C++ SkOpSegment::span方法代码示例

SkOpSegment* FindSortableTop(const SkTArray<SkOpContour*, true>& contourList,
        SkOpAngle::IncludeType angleIncludeType, bool* firstContour, int* indexPtr,
        int* endIndexPtr, SkPoint* topLeft, bool* unsortable, bool* done, bool* onlyVertical,
        bool firstPass) {
    SkOpSegment* current = findTopSegment(contourList, indexPtr, endIndexPtr, topLeft, unsortable,
            done, firstPass);
    if (!current) {
        return NULL;
    }
    const int startIndex = *indexPtr;
    const int endIndex = *endIndexPtr;
    if (*firstContour) {
        current->initWinding(startIndex, endIndex, angleIncludeType);
        *firstContour = false;
        return current;
    }
    int minIndex = SkMin32(startIndex, endIndex);
    int sumWinding = current->windSum(minIndex);
    if (sumWinding == SK_MinS32) {
        int index = endIndex;
        int oIndex = startIndex;
        do { 
            const SkOpSpan& span = current->span(index);
            if ((oIndex < index ? span.fFromAngle : span.fToAngle) == NULL) {
                current->addSimpleAngle(index);
            }
            sumWinding = current->computeSum(oIndex, index, angleIncludeType);
            SkTSwap(index, oIndex);
        } while (sumWinding == SK_MinS32 && index == startIndex);
    }
    if (sumWinding != SK_MinS32 && sumWinding != SK_NaN32) {
        return current;
    }
    int contourWinding;
    int oppContourWinding = 0;
    // the simple upward projection of the unresolved points hit unsortable angles
    // shoot rays at right angles to the segment to find its winding, ignoring angle cases
    bool tryAgain;
    double tHit;
    SkScalar hitDx = 0;
    SkScalar hitOppDx = 0;
    // keep track of subsequent returns to detect infinite loops
    SkTDArray<SortableTop> sortableTops;
    do {
        // if current is vertical, find another candidate which is not
        // if only remaining candidates are vertical, then they can be marked done
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        skipVertical(contourList, &current, indexPtr, endIndexPtr);
        SkASSERT(current);  // FIXME: if null, all remaining are vertical
        SkASSERT(*indexPtr != *endIndexPtr && *indexPtr >= 0 && *endIndexPtr >= 0);
        tryAgain = false;
        contourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitDx, &tryAgain, onlyVertical, false);
        if (tryAgain) {
            bool giveUp = false;
            int count = sortableTops.count();
            for (int index = 0; index < count; ++index) {
                const SortableTop& prev = sortableTops[index];
                if (giveUp) {
                    prev.fSegment->markDoneFinal(prev.fIndex);
                } else if (prev.fSegment == current
                        && (prev.fIndex == *indexPtr || prev.fEndIndex == *endIndexPtr)) {
                    // remaining edges are non-vertical and cannot have their winding computed
                    // mark them as done and return, and hope that assembly can fill the holes
                    giveUp = true;
                    index = -1;
                }
            }
            if (giveUp) {
                *done = true;
                return NULL;
            }
        }
        SortableTop* sortableTop = sortableTops.append();
        sortableTop->fSegment = current;
        sortableTop->fIndex = *indexPtr;
        sortableTop->fEndIndex = *endIndexPtr;
#if DEBUG_SORT
        SkDebugf("%s current=%d index=%d endIndex=%d tHit=%1.9g hitDx=%1.9g try=%d vert=%d\n",
                __FUNCTION__, current->debugID(), *indexPtr, *endIndexPtr, tHit, hitDx, tryAgain,
                *onlyVertical);
#endif
        if (*onlyVertical) {
            return current;
        }
        if (tryAgain) {
            continue;
        }
        if (angleIncludeType < SkOpAngle::kBinarySingle) {
            break;
        }
        oppContourWinding = rightAngleWinding(contourList, &current, indexPtr, endIndexPtr, &tHit,
                &hitOppDx, &tryAgain, NULL, true);
    } while (tryAgain);
    bool success = current->initWinding(*indexPtr, *endIndexPtr, tHit, contourWinding, hitDx,
            oppContourWinding, hitOppDx);
    if (current->done()) {
        return NULL;
    } else if (!success) {  // check if the span has a valid winding
        int min = SkTMin(*indexPtr, *endIndexPtr);
//.........这里部分代码省略.........

SkOpSegment* FindChase(SkTDArray<SkOpSpan*>& chase, int& tIndex, int& endIndex) {
    while (chase.count()) {
        SkOpSpan* span;
        chase.pop(&span);
        const SkOpSpan& backPtr = span->fOther->span(span->fOtherIndex);
        SkOpSegment* segment = backPtr.fOther;
        tIndex = backPtr.fOtherIndex;
        SkSTArray<SkOpAngle::kStackBasedCount, SkOpAngle, true> angles;
        int done = 0;
        if (segment->activeAngle(tIndex, &done, &angles)) {
            SkOpAngle* last = angles.end() - 1;
            tIndex = last->start();
            endIndex = last->end();
#if TRY_ROTATE
            *chase.insert(0) = span;
#else
            *chase.append() = span;
#endif
            return last->segment();
        }
        if (done == angles.count()) {
            continue;
        }
        SkSTArray<SkOpAngle::kStackBasedCount, SkOpAngle*, true> sorted;
        bool sortable = SkOpSegment::SortAngles(angles, &sorted,
                                                SkOpSegment::kMayBeUnordered_SortAngleKind);
        int angleCount = sorted.count();
#if DEBUG_SORT
        sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0, 0, sortable);
#endif
        if (!sortable) {
            continue;
        }
        // find first angle, initialize winding to computed fWindSum
        int firstIndex = -1;
        const SkOpAngle* angle;
        int winding;
        do {
            angle = sorted[++firstIndex];
            segment = angle->segment();
            winding = segment->windSum(angle);
        } while (winding == SK_MinS32);
        int spanWinding = segment->spanSign(angle->start(), angle->end());
#if DEBUG_WINDING
        SkDebugf("%s winding=%d spanWinding=%d\n",
                 __FUNCTION__, winding, spanWinding);
#endif
        // turn span winding into contour winding
        if (spanWinding * winding < 0) {
            winding += spanWinding;
        }
#if DEBUG_SORT
        segment->debugShowSort(__FUNCTION__, sorted, firstIndex, winding, 0, sortable);
#endif
        // we care about first sign and whether wind sum indicates this
        // edge is inside or outside. Maybe need to pass span winding
        // or first winding or something into this function?
        // advance to first undone angle, then return it and winding
        // (to set whether edges are active or not)
        int nextIndex = firstIndex + 1;
        int lastIndex = firstIndex != 0 ? firstIndex : angleCount;
        angle = sorted[firstIndex];
        winding -= angle->segment()->spanSign(angle);
        do {
            SkASSERT(nextIndex != firstIndex);
            if (nextIndex == angleCount) {
                nextIndex = 0;
            }
            angle = sorted[nextIndex];
            segment = angle->segment();
            int maxWinding = winding;
            winding -= segment->spanSign(angle);
#if DEBUG_SORT
            SkDebugf("%s id=%d maxWinding=%d winding=%d sign=%d\n", __FUNCTION__,
                     segment->debugID(), maxWinding, winding, angle->sign());
#endif
            tIndex = angle->start();
            endIndex = angle->end();
            int lesser = SkMin32(tIndex, endIndex);
            const SkOpSpan& nextSpan = segment->span(lesser);
            if (!nextSpan.fDone) {
                // FIXME: this be wrong? assign startWinding if edge is in
                // same direction. If the direction is opposite, winding to
                // assign is flipped sign or +/- 1?
                if (SkOpSegment::UseInnerWinding(maxWinding, winding)) {
                    maxWinding = winding;
                }
                segment->markAndChaseWinding(angle, maxWinding, 0);
                break;
            }
        } while (++nextIndex != lastIndex);
        *chase.insert(0) = span;
        return segment;
    }
    return NULL;
}

SkOpSegment* FindChase(SkTDArray<SkOpSpan*>* chase, int* tIndex, int* endIndex) {
    while (chase->count()) {
        SkOpSpan* span;
        chase->pop(&span);
        const SkOpSpan& backPtr = span->fOther->span(span->fOtherIndex);
        SkOpSegment* segment = backPtr.fOther;
        *tIndex = backPtr.fOtherIndex;
        bool sortable = true;
        bool done = true;
        *endIndex = -1;
        if (const SkOpAngle* last = segment->activeAngle(*tIndex, tIndex, endIndex, &done,
                &sortable)) {
            *tIndex = last->start();
            *endIndex = last->end();
    #if TRY_ROTATE
            *chase->insert(0) = span;
    #else
            *chase->append() = span;
    #endif
            return last->segment();
        }
        if (done) {
            continue;
        }
        if (!sortable) {
            continue;
        }
        // find first angle, initialize winding to computed wind sum
        const SkOpAngle* angle = segment->spanToAngle(*tIndex, *endIndex);
        const SkOpAngle* firstAngle;
        SkDEBUGCODE(firstAngle = angle);
        SkDEBUGCODE(bool loop = false);
        int winding;
        do {
            angle = angle->next();
            SkASSERT(angle != firstAngle || !loop);
            SkDEBUGCODE(loop |= angle == firstAngle);
            segment = angle->segment();
            winding = segment->windSum(angle);
        } while (winding == SK_MinS32);
        int spanWinding = segment->spanSign(angle->start(), angle->end());
    #if DEBUG_WINDING
        SkDebugf("%s winding=%d spanWinding=%d\n", __FUNCTION__, winding, spanWinding);
    #endif
        // turn span winding into contour winding
        if (spanWinding * winding < 0) {
            winding += spanWinding;
        }
        // we care about first sign and whether wind sum indicates this
        // edge is inside or outside. Maybe need to pass span winding
        // or first winding or something into this function?
        // advance to first undone angle, then return it and winding
        // (to set whether edges are active or not)
        firstAngle = angle;
        winding -= firstAngle->segment()->spanSign(firstAngle);
        while ((angle = angle->next()) != firstAngle) {
            segment = angle->segment();
            int maxWinding = winding;
            winding -= segment->spanSign(angle);
    #if DEBUG_SORT
            SkDebugf("%s id=%d maxWinding=%d winding=%d sign=%d\n", __FUNCTION__,
                    segment->debugID(), maxWinding, winding, angle->sign());
    #endif
            *tIndex = angle->start();
            *endIndex = angle->end();
            int lesser = SkMin32(*tIndex, *endIndex);
            const SkOpSpan& nextSpan = segment->span(lesser);
            if (!nextSpan.fDone) {
            // FIXME: this be wrong? assign startWinding if edge is in
            // same direction. If the direction is opposite, winding to
            // assign is flipped sign or +/- 1?
                if (SkOpSegment::UseInnerWinding(maxWinding, winding)) {
                    maxWinding = winding;
                }
                // allowed to do nothing
                (void) segment->markAndChaseWinding(angle, maxWinding, 0, NULL);
                break;
            }
        }
        *chase->insert(0) = span;
        return segment;
    }
    return NULL;
}