blob: efa50bc5390849ac437bcbdba8ed1b53e1f3a92f [file] [log] [blame]
/*
* 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 "include/core/SkRegion.h"
#include "include/private/SkMacros.h"
#include "include/private/SkTemplates.h"
#include "include/private/SkTo.h"
#include "src/core/SkRegionPriv.h"
#include "src/core/SkSafeMath.h"
#include "src/utils/SkUTF.h"
#include <utility>
/* Region Layout
*
* TOP
*
* [ Bottom, X-Intervals, [Left, Right]..., X-Sentinel ]
* ...
*
* Y-Sentinel
*/
/////////////////////////////////////////////////////////////////////////////////////////////////
#define SkRegion_gEmptyRunHeadPtr ((SkRegionPriv::RunHead*)-1)
#define SkRegion_gRectRunHeadPtr nullptr
constexpr int kRunArrayStackCount = 256;
// This is a simple data structure which is like a SkSTArray<N,T,true>, except that:
// - It does not initialize memory.
// - It does not distinguish between reserved space and initialized space.
// - resizeToAtLeast() instead of resize()
// - Uses sk_realloc_throw()
// - Can never be made smaller.
// Measurement: for the `region_union_16` benchmark, this is 6% faster.
class RunArray {
public:
RunArray() { fPtr = fStack; }
#ifdef SK_DEBUG
int count() const { return fCount; }
#endif
SkRegionPriv::RunType& operator[](int i) {
SkASSERT((unsigned)i < (unsigned)fCount);
return fPtr[i];
}
/** Resize the array to a size greater-than-or-equal-to count. */
void resizeToAtLeast(int count) {
if (count > fCount) {
// leave at least 50% extra space for future growth.
count += count >> 1;
fMalloc.realloc(count);
if (fPtr == fStack) {
memcpy(fMalloc.get(), fStack, fCount * sizeof(SkRegionPriv::RunType));
}
fPtr = fMalloc.get();
fCount = count;
}
}
private:
SkRegionPriv::RunType fStack[kRunArrayStackCount];
SkAutoTMalloc<SkRegionPriv::RunType> fMalloc;
int fCount = kRunArrayStackCount;
SkRegionPriv::RunType* fPtr; // non-owning pointer
};
/* Pass in the beginning with the intervals.
* We back up 1 to read the interval-count.
* Return the beginning of the next scanline (i.e. the next Y-value)
*/
static SkRegionPriv::RunType* skip_intervals(const SkRegionPriv::RunType runs[]) {
int intervals = runs[-1];
#ifdef SK_DEBUG
if (intervals > 0) {
SkASSERT(runs[0] < runs[1]);
SkASSERT(runs[1] < SkRegion_kRunTypeSentinel);
} else {
SkASSERT(0 == intervals);
SkASSERT(SkRegion_kRunTypeSentinel == runs[0]);
}
#endif
runs += intervals * 2 + 1;
return const_cast<SkRegionPriv::RunType*>(runs);
}
bool SkRegion::RunsAreARect(const SkRegion::RunType runs[], int count,
SkIRect* bounds) {
assert_sentinel(runs[0], false); // top
SkASSERT(count >= kRectRegionRuns);
if (count == kRectRegionRuns) {
assert_sentinel(runs[1], false); // bottom
SkASSERT(1 == runs[2]);
assert_sentinel(runs[3], false); // left
assert_sentinel(runs[4], false); // right
assert_sentinel(runs[5], true);
assert_sentinel(runs[6], true);
SkASSERT(runs[0] < runs[1]); // valid height
SkASSERT(runs[3] < runs[4]); // valid width
bounds->setLTRB(runs[3], runs[0], runs[4], runs[1]);
return true;
}
return false;
}
//////////////////////////////////////////////////////////////////////////
SkRegion::SkRegion() {
fBounds.setEmpty();
fRunHead = SkRegion_gEmptyRunHeadPtr;
}
SkRegion::SkRegion(const SkRegion& src) {
fRunHead = SkRegion_gEmptyRunHeadPtr; // just need a value that won't trigger sk_free(fRunHead)
this->setRegion(src);
}
SkRegion::SkRegion(const SkIRect& rect) {
fRunHead = SkRegion_gEmptyRunHeadPtr; // just need a value that won't trigger sk_free(fRunHead)
this->setRect(rect);
}
SkRegion::~SkRegion() {
this->freeRuns();
}
void SkRegion::freeRuns() {
if (this->isComplex()) {
SkASSERT(fRunHead->fRefCnt >= 1);
if (--fRunHead->fRefCnt == 0) {
sk_free(fRunHead);
}
}
}
void SkRegion::allocateRuns(int count, int ySpanCount, int intervalCount) {
fRunHead = RunHead::Alloc(count, ySpanCount, intervalCount);
}
void SkRegion::allocateRuns(int count) {
fRunHead = RunHead::Alloc(count);
}
void SkRegion::allocateRuns(const RunHead& head) {
fRunHead = RunHead::Alloc(head.fRunCount,
head.getYSpanCount(),
head.getIntervalCount());
}
SkRegion& SkRegion::operator=(const SkRegion& src) {
(void)this->setRegion(src);
return *this;
}
void SkRegion::swap(SkRegion& other) {
using std::swap;
swap(fBounds, other.fBounds);
swap(fRunHead, other.fRunHead);
}
int SkRegion::computeRegionComplexity() const {
if (this->isEmpty()) {
return 0;
} else if (this->isRect()) {
return 1;
}
return fRunHead->getIntervalCount();
}
bool SkRegion::setEmpty() {
this->freeRuns();
fBounds.setEmpty();
fRunHead = SkRegion_gEmptyRunHeadPtr;
return false;
}
bool SkRegion::setRect(const SkIRect& r) {
if (r.isEmpty() ||
SkRegion_kRunTypeSentinel == r.right() ||
SkRegion_kRunTypeSentinel == r.bottom()) {
return this->setEmpty();
}
this->freeRuns();
fBounds = r;
fRunHead = SkRegion_gRectRunHeadPtr;
return true;
}
bool SkRegion::setRegion(const SkRegion& src) {
if (this != &src) {
this->freeRuns();
fBounds = src.fBounds;
fRunHead = src.fRunHead;
if (this->isComplex()) {
fRunHead->fRefCnt++;
}
}
return fRunHead != SkRegion_gEmptyRunHeadPtr;
}
bool SkRegion::op(const SkIRect& rect, const SkRegion& rgn, Op op) {
SkRegion tmp(rect);
return this->op(tmp, rgn, op);
}
bool SkRegion::op(const SkRegion& rgn, const SkIRect& rect, Op op) {
SkRegion tmp(rect);
return this->op(rgn, tmp, op);
}
///////////////////////////////////////////////////////////////////////////////
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
#include <stdio.h>
char* SkRegion::toString() {
Iterator iter(*this);
int count = 0;
while (!iter.done()) {
count++;
iter.next();
}
// 4 ints, up to 10 digits each plus sign, 3 commas, '(', ')', SkRegion() and '\0'
const int max = (count*((11*4)+5))+11+1;
char* result = (char*)sk_malloc_throw(max);
if (result == nullptr) {
return nullptr;
}
count = snprintf(result, max, "SkRegion(");
iter.reset(*this);
while (!iter.done()) {
const SkIRect& r = iter.rect();
count += snprintf(result+count, max - count,
"(%d,%d,%d,%d)", r.fLeft, r.fTop, r.fRight, r.fBottom);
iter.next();
}
count += snprintf(result+count, max - count, ")");
return result;
}
#endif
///////////////////////////////////////////////////////////////////////////////
int SkRegion::count_runtype_values(int* itop, int* ibot) const {
int maxT;
if (this->isRect()) {
maxT = 2;
} else {
SkASSERT(this->isComplex());
maxT = fRunHead->getIntervalCount() * 2;
}
*itop = fBounds.fTop;
*ibot = fBounds.fBottom;
return maxT;
}
static bool isRunCountEmpty(int count) {
return count <= 2;
}
bool SkRegion::setRuns(RunType runs[], int count) {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
SkASSERT(count > 0);
if (isRunCountEmpty(count)) {
// SkDEBUGF("setRuns: empty\n");
assert_sentinel(runs[count-1], true);
return this->setEmpty();
}
// trim off any empty spans from the top and bottom
// weird I should need this, perhaps op() could be smarter...
if (count > kRectRegionRuns) {
RunType* stop = runs + count;
assert_sentinel(runs[0], false); // top
assert_sentinel(runs[1], false); // bottom
// runs[2] is uncomputed intervalCount
if (runs[3] == SkRegion_kRunTypeSentinel) { // should be first left...
runs += 3; // skip empty initial span
runs[0] = runs[-2]; // set new top to prev bottom
assert_sentinel(runs[1], false); // bot: a sentinal would mean two in a row
assert_sentinel(runs[2], false); // intervalcount
assert_sentinel(runs[3], false); // left
assert_sentinel(runs[4], false); // right
}
assert_sentinel(stop[-1], true);
assert_sentinel(stop[-2], true);
// now check for a trailing empty span
if (stop[-5] == SkRegion_kRunTypeSentinel) { // eek, stop[-4] was a bottom with no x-runs
stop[-4] = SkRegion_kRunTypeSentinel; // kill empty last span
stop -= 3;
assert_sentinel(stop[-1], true); // last y-sentinel
assert_sentinel(stop[-2], true); // last x-sentinel
assert_sentinel(stop[-3], false); // last right
assert_sentinel(stop[-4], false); // last left
assert_sentinel(stop[-5], false); // last interval-count
assert_sentinel(stop[-6], false); // last bottom
}
count = (int)(stop - runs);
}
SkASSERT(count >= kRectRegionRuns);
if (SkRegion::RunsAreARect(runs, count, &fBounds)) {
return this->setRect(fBounds);
}
// if we get here, we need to become a complex region
if (!this->isComplex() || fRunHead->fRunCount != count) {
this->freeRuns();
this->allocateRuns(count);
SkASSERT(this->isComplex());
}
// must call this before we can write directly into runs()
// in case we are sharing the buffer with another region (copy on write)
fRunHead = fRunHead->ensureWritable();
memcpy(fRunHead->writable_runs(), runs, count * sizeof(RunType));
fRunHead->computeRunBounds(&fBounds);
// Our computed bounds might be too large, so we have to check here.
if (fBounds.isEmpty()) {
return this->setEmpty();
}
SkDEBUGCODE(SkRegionPriv::Validate(*this));
return true;
}
void SkRegion::BuildRectRuns(const SkIRect& bounds,
RunType runs[kRectRegionRuns]) {
runs[0] = bounds.fTop;
runs[1] = bounds.fBottom;
runs[2] = 1; // 1 interval for this scanline
runs[3] = bounds.fLeft;
runs[4] = bounds.fRight;
runs[5] = SkRegion_kRunTypeSentinel;
runs[6] = SkRegion_kRunTypeSentinel;
}
bool SkRegion::contains(int32_t x, int32_t y) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
if (!fBounds.contains(x, y)) {
return false;
}
if (this->isRect()) {
return true;
}
SkASSERT(this->isComplex());
const RunType* runs = fRunHead->findScanline(y);
// Skip the Bottom and IntervalCount
runs += 2;
// Just walk this scanline, checking each interval. The X-sentinel will
// appear as a left-inteval (runs[0]) and should abort the search.
//
// We could do a bsearch, using interval-count (runs[1]), but need to time
// when that would be worthwhile.
//
for (;;) {
if (x < runs[0]) {
break;
}
if (x < runs[1]) {
return true;
}
runs += 2;
}
return false;
}
static SkRegionPriv::RunType scanline_bottom(const SkRegionPriv::RunType runs[]) {
return runs[0];
}
static const SkRegionPriv::RunType* scanline_next(const SkRegionPriv::RunType runs[]) {
// skip [B N [L R]... S]
return runs + 2 + runs[1] * 2 + 1;
}
static bool scanline_contains(const SkRegionPriv::RunType runs[],
SkRegionPriv::RunType L, SkRegionPriv::RunType R) {
runs += 2; // skip Bottom and IntervalCount
for (;;) {
if (L < runs[0]) {
break;
}
if (R <= runs[1]) {
return true;
}
runs += 2;
}
return false;
}
bool SkRegion::contains(const SkIRect& r) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
if (!fBounds.contains(r)) {
return false;
}
if (this->isRect()) {
return true;
}
SkASSERT(this->isComplex());
const RunType* scanline = fRunHead->findScanline(r.fTop);
for (;;) {
if (!scanline_contains(scanline, r.fLeft, r.fRight)) {
return false;
}
if (r.fBottom <= scanline_bottom(scanline)) {
break;
}
scanline = scanline_next(scanline);
}
return true;
}
bool SkRegion::contains(const SkRegion& rgn) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
SkDEBUGCODE(SkRegionPriv::Validate(rgn));
if (this->isEmpty() || rgn.isEmpty() || !fBounds.contains(rgn.fBounds)) {
return false;
}
if (this->isRect()) {
return true;
}
if (rgn.isRect()) {
return this->contains(rgn.getBounds());
}
/*
* A contains B is equivalent to
* B - A == 0
*/
return !Oper(rgn, *this, kDifference_Op, nullptr);
}
const SkRegion::RunType* SkRegion::getRuns(RunType tmpStorage[],
int* intervals) const {
SkASSERT(tmpStorage && intervals);
const RunType* runs = tmpStorage;
if (this->isEmpty()) {
tmpStorage[0] = SkRegion_kRunTypeSentinel;
*intervals = 0;
} else if (this->isRect()) {
BuildRectRuns(fBounds, tmpStorage);
*intervals = 1;
} else {
runs = fRunHead->readonly_runs();
*intervals = fRunHead->getIntervalCount();
}
return runs;
}
///////////////////////////////////////////////////////////////////////////////
static bool scanline_intersects(const SkRegionPriv::RunType runs[],
SkRegionPriv::RunType L, SkRegionPriv::RunType R) {
runs += 2; // skip Bottom and IntervalCount
for (;;) {
if (R <= runs[0]) {
break;
}
if (L < runs[1]) {
return true;
}
runs += 2;
}
return false;
}
bool SkRegion::intersects(const SkIRect& r) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
if (this->isEmpty() || r.isEmpty()) {
return false;
}
SkIRect sect;
if (!sect.intersect(fBounds, r)) {
return false;
}
if (this->isRect()) {
return true;
}
SkASSERT(this->isComplex());
const RunType* scanline = fRunHead->findScanline(sect.fTop);
for (;;) {
if (scanline_intersects(scanline, sect.fLeft, sect.fRight)) {
return true;
}
if (sect.fBottom <= scanline_bottom(scanline)) {
break;
}
scanline = scanline_next(scanline);
}
return false;
}
bool SkRegion::intersects(const SkRegion& rgn) const {
if (this->isEmpty() || rgn.isEmpty()) {
return false;
}
if (!SkIRect::Intersects(fBounds, rgn.fBounds)) {
return false;
}
bool weAreARect = this->isRect();
bool theyAreARect = rgn.isRect();
if (weAreARect && theyAreARect) {
return true;
}
if (weAreARect) {
return rgn.intersects(this->getBounds());
}
if (theyAreARect) {
return this->intersects(rgn.getBounds());
}
// both of us are complex
return Oper(*this, rgn, kIntersect_Op, nullptr);
}
///////////////////////////////////////////////////////////////////////////////
bool SkRegion::operator==(const SkRegion& b) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
SkDEBUGCODE(SkRegionPriv::Validate(b));
if (this == &b) {
return true;
}
if (fBounds != b.fBounds) {
return false;
}
const SkRegion::RunHead* ah = fRunHead;
const SkRegion::RunHead* bh = b.fRunHead;
// this catches empties and rects being equal
if (ah == bh) {
return true;
}
// now we insist that both are complex (but different ptrs)
if (!this->isComplex() || !b.isComplex()) {
return false;
}
return ah->fRunCount == bh->fRunCount &&
!memcmp(ah->readonly_runs(), bh->readonly_runs(),
ah->fRunCount * sizeof(SkRegion::RunType));
}
// Return a (new) offset such that when applied (+=) to min and max, we don't overflow/underflow
static int32_t pin_offset_s32(int32_t min, int32_t max, int32_t offset) {
SkASSERT(min <= max);
const int32_t lo = -SK_MaxS32-1,
hi = +SK_MaxS32;
if ((int64_t)min + offset < lo) { offset = lo - min; }
if ((int64_t)max + offset > hi) { offset = hi - max; }
return offset;
}
void SkRegion::translate(int dx, int dy, SkRegion* dst) const {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
if (nullptr == dst) {
return;
}
if (this->isEmpty()) {
dst->setEmpty();
return;
}
// pin dx and dy so we don't overflow our existing bounds
dx = pin_offset_s32(fBounds.fLeft, fBounds.fRight, dx);
dy = pin_offset_s32(fBounds.fTop, fBounds.fBottom, dy);
if (this->isRect()) {
dst->setRect(fBounds.makeOffset(dx, dy));
} else {
if (this == dst) {
dst->fRunHead = dst->fRunHead->ensureWritable();
} else {
SkRegion tmp;
tmp.allocateRuns(*fRunHead);
SkASSERT(tmp.isComplex());
tmp.fBounds = fBounds;
dst->swap(tmp);
}
dst->fBounds.offset(dx, dy);
const RunType* sruns = fRunHead->readonly_runs();
RunType* druns = dst->fRunHead->writable_runs();
*druns++ = (SkRegion::RunType)(*sruns++ + dy); // top
for (;;) {
int bottom = *sruns++;
if (bottom == SkRegion_kRunTypeSentinel) {
break;
}
*druns++ = (SkRegion::RunType)(bottom + dy); // bottom;
*druns++ = *sruns++; // copy intervalCount;
for (;;) {
int x = *sruns++;
if (x == SkRegion_kRunTypeSentinel) {
break;
}
*druns++ = (SkRegion::RunType)(x + dx);
*druns++ = (SkRegion::RunType)(*sruns++ + dx);
}
*druns++ = SkRegion_kRunTypeSentinel; // x sentinel
}
*druns++ = SkRegion_kRunTypeSentinel; // y sentinel
SkASSERT(sruns - fRunHead->readonly_runs() == fRunHead->fRunCount);
SkASSERT(druns - dst->fRunHead->readonly_runs() == dst->fRunHead->fRunCount);
}
SkDEBUGCODE(SkRegionPriv::Validate(*this));
}
///////////////////////////////////////////////////////////////////////////////
bool SkRegion::setRects(const SkIRect rects[], int count) {
if (0 == count) {
this->setEmpty();
} else {
this->setRect(rects[0]);
for (int i = 1; i < count; i++) {
this->op(rects[i], kUnion_Op);
}
}
return !this->isEmpty();
}
///////////////////////////////////////////////////////////////////////////////
#if defined _WIN32 // disable warning : local variable used without having been initialized
#pragma warning ( push )
#pragma warning ( disable : 4701 )
#endif
#ifdef SK_DEBUG
static void assert_valid_pair(int left, int rite)
{
SkASSERT(left == SkRegion_kRunTypeSentinel || left < rite);
}
#else
#define assert_valid_pair(left, rite)
#endif
struct spanRec {
const SkRegionPriv::RunType* fA_runs;
const SkRegionPriv::RunType* fB_runs;
int fA_left, fA_rite, fB_left, fB_rite;
int fLeft, fRite, fInside;
void init(const SkRegionPriv::RunType a_runs[],
const SkRegionPriv::RunType b_runs[]) {
fA_left = *a_runs++;
fA_rite = *a_runs++;
fB_left = *b_runs++;
fB_rite = *b_runs++;
fA_runs = a_runs;
fB_runs = b_runs;
}
bool done() const {
SkASSERT(fA_left <= SkRegion_kRunTypeSentinel);
SkASSERT(fB_left <= SkRegion_kRunTypeSentinel);
return fA_left == SkRegion_kRunTypeSentinel &&
fB_left == SkRegion_kRunTypeSentinel;
}
void next() {
assert_valid_pair(fA_left, fA_rite);
assert_valid_pair(fB_left, fB_rite);
int inside, left, rite SK_INIT_TO_AVOID_WARNING;
bool a_flush = false;
bool b_flush = false;
int a_left = fA_left;
int a_rite = fA_rite;
int b_left = fB_left;
int b_rite = fB_rite;
if (a_left < b_left) {
inside = 1;
left = a_left;
if (a_rite <= b_left) { // [...] <...>
rite = a_rite;
a_flush = true;
} else { // [...<..]...> or [...<...>...]
rite = a_left = b_left;
}
} else if (b_left < a_left) {
inside = 2;
left = b_left;
if (b_rite <= a_left) { // [...] <...>
rite = b_rite;
b_flush = true;
} else { // [...<..]...> or [...<...>...]
rite = b_left = a_left;
}
} else { // a_left == b_left
inside = 3;
left = a_left; // or b_left
if (a_rite <= b_rite) {
rite = b_left = a_rite;
a_flush = true;
}
if (b_rite <= a_rite) {
rite = a_left = b_rite;
b_flush = true;
}
}
if (a_flush) {
a_left = *fA_runs++;
a_rite = *fA_runs++;
}
if (b_flush) {
b_left = *fB_runs++;
b_rite = *fB_runs++;
}
SkASSERT(left <= rite);
// now update our state
fA_left = a_left;
fA_rite = a_rite;
fB_left = b_left;
fB_rite = b_rite;
fLeft = left;
fRite = rite;
fInside = inside;
}
};
static int distance_to_sentinel(const SkRegionPriv::RunType* runs) {
const SkRegionPriv::RunType* ptr = runs;
while (*ptr != SkRegion_kRunTypeSentinel) { ptr += 2; }
return ptr - runs;
}
static int operate_on_span(const SkRegionPriv::RunType a_runs[],
const SkRegionPriv::RunType b_runs[],
RunArray* array, int dstOffset,
int min, int max) {
// This is a worst-case for this span plus two for TWO terminating sentinels.
array->resizeToAtLeast(
dstOffset + distance_to_sentinel(a_runs) + distance_to_sentinel(b_runs) + 2);
SkRegionPriv::RunType* dst = &(*array)[dstOffset]; // get pointer AFTER resizing.
spanRec rec;
bool firstInterval = true;
rec.init(a_runs, b_runs);
while (!rec.done()) {
rec.next();
int left = rec.fLeft;
int rite = rec.fRite;
// add left,rite to our dst buffer (checking for coincidence
if ((unsigned)(rec.fInside - min) <= (unsigned)(max - min) &&
left < rite) { // skip if equal
if (firstInterval || *(dst - 1) < left) {
*dst++ = (SkRegionPriv::RunType)(left);
*dst++ = (SkRegionPriv::RunType)(rite);
firstInterval = false;
} else {
// update the right edge
*(dst - 1) = (SkRegionPriv::RunType)(rite);
}
}
}
SkASSERT(dst < &(*array)[array->count() - 1]);
*dst++ = SkRegion_kRunTypeSentinel;
return dst - &(*array)[0];
}
#if defined _WIN32
#pragma warning ( pop )
#endif
static const struct {
uint8_t fMin;
uint8_t fMax;
} gOpMinMax[] = {
{ 1, 1 }, // Difference
{ 3, 3 }, // Intersection
{ 1, 3 }, // Union
{ 1, 2 } // XOR
};
// need to ensure that the op enum lines up with our minmax array
static_assert(0 == SkRegion::kDifference_Op, "");
static_assert(1 == SkRegion::kIntersect_Op, "");
static_assert(2 == SkRegion::kUnion_Op, "");
static_assert(3 == SkRegion::kXOR_Op, "");
class RgnOper {
public:
RgnOper(int top, RunArray* array, SkRegion::Op op)
: fMin(gOpMinMax[op].fMin)
, fMax(gOpMinMax[op].fMax)
, fArray(array)
, fTop((SkRegionPriv::RunType)top) // just a first guess, we might update this
{ SkASSERT((unsigned)op <= 3); }
void addSpan(int bottom, const SkRegionPriv::RunType a_runs[],
const SkRegionPriv::RunType b_runs[]) {
// skip X values and slots for the next Y+intervalCount
int start = fPrevDst + fPrevLen + 2;
// start points to beginning of dst interval
int stop = operate_on_span(a_runs, b_runs, fArray, start, fMin, fMax);
size_t len = SkToSizeT(stop - start);
SkASSERT(len >= 1 && (len & 1) == 1);
SkASSERT(SkRegion_kRunTypeSentinel == (*fArray)[stop - 1]);
// Assert memcmp won't exceed fArray->count().
SkASSERT(fArray->count() >= SkToInt(start + len - 1));
if (fPrevLen == len &&
(1 == len || !memcmp(&(*fArray)[fPrevDst],
&(*fArray)[start],
(len - 1) * sizeof(SkRegionPriv::RunType)))) {
// update Y value
(*fArray)[fPrevDst - 2] = (SkRegionPriv::RunType)bottom;
} else { // accept the new span
if (len == 1 && fPrevLen == 0) {
fTop = (SkRegionPriv::RunType)bottom; // just update our bottom
} else {
(*fArray)[start - 2] = (SkRegionPriv::RunType)bottom;
(*fArray)[start - 1] = SkToS32(len >> 1);
fPrevDst = start;
fPrevLen = len;
}
}
}
int flush() {
(*fArray)[fStartDst] = fTop;
// Previously reserved enough for TWO sentinals.
SkASSERT(fArray->count() > SkToInt(fPrevDst + fPrevLen));
(*fArray)[fPrevDst + fPrevLen] = SkRegion_kRunTypeSentinel;
return (int)(fPrevDst - fStartDst + fPrevLen + 1);
}
bool isEmpty() const { return 0 == fPrevLen; }
uint8_t fMin, fMax;
private:
RunArray* fArray;
int fStartDst = 0;
int fPrevDst = 1;
size_t fPrevLen = 0; // will never match a length from operate_on_span
SkRegionPriv::RunType fTop;
};
// want a unique value to signal that we exited due to quickExit
#define QUICK_EXIT_TRUE_COUNT (-1)
static int operate(const SkRegionPriv::RunType a_runs[],
const SkRegionPriv::RunType b_runs[],
RunArray* dst,
SkRegion::Op op,
bool quickExit) {
const SkRegionPriv::RunType gEmptyScanline[] = {
0, // dummy bottom value
0, // zero intervals
SkRegion_kRunTypeSentinel,
// just need a 2nd value, since spanRec.init() reads 2 values, even
// though if the first value is the sentinel, it ignores the 2nd value.
// w/o the 2nd value here, we might read uninitialized memory.
// This happens when we are using gSentinel, which is pointing at
// our sentinel value.
0
};
const SkRegionPriv::RunType* const gSentinel = &gEmptyScanline[2];
int a_top = *a_runs++;
int a_bot = *a_runs++;
int b_top = *b_runs++;
int b_bot = *b_runs++;
a_runs += 1; // skip the intervalCount;
b_runs += 1; // skip the intervalCount;
// Now a_runs and b_runs to their intervals (or sentinel)
assert_sentinel(a_top, false);
assert_sentinel(a_bot, false);
assert_sentinel(b_top, false);
assert_sentinel(b_bot, false);
RgnOper oper(SkMin32(a_top, b_top), dst, op);
int prevBot = SkRegion_kRunTypeSentinel; // so we fail the first test
while (a_bot < SkRegion_kRunTypeSentinel ||
b_bot < SkRegion_kRunTypeSentinel) {
int top, bot SK_INIT_TO_AVOID_WARNING;
const SkRegionPriv::RunType* run0 = gSentinel;
const SkRegionPriv::RunType* run1 = gSentinel;
bool a_flush = false;
bool b_flush = false;
if (a_top < b_top) {
top = a_top;
run0 = a_runs;
if (a_bot <= b_top) { // [...] <...>
bot = a_bot;
a_flush = true;
} else { // [...<..]...> or [...<...>...]
bot = a_top = b_top;
}
} else if (b_top < a_top) {
top = b_top;
run1 = b_runs;
if (b_bot <= a_top) { // [...] <...>
bot = b_bot;
b_flush = true;
} else { // [...<..]...> or [...<...>...]
bot = b_top = a_top;
}
} else { // a_top == b_top
top = a_top; // or b_top
run0 = a_runs;
run1 = b_runs;
if (a_bot <= b_bot) {
bot = b_top = a_bot;
a_flush = true;
}
if (b_bot <= a_bot) {
bot = a_top = b_bot;
b_flush = true;
}
}
if (top > prevBot) {
oper.addSpan(top, gSentinel, gSentinel);
}
oper.addSpan(bot, run0, run1);
if (quickExit && !oper.isEmpty()) {
return QUICK_EXIT_TRUE_COUNT;
}
if (a_flush) {
a_runs = skip_intervals(a_runs);
a_top = a_bot;
a_bot = *a_runs++;
a_runs += 1; // skip uninitialized intervalCount
if (a_bot == SkRegion_kRunTypeSentinel) {
a_top = a_bot;
}
}
if (b_flush) {
b_runs = skip_intervals(b_runs);
b_top = b_bot;
b_bot = *b_runs++;
b_runs += 1; // skip uninitialized intervalCount
if (b_bot == SkRegion_kRunTypeSentinel) {
b_top = b_bot;
}
}
prevBot = bot;
}
return oper.flush();
}
///////////////////////////////////////////////////////////////////////////////
/* Given count RunTypes in a complex region, return the worst case number of
logical intervals that represents (i.e. number of rects that would be
returned from the iterator).
We could just return count/2, since there must be at least 2 values per
interval, but we can first trim off the const overhead of the initial TOP
value, plus the final BOTTOM + 2 sentinels.
*/
#if 0 // UNUSED
static int count_to_intervals(int count) {
SkASSERT(count >= 6); // a single rect is 6 values
return (count - 4) >> 1;
}
#endif
static bool setEmptyCheck(SkRegion* result) {
return result ? result->setEmpty() : false;
}
static bool setRectCheck(SkRegion* result, const SkIRect& rect) {
return result ? result->setRect(rect) : !rect.isEmpty();
}
static bool setRegionCheck(SkRegion* result, const SkRegion& rgn) {
return result ? result->setRegion(rgn) : !rgn.isEmpty();
}
bool SkRegion::Oper(const SkRegion& rgnaOrig, const SkRegion& rgnbOrig, Op op,
SkRegion* result) {
SkASSERT((unsigned)op < kOpCount);
if (kReplace_Op == op) {
return setRegionCheck(result, rgnbOrig);
}
// swith to using pointers, so we can swap them as needed
const SkRegion* rgna = &rgnaOrig;
const SkRegion* rgnb = &rgnbOrig;
// after this point, do not refer to rgnaOrig or rgnbOrig!!!
// collaps difference and reverse-difference into just difference
if (kReverseDifference_Op == op) {
using std::swap;
swap(rgna, rgnb);
op = kDifference_Op;
}
SkIRect bounds;
bool a_empty = rgna->isEmpty();
bool b_empty = rgnb->isEmpty();
bool a_rect = rgna->isRect();
bool b_rect = rgnb->isRect();
switch (op) {
case kDifference_Op:
if (a_empty) {
return setEmptyCheck(result);
}
if (b_empty || !SkIRect::Intersects(rgna->fBounds, rgnb->fBounds)) {
return setRegionCheck(result, *rgna);
}
if (b_rect && rgnb->fBounds.containsNoEmptyCheck(rgna->fBounds)) {
return setEmptyCheck(result);
}
break;
case kIntersect_Op:
if ((a_empty | b_empty)
|| !bounds.intersect(rgna->fBounds, rgnb->fBounds)) {
return setEmptyCheck(result);
}
if (a_rect & b_rect) {
return setRectCheck(result, bounds);
}
if (a_rect && rgna->fBounds.contains(rgnb->fBounds)) {
return setRegionCheck(result, *rgnb);
}
if (b_rect && rgnb->fBounds.contains(rgna->fBounds)) {
return setRegionCheck(result, *rgna);
}
break;
case kUnion_Op:
if (a_empty) {
return setRegionCheck(result, *rgnb);
}
if (b_empty) {
return setRegionCheck(result, *rgna);
}
if (a_rect && rgna->fBounds.contains(rgnb->fBounds)) {
return setRegionCheck(result, *rgna);
}
if (b_rect && rgnb->fBounds.contains(rgna->fBounds)) {
return setRegionCheck(result, *rgnb);
}
break;
case kXOR_Op:
if (a_empty) {
return setRegionCheck(result, *rgnb);
}
if (b_empty) {
return setRegionCheck(result, *rgna);
}
break;
default:
SkDEBUGFAIL("unknown region op");
return false;
}
RunType tmpA[kRectRegionRuns];
RunType tmpB[kRectRegionRuns];
int a_intervals, b_intervals;
const RunType* a_runs = rgna->getRuns(tmpA, &a_intervals);
const RunType* b_runs = rgnb->getRuns(tmpB, &b_intervals);
RunArray array;
int count = operate(a_runs, b_runs, &array, op, nullptr == result);
SkASSERT(count <= array.count());
if (result) {
SkASSERT(count >= 0);
return result->setRuns(&array[0], count);
} else {
return (QUICK_EXIT_TRUE_COUNT == count) || !isRunCountEmpty(count);
}
}
bool SkRegion::op(const SkRegion& rgna, const SkRegion& rgnb, Op op) {
SkDEBUGCODE(SkRegionPriv::Validate(*this));
return SkRegion::Oper(rgna, rgnb, op, this);
}
///////////////////////////////////////////////////////////////////////////////
#include "src/core/SkBuffer.h"
size_t SkRegion::writeToMemory(void* storage) const {
if (nullptr == storage) {
size_t size = sizeof(int32_t); // -1 (empty), 0 (rect), runCount
if (!this->isEmpty()) {
size += sizeof(fBounds);
if (this->isComplex()) {
size += 2 * sizeof(int32_t); // ySpanCount + intervalCount
size += fRunHead->fRunCount * sizeof(RunType);
}
}
return size;
}
SkWBuffer buffer(storage);
if (this->isEmpty()) {
buffer.write32(-1);
} else {
bool isRect = this->isRect();
buffer.write32(isRect ? 0 : fRunHead->fRunCount);
buffer.write(&fBounds, sizeof(fBounds));
if (!isRect) {
buffer.write32(fRunHead->getYSpanCount());
buffer.write32(fRunHead->getIntervalCount());
buffer.write(fRunHead->readonly_runs(),
fRunHead->fRunCount * sizeof(RunType));
}
}
return buffer.pos();
}
static bool validate_run_count(int ySpanCount, int intervalCount, int runCount) {
// return 2 + 3 * ySpanCount + 2 * intervalCount;
if (ySpanCount < 1 || intervalCount < 2) {
return false;
}
SkSafeMath safeMath;
int sum = 2;
sum = safeMath.addInt(sum, ySpanCount);
sum = safeMath.addInt(sum, ySpanCount);
sum = safeMath.addInt(sum, ySpanCount);
sum = safeMath.addInt(sum, intervalCount);
sum = safeMath.addInt(sum, intervalCount);
return safeMath && sum == runCount;
}
// Validate that a memory sequence is a valid region.
// Try to check all possible errors.
// never read beyond &runs[runCount-1].
static bool validate_run(const int32_t* runs,
int runCount,
const SkIRect& givenBounds,
int32_t ySpanCount,
int32_t intervalCount) {
// Region Layout:
// Top ( Bottom Span_Interval_Count ( Left Right )* Sentinel )+ Sentinel
if (!validate_run_count(SkToInt(ySpanCount), SkToInt(intervalCount), runCount)) {
return false;
}
SkASSERT(runCount >= 7); // 7==SkRegion::kRectRegionRuns
// quick sanity check:
if (runs[runCount - 1] != SkRegion_kRunTypeSentinel ||
runs[runCount - 2] != SkRegion_kRunTypeSentinel) {
return false;
}
const int32_t* const end = runs + runCount;
SkIRect bounds = {0, 0, 0 ,0}; // calulated bounds
SkIRect rect = {0, 0, 0, 0}; // current rect
rect.fTop = *runs++;
if (rect.fTop == SkRegion_kRunTypeSentinel) {
return false; // no rect can contain SkRegion_kRunTypeSentinel
}
if (rect.fTop != givenBounds.fTop) {
return false; // Must not begin with empty span that does not contribute to bounds.
}
do {
--ySpanCount;
if (ySpanCount < 0) {
return false; // too many yspans
}
rect.fBottom = *runs++;
if (rect.fBottom == SkRegion_kRunTypeSentinel) {
return false;
}
if (rect.fBottom > givenBounds.fBottom) {
return false; // Must not end with empty span that does not contribute to bounds.
}
if (rect.fBottom <= rect.fTop) {
return false; // y-intervals must be ordered; rects must be non-empty.
}
int32_t xIntervals = *runs++;
SkASSERT(runs < end);
if (xIntervals < 0 || xIntervals > intervalCount || runs + 1 + 2 * xIntervals > end) {
return false;
}
intervalCount -= xIntervals;
bool firstInterval = true;
int32_t lastRight = 0; // check that x-intervals are distinct and ordered.
while (xIntervals-- > 0) {
rect.fLeft = *runs++;
rect.fRight = *runs++;
if (rect.fLeft == SkRegion_kRunTypeSentinel ||
rect.fRight == SkRegion_kRunTypeSentinel ||
rect.fLeft >= rect.fRight || // check non-empty rect
(!firstInterval && rect.fLeft <= lastRight)) {
return false;
}
lastRight = rect.fRight;
firstInterval = false;
bounds.join(rect);
}
if (*runs++ != SkRegion_kRunTypeSentinel) {
return false; // required check sentinal.
}
rect.fTop = rect.fBottom;
SkASSERT(runs < end);
} while (*runs != SkRegion_kRunTypeSentinel);
++runs;
if (ySpanCount != 0 || intervalCount != 0 || givenBounds != bounds) {
return false;
}
SkASSERT(runs == end); // if ySpanCount && intervalCount are right, must be correct length.
return true;
}
size_t SkRegion::readFromMemory(const void* storage, size_t length) {
SkRBuffer buffer(storage, length);
SkRegion tmp;
int32_t count;
// Serialized Region Format:
// Empty:
// -1
// Simple Rect:
// 0 LEFT TOP RIGHT BOTTOM
// Complex Region:
// COUNT LEFT TOP RIGHT BOTTOM Y_SPAN_COUNT TOTAL_INTERVAL_COUNT [RUNS....]
if (!buffer.readS32(&count) || count < -1) {
return 0;
}
if (count >= 0) {
if (!buffer.read(&tmp.fBounds, sizeof(tmp.fBounds)) || tmp.fBounds.isEmpty()) {
return 0; // Short buffer or bad bounds for non-empty region; report failure.
}
if (count == 0) {
tmp.fRunHead = SkRegion_gRectRunHeadPtr;
} else {
int32_t ySpanCount, intervalCount;
if (!buffer.readS32(&ySpanCount) ||
!buffer.readS32(&intervalCount) ||
buffer.available() < count * sizeof(int32_t)) {
return 0;
}
if (!validate_run((const int32_t*)((const char*)storage + buffer.pos()), count,
tmp.fBounds, ySpanCount, intervalCount)) {
return 0; // invalid runs, don't even allocate
}
tmp.allocateRuns(count, ySpanCount, intervalCount);
SkASSERT(tmp.isComplex());
SkAssertResult(buffer.read(tmp.fRunHead->writable_runs(), count * sizeof(int32_t)));
}
}
SkASSERT(tmp.isValid());
SkASSERT(buffer.isValid());
this->swap(tmp);
return buffer.pos();
}
///////////////////////////////////////////////////////////////////////////////
bool SkRegion::isValid() const {
if (this->isEmpty()) {
return fBounds == SkIRect{0, 0, 0, 0};
}
if (fBounds.isEmpty()) {
return false;
}
if (this->isRect()) {
return true;
}
return fRunHead && fRunHead->fRefCnt > 0 &&
validate_run(fRunHead->readonly_runs(), fRunHead->fRunCount, fBounds,
fRunHead->getYSpanCount(), fRunHead->getIntervalCount());
}
#ifdef SK_DEBUG
void SkRegionPriv::Validate(const SkRegion& rgn) { SkASSERT(rgn.isValid()); }
void SkRegion::dump() const {
if (this->isEmpty()) {
SkDebugf(" rgn: empty\n");
} else {
SkDebugf(" rgn: [%d %d %d %d]", fBounds.fLeft, fBounds.fTop, fBounds.fRight, fBounds.fBottom);
if (this->isComplex()) {
const RunType* runs = fRunHead->readonly_runs();
for (int i = 0; i < fRunHead->fRunCount; i++)
SkDebugf(" %d", runs[i]);
}
SkDebugf("\n");
}
}
#endif
///////////////////////////////////////////////////////////////////////////////
SkRegion::Iterator::Iterator(const SkRegion& rgn) {
this->reset(rgn);
}
bool SkRegion::Iterator::rewind() {
if (fRgn) {
this->reset(*fRgn);
return true;
}
return false;
}
void SkRegion::Iterator::reset(const SkRegion& rgn) {
fRgn = &rgn;
if (rgn.isEmpty()) {
fDone = true;
} else {
fDone = false;
if (rgn.isRect()) {
fRect = rgn.fBounds;
fRuns = nullptr;
} else {
fRuns = rgn.fRunHead->readonly_runs();
fRect.setLTRB(fRuns[3], fRuns[0], fRuns[4], fRuns[1]);
fRuns += 5;
// Now fRuns points to the 2nd interval (or x-sentinel)
}
}
}
void SkRegion::Iterator::next() {
if (fDone) {
return;
}
if (fRuns == nullptr) { // rect case
fDone = true;
return;
}
const RunType* runs = fRuns;
if (runs[0] < SkRegion_kRunTypeSentinel) { // valid X value
fRect.fLeft = runs[0];
fRect.fRight = runs[1];
runs += 2;
} else { // we're at the end of a line
runs += 1;
if (runs[0] < SkRegion_kRunTypeSentinel) { // valid Y value
int intervals = runs[1];
if (0 == intervals) { // empty line
fRect.fTop = runs[0];
runs += 3;
} else {
fRect.fTop = fRect.fBottom;
}
fRect.fBottom = runs[0];
assert_sentinel(runs[2], false);
assert_sentinel(runs[3], false);
fRect.fLeft = runs[2];
fRect.fRight = runs[3];
runs += 4;
} else { // end of rgn
fDone = true;
}
}
fRuns = runs;
}
SkRegion::Cliperator::Cliperator(const SkRegion& rgn, const SkIRect& clip)
: fIter(rgn), fClip(clip), fDone(true) {
const SkIRect& r = fIter.rect();
while (!fIter.done()) {
if (r.fTop >= clip.fBottom) {
break;
}
if (fRect.intersect(clip, r)) {
fDone = false;
break;
}
fIter.next();
}
}
void SkRegion::Cliperator::next() {
if (fDone) {
return;
}
const SkIRect& r = fIter.rect();
fDone = true;
fIter.next();
while (!fIter.done()) {
if (r.fTop >= fClip.fBottom) {
break;
}
if (fRect.intersect(fClip, r)) {
fDone = false;
break;
}
fIter.next();
}
}
///////////////////////////////////////////////////////////////////////////////
SkRegion::Spanerator::Spanerator(const SkRegion& rgn, int y, int left,
int right) {
SkDEBUGCODE(SkRegionPriv::Validate(rgn));
const SkIRect& r = rgn.getBounds();
fDone = true;
if (!rgn.isEmpty() && y >= r.fTop && y < r.fBottom &&
right > r.fLeft && left < r.fRight) {
if (rgn.isRect()) {
if (left < r.fLeft) {
left = r.fLeft;
}
if (right > r.fRight) {
right = r.fRight;
}
fLeft = left;
fRight = right;
fRuns = nullptr; // means we're a rect, not a rgn
fDone = false;
} else {
const SkRegion::RunType* runs = rgn.fRunHead->findScanline(y);
runs += 2; // skip Bottom and IntervalCount
for (;;) {
// runs[0..1] is to the right of the span, so we're done
if (runs[0] >= right) {
break;
}
// runs[0..1] is to the left of the span, so continue
if (runs[1] <= left) {
runs += 2;
continue;
}
// runs[0..1] intersects the span
fRuns = runs;
fLeft = left;
fRight = right;
fDone = false;
break;
}
}
}
}
bool SkRegion::Spanerator::next(int* left, int* right) {
if (fDone) {
return false;
}
if (fRuns == nullptr) { // we're a rect
fDone = true; // ok, now we're done
if (left) {
*left = fLeft;
}
if (right) {
*right = fRight;
}
return true; // this interval is legal
}
const SkRegion::RunType* runs = fRuns;
if (runs[0] >= fRight) {
fDone = true;
return false;
}
SkASSERT(runs[1] > fLeft);
if (left) {
*left = SkMax32(fLeft, runs[0]);
}
if (right) {
*right = SkMin32(fRight, runs[1]);
}
fRuns = runs + 2;
return true;
}
///////////////////////////////////////////////////////////////////////////////////////////////////
static void visit_pairs(int pairCount, int y, const int32_t pairs[],
const std::function<void(const SkIRect&)>& visitor) {
for (int i = 0; i < pairCount; ++i) {
visitor({ pairs[0], y, pairs[1], y + 1 });
pairs += 2;
}
}
void SkRegionPriv::VisitSpans(const SkRegion& rgn,
const std::function<void(const SkIRect&)>& visitor) {
if (rgn.isEmpty()) {
return;
}
if (rgn.isRect()) {
visitor(rgn.getBounds());
} else {
const int32_t* p = rgn.fRunHead->readonly_runs();
int32_t top = *p++;
int32_t bot = *p++;
do {
int pairCount = *p++;
if (pairCount == 1) {
visitor({ p[0], top, p[1], bot });
p += 2;
} else if (pairCount > 1) {
// we have to loop repeated in Y, sending each interval in Y -> X order
for (int y = top; y < bot; ++y) {
visit_pairs(pairCount, y, p, visitor);
}
p += pairCount * 2;
}
assert_sentinel(*p, true);
p += 1; // skip sentinel
// read next bottom or sentinel
top = bot;
bot = *p++;
} while (!SkRegionValueIsSentinel(bot));
}
}