SkScan_AAAPath.cpp File Reference

#include "include/core/SkColor.h"
#include "include/core/SkPath.h"
#include "include/core/SkPathTypes.h"
#include "include/core/SkRect.h"
#include "include/private/base/SkAlign.h"
#include "include/private/base/SkAssert.h"
#include "include/private/base/SkFixed.h"
#include "include/private/base/SkMath.h"
#include "include/private/base/SkSafe32.h"
#include "include/private/base/SkTo.h"
#include "src/base/SkTSort.h"
#include "src/core/SkAlphaRuns.h"
#include "src/core/SkAnalyticEdge.h"
#include "src/core/SkBlitter.h"
#include "src/core/SkEdge.h"
#include "src/core/SkEdgeBuilder.h"
#include "src/core/SkMask.h"
#include "src/core/SkScan.h"
#include "src/core/SkScanPriv.h"
#include <algorithm>
#include <cstdint>
#include <cstring>

Go to the source code of this file.

Classes
class	AdditiveBlitter
class	MaskAdditiveBlitter
class	RunBasedAdditiveBlitter
class	SafeRLEAdditiveBlitter

Functions
static void	add_alpha (SkAlpha *alpha, SkAlpha delta)
static void	safely_add_alpha (SkAlpha *alpha, SkAlpha delta)
static SkAlpha	trapezoid_to_alpha (SkFixed l1, SkFixed l2)
static SkAlpha	partial_triangle_to_alpha (SkFixed a, SkFixed b)
static SkAlpha	get_partial_alpha (SkAlpha alpha, SkFixed partialHeight)
static SkAlpha	get_partial_alpha (SkAlpha alpha, SkAlpha fullAlpha)
static SkAlpha	fixed_to_alpha (SkFixed f)
static SkFixed	approximate_intersection (SkFixed l1, SkFixed r1, SkFixed l2, SkFixed r2)
static void	compute_alpha_above_line (SkAlpha *alphas, SkFixed l, SkFixed r, SkFixed dY, SkAlpha fullAlpha)
static void	compute_alpha_below_line (SkAlpha *alphas, SkFixed l, SkFixed r, SkFixed dY, SkAlpha fullAlpha)
static void	blit_single_alpha (AdditiveBlitter *blitter, int y, int x, SkAlpha alpha, SkAlpha fullAlpha, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, bool needSafeCheck)
static void	blit_two_alphas (AdditiveBlitter *blitter, int y, int x, SkAlpha a1, SkAlpha a2, SkAlpha fullAlpha, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, bool needSafeCheck)
static void	blit_full_alpha (AdditiveBlitter *blitter, int y, int x, int len, SkAlpha fullAlpha, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, bool needSafeCheck)
static void	blit_aaa_trapezoid_row (AdditiveBlitter *blitter, int y, SkFixed ul, SkFixed ur, SkFixed ll, SkFixed lr, SkFixed lDY, SkFixed rDY, SkAlpha fullAlpha, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, bool needSafeCheck)
static void	blit_trapezoid_row (AdditiveBlitter *blitter, int y, SkFixed ul, SkFixed ur, SkFixed ll, SkFixed lr, SkFixed lDY, SkFixed rDY, SkAlpha fullAlpha, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter=false, bool needSafeCheck=false)
static bool	operator< (const SkAnalyticEdge &a, const SkAnalyticEdge &b)
static SkAnalyticEdge *	sort_edges (SkAnalyticEdge *list[], int count, SkAnalyticEdge **last)
static void	validate_sort (const SkAnalyticEdge *edge)
static bool	is_smooth_enough (SkAnalyticEdge *thisEdge, SkAnalyticEdge *nextEdge, int stop_y)
static bool	is_smooth_enough (SkAnalyticEdge *leftE, SkAnalyticEdge *riteE, SkAnalyticEdge *currE, int stop_y)
static void	aaa_walk_convex_edges (SkAnalyticEdge *prevHead, AdditiveBlitter *blitter, int start_y, int stop_y, SkFixed leftBound, SkFixed riteBound, bool isUsingMask)
static void	update_next_next_y (SkFixed y, SkFixed nextY, SkFixed *nextNextY)
static void	check_intersection (const SkAnalyticEdge *edge, SkFixed nextY, SkFixed *nextNextY)
static void	insert_new_edges (SkAnalyticEdge *newEdge, SkFixed y, SkFixed *nextNextY)
static void	validate_edges_for_y (const SkAnalyticEdge *edge, SkFixed y)
static bool	edges_too_close (SkAnalyticEdge *prev, SkAnalyticEdge *next, SkFixed lowerY)
static bool	edges_too_close (int prevRite, SkFixed ul, SkFixed ll)
static void	blit_saved_trapezoid (SkAnalyticEdge *leftE, SkFixed lowerY, SkFixed lowerLeft, SkFixed lowerRite, AdditiveBlitter *blitter, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, SkFixed leftClip, SkFixed rightClip)
static void	deferred_blit (SkAnalyticEdge *leftE, SkAnalyticEdge *riteE, SkFixed left, SkFixed leftDY, SkFixed y, SkFixed nextY, bool isIntegralNextY, bool leftEnds, bool riteEnds, AdditiveBlitter *blitter, SkAlpha *maskRow, bool isUsingMask, bool noRealBlitter, SkFixed leftClip, SkFixed rightClip, int yShift)
static void	aaa_walk_edges (SkAnalyticEdge *prevHead, SkAnalyticEdge *nextTail, SkPathFillType fillType, AdditiveBlitter *blitter, int start_y, int stop_y, SkFixed leftClip, SkFixed rightClip, bool isUsingMask, bool forceRLE, bool useDeferred, bool skipIntersect)
static void	aaa_fill_path (const SkPath &path, const SkIRect &clipRect, AdditiveBlitter *blitter, int start_y, int stop_y, bool pathContainedInClip, bool isUsingMask, bool forceRLE)
static bool	try_blit_fat_anti_rect (SkBlitter *blitter, const SkPath &path, const SkIRect &clip)

Function Documentation

aaa_fill_path()

static void aaa_fill_path ( const SkPath &  path, const SkIRect &  clipRect, AdditiveBlitter *  blitter, int  start_y, int  stop_y, bool  pathContainedInClip, bool  isUsingMask, bool  forceRLE  )

static

Definition at line 1840 of file SkScan_AAAPath.cpp.

                                         {  // forceRLE implies that SkAAClip is calling us
    SkASSERT(blitter);
 
    SkAnalyticEdgeBuilder builder;
    int              count = builder.buildEdges(path, pathContainedInClip ? nullptr : &clipRect);
    SkAnalyticEdge** list  = builder.analyticEdgeList();
 
    SkIRect rect = clipRect;
    if (0 == count) {
        if (path.isInverseFillType()) {
            /*
             *  Since we are in inverse-fill, our caller has already drawn above
             *  our top (start_y) and will draw below our bottom (stop_y). Thus
             *  we need to restrict our drawing to the intersection of the clip
             *  and those two limits.
             */
            if (rect.fTop < start_y) {
                rect.fTop = start_y;
            }
            if (rect.fBottom > stop_y) {
                rect.fBottom = stop_y;
            }
            if (!rect.isEmpty()) {
                blitter->getRealBlitter()->blitRect(
                        rect.fLeft, rect.fTop, rect.width(), rect.height());
            }
        }
        return;
    }
 
    SkAnalyticEdge headEdge, tailEdge, *last;
    // this returns the first and last edge after they're sorted into a dlink list
    SkAnalyticEdge* edge = sort_edges(list, count, &last);
 
    headEdge.fRiteE  = nullptr;
    headEdge.fPrev   = nullptr;
    headEdge.fNext   = edge;
    headEdge.fUpperY = headEdge.fLowerY = SK_MinS32;
    headEdge.fX                         = SK_MinS32;
    headEdge.fDX                        = 0;
    headEdge.fDY                        = SK_MaxS32;
    headEdge.fUpperX                    = SK_MinS32;
    edge->fPrev                         = &headEdge;
 
    tailEdge.fRiteE  = nullptr;
    tailEdge.fPrev   = last;
    tailEdge.fNext   = nullptr;
    tailEdge.fUpperY = tailEdge.fLowerY = SK_MaxS32;
    tailEdge.fX                         = SK_MaxS32;
    tailEdge.fDX                        = 0;
    tailEdge.fDY                        = SK_MaxS32;
    tailEdge.fUpperX                    = SK_MaxS32;
    last->fNext                         = &tailEdge;
 
    // now edge is the head of the sorted linklist
 
    if (!pathContainedInClip && start_y < clipRect.fTop) {
        start_y = clipRect.fTop;
    }
    if (!pathContainedInClip && stop_y > clipRect.fBottom) {
        stop_y = clipRect.fBottom;
    }
 
    SkFixed leftBound  = SkIntToFixed(rect.fLeft);
    SkFixed rightBound = SkIntToFixed(rect.fRight);
    if (isUsingMask) {
        // If we're using mask, then we have to limit the bound within the path bounds.
        // Otherwise, the edge drift may access an invalid address inside the mask.
        SkIRect ir;
        path.getBounds().roundOut(&ir);
        leftBound  = std::max(leftBound, SkIntToFixed(ir.fLeft));
        rightBound = std::min(rightBound, SkIntToFixed(ir.fRight));
    }
 
    if (!path.isInverseFillType() && path.isConvex() && count >= 2) {
        aaa_walk_convex_edges(
                &headEdge, blitter, start_y, stop_y, leftBound, rightBound, isUsingMask);
    } else {
        // Only use deferred blitting if there are many edges.
        bool useDeferred =
                count >
                (SkFixedFloorToInt(tailEdge.fPrev->fLowerY - headEdge.fNext->fUpperY) + 1) * 4;
 
        // We skip intersection computation if there are many points which probably already
        // give us enough fractional scan lines.
        bool skipIntersect = path.countPoints() > (stop_y - start_y) * 2;
 
        aaa_walk_edges(&headEdge,
                       &tailEdge,
                       path.getFillType(),
                       blitter,
                       start_y,
                       stop_y,
                       leftBound,
                       rightBound,
                       isUsingMask,
                       forceRLE,
                       useDeferred,
                       skipIntersect);
    }
}

aaa_walk_convex_edges()

static void aaa_walk_convex_edges ( SkAnalyticEdge *  prevHead, AdditiveBlitter *  blitter, int  start_y, int  stop_y, SkFixed  leftBound, SkFixed  riteBound, bool  isUsingMask  )

static

Definition at line 1090 of file SkScan_AAAPath.cpp.

                                                                {
    validate_sort((SkAnalyticEdge*)prevHead->fNext);
 
    SkAnalyticEdge* leftE = (SkAnalyticEdge*)prevHead->fNext;
    SkAnalyticEdge* riteE = (SkAnalyticEdge*)leftE->fNext;
    SkAnalyticEdge* currE = (SkAnalyticEdge*)riteE->fNext;
 
    SkFixed y = std::max(leftE->fUpperY, riteE->fUpperY);
 
    for (;;) {
        // We have to check fLowerY first because some edges might be alone (e.g., there's only
        // a left edge but no right edge in a given y scan line) due to precision limit.
        while (leftE->fLowerY <= y) {  // Due to smooth jump, we may pass multiple short edges
            if (!leftE->update(y)) {
                if (SkFixedFloorToInt(currE->fUpperY) >= stop_y) {
                    goto END_WALK;
                }
                leftE = currE;
                currE = (SkAnalyticEdge*)currE->fNext;
            }
        }
        while (riteE->fLowerY <= y) {  // Due to smooth jump, we may pass multiple short edges
            if (!riteE->update(y)) {
                if (SkFixedFloorToInt(currE->fUpperY) >= stop_y) {
                    goto END_WALK;
                }
                riteE = currE;
                currE = (SkAnalyticEdge*)currE->fNext;
            }
        }
 
        SkASSERT(leftE);
        SkASSERT(riteE);
 
        // check our bottom clip
        if (SkFixedFloorToInt(y) >= stop_y) {
            break;
        }
 
        SkASSERT(SkFixedFloorToInt(leftE->fUpperY) <= stop_y);
        SkASSERT(SkFixedFloorToInt(riteE->fUpperY) <= stop_y);
 
        leftE->goY(y);
        riteE->goY(y);
 
        if (leftE->fX > riteE->fX || (leftE->fX == riteE->fX && leftE->fDX > riteE->fDX)) {
            std::swap(leftE, riteE);
        }
 
        SkFixed local_bot_fixed = std::min(leftE->fLowerY, riteE->fLowerY);
        if (is_smooth_enough(leftE, riteE, currE, stop_y)) {
            local_bot_fixed = SkFixedCeilToFixed(local_bot_fixed);
        }
        local_bot_fixed = std::min(local_bot_fixed, SkIntToFixed(stop_y));
 
        SkFixed left  = std::max(leftBound, leftE->fX);
        SkFixed dLeft = leftE->fDX;
        SkFixed rite  = std::min(riteBound, riteE->fX);
        SkFixed dRite = riteE->fDX;
        if (0 == (dLeft | dRite)) {
            int     fullLeft    = SkFixedCeilToInt(left);
            int     fullRite    = SkFixedFloorToInt(rite);
            SkFixed partialLeft = SkIntToFixed(fullLeft) - left;
            SkFixed partialRite = rite - SkIntToFixed(fullRite);
            int     fullTop     = SkFixedCeilToInt(y);
            int     fullBot     = SkFixedFloorToInt(local_bot_fixed);
            SkFixed partialTop  = SkIntToFixed(fullTop) - y;
            SkFixed partialBot  = local_bot_fixed - SkIntToFixed(fullBot);
            if (fullTop > fullBot) {  // The rectangle is within one pixel height...
                partialTop -= (SK_Fixed1 - partialBot);
                partialBot = 0;
            }
 
            if (fullRite >= fullLeft) {
                if (partialTop > 0) {  // blit first partial row
                    if (partialLeft > 0) {
                        blitter->blitAntiH(fullLeft - 1,
                                           fullTop - 1,
                                           fixed_to_alpha(SkFixedMul(partialTop, partialLeft)));
                    }
                    blitter->blitAntiH(
                            fullLeft, fullTop - 1, fullRite - fullLeft, fixed_to_alpha(partialTop));
                    if (partialRite > 0) {
                        blitter->blitAntiH(fullRite,
                                           fullTop - 1,
                                           fixed_to_alpha(SkFixedMul(partialTop, partialRite)));
                    }
                    blitter->flush_if_y_changed(y, y + partialTop);
                }
 
                // Blit all full-height rows from fullTop to fullBot
                if (fullBot > fullTop &&
                    // SkAAClip cannot handle the empty rect so check the non-emptiness here
                    // (bug chromium:662800)
                    (fullRite > fullLeft || fixed_to_alpha(partialLeft) > 0 ||
                     fixed_to_alpha(partialRite) > 0)) {
                    blitter->getRealBlitter()->blitAntiRect(fullLeft - 1,
                                                            fullTop,
                                                            fullRite - fullLeft,
                                                            fullBot - fullTop,
                                                            fixed_to_alpha(partialLeft),
                                                            fixed_to_alpha(partialRite));
                }
 
                if (partialBot > 0) {  // blit last partial row
                    if (partialLeft > 0) {
                        blitter->blitAntiH(fullLeft - 1,
                                           fullBot,
                                           fixed_to_alpha(SkFixedMul(partialBot, partialLeft)));
                    }
                    blitter->blitAntiH(
                            fullLeft, fullBot, fullRite - fullLeft, fixed_to_alpha(partialBot));
                    if (partialRite > 0) {
                        blitter->blitAntiH(fullRite,
                                           fullBot,
                                           fixed_to_alpha(SkFixedMul(partialBot, partialRite)));
                    }
                }
            } else {
                // Normal conditions, this means left and rite are within the same pixel, but if
                // both left and rite were < leftBounds or > rightBounds, both edges are clipped and
                // we should not do any blitting (particularly since the negative width saturates to
                // full alpha).
                SkFixed width = rite - left;
                if (width > 0) {
                    if (partialTop > 0) {
                        blitter->blitAntiH(fullLeft - 1,
                                           fullTop - 1,
                                           1,
                                           fixed_to_alpha(SkFixedMul(partialTop, width)));
                        blitter->flush_if_y_changed(y, y + partialTop);
                    }
                    if (fullBot > fullTop) {
                        blitter->getRealBlitter()->blitV(
                                fullLeft - 1, fullTop, fullBot - fullTop, fixed_to_alpha(width));
                    }
                    if (partialBot > 0) {
                        blitter->blitAntiH(fullLeft - 1,
                                           fullBot,
                                           1,
                                           fixed_to_alpha(SkFixedMul(partialBot, width)));
                    }
                }
            }
 
            y = local_bot_fixed;
        } else {
            // The following constant are used to snap X
            // We snap X mainly for speedup (no tiny triangle) and
            // avoiding edge cases caused by precision errors
            const SkFixed kSnapDigit = SK_Fixed1 >> 4;
            const SkFixed kSnapHalf  = kSnapDigit >> 1;
            const SkFixed kSnapMask  = (-1 ^ (kSnapDigit - 1));
            left += kSnapHalf;
            rite += kSnapHalf;  // For fast rounding
 
            // Number of blit_trapezoid_row calls we'll have
            int count = SkFixedCeilToInt(local_bot_fixed) - SkFixedFloorToInt(y);
 
            // If we're using mask blitter, we advance the mask row in this function
            // to save some "if" condition checks.
            SkAlpha* maskRow = nullptr;
            if (isUsingMask) {
                maskRow = static_cast<MaskAdditiveBlitter*>(blitter)->getRow(y >> 16);
            }
 
            // Instead of writing one loop that handles both partial-row blit_trapezoid_row
            // and full-row trapezoid_row together, we use the following 3-stage flow to
            // handle partial-row blit and full-row blit separately. It will save us much time
            // on changing y, left, and rite.
            if (count > 1) {
                if ((int)(y & 0xFFFF0000) != y) {  // There's a partial-row on the top
                    count--;
                    SkFixed nextY    = SkFixedCeilToFixed(y + 1);
                    SkFixed dY       = nextY - y;
                    SkFixed nextLeft = left + SkFixedMul(dLeft, dY);
                    SkFixed nextRite = rite + SkFixedMul(dRite, dY);
                    SkASSERT((left & kSnapMask) >= leftBound && (rite & kSnapMask) <= riteBound &&
                             (nextLeft & kSnapMask) >= leftBound &&
                             (nextRite & kSnapMask) <= riteBound);
                    blit_trapezoid_row(blitter,
                                       y >> 16,
                                       left & kSnapMask,
                                       rite & kSnapMask,
                                       nextLeft & kSnapMask,
                                       nextRite & kSnapMask,
                                       leftE->fDY,
                                       riteE->fDY,
                                       get_partial_alpha(0xFF, dY),
                                       maskRow,
                                       isUsingMask);
                    blitter->flush_if_y_changed(y, nextY);
                    left = nextLeft;
                    rite = nextRite;
                    y    = nextY;
                }
 
                while (count > 1) {  // Full rows in the middle
                    count--;
                    if (isUsingMask) {
                        maskRow = static_cast<MaskAdditiveBlitter*>(blitter)->getRow(y >> 16);
                    }
                    SkFixed nextY = y + SK_Fixed1, nextLeft = left + dLeft, nextRite = rite + dRite;
                    SkASSERT((left & kSnapMask) >= leftBound && (rite & kSnapMask) <= riteBound &&
                             (nextLeft & kSnapMask) >= leftBound &&
                             (nextRite & kSnapMask) <= riteBound);
                    blit_trapezoid_row(blitter,
                                       y >> 16,
                                       left & kSnapMask,
                                       rite & kSnapMask,
                                       nextLeft & kSnapMask,
                                       nextRite & kSnapMask,
                                       leftE->fDY,
                                       riteE->fDY,
                                       0xFF,
                                       maskRow,
                                       isUsingMask);
                    blitter->flush_if_y_changed(y, nextY);
                    left = nextLeft;
                    rite = nextRite;
                    y    = nextY;
                }
            }
 
            if (isUsingMask) {
                maskRow = static_cast<MaskAdditiveBlitter*>(blitter)->getRow(y >> 16);
            }
 
            SkFixed dY = local_bot_fixed - y;  // partial-row on the bottom
            SkASSERT(dY <= SK_Fixed1);
            // Smooth jumping to integer y may make the last nextLeft/nextRite out of bound.
            // Take them back into the bound here.
            // Note that we substract kSnapHalf later so we have to add them to leftBound/riteBound
            SkFixed nextLeft = std::max(left + SkFixedMul(dLeft, dY), leftBound + kSnapHalf);
            SkFixed nextRite = std::min(rite + SkFixedMul(dRite, dY), riteBound + kSnapHalf);
            SkASSERT((left & kSnapMask) >= leftBound && (rite & kSnapMask) <= riteBound &&
                     (nextLeft & kSnapMask) >= leftBound && (nextRite & kSnapMask) <= riteBound);
            blit_trapezoid_row(blitter,
                               y >> 16,
                               left & kSnapMask,
                               rite & kSnapMask,
                               nextLeft & kSnapMask,
                               nextRite & kSnapMask,
                               leftE->fDY,
                               riteE->fDY,
                               get_partial_alpha(0xFF, dY),
                               maskRow,
                               isUsingMask);
            blitter->flush_if_y_changed(y, local_bot_fixed);
            left = nextLeft;
            rite = nextRite;
            y    = local_bot_fixed;
            left -= kSnapHalf;
            rite -= kSnapHalf;
        }
 
        leftE->fX = left;
        riteE->fX = rite;
        leftE->fY = riteE->fY = y;
    }
 
END_WALK:;
}

aaa_walk_edges()

static void aaa_walk_edges ( SkAnalyticEdge *  prevHead, SkAnalyticEdge *  nextTail, SkPathFillType  fillType, AdditiveBlitter *  blitter, int  start_y, int  stop_y, SkFixed  leftClip, SkFixed  rightClip, bool  isUsingMask, bool  forceRLE, bool  useDeferred, bool  skipIntersect  )

static

Definition at line 1546 of file SkScan_AAAPath.cpp.

                                                           {
    prevHead->fX = prevHead->fUpperX = leftClip;
    nextTail->fX = nextTail->fUpperX = rightClip;
    SkFixed y                        = std::max(prevHead->fNext->fUpperY, SkIntToFixed(start_y));
    SkFixed nextNextY                = SK_MaxS32;
 
    {
        SkAnalyticEdge* edge;
        for (edge = prevHead->fNext; edge->fUpperY <= y; edge = edge->fNext) {
            edge->goY(y);
            update_next_next_y(edge->fLowerY, y, &nextNextY);
        }
        update_next_next_y(edge->fUpperY, y, &nextNextY);
    }
 
    int windingMask = SkPathFillType_IsEvenOdd(fillType) ? 1 : -1;
    bool isInverse  = SkPathFillType_IsInverse(fillType);
 
    if (isInverse && SkIntToFixed(start_y) != y) {
        int width = SkFixedFloorToInt(rightClip - leftClip);
        if (SkFixedFloorToInt(y) != start_y) {
            blitter->getRealBlitter()->blitRect(
                    SkFixedFloorToInt(leftClip), start_y, width, SkFixedFloorToInt(y) - start_y);
            start_y = SkFixedFloorToInt(y);
        }
        SkAlpha* maskRow =
                isUsingMask ? static_cast<MaskAdditiveBlitter*>(blitter)->getRow(start_y) : nullptr;
        blit_full_alpha(blitter,
                        start_y,
                        SkFixedFloorToInt(leftClip),
                        width,
                        fixed_to_alpha(y - SkIntToFixed(start_y)),
                        maskRow,
                        isUsingMask,
                        false,
                        false);
    }
 
    while (true) {
        int             w               = 0;
        bool            in_interval     = isInverse;
        SkFixed         prevX           = prevHead->fX;
        SkFixed         nextY           = std::min(nextNextY, SkFixedCeilToFixed(y + 1));
        bool            isIntegralNextY = (nextY & (SK_Fixed1 - 1)) == 0;
        SkAnalyticEdge* currE           = prevHead->fNext;
        SkAnalyticEdge* leftE           = prevHead;
        SkFixed         left            = leftClip;
        SkFixed         leftDY          = 0;
        bool            leftEnds        = false;
        int             prevRite        = SkFixedFloorToInt(leftClip);
 
        nextNextY = SK_MaxS32;
 
        SkASSERT((nextY & ((SK_Fixed1 >> 2) - 1)) == 0);
        int yShift = 0;
        if ((nextY - y) & (SK_Fixed1 >> 2)) {
            yShift = 2;
            nextY  = y + (SK_Fixed1 >> 2);
        } else if ((nextY - y) & (SK_Fixed1 >> 1)) {
            yShift = 1;
            SkASSERT(nextY == y + (SK_Fixed1 >> 1));
        }
 
        SkAlpha fullAlpha = fixed_to_alpha(nextY - y);
 
        // If we're using mask blitter, we advance the mask row in this function
        // to save some "if" condition checks.
        SkAlpha* maskRow = nullptr;
        if (isUsingMask) {
            maskRow = static_cast<MaskAdditiveBlitter*>(blitter)->getRow(SkFixedFloorToInt(y));
        }
 
        SkASSERT(currE->fPrev == prevHead);
        validate_edges_for_y(currE, y);
 
        // Even if next - y == SK_Fixed1, we can still break the left-to-right order requirement
        // of the SKAAClip: |\| (two trapezoids with overlapping middle wedges)
        bool noRealBlitter = forceRLE;  // forceRLE && (nextY - y != SK_Fixed1);
 
        while (currE->fUpperY <= y) {
            SkASSERT(currE->fLowerY >= nextY);
            SkASSERT(currE->fY == y);
 
            w += currE->fWinding;
            bool prev_in_interval = in_interval;
            in_interval           = !(w & windingMask) == isInverse;
 
            bool isLeft   = in_interval && !prev_in_interval;
            bool isRite   = !in_interval && prev_in_interval;
            bool currEnds = currE->fLowerY == nextY;
 
            if (useDeferred) {
                if (currE->fRiteE && !isLeft) {
                    // currE is a left edge previously, but now it's not.
                    // Blit the trapezoid between fSavedY and y.
                    SkASSERT(currE->fRiteE->fY == y);
                    blit_saved_trapezoid(currE,
                                         y,
                                         currE->fX,
                                         currE->fRiteE->fX,
                                         blitter,
                                         maskRow,
                                         isUsingMask,
                                         noRealBlitter,
                                         leftClip,
                                         rightClip);
                }
                if (leftE->fRiteE == currE && !isRite) {
                    // currE is a right edge previously, but now it's not.
                    // Moreover, its corresponding leftE doesn't change (otherwise we'll handle it
                    // in the previous if clause). Hence we blit the trapezoid.
                    blit_saved_trapezoid(leftE,
                                         y,
                                         left,
                                         currE->fX,
                                         blitter,
                                         maskRow,
                                         isUsingMask,
                                         noRealBlitter,
                                         leftClip,
                                         rightClip);
                }
            }
 
            if (isRite) {
                if (useDeferred) {
                    deferred_blit(leftE,
                                  currE,
                                  left,
                                  leftDY,
                                  y,
                                  nextY,
                                  isIntegralNextY,
                                  leftEnds,
                                  currEnds,
                                  blitter,
                                  maskRow,
                                  isUsingMask,
                                  noRealBlitter,
                                  leftClip,
                                  rightClip,
                                  yShift);
                } else {
                    SkFixed rite = currE->fX;
                    currE->goY(nextY, yShift);
                    SkFixed nextLeft = std::max(leftClip, leftE->fX);
                    rite             = std::min(rightClip, rite);
                    SkFixed nextRite = std::min(rightClip, currE->fX);
                    blit_trapezoid_row(
                            blitter,
                            y >> 16,
                            left,
                            rite,
                            nextLeft,
                            nextRite,
                            leftDY,
                            currE->fDY,
                            fullAlpha,
                            maskRow,
                            isUsingMask,
                            noRealBlitter || (fullAlpha == 0xFF &&
                                              (edges_too_close(prevRite, left, leftE->fX) ||
                                               edges_too_close(currE, currE->fNext, nextY))),
                            true);
                    prevRite = SkFixedCeilToInt(std::max(rite, currE->fX));
                }
            } else {
                if (isLeft) {
                    left     = std::max(currE->fX, leftClip);
                    leftDY   = currE->fDY;
                    leftE    = currE;
                    leftEnds = leftE->fLowerY == nextY;
                }
                currE->goY(nextY, yShift);
            }
 
            SkAnalyticEdge* next = currE->fNext;
            SkFixed         newX;
 
            while (currE->fLowerY <= nextY) {
                if (currE->fCurveCount < 0) {
                    SkAnalyticCubicEdge* cubicEdge = (SkAnalyticCubicEdge*)currE;
                    cubicEdge->keepContinuous();
                    if (!cubicEdge->updateCubic()) {
                        break;
                    }
                } else if (currE->fCurveCount > 0) {
                    SkAnalyticQuadraticEdge* quadEdge = (SkAnalyticQuadraticEdge*)currE;
                    quadEdge->keepContinuous();
                    if (!quadEdge->updateQuadratic()) {
                        break;
                    }
                } else {
                    break;
                }
            }
            SkASSERT(currE->fY == nextY);
 
            if (currE->fLowerY <= nextY) {
                remove_edge(currE);
            } else {
                update_next_next_y(currE->fLowerY, nextY, &nextNextY);
                newX = currE->fX;
                SkASSERT(currE->fLowerY > nextY);
                if (newX < prevX) {  // ripple currE backwards until it is x-sorted
                    // If the crossing edge is a right edge, blit the saved trapezoid.
                    if (leftE->fRiteE == currE && useDeferred) {
                        SkASSERT(leftE->fY == nextY && currE->fY == nextY);
                        blit_saved_trapezoid(leftE,
                                             nextY,
                                             leftE->fX,
                                             currE->fX,
                                             blitter,
                                             maskRow,
                                             isUsingMask,
                                             noRealBlitter,
                                             leftClip,
                                             rightClip);
                    }
                    backward_insert_edge_based_on_x(currE);
                } else {
                    prevX = newX;
                }
                if (!skipIntersect) {
                    check_intersection(currE, nextY, &nextNextY);
                }
            }
 
            currE = next;
            SkASSERT(currE);
        }
 
        // was our right-edge culled away?
        if (in_interval) {
            if (useDeferred) {
                deferred_blit(leftE,
                              nextTail,
                              left,
                              leftDY,
                              y,
                              nextY,
                              isIntegralNextY,
                              leftEnds,
                              false,
                              blitter,
                              maskRow,
                              isUsingMask,
                              noRealBlitter,
                              leftClip,
                              rightClip,
                              yShift);
            } else {
                blit_trapezoid_row(blitter,
                                   y >> 16,
                                   left,
                                   rightClip,
                                   std::max(leftClip, leftE->fX),
                                   rightClip,
                                   leftDY,
                                   0,
                                   fullAlpha,
                                   maskRow,
                                   isUsingMask,
                                   noRealBlitter || (fullAlpha == 0xFF &&
                                                     edges_too_close(leftE->fPrev, leftE, nextY)),
                                   true);
            }
        }
 
        if (forceRLE) {
            ((RunBasedAdditiveBlitter*)blitter)->flush_if_y_changed(y, nextY);
        }
 
        y = nextY;
        if (y >= SkIntToFixed(stop_y)) {
            break;
        }
 
        // now currE points to the first edge with a fUpperY larger than the previous y
        insert_new_edges(currE, y, &nextNextY);
    }
}

add_alpha()

static void add_alpha ( SkAlpha *  alpha, SkAlpha  delta  )

static

Definition at line 90 of file SkScan_AAAPath.cpp.

                                                     {
    SkASSERT(*alpha + delta <= 256);
    *alpha = SkAlphaRuns::CatchOverflow(*alpha + delta);
}

approximate_intersection()

static SkFixed approximate_intersection ( SkFixed  l1, SkFixed  r1, SkFixed  l2, SkFixed  r2  )

static

Definition at line 578 of file SkScan_AAAPath.cpp.

                                                                                        {
    if (l1 > r1) {
        std::swap(l1, r1);
    }
    if (l2 > r2) {
        std::swap(l2, r2);
    }
    return (std::max(l1, l2) + std::min(r1, r2)) / 2;
}

blit_aaa_trapezoid_row()

static void blit_aaa_trapezoid_row ( AdditiveBlitter *  blitter, int  y, SkFixed  ul, SkFixed  ur, SkFixed  ll, SkFixed  lr, SkFixed  lDY, SkFixed  rDY, SkAlpha  fullAlpha, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, bool  needSafeCheck  )

static

Definition at line 723 of file SkScan_AAAPath.cpp.

                                                                   {
    int L = SkFixedFloorToInt(ul), R = SkFixedCeilToInt(lr);
    int len = R - L;
 
    if (len == 1) {
        SkAlpha alpha = trapezoid_to_alpha(ur - ul, lr - ll);
        blit_single_alpha(blitter,
                          y,
                          L,
                          alpha,
                          fullAlpha,
                          maskRow,
                          isUsingMask,
                          noRealBlitter,
                          needSafeCheck);
        return;
    }
 
    const int kQuickLen = 31;
    alignas(2) char quickMemory[(sizeof(SkAlpha) * 2 + sizeof(int16_t)) * (kQuickLen + 1)];
    SkAlpha*  alphas;
 
    if (len <= kQuickLen) {
        alphas = (SkAlpha*)quickMemory;
    } else {
        alphas = new SkAlpha[(len + 1) * (sizeof(SkAlpha) * 2 + sizeof(int16_t))];
    }
 
    SkAlpha* tempAlphas = alphas + len + 1;
    int16_t* runs       = (int16_t*)(alphas + (len + 1) * 2);
 
    for (int i = 0; i < len; ++i) {
        runs[i]   = 1;
        alphas[i] = fullAlpha;
    }
    runs[len] = 0;
 
    int uL = SkFixedFloorToInt(ul);
    int lL = SkFixedCeilToInt(ll);
    if (uL + 2 == lL) {  // We only need to compute two triangles, accelerate this special case
        SkFixed first  = SkIntToFixed(uL) + SK_Fixed1 - ul;
        SkFixed second = ll - ul - first;
        SkAlpha a1     = fullAlpha - partial_triangle_to_alpha(first, lDY);
        SkAlpha a2     = partial_triangle_to_alpha(second, lDY);
        alphas[0]      = alphas[0] > a1 ? alphas[0] - a1 : 0;
        alphas[1]      = alphas[1] > a2 ? alphas[1] - a2 : 0;
    } else {
        compute_alpha_below_line(
                tempAlphas + uL - L, ul - SkIntToFixed(uL), ll - SkIntToFixed(uL), lDY, fullAlpha);
        for (int i = uL; i < lL; ++i) {
            if (alphas[i - L] > tempAlphas[i - L]) {
                alphas[i - L] -= tempAlphas[i - L];
            } else {
                alphas[i - L] = 0;
            }
        }
    }
 
    int uR = SkFixedFloorToInt(ur);
    int lR = SkFixedCeilToInt(lr);
    if (uR + 2 == lR) {  // We only need to compute two triangles, accelerate this special case
        SkFixed first   = SkIntToFixed(uR) + SK_Fixed1 - ur;
        SkFixed second  = lr - ur - first;
        SkAlpha a1      = partial_triangle_to_alpha(first, rDY);
        SkAlpha a2      = fullAlpha - partial_triangle_to_alpha(second, rDY);
        alphas[len - 2] = alphas[len - 2] > a1 ? alphas[len - 2] - a1 : 0;
        alphas[len - 1] = alphas[len - 1] > a2 ? alphas[len - 1] - a2 : 0;
    } else {
        compute_alpha_above_line(
                tempAlphas + uR - L, ur - SkIntToFixed(uR), lr - SkIntToFixed(uR), rDY, fullAlpha);
        for (int i = uR; i < lR; ++i) {
            if (alphas[i - L] > tempAlphas[i - L]) {
                alphas[i - L] -= tempAlphas[i - L];
            } else {
                alphas[i - L] = 0;
            }
        }
    }
 
    if (isUsingMask) {
        for (int i = 0; i < len; ++i) {
            if (needSafeCheck) {
                safely_add_alpha(&maskRow[L + i], alphas[i]);
            } else {
                add_alpha(&maskRow[L + i], alphas[i]);
            }
        }
    } else {
        if (fullAlpha == 0xFF && !noRealBlitter) {
            // Real blitter is faster than RunBasedAdditiveBlitter
            blitter->getRealBlitter()->blitAntiH(L, y, alphas, runs);
        } else {
            blitter->blitAntiH(L, y, alphas, len);
        }
    }
 
    if (len > kQuickLen) {
        delete[] alphas;
    }
}

blit_full_alpha()

static void blit_full_alpha ( AdditiveBlitter *  blitter, int  y, int  x, int  len, SkAlpha  fullAlpha, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, bool  needSafeCheck  )

static

Definition at line 697 of file SkScan_AAAPath.cpp.

                                                {
    if (isUsingMask) {
        for (int i = 0; i < len; ++i) {
            if (needSafeCheck) {
                safely_add_alpha(&maskRow[x + i], fullAlpha);
            } else {
                add_alpha(&maskRow[x + i], fullAlpha);
            }
        }
    } else {
        if (fullAlpha == 0xFF && !noRealBlitter) {
            blitter->getRealBlitter()->blitH(x, y, len);
        } else {
            blitter->blitAntiH(x, y, len, fullAlpha);
        }
    }
}

blit_saved_trapezoid()

static void blit_saved_trapezoid ( SkAnalyticEdge *  leftE, SkFixed  lowerY, SkFixed  lowerLeft, SkFixed  lowerRite, AdditiveBlitter *  blitter, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, SkFixed  leftClip, SkFixed  rightClip  )

static

Definition at line 1451 of file SkScan_AAAPath.cpp.

                                                             {
    SkAnalyticEdge* riteE = leftE->fRiteE;
    SkASSERT(riteE);
    SkASSERT(riteE->fNext == nullptr || leftE->fSavedY == riteE->fSavedY);
    SkASSERT(SkFixedFloorToInt(lowerY - 1) == SkFixedFloorToInt(leftE->fSavedY));
    int y = SkFixedFloorToInt(leftE->fSavedY);
    // Instead of using fixed_to_alpha(lowerY - leftE->fSavedY), we use the following fullAlpha
    // to elimiate cumulative error: if there are many fractional y scan lines within the
    // same row, the former may accumulate the rounding error while the later won't.
    SkAlpha fullAlpha = fixed_to_alpha(lowerY - SkIntToFixed(y)) -
                        fixed_to_alpha(leftE->fSavedY - SkIntToFixed(y));
    // We need fSavedDY because the (quad or cubic) edge might be updated
    blit_trapezoid_row(
            blitter,
            y,
            std::max(leftE->fSavedX, leftClip),
            std::min(riteE->fSavedX, rightClip),
            std::max(lowerLeft, leftClip),
            std::min(lowerRite, rightClip),
            leftE->fSavedDY,
            riteE->fSavedDY,
            fullAlpha,
            maskRow,
            isUsingMask,
            noRealBlitter || (fullAlpha == 0xFF && (edges_too_close(leftE->fPrev, leftE, lowerY) ||
                                                    edges_too_close(riteE, riteE->fNext, lowerY))),
            true);
    leftE->fRiteE = nullptr;
}

blit_single_alpha()

static void blit_single_alpha ( AdditiveBlitter *  blitter, int  y, int  x, SkAlpha  alpha, SkAlpha  fullAlpha, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, bool  needSafeCheck  )

static

Definition at line 643 of file SkScan_AAAPath.cpp.

                                                  {
    if (isUsingMask) {
        if (fullAlpha == 0xFF && !noRealBlitter) {  // noRealBlitter is needed for concave paths
            maskRow[x] = alpha;
        } else if (needSafeCheck) {
            safely_add_alpha(&maskRow[x], get_partial_alpha(alpha, fullAlpha));
        } else {
            add_alpha(&maskRow[x], get_partial_alpha(alpha, fullAlpha));
        }
    } else {
        if (fullAlpha == 0xFF && !noRealBlitter) {
            blitter->getRealBlitter()->blitV(x, y, 1, alpha);
        } else {
            blitter->blitAntiH(x, y, get_partial_alpha(alpha, fullAlpha));
        }
    }
}

blit_trapezoid_row()

static void blit_trapezoid_row ( AdditiveBlitter *  blitter, int  y, SkFixed  ul, SkFixed  ur, SkFixed  ll, SkFixed  lr, SkFixed  lDY, SkFixed  rDY, SkAlpha  fullAlpha, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter = false, bool  needSafeCheck = false  )

static

Definition at line 836 of file SkScan_AAAPath.cpp.

                                                           {
    SkASSERT(lDY >= 0 && rDY >= 0);  // We should only send in the absolte value
 
    if (ul > ur) {
        return;
    }
 
    // Edge crosses. Approximate it. This should only happend due to precision limit,
    // so the approximation could be very coarse.
    if (ll > lr) {
        ll = lr = approximate_intersection(ul, ll, ur, lr);
    }
 
    if (ul == ur && ll == lr) {
        return;  // empty trapzoid
    }
 
    // We're going to use the left line ul-ll and the rite line ur-lr
    // to exclude the area that's not covered by the path.
    // Swapping (ul, ll) or (ur, lr) won't affect that exclusion
    // so we'll do that for simplicity.
    if (ul > ll) {
        std::swap(ul, ll);
    }
    if (ur > lr) {
        std::swap(ur, lr);
    }
 
    SkFixed joinLeft = SkFixedCeilToFixed(ll);
    SkFixed joinRite = SkFixedFloorToFixed(ur);
    if (joinLeft <= joinRite) {  // There's a rect from joinLeft to joinRite that we can blit
        if (ul < joinLeft) {
            int len = SkFixedCeilToInt(joinLeft - ul);
            if (len == 1) {
                SkAlpha alpha = trapezoid_to_alpha(joinLeft - ul, joinLeft - ll);
                blit_single_alpha(blitter,
                                  y,
                                  ul >> 16,
                                  alpha,
                                  fullAlpha,
                                  maskRow,
                                  isUsingMask,
                                  noRealBlitter,
                                  needSafeCheck);
            } else if (len == 2) {
                SkFixed first  = joinLeft - SK_Fixed1 - ul;
                SkFixed second = ll - ul - first;
                SkAlpha a1     = partial_triangle_to_alpha(first, lDY);
                SkAlpha a2     = fullAlpha - partial_triangle_to_alpha(second, lDY);
                blit_two_alphas(blitter,
                                y,
                                ul >> 16,
                                a1,
                                a2,
                                fullAlpha,
                                maskRow,
                                isUsingMask,
                                noRealBlitter,
                                needSafeCheck);
            } else {
                blit_aaa_trapezoid_row(blitter,
                                       y,
                                       ul,
                                       joinLeft,
                                       ll,
                                       joinLeft,
                                       lDY,
                                       SK_MaxS32,
                                       fullAlpha,
                                       maskRow,
                                       isUsingMask,
                                       noRealBlitter,
                                       needSafeCheck);
            }
        }
        // SkAAClip requires that we blit from left to right.
        // Hence we must blit [ul, joinLeft] before blitting [joinLeft, joinRite]
        if (joinLeft < joinRite) {
            blit_full_alpha(blitter,
                            y,
                            SkFixedFloorToInt(joinLeft),
                            SkFixedFloorToInt(joinRite - joinLeft),
                            fullAlpha,
                            maskRow,
                            isUsingMask,
                            noRealBlitter,
                            needSafeCheck);
        }
        if (lr > joinRite) {
            int len = SkFixedCeilToInt(lr - joinRite);
            if (len == 1) {
                SkAlpha alpha = trapezoid_to_alpha(ur - joinRite, lr - joinRite);
                blit_single_alpha(blitter,
                                  y,
                                  joinRite >> 16,
                                  alpha,
                                  fullAlpha,
                                  maskRow,
                                  isUsingMask,
                                  noRealBlitter,
                                  needSafeCheck);
            } else if (len == 2) {
                SkFixed first  = joinRite + SK_Fixed1 - ur;
                SkFixed second = lr - ur - first;
                SkAlpha a1     = fullAlpha - partial_triangle_to_alpha(first, rDY);
                SkAlpha a2     = partial_triangle_to_alpha(second, rDY);
                blit_two_alphas(blitter,
                                y,
                                joinRite >> 16,
                                a1,
                                a2,
                                fullAlpha,
                                maskRow,
                                isUsingMask,
                                noRealBlitter,
                                needSafeCheck);
            } else {
                blit_aaa_trapezoid_row(blitter,
                                       y,
                                       joinRite,
                                       ur,
                                       joinRite,
                                       lr,
                                       SK_MaxS32,
                                       rDY,
                                       fullAlpha,
                                       maskRow,
                                       isUsingMask,
                                       noRealBlitter,
                                       needSafeCheck);
            }
        }
    } else {
        blit_aaa_trapezoid_row(blitter,
                               y,
                               ul,
                               ur,
                               ll,
                               lr,
                               lDY,
                               rDY,
                               fullAlpha,
                               maskRow,
                               isUsingMask,
                               noRealBlitter,
                               needSafeCheck);
    }
}

blit_two_alphas()

static void blit_two_alphas ( AdditiveBlitter *  blitter, int  y, int  x, SkAlpha  a1, SkAlpha  a2, SkAlpha  fullAlpha, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, bool  needSafeCheck  )

static

Definition at line 669 of file SkScan_AAAPath.cpp.

                                                {
    if (isUsingMask) {
        if (needSafeCheck) {
            safely_add_alpha(&maskRow[x], a1);
            safely_add_alpha(&maskRow[x + 1], a2);
        } else {
            add_alpha(&maskRow[x], a1);
            add_alpha(&maskRow[x + 1], a2);
        }
    } else {
        if (fullAlpha == 0xFF && !noRealBlitter) {
            blitter->getRealBlitter()->blitAntiH2(x, y, a1, a2);
        } else {
            blitter->blitAntiH(x, y, a1);
            blitter->blitAntiH(x + 1, y, a2);
        }
    }
}

check_intersection()

static void check_intersection ( const SkAnalyticEdge *  edge, SkFixed  nextY, SkFixed *  nextNextY  )

static

Definition at line 1364 of file SkScan_AAAPath.cpp.

                                                                                              {
    if (edge->fPrev->fPrev && edge->fPrev->fX + edge->fPrev->fDX > edge->fX + edge->fDX) {
        *nextNextY = nextY + (SK_Fixed1 >> SkAnalyticEdge::kDefaultAccuracy);
    }
}

compute_alpha_above_line()

static void compute_alpha_above_line ( SkAlpha *  alphas, SkFixed  l, SkFixed  r, SkFixed  dY, SkAlpha  fullAlpha  )

static

Definition at line 589 of file SkScan_AAAPath.cpp.

                                                         {
    SkASSERT(l <= r);
    SkASSERT(l >> 16 == 0);
    int R = SkFixedCeilToInt(r);
    if (R == 0) {
        return;
    } else if (R == 1) {
        alphas[0] = get_partial_alpha(((R << 17) - l - r) >> 9, fullAlpha);
    } else {
        SkFixed first   = SK_Fixed1 - l;        // horizontal edge length of the left-most triangle
        SkFixed last    = r - ((R - 1) << 16);  // horizontal edge length of the right-most triangle
        SkFixed firstH  = SkFixedMul(first, dY);  // vertical edge of the left-most triangle
        alphas[0]       = SkFixedMul(first, firstH) >> 9;  // triangle alpha
        SkFixed alpha16 = firstH + (dY >> 1);              // rectangle plus triangle
        for (int i = 1; i < R - 1; ++i) {
            alphas[i] = alpha16 >> 8;
            alpha16 += dY;
        }
        alphas[R - 1] = fullAlpha - partial_triangle_to_alpha(last, dY);
    }
}

compute_alpha_below_line()

static void compute_alpha_below_line ( SkAlpha *  alphas, SkFixed  l, SkFixed  r, SkFixed  dY, SkAlpha  fullAlpha  )

static

Definition at line 616 of file SkScan_AAAPath.cpp.

                                                         {
    SkASSERT(l <= r);
    SkASSERT(l >> 16 == 0);
    int R = SkFixedCeilToInt(r);
    if (R == 0) {
        return;
    } else if (R == 1) {
        alphas[0] = get_partial_alpha(trapezoid_to_alpha(l, r), fullAlpha);
    } else {
        SkFixed first   = SK_Fixed1 - l;        // horizontal edge length of the left-most triangle
        SkFixed last    = r - ((R - 1) << 16);  // horizontal edge length of the right-most triangle
        SkFixed lastH   = SkFixedMul(last, dY);          // vertical edge of the right-most triangle
        alphas[R - 1]   = SkFixedMul(last, lastH) >> 9;  // triangle alpha
        SkFixed alpha16 = lastH + (dY >> 1);             // rectangle plus triangle
        for (int i = R - 2; i > 0; i--) {
            alphas[i] = (alpha16 >> 8) & 0xFF;
            alpha16 += dY;
        }
        alphas[0] = fullAlpha - partial_triangle_to_alpha(first, dY);
    }
}

deferred_blit()

static void deferred_blit ( SkAnalyticEdge *  leftE, SkAnalyticEdge *  riteE, SkFixed  left, SkFixed  leftDY, SkFixed  y, SkFixed  nextY, bool  isIntegralNextY, bool  leftEnds, bool  riteEnds, AdditiveBlitter *  blitter, SkAlpha *  maskRow, bool  isUsingMask, bool  noRealBlitter, SkFixed  leftClip, SkFixed  rightClip, int  yShift  )

static

Definition at line 1490 of file SkScan_AAAPath.cpp.

                                                   {
    if (leftE->fRiteE && leftE->fRiteE != riteE) {
        // leftE's right edge changed. Blit the saved trapezoid.
        SkASSERT(leftE->fRiteE->fNext == nullptr || leftE->fRiteE->fY == y);
        blit_saved_trapezoid(leftE,
                             y,
                             left,
                             leftE->fRiteE->fX,
                             blitter,
                             maskRow,
                             isUsingMask,
                             noRealBlitter,
                             leftClip,
                             rightClip);
    }
    if (!leftE->fRiteE) {
        // Save and defer blitting the trapezoid
        SkASSERT(riteE->fRiteE == nullptr);
        SkASSERT(leftE->fPrev == nullptr || leftE->fY == nextY);
        SkASSERT(riteE->fNext == nullptr || riteE->fY == y);
        leftE->saveXY(left, y, leftDY);
        riteE->saveXY(riteE->fX, y, riteE->fDY);
        leftE->fRiteE = riteE;
    }
    SkASSERT(leftE->fPrev == nullptr || leftE->fY == nextY);
    riteE->goY(nextY, yShift);
    // Always blit when edges end or nextY is integral
    if (isIntegralNextY || leftEnds || riteEnds) {
        blit_saved_trapezoid(leftE,
                             nextY,
                             leftE->fX,
                             riteE->fX,
                             blitter,
                             maskRow,
                             isUsingMask,
                             noRealBlitter,
                             leftClip,
                             rightClip);
    }
}

edges_too_close() [1/2]

static bool edges_too_close ( int  prevRite, SkFixed  ul, SkFixed  ll  )

static

Definition at line 1447 of file SkScan_AAAPath.cpp.

                                                                  {
    return prevRite > SkFixedFloorToInt(ul) || prevRite > SkFixedFloorToInt(ll);
}

edges_too_close() [2/2]

static bool edges_too_close ( SkAnalyticEdge *  prev, SkAnalyticEdge *  next, SkFixed  lowerY  )

static

Definition at line 1426 of file SkScan_AAAPath.cpp.

                                                                                        {
    // When next->fDX == 0, prev->fX >= next->fX - SkAbs32(next->fDX) would be false
    // even if prev->fX and next->fX are close and within one pixel (e.g., prev->fX == 0.1,
    // next->fX == 0.9). Adding SLACK = 1 to the formula would guarantee it to be true if two
    // edges prev and next are within one pixel.
    constexpr SkFixed SLACK = SK_Fixed1;
 
    // Note that even if the following test failed, the edges might still be very close to each
    // other at some point within the current pixel row because of prev->fDX and next->fDX.
    // However, to handle that case, we have to sacrafice more performance.
    // I think the current quality is good enough (mainly by looking at Nebraska-StateSeal.svg)
    // so I'll ignore fDX for performance tradeoff.
    return next && prev && next->fUpperY < lowerY &&
           prev->fX + SLACK >= next->fX - SkAbs32(next->fDX);
    // The following is more accurate but also slower.
    // return (prev && prev->fPrev && next && next->fNext != nullptr && next->fUpperY < lowerY &&
    //     prev->fX + SkAbs32(prev->fDX) + SLACK >= next->fX - SkAbs32(next->fDX));
}

fixed_to_alpha()

static SkAlpha fixed_to_alpha ( SkFixed  f )

static

Definition at line 571 of file SkScan_AAAPath.cpp.

                                         {
    SkASSERT(f <= SK_Fixed1);
    return get_partial_alpha(0xFF, f);
}

get_partial_alpha() [1/2]

static SkAlpha get_partial_alpha ( SkAlpha  alpha, SkAlpha  fullAlpha  )

static

Definition at line 564 of file SkScan_AAAPath.cpp.

                                                                   {
    return (alpha * fullAlpha) >> 8;
}

get_partial_alpha() [2/2]

static SkAlpha get_partial_alpha ( SkAlpha  alpha, SkFixed  partialHeight  )

static

Definition at line 560 of file SkScan_AAAPath.cpp.

                                                                       {
    return SkToU8(SkFixedRoundToInt(alpha * partialHeight));
}

insert_new_edges()

static void insert_new_edges ( SkAnalyticEdge *  newEdge, SkFixed  y, SkFixed *  nextNextY  )

static

Definition at line 1370 of file SkScan_AAAPath.cpp.

                                                                                     {
    if (newEdge->fUpperY > y) {
        update_next_next_y(newEdge->fUpperY, y, nextNextY);
        return;
    }
    SkAnalyticEdge* prev = newEdge->fPrev;
    if (prev->fX <= newEdge->fX) {
        while (newEdge->fUpperY <= y) {
            check_intersection(newEdge, y, nextNextY);
            update_next_next_y(newEdge->fLowerY, y, nextNextY);
            newEdge = newEdge->fNext;
        }
        update_next_next_y(newEdge->fUpperY, y, nextNextY);
        return;
    }
    // find first x pos to insert
    SkAnalyticEdge* start = backward_insert_start(prev, newEdge->fX);
    // insert the lot, fixing up the links as we go
    do {
        SkAnalyticEdge* next = newEdge->fNext;
        do {
            if (start->fNext == newEdge) {
                goto nextEdge;
            }
            SkAnalyticEdge* after = start->fNext;
            if (after->fX >= newEdge->fX) {
                break;
            }
            SkASSERT(start != after);
            start = after;
        } while (true);
        remove_edge(newEdge);
        insert_edge_after(newEdge, start);
    nextEdge:
        check_intersection(newEdge, y, nextNextY);
        update_next_next_y(newEdge->fLowerY, y, nextNextY);
        start   = newEdge;
        newEdge = next;
    } while (newEdge->fUpperY <= y);
    update_next_next_y(newEdge->fUpperY, y, nextNextY);
}

is_smooth_enough() [1/2]

static bool is_smooth_enough ( SkAnalyticEdge *  leftE, SkAnalyticEdge *  riteE, SkAnalyticEdge *  currE, int  stop_y  )

static

Definition at line 1065 of file SkScan_AAAPath.cpp.

                                                     {
    if (currE->fUpperY >= SkLeftShift(stop_y, 16)) {
        return false;  // We're at the end so we won't skip anything
    }
    if (leftE->fLowerY + SK_Fixed1 < riteE->fLowerY) {
        return is_smooth_enough(leftE, currE, stop_y);  // Only leftE is changing
    } else if (leftE->fLowerY > riteE->fLowerY + SK_Fixed1) {
        return is_smooth_enough(riteE, currE, stop_y);  // Only riteE is changing
    }
 
    // Now both edges are changing, find the second next edge
    SkAnalyticEdge* nextCurrE = currE->fNext;
    if (nextCurrE->fUpperY >= stop_y << 16) {  // Check if we're at the end
        return false;
    }
    // Ensure that currE is the next left edge and nextCurrE is the next right edge. Swap if not.
    if (nextCurrE->fUpperX < currE->fUpperX) {
        std::swap(currE, nextCurrE);
    }
    return is_smooth_enough(leftE, currE, stop_y) && is_smooth_enough(riteE, nextCurrE, stop_y);
}

is_smooth_enough() [2/2]

static bool is_smooth_enough ( SkAnalyticEdge *  thisEdge, SkAnalyticEdge *  nextEdge, int  stop_y  )

static

Definition at line 1044 of file SkScan_AAAPath.cpp.

                                                                                             {
    if (thisEdge->fCurveCount < 0) {
        const SkCubicEdge& cEdge   = static_cast<SkAnalyticCubicEdge*>(thisEdge)->fCEdge;
        int                ddshift = cEdge.fCurveShift;
        return SkAbs32(cEdge.fCDx) >> 1 >= SkAbs32(cEdge.fCDDx) >> ddshift &&
               SkAbs32(cEdge.fCDy) >> 1 >= SkAbs32(cEdge.fCDDy) >> ddshift &&
               // current Dy is (fCDy - (fCDDy >> ddshift)) >> dshift
               (cEdge.fCDy - (cEdge.fCDDy >> ddshift)) >> cEdge.fCubicDShift >= SK_Fixed1;
    } else if (thisEdge->fCurveCount > 0) {
        const SkQuadraticEdge& qEdge = static_cast<SkAnalyticQuadraticEdge*>(thisEdge)->fQEdge;
        return SkAbs32(qEdge.fQDx) >> 1 >= SkAbs32(qEdge.fQDDx) &&
               SkAbs32(qEdge.fQDy) >> 1 >= SkAbs32(qEdge.fQDDy) &&
               // current Dy is (fQDy - fQDDy) >> shift
               (qEdge.fQDy - qEdge.fQDDy) >> qEdge.fCurveShift >= SK_Fixed1;
    }
    return SkAbs32(nextEdge->fDX - thisEdge->fDX) <= SK_Fixed1 &&  // DDx should be small
           nextEdge->fLowerY - nextEdge->fUpperY >= SK_Fixed1;     // Dy should be large
}

operator<()

static bool operator< ( const SkAnalyticEdge &  a, const SkAnalyticEdge &  b  )

static

Definition at line 997 of file SkScan_AAAPath.cpp.

                                                                        {
    int valuea = a.fUpperY;
    int valueb = b.fUpperY;
 
    if (valuea == valueb) {
        valuea = a.fX;
        valueb = b.fX;
    }
 
    if (valuea == valueb) {
        valuea = a.fDX;
        valueb = b.fDX;
    }
 
    return valuea < valueb;
}

partial_triangle_to_alpha()

static SkAlpha partial_triangle_to_alpha ( SkFixed  a, SkFixed  b  )

static

Definition at line 541 of file SkScan_AAAPath.cpp.

                                                               {
    SkASSERT(a <= SK_Fixed1);
#if 0
    // TODO(mtklein): skia:8877
    SkASSERT(b <= SK_Fixed1);
#endif
 
    // Approximating...
    // SkFixed area = SkFixedMul(a, SkFixedMul(a,b)) / 2;
    SkFixed area = (a >> 11) * (a >> 11) * (b >> 11);
 
#if 0
    // TODO(mtklein): skia:8877
    return SkTo<SkAlpha>(area >> 8);
#else
    return SkTo<SkAlpha>((area >> 8) & 0xFF);
#endif
}

safely_add_alpha()

static void safely_add_alpha ( SkAlpha *  alpha, SkAlpha  delta  )

static

Definition at line 95 of file SkScan_AAAPath.cpp.

                                                            {
    *alpha = std::min(0xFF, *alpha + delta);
}

sort_edges()

static SkAnalyticEdge * sort_edges ( SkAnalyticEdge *  list[], int  count, SkAnalyticEdge **  last  )

static

Definition at line 1014 of file SkScan_AAAPath.cpp.

                                                                                            {
    SkTQSort(list, list + count);
 
    // now make the edges linked in sorted order
    for (int i = 1; i < count; ++i) {
        list[i - 1]->fNext = list[i];
        list[i]->fPrev     = list[i - 1];
    }
 
    *last = list[count - 1];
    return list[0];
}

trapezoid_to_alpha()

static SkAlpha trapezoid_to_alpha ( SkFixed  l1, SkFixed  l2  )

static

Definition at line 534 of file SkScan_AAAPath.cpp.

                                                          {
    SkASSERT(l1 >= 0 && l2 >= 0);
    SkFixed area = (l1 + l2) / 2;
    return SkTo<SkAlpha>(area >> 8);
}

try_blit_fat_anti_rect()

static bool try_blit_fat_anti_rect ( SkBlitter *  blitter, const SkPath &  path, const SkIRect &  clip  )

inlinestatic

Definition at line 1950 of file SkScan_AAAPath.cpp.

                                                               {
    SkRect rect;
    if (!path.isRect(&rect)) {
        return false; // not rect
    }
    if (!rect.intersect(SkRect::Make(clip))) {
        return true; // The intersection is empty. Hence consider it done.
    }
    SkIRect bounds = rect.roundOut();
    if (bounds.width() < 3) {
        return false; // not fat
    }
    blitter->blitFatAntiRect(rect);
    return true;
}

update_next_next_y()

static void update_next_next_y ( SkFixed  y, SkFixed  nextY, SkFixed *  nextNextY  )

static

Definition at line 1360 of file SkScan_AAAPath.cpp.

                                                                             {
    *nextNextY = y > nextY && y < *nextNextY ? y : *nextNextY;
}

validate_edges_for_y()

static void validate_edges_for_y ( const SkAnalyticEdge *  edge, SkFixed  y  )

static

Definition at line 1412 of file SkScan_AAAPath.cpp.

                                                                        {
#ifdef SK_DEBUG
    while (edge->fUpperY <= y) {
        SkASSERT(edge->fPrev && edge->fNext);
        SkASSERT(edge->fPrev->fNext == edge);
        SkASSERT(edge->fNext->fPrev == edge);
        SkASSERT(edge->fUpperY <= edge->fLowerY);
        SkASSERT(edge->fPrev->fPrev == nullptr || edge->fPrev->fX <= edge->fX);
        edge = edge->fNext;
    }
#endif
}

validate_sort()

static void validate_sort ( const SkAnalyticEdge *  edge )

static

Definition at line 1027 of file SkScan_AAAPath.cpp.

                                                      {
#ifdef SK_DEBUG
    SkFixed y = SkIntToFixed(-32768);
 
    while (edge->fUpperY != SK_MaxS32) {
        edge->validate();
        SkASSERT(y <= edge->fUpperY);
 
        y    = edge->fUpperY;
        edge = (SkAnalyticEdge*)edge->fNext;
    }
#endif
}