From 1f806aa1b40db276dad359863d018171080d93f9 Mon Sep 17 00:00:00 2001 From: Lars Knoll Date: Thu, 14 Apr 2011 21:38:45 +0200 Subject: New algorithm for drawing thin lines Added a new QCosmeticStroker class for drawing thin lines. The class can handle both aliased and antialiased lines. The code replaces all the midpoint line drawing algorithms in the raster paintengine and gives correct subpixel positioning for lines. It gives around 30% to 50% speedup against the midpoint algorithm. If we missed that fast path, the speedup is around between a factor of 6 to 8 for lines and aliased paths and 100 and 400 for antialiased paths. Reviewed-by: Kim (cherry picked from commit 37c329a3e35fabc88fbcad824a69f37c671d2132) --- src/gui/painting/qcosmeticstroker.cpp | 954 ++++++++++++++++++++++++++++++++++ 1 file changed, 954 insertions(+) create mode 100644 src/gui/painting/qcosmeticstroker.cpp (limited to 'src/gui/painting/qcosmeticstroker.cpp') diff --git a/src/gui/painting/qcosmeticstroker.cpp b/src/gui/painting/qcosmeticstroker.cpp new file mode 100644 index 0000000000..498b1546e2 --- /dev/null +++ b/src/gui/painting/qcosmeticstroker.cpp @@ -0,0 +1,954 @@ +#include "qcosmeticstroker_p.h" +#include "private/qpainterpath_p.h" +#include +#include + +#if 0 +inline QString capString(int caps) +{ + QString str; + if (caps & QCosmeticStroker::CapBegin) { + str += "CapBegin "; + } + if (caps & QCosmeticStroker::CapEnd) { + str += "CapEnd "; + } + return str; +} +#endif + +#define toF26Dot6(x) ((int)((x)*64.)) + +static inline uint sourceOver(uint d, uint color) +{ + return color + BYTE_MUL(d, qAlpha(~color)); +} + +inline static int F16Dot16FixedDiv(int x, int y) +{ + if (qAbs(x) > 0x7fff) + return (((qlonglong)x) << 16) / y; + return (x << 16) / y; +} + +typedef void (*DrawPixel)(QCosmeticStroker *stroker, int x, int y, int coverage); + +namespace { + +struct Dasher { + QCosmeticStroker *stroker; + int *pattern; + int offset; + int dashIndex; + int dashOn; + + Dasher(QCosmeticStroker *s, bool reverse, int start, int stop) + : stroker(s) + { + int delta = stop - start; + if (reverse) { + pattern = stroker->reversePattern; + offset = stroker->patternLength - stroker->patternOffset - delta - ((start & 63) - 32); + dashOn = 0; + } else { + pattern = stroker->pattern; + offset = stroker->patternOffset - ((start & 63) - 32); + dashOn = 1; + } + offset %= stroker->patternLength; + if (offset < 0) + offset += stroker->patternLength; + + dashIndex = 0; + while (offset>= pattern[dashIndex]) + ++dashIndex; + +// qDebug() << " dasher" << offset/64. << reverse << dashIndex; + stroker->patternOffset += delta; + stroker->patternOffset %= stroker->patternLength; + } + + bool on() const { + return (dashIndex + dashOn) & 1; + } + void adjust() { + offset += 64; + if (offset >= pattern[dashIndex]) { + ++dashIndex; + dashIndex %= stroker->patternSize; + } + offset %= stroker->patternLength; +// qDebug() << "dasher.adjust" << offset/64. << dashIndex; + } +}; + +struct NoDasher { + NoDasher(QCosmeticStroker *, bool, int, int) {} + bool on() const { return true; } + void adjust(int = 0) {} +}; + +}; + +template +static void drawLine(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); +template +static void drawLineAA(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); + +inline void drawPixel(QCosmeticStroker *stroker, int x, int y, int coverage) +{ + int lastx = stroker->spans[stroker->current_span-1].x + stroker->spans[stroker->current_span-1].len ; + int lasty = stroker->spans[stroker->current_span-1].y; + + if (stroker->current_span == QCosmeticStroker::NSPANS || y < lasty || (y == lasty && x < lastx)) { + stroker->blend(stroker->current_span, stroker->spans, &stroker->state->penData); + stroker->current_span = 0; + } + + stroker->spans[stroker->current_span].x = ushort(x); + stroker->spans[stroker->current_span].len = 1; + stroker->spans[stroker->current_span].y = y; + stroker->spans[stroker->current_span].coverage = coverage*stroker->opacity >> 8; + ++stroker->current_span; +} + +inline void drawPixelARGB32(QCosmeticStroker *stroker, int x, int y, int coverage) +{ + const QRect &cl = stroker->clip; + if (x < cl.x() || x > cl.right() || y < cl.y() || y > cl.bottom()) + return; + + int offset = x + stroker->ppl*y; + uint c = BYTE_MUL(stroker->color, coverage); + stroker->pixels[offset] = sourceOver(stroker->pixels[offset], c); +} + +inline void drawPixelARGB32Opaque(QCosmeticStroker *stroker, int x, int y, int) +{ + const QRect &cl = stroker->clip; + if (x < cl.x() || x > cl.right() || y < cl.y() || y > cl.bottom()) + return; + + int offset = x + stroker->ppl*y; + stroker->pixels[offset] = sourceOver(stroker->pixels[offset], stroker->color); +} + +enum StrokeSelection { + Aliased = 0, + AntiAliased = 1, + Solid = 0, + Dashed = 2, + RegularDraw = 0, + FastDraw = 4 +}; + +static StrokeLine strokeLine(int strokeSelection) +{ + StrokeLine stroke; + + switch (strokeSelection) { + case Aliased|Solid|RegularDraw: + stroke = &::drawLine; + break; + case Aliased|Solid|FastDraw: + stroke = &::drawLine; + break; + case Aliased|Dashed|RegularDraw: + stroke = &::drawLine; + break; + case Aliased|Dashed|FastDraw: + stroke = &::drawLine; + break; + case AntiAliased|Solid|RegularDraw: + stroke = &drawLineAA; + break; + case AntiAliased|Solid|FastDraw: + stroke = &drawLineAA; + break; + case AntiAliased|Dashed|RegularDraw: + stroke = &drawLineAA; + break; + case AntiAliased|Dashed|FastDraw: + stroke = &drawLineAA; + break; + default: + Q_ASSERT(false); + stroke = 0; + } + return stroke; +} + +void QCosmeticStroker::setup() +{ + blend = state->penData.blend; + if (state->clip && state->clip->enabled && state->clip->hasRectClip && !state->clip->clipRect.isEmpty()) { + clip &= state->clip->clipRect; + blend = state->penData.unclipped_blend; + } + + int strokeSelection = 0; + if (blend == state->penData.unclipped_blend + && state->penData.type == QSpanData::Solid + && (state->penData.rasterBuffer->format == QImage::Format_ARGB32_Premultiplied + || state->penData.rasterBuffer->format == QImage::Format_RGB32) + && state->compositionMode() == QPainter::CompositionMode_SourceOver) + strokeSelection |= FastDraw; + + if (state->renderHints & QPainter::Antialiasing) + strokeSelection |= AntiAliased; + + const QVector &penPattern = state->lastPen.dashPattern(); + if (penPattern.isEmpty()) { + Q_ASSERT(!pattern && !reversePattern); + pattern = 0; + reversePattern = 0; + patternLength = 0; + patternSize = 0; + } else { + pattern = (int *)malloc(penPattern.size()*sizeof(int)); + reversePattern = (int *)malloc(penPattern.size()*sizeof(int)); + patternSize = penPattern.size(); + + patternLength = 0; + for (int i = 0; i < patternSize; ++i) { + patternLength += (int) qMax(1. , penPattern.at(i)*64.); + pattern[i] = patternLength; + } + patternLength = 0; + for (int i = 0; i < patternSize; ++i) { + patternLength += (int) qMax(1., penPattern.at(patternSize - 1 - i)*64.); + reversePattern[i] = patternLength; + } + strokeSelection |= Dashed; +// qDebug() << "setup: size=" << patternSize << "length=" << patternLength/64.; + } + + stroke = strokeLine(strokeSelection); + + qreal width = state->lastPen.widthF(); + if (width == 0) + opacity = 256; + else if (state->lastPen.isCosmetic()) + opacity = (int) 256*width; + else + opacity = (int) 256*width*state->txscale; + opacity = qBound(0, opacity, 256); + + drawCaps = state->lastPen.capStyle() != Qt::FlatCap; + + if (strokeSelection & FastDraw) { + color = INTERPOLATE_PIXEL_256(state->penData.solid.color, opacity, 0, 0); + QRasterBuffer *buffer = state->penData.rasterBuffer; + pixels = (uint *)buffer->buffer(); + ppl = buffer->bytesPerLine()>>2; + } + + // setup FP clip bounds + xmin = clip.left() - 1; + xmax = clip.right() + 2; + ymin = clip.top() - 1; + ymax = clip.bottom() + 2; + + lastPixel.x = -1; +} + +// returns true if the whole line gets clipped away +bool QCosmeticStroker::clipLine(qreal &x1, qreal &y1, qreal &x2, qreal &y2) +{ + // basic/rough clipping is done in floating point coordinates to avoid + // integer overflow problems. + if (x1 < xmin) { + if (x2 <= xmin) + goto clipped; + y1 += (y2 - y1)/(x2 - x1) * (xmin - x1); + x1 = xmin; + } else if (x1 > xmax) { + if (x2 >= xmax) + goto clipped; + y1 += (y2 - y1)/(x2 - x1) * (xmax - x1); + x1 = xmax; + } + if (x2 < xmin) { + lastPixel.x = -1; + y2 += (y2 - y1)/(x2 - x1) * (xmin - x2); + x2 = xmin; + } else if (x2 > xmax) { + lastPixel.x = -1; + y2 += (y2 - y1)/(x2 - x1) * (xmax - x2); + x2 = xmax; + } + + if (y1 < ymin) { + if (y2 <= ymin) + goto clipped; + x1 += (x2 - x1)/(y2 - y1) * (ymin - y1); + y1 = ymin; + } else if (y1 > ymax) { + if (y2 >= ymax) + goto clipped; + x1 += (x2 - x1)/(y2 - y1) * (ymax - y1); + y1 = ymax; + } + if (y2 < ymin) { + lastPixel.x = -1; + x2 += (x2 - x1)/(y2 - y1) * (ymin - y2); + y2 = ymin; + } else if (y2 > ymax) { + lastPixel.x = -1; + x2 += (x2 - x1)/(y2 - y1) * (ymax - y2); + y2 = ymax; + } + + return false; + + clipped: + lastPixel.x = -1; + return true; +} + + +void QCosmeticStroker::drawLine(const QPointF &p1, const QPointF &p2) +{ + QPointF start = p1 * state->matrix; + QPointF end = p2 * state->matrix; + + patternOffset = state->lastPen.dashOffset()*64; + lastPixel.x = -1; + + stroke(this, start.x(), start.y(), end.x(), end.y(), drawCaps ? CapBegin|CapEnd : 0); + + blend(current_span, spans, &state->penData); + current_span = 0; +} + +void QCosmeticStroker::drawPoints(const QPoint *points, int num) +{ + const QPoint *end = points + num; + while (points < end) { + QPointF p = QPointF(*points) * state->matrix; + drawPixel(this, qRound(p.x()), qRound(p.y()), 255); + ++points; + } + + blend(current_span, spans, &state->penData); + current_span = 0; +} + +void QCosmeticStroker::drawPoints(const QPointF *points, int num) +{ + const QPointF *end = points + num; + while (points < end) { + QPointF p = (*points) * state->matrix; + drawPixel(this, qRound(p.x()), qRound(p.y()), 255); + ++points; + } + + blend(current_span, spans, &state->penData); + current_span = 0; +} + +void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal ry2) +{ + // this is basically the same code as used in the aliased stroke method, + // but it only determines the direction and last point of a line + // + // This is being used to have proper dropout control for closed contours + // by calculating the direction and last pixel of the last segment in the contour. + // the info is then used to perform dropout control when drawing the first line segment + // of the contour + lastPixel.x = -1; + lastPixel.y = -1; + + if (clipLine(rx1, ry1, rx2, ry2)) + return; + + int x1 = toF26Dot6(rx1); + int y1 = toF26Dot6(ry1); + int x2 = toF26Dot6(rx2); + int y2 = toF26Dot6(ry2); + + int dx = qAbs(x2 - x1); + int dy = qAbs(y2 - y1); + + if (dx < dy) { + // vertical + bool swapped = false; + if (y1 > y2) { + swapped = true; + qSwap(y1, y2); + qSwap(x1, x2); + } + int xinc = F16Dot16FixedDiv(x2 - x1, y2 - y1); + int x = x1 << 10; + + int y = (y1+32) >> 6; + int ys = (y2+32) >> 6; + + if (y != ys) { + x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; + + if (swapped) { + lastPixel.x = x >> 16; + lastPixel.y = y; + lastDir = QCosmeticStroker::BottomToTop; + } else { + lastPixel.x = (x + (ys - y - 1)*xinc) >> 16; + lastPixel.y = ys - 1; + lastDir = QCosmeticStroker::TopToBottom; + } + lastAxisAligned = qAbs(xinc) < (1 << 14); + } + } else { + // horizontal + if (!dx) + return; + + bool swapped = false; + if (x1 > x2) { + swapped = true; + qSwap(x1, x2); + qSwap(y1, y2); + } + int yinc = F16Dot16FixedDiv(y2 - y1, x2 - x1); + int y = y1 << 10; + + int x = (x1+32) >> 6; + int xs = (x2+32) >> 6; + + if (x != xs) { + y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; + + if (swapped) { + lastPixel.x = x; + lastPixel.y = y >> 16; + lastDir = QCosmeticStroker::RightToLeft; + } else { + lastPixel.x = xs - 1; + lastPixel.y = (y + (xs - x - 1)*yinc) >> 16; + lastDir = QCosmeticStroker::LeftToRight; + } + lastAxisAligned = qAbs(yinc) < (1 << 14); + } + } +// qDebug() << " moveTo: setting last pixel to x/y dir" << lastPixel.x << lastPixel.y << lastDir; +} + +static inline const QPainterPath::ElementType *subPath(const QPainterPath::ElementType *t, const QPainterPath::ElementType *end, + const qreal *points, bool *closed) +{ + const QPainterPath::ElementType *start = t; + ++t; + + // find out if the subpath is closed + while (t < end) { + if (*t == QPainterPath::MoveToElement) + break; + ++t; + } + + int offset = t - start - 1; +// qDebug() << "subpath" << offset << points[0] << points[1] << points[2*offset] << points[2*offset+1]; + *closed = (points[0] == points[2*offset] && points[1] == points[2*offset + 1]); + + return t; +} + +void QCosmeticStroker::drawPath(const QVectorPath &path) +{ +// qDebug() << ">>>> drawpath" << path.convertToPainterPath() +// << "antialiasing:" << (bool)(state->renderHints & QPainter::Antialiasing) << " implicit close:" << path.hasImplicitClose(); + if (path.isEmpty()) + return; + + const qreal *points = path.points(); + const QPainterPath::ElementType *type = path.elements(); + + if (type) { + const QPainterPath::ElementType *end = type + path.elementCount(); + + while (type < end) { + Q_ASSERT(type == path.elements() || *type == QPainterPath::MoveToElement); + + QPointF p = QPointF(points[0], points[1]) * state->matrix; + QPointF movedTo = p; + patternOffset = state->lastPen.dashOffset()*64; + lastPixel.x = -1; + + bool closed; + const QPainterPath::ElementType *e = subPath(type, end, points, &closed); + if (closed) { + const qreal *p = points + 2*(e-type); + calculateLastPoint(p[-4], p[-3], p[-2], p[-1]); + } + int caps = (!closed & drawCaps) ? CapBegin : NoCaps; +// qDebug() << "closed =" << closed << capString(caps); + + points += 2; + ++type; + + while (type < e) { + QPointF p2 = QPointF(points[0], points[1]) * state->matrix; + switch (*type) { + case QPainterPath::MoveToElement: + Q_ASSERT(!"Logic error"); + break; + + case QPainterPath::LineToElement: + if (!closed && drawCaps && type == e - 1) + caps |= CapEnd; + stroke(this, p.x(), p.y(), p2.x(), p2.y(), caps); + p = p2; + points += 2; + ++type; + break; + + case QPainterPath::CurveToElement: { + if (!closed && drawCaps && type == e - 3) + caps |= CapEnd; + QPointF p3 = QPointF(points[2], points[3]) * state->matrix; + QPointF p4 = QPointF(points[4], points[5]) * state->matrix; + renderCubic(p, p2, p3, p4, caps); + p = p4; + type += 3; + points += 6; + break; + } + case QPainterPath::CurveToDataElement: + Q_ASSERT(!"QPainterPath::toSubpathPolygons(), bad element type"); + break; + } + caps = NoCaps; + } + } + } else { // !type, simple polygon + QPointF p = QPointF(points[0], points[1]) * state->matrix; + QPointF movedTo = p; + patternOffset = state->lastPen.dashOffset()*64; + lastPixel.x = -1; + + const qreal *end = points + 2*path.elementCount(); + // handle closed path case + bool closed = path.hasImplicitClose() || (points[0] == end[-2] && points[1] == end[-1]); + int caps = (!closed & drawCaps) ? CapBegin : NoCaps; + if (closed) + calculateLastPoint(end[-2], end[-1], points[0], points[1]); + + points += 2; + while (points < end) { + QPointF p2 = QPointF(points[0], points[1]) * state->matrix; + + if (!closed && drawCaps && points == end - 2) + caps |= CapEnd; + + stroke(this, p.x(), p.y(), p2.x(), p2.y(), caps); + + p = p2; + points += 2; + caps = NoCaps; + } + if (path.hasImplicitClose()) + stroke(this, p.x(), p.y(), movedTo.x(), movedTo.y(), NoCaps); + } + + + blend(current_span, spans, &state->penData); + current_span = 0; +} + +void QCosmeticStroker::renderCubic(const QPointF &p1, const QPointF &p2, const QPointF &p3, const QPointF &p4, int caps) +{ +// qDebug() << ">>>> renderCubic" << p1 << p2 << p3 << p4 << capString(caps); + const int maxSubDivisions = 6; + PointF points[3*maxSubDivisions + 4]; + + points[3].x = p1.x(); + points[3].y = p1.y(); + points[2].x = p2.x(); + points[2].y = p2.y(); + points[1].x = p3.x(); + points[1].y = p3.y(); + points[0].x = p4.x(); + points[0].y = p4.y(); + + PointF *p = points; + int level = maxSubDivisions; + + renderCubicSubdivision(p, level, caps); +} + +static void splitCubic(QCosmeticStroker::PointF *points) +{ + const qreal half = .5; + qreal a, b, c, d; + + points[6].x = points[3].x; + c = points[1].x; + d = points[2].x; + points[1].x = a = ( points[0].x + c ) * half; + points[5].x = b = ( points[3].x + d ) * half; + c = ( c + d ) * half; + points[2].x = a = ( a + c ) * half; + points[4].x = b = ( b + c ) * half; + points[3].x = ( a + b ) * half; + + points[6].y = points[3].y; + c = points[1].y; + d = points[2].y; + points[1].y = a = ( points[0].y + c ) * half; + points[5].y = b = ( points[3].y + d ) * half; + c = ( c + d ) * half; + points[2].y = a = ( a + c ) * half; + points[4].y = b = ( b + c ) * half; + points[3].y = ( a + b ) * half; +} + +void QCosmeticStroker::renderCubicSubdivision(QCosmeticStroker::PointF *points, int level, int caps) +{ + if (level) { + qreal dx = points[3].x - points[0].x; + qreal dy = points[3].y - points[0].y; + qreal len = ((qreal).25) * (qAbs(dx) + qAbs(dy)); + + if (qAbs(dx * (points[0].y - points[2].y) - dy * (points[0].x - points[2].x)) > len || + qAbs(dx * (points[0].y - points[1].y) - dy * (points[0].x - points[1].x)) > len) { + splitCubic(points); + + --level; + renderCubicSubdivision(points + 3, level, caps & CapBegin); + renderCubicSubdivision(points, level, caps & CapEnd); + return; + } + } + + stroke(this, points[3].x, points[3].y, points[0].x, points[0].y, caps); +} + +static inline int swapCaps(int caps) +{ + return ((caps & QCosmeticStroker::CapBegin) << 1) | + ((caps & QCosmeticStroker::CapEnd) >> 1); +} + +// adjust line by half a pixel +static inline void capAdjust(int caps, int &x1, int &x2, int &y, int yinc) +{ + if (caps & QCosmeticStroker::CapBegin) { + x1 -= 32; + y -= yinc >> 1; + } + if (caps & QCosmeticStroker::CapEnd) { + x2 += 32; + } +} + +/* + The hard part about this is dropout control and avoiding douple drawing of points when + the drawing shifts from horizontal to vertical or back. + */ +template +static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) +{ + if (stroker->clipLine(rx1, ry1, rx2, ry2)) + return; + + static const int half = 32; + int x1 = toF26Dot6(rx1) + half; + int y1 = toF26Dot6(ry1) + half; + int x2 = toF26Dot6(rx2) + half; + int y2 = toF26Dot6(ry2) + half; + + int dx = qAbs(x2 - x1); + int dy = qAbs(y2 - y1); + + QCosmeticStroker::Point last = stroker->lastPixel; + +// qDebug() << "stroke" << x1/64. << y1/64. << x2/64. << y2/64. << capString(caps); + + if (dx < dy) { + // vertical + + bool swapped = false; + if (y1 > y2) { + swapped = true; + qSwap(y1, y2); + qSwap(x1, x2); + caps = swapCaps(caps); + --x1; --x2; --y1; --y2; + } + int xinc = F16Dot16FixedDiv(x2 - x1, y2 - y1); + int x = x1 << 10; + + capAdjust(caps, y1, y2, x, xinc); + + int y = (y1+32) >> 6; + int ys = (y2+32) >> 6; + + if (y != ys) { + x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; + + // calculate first and last pixel and perform dropout control + QCosmeticStroker::Direction dir = QCosmeticStroker::TopToBottom; + QCosmeticStroker::Point first; + first.x = x >> 16; + first.y = y; + last.x = (x + (ys - y - 1)*xinc) >> 16; + last.y = ys - 1; + if (swapped) { + qSwap(first, last); + dir = QCosmeticStroker::BottomToTop; + } + bool axisAligned = qAbs(xinc) < (1 << 14); + if (stroker->lastPixel.x >= 0) { + if (first.x == stroker->lastPixel.x && + first.y == stroker->lastPixel.y) { + // remove duplicated pixel + if (swapped) { + --ys; + } else { + ++y; + x += xinc; + } + } else if (stroker->lastDir != dir && + (((axisAligned && stroker->lastAxisAligned) && + stroker->lastPixel.x != first.x && stroker->lastPixel.y != first.y) || + (qAbs(stroker->lastPixel.x - first.x) > 1 && + qAbs(stroker->lastPixel.y - first.y) > 1))) { + // have a missing pixel, insert it + if (swapped) { + ++ys; + } else { + --y; + x -= xinc; + } + } + } + stroker->lastDir = dir; + stroker->lastAxisAligned = axisAligned; + + Dasher dasher(stroker, swapped, y << 6, ys << 6); + + do { + if (dasher.on()) + drawPixel(stroker, x >> 16, y, 255); + dasher.adjust(); + x += xinc; + } while (++y < ys); + } + } else { + // horizontal + if (!dx) + return; + + bool swapped = false; + if (x1 > x2) { + swapped = true; + qSwap(x1, x2); + qSwap(y1, y2); + caps = swapCaps(caps); + --x1; --x2; --y1; --y2; + } + int yinc = F16Dot16FixedDiv(y2 - y1, x2 - x1); + int y = y1 << 10; + + capAdjust(caps, x1, x2, y, yinc); + + int x = (x1+32) >> 6; + int xs = (x2+32) >> 6; + + + if (x != xs) { + y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; + + // calculate first and last pixel to perform dropout control + QCosmeticStroker::Direction dir = QCosmeticStroker::LeftToRight; + QCosmeticStroker::Point first; + first.x = x; + first.y = y >> 16; + last.x = xs - 1; + last.y = (y + (xs - x - 1)*yinc) >> 16; + if (swapped) { + qSwap(first, last); + dir = QCosmeticStroker::RightToLeft; + } + bool axisAligned = qAbs(yinc) < (1 << 14); + if (stroker->lastPixel.x >= 0) { + if (first.x == stroker->lastPixel.x && first.y == stroker->lastPixel.y) { + // remove duplicated pixel + if (swapped) { + --xs; + } else { + ++x; + y += yinc; + } + } else if (stroker->lastDir != dir && + (((axisAligned && stroker->lastAxisAligned) && + stroker->lastPixel.x != first.x && stroker->lastPixel.y != first.y) || + (qAbs(stroker->lastPixel.x - first.x) > 1 && + qAbs(stroker->lastPixel.y - first.y) > 1))) { + // have a missing pixel, insert it + if (swapped) { + ++xs; + } else { + --x; + y -= yinc; + } + } + } + stroker->lastDir = dir; + stroker->lastAxisAligned = axisAligned; + + Dasher dasher(stroker, swapped, x << 6, xs << 6); + + do { + if (dasher.on()) + drawPixel(stroker, x, y >> 16, 255); + dasher.adjust(); + y += yinc; + } while (++x < xs); + } + } + stroker->lastPixel = last; +} + + +template +static void drawLineAA(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) +{ + if (stroker->clipLine(rx1, ry1, rx2, ry2)) + return; + + int x1 = toF26Dot6(rx1); + int y1 = toF26Dot6(ry1); + int x2 = toF26Dot6(rx2); + int y2 = toF26Dot6(ry2); + + int dx = x2 - x1; + int dy = y2 - y1; + + if (qAbs(dx) < qAbs(dy)) { + // vertical + + int xinc = F16Dot16FixedDiv(dx, dy); + + bool swapped = false; + if (y1 > y2) { + qSwap(y1, y2); + qSwap(x1, x2); + swapped = true; + caps = swapCaps(caps); + } + + int x = (x1 - 32) << 10; + x -= ( ((y1 & 63) - 32) * xinc ) >> 6; + + capAdjust(caps, y1, y2, x, xinc); + + Dasher dasher(stroker, swapped, y1, y2); + + int y = y1 >> 6; + int ys = y2 >> 6; + + int alphaStart, alphaEnd; + if (y == ys) { + alphaStart = y2 - y1; + Q_ASSERT(alphaStart >= 0 && alphaStart < 64); + alphaEnd = 0; + } else { + alphaStart = 64 - (y1 & 63); + alphaEnd = (y2 & 63); + } +// qDebug() << "vertical" << x1/64. << y1/64. << x2/64. << y2/64.; +// qDebug() << " x=" << x << "dx=" << dx << "xi=" << (x>>16) << "xsi=" << ((x+(ys-y)*dx)>>16) << "y=" << y << "ys=" << ys; + + // draw first pixel + if (dasher.on()) { + uint alpha = (quint8)(x >> 8); + drawPixel(stroker, x>>16, y, (255-alpha) * alphaStart >> 6); + drawPixel(stroker, (x>>16) + 1, y, alpha * alphaStart >> 6); + } + dasher.adjust(); + x += xinc; + ++y; + if (y < ys) { + do { + if (dasher.on()) { + uint alpha = (quint8)(x >> 8); + drawPixel(stroker, x>>16, y, (255-alpha)); + drawPixel(stroker, (x>>16) + 1, y, alpha); + } + dasher.adjust(); + x += xinc; + } while (++y < ys); + } + // draw last pixel + if (alphaEnd && dasher.on()) { + uint alpha = (quint8)(x >> 8); + drawPixel(stroker, x>>16, y, (255-alpha) * alphaEnd >> 6); + drawPixel(stroker, (x>>16) + 1, y, alpha * alphaEnd >> 6); + } + } else { + // horizontal + if (!dx) + return; + + int yinc = F16Dot16FixedDiv(dy, dx); + + bool swapped = false; + if (x1 > x2) { + qSwap(x1, x2); + qSwap(y1, y2); + swapped = true; + caps = swapCaps(caps); + } + + int y = (y1 - 32) << 10; + y -= ( ((x1 & 63) - 32) * yinc ) >> 6; + + capAdjust(caps, x1, x2, y, yinc); + + Dasher dasher(stroker, swapped, x1, x2); + + int x = x1 >> 6; + int xs = x2 >> 6; + +// qDebug() << "horizontal" << x1/64. << y1/64. << x2/64. << y2/64.; +// qDebug() << " y=" << y << "dy=" << dy << "x=" << x << "xs=" << xs << "yi=" << (y>>16) << "ysi=" << ((y+(xs-x)*dy)>>16); + int alphaStart, alphaEnd; + if (x == xs) { + alphaStart = x2 - x1; + Q_ASSERT(alphaStart >= 0 && alphaStart < 64); + alphaEnd = 0; + } else { + alphaStart = 64 - (x1 & 63); + alphaEnd = (x2 & 63); + } + + // draw first pixel + if (dasher.on()) { + uint alpha = (quint8)(y >> 8); + drawPixel(stroker, x, y>>16, (255-alpha) * alphaStart >> 6); + drawPixel(stroker, x, (y>>16) + 1, alpha * alphaStart >> 6); + } + dasher.adjust(); + y += yinc; + ++x; + // draw line + if (x < xs) { + do { + if (dasher.on()) { + uint alpha = (quint8)(y >> 8); + drawPixel(stroker, x, y>>16, (255-alpha)); + drawPixel(stroker, x, (y>>16) + 1, alpha); + } + dasher.adjust(); + y += yinc; + } while (++x < xs); + } + // draw last pixel + if (alphaEnd && dasher.on()) { + uint alpha = (quint8)(y >> 8); + drawPixel(stroker, x, y>>16, (255-alpha) * alphaEnd >> 6); + drawPixel(stroker, x, (y>>16) + 1, alpha * alphaEnd >> 6); + } + } +} -- cgit v1.2.3