT(minY < maxY);
if (maxY <= bounds.fTop || minY >= bounds.fBottom) {
return false;
}
// Now we actually perform the chop, removing the excess to the top and
// bottom of the bounds (keeping our new line "in phase" with the dash,
// hence the (mod intervalLength).
if (minY < bounds.fTop) {
minY = bounds.fTop - SkScalarMod(bounds.fTop - minY, intervalLength);
}
if (maxY > bounds.fBottom) {
maxY = bounds.fBottom + SkScalarMod(maxY - bounds.fBottom, intervalLength);
}
SkASSERT(maxY > minY);
if (dy < 0) {
SkTSwap(minY, maxY);
}
pts[0].fY = minY;
pts[1].fY = maxY;
}
return true;
}
// Currently asPoints is more restrictive then it needs to be. In the future
// we need to:
// allow kRound_Cap capping (could allow rotations in the matrix with this)
// allow paths to be returned
bool SkDashPathEffect::asPoints(PointData* results,
const SkPath& src,
const SkStrokeRec& rec,
const SkMatrix& matrix,
const SkRect* cullRect) const {
// width < 0 -> fill && width == 0 -> hairline so requiring width > 0 rules both out
if (0 >= rec.getWidth()) {
return false;
}
// TODO: this next test could be eased up. We could allow any number of
// intervals as long as all the ons match and all the offs match.
// Additionally, they do not necessarily need to be integers.
// We cannot allow arbitrary intervals since we want the returned points
// to be uniformly sized.
if (fCount != 2 ||
!SkScalarNearlyEqual(fIntervals[0], fIntervals[1]) ||
!SkScalarIsInt(fIntervals[0]) ||
!SkScalarIsInt(fIntervals[1])) {
return false;
}
SkPoint pts[2];
if (!src.isLine(pts)) {
return false;
}
// TODO: this test could be eased up to allow circles
if (SkPaint::kButt_Cap != rec.getCap()) {
return false;
}
// TODO: this test could be eased up for circles. Rotations could be allowed.
if (!matrix.rectStaysRect()) {
return false;
}
// See if the line can be limited to something plausible.
if (!cull_line(pts, rec, matrix, cullRect, fIntervalLength)) {
return false;
}
SkScalar length = SkPoint::Distance(pts[1], pts[0]);
SkVector tangent = pts[1] - pts[0];
if (tangent.isZero()) {
return false;
}
tangent.scale(SkScalarInvert(length));
// TODO: make this test for horizontal & vertical lines more robust
bool isXAxis = true;
if (SkScalarNearlyEqual(SK_Scalar1, tangent.fX) ||
SkScalarNearlyEqual(-SK_Scalar1, tangent.fX)) {
results->fSize.set(SkScalarHalf(fIntervals[0]), SkScalarHalf(rec.getWidth()));
} else if (SkScalarNearlyEqual(SK_Scalar1, tangent.fY) ||
SkScalarNearlyEqual(-SK_Scalar1, tangent.fY)) {
results->fSize.set(SkScalarHalf(rec.getWidth()), SkScalarHalf(fIntervals[0]));
isXAxis = false;
} else if (SkPaint::kRound_Cap != rec.getCap()) {
// Angled lines don't have axis-aligned boxes.
return false;
}
if (results) {
results->fFlags = 0;
SkScalar clampedInitialDashLength = SkMinScalar(length, fInitialDashLength);
if (SkPaint::kRound_Cap == rec.getCap()) {
results->fFlags |= PointData::kCircles_PointFlag;
}
results->fNumPoints = 0;
SkScalar len2 = length;
if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
SkASSERT(len2 >= clampedInitialDashLength);
if (0 == fInitialDashIndex) {
if (clampedInitialDashLength > 0) {
if (clampedInitialDashLength >= fIntervals[0]) {
++results->fNumPoints; // partial first dash
}
len2 -= clampedInitialDashLength;
}
len2 -= fIntervals[1]; // also skip first space
if (len2 < 0) {
len2 = 0;
}
} else {
len2 -= clampedInitialDashLength; // skip initial partial empty
}
}
// Too many midpoints can cause results->fNumPoints to overflow or
// otherwise cause the results->fPoints allocation below to OOM.
// Cap it to a sane value.
SkScalar numIntervals = len2 / fIntervalLength;
if (!SkScalarIsFinite(numIntervals) || numIntervals > SkDashPath::kMaxDashCount) {
return false;
}
int numMidPoints = SkScalarFloorToInt(numIntervals);
results->fNumPoints += numMidPoints;
len2 -= numMidPoints * fIntervalLength;
bool partialLast = false;
if (len2 > 0) {
if (len2 < fIntervals[0]) {
partialLast = true;
} else {
++numMidPoints;
++results->fNumPoints;
}
}
results->fPoints = new SkPoint[results->fNumPoints];
SkScalar distance = 0;
int curPt = 0;
if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
SkASSERT(clampedInitialDashLength <= length);
if (0 == fInitialDashIndex) {
if (clampedInitialDashLength > 0) {
// partial first block
SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
SkScalar x = pts[0].fX + tangent.fX * SkScalarHalf(clampedInitialDashLength);
SkScalar y = pts[0].fY + tangent.fY * SkScalarHalf(clampedInitialDashLength);
SkScalar halfWidth, halfHeight;
if (isXAxis) {
halfWidth = SkScalarHalf(clampedInitialDashLength);
halfHeight = SkScalarHalf(rec.getWidth());
} else {
halfWidth = SkScalarHalf(rec.getWidth());
halfHeight = SkScalarHalf(clampedInitialDashLength);
}
if (clampedInitialDashLength < fIntervals[0]) {
// This one will not be like the others
results->fFirst.addRect(x - halfWidth, y - halfHeight,
x + halfWidth, y + halfHeight);
} else {
SkASSERT(curPt < results->fNumPoints);
results->fPoints[curPt].set(x, y);
++curPt;
}
distance += clampedInitialDashLength;
}
distance += fIntervals[1]; // skip over the next blank block too
} else {
distance += clampedInitialDashLength;
}
}
if (0 != numMidPoints) {
distance += SkScalarHalf(fIntervals[0]);
for (int i = 0; i < numMidPoints; ++i) {
SkScalar x = pts[0].fX + tangent.fX * distance;
SkScalar y = pts[0].fY + tangent.fY * distance;
SkASSERT(curPt < results->fNumPoints);
results->fPoints[curPt].set(x, y);
++curPt;
distance += fIntervalLength;
}
distance -= SkScalarHalf(fIntervals[0]);
}
if (partialLast) {
// partial final block
SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
SkScalar temp = length - distance;
SkASSERT(temp < fIntervals[0]);
SkScalar x = pts[0].fX + tangent.fX * (distance + SkScalarHalf(temp));
SkScalar y = pts[0].fY + tangent.fY * (distance + SkScalarHalf(temp));
SkScalar halfWidth, halfHeight;
if (isXAxis) {
halfWidth = SkScalarHalf(temp);
halfHeight = SkScalarHalf(rec.getWidth());
} else {
halfWidth = SkScalarHalf(rec.getWidth());
halfHeight = SkScalarHalf(temp);
}
results->fLast.addRect(x - halfWidth, y - halfHeight,
x + halfWidth, y + halfHeight);
}
SkASSERT(curPt == results->fNumPoints);
}
return true;
}
SkPathEffect::DashType SkDashPathEffect::asADash(DashInfo* info) const {
if (info) {
if (info->fCount >= fCount && info->fIntervals) {
memcpy(info->fIntervals, fIntervals, fCount * sizeof(SkScalar));
}
info->fCount = fCount;
info->fPhase = fPhase;
}
return kDash_DashType;
}
void SkDashPathEffect::flatten(SkWriteBuffer& buffer) const {
buffer.writeScalar(fPhase);
buffer.writeScalarArray(fIntervals, fCount);
}
sk_sp<SkFlattenable> SkDashPathEffect::CreateProc(SkReadBuffer& buffer) {
const SkScalar phase = buffer.readScalar();
uint32_t count = buffer.getArrayCount();
SkAutoSTArray<32, SkScalar> intervals(count);
if (buffer.readScalarArray(intervals.get(), count)) {
return Make(intervals.get(), SkToInt(count), phase);
}
return nullptr;
}
#ifndef SK_IGNORE_TO_STRING
void SkDashPathEffect::toString(SkString* str) const {
str->appendf("SkDashPathEffect: (");
str->appendf("count: %d phase %.2f intervals: (", fCount, fPhase);
for (int i = 0; i < fCount; ++i) {
str->appendf("%.2f", fIntervals[i]);
if (i < fCount-1) {
str->appendf(", ");
}
}
str->appendf("))");
}
#endif
//////////////////////////////////////////////////////////////////////////////////////////////////
sk_sp<SkPathEffect> SkDashPathEffect::Make(const SkScalar intervals[], int count, SkScalar phase) {
if (!SkDashPath::ValidDashPath(phase, intervals, count)) {
return nullptr;
}
return sk_sp<SkPathEffect>(new SkDashPathEffect(intervals, count, phase));
}