amass/qt6windows7
1
0
Fork 0
mirror of https://github.com/crystalidea/qt6windows7.git synced 2024-11-29 23:45:50 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity
18a0664193
qt6windows7/src/gui/painting/qtriangulatingstroker.cpp
kleuter 85d238dfda qt 6.5.1 original
2023-10-29 23:33:08 +01:00

607 lines
20 KiB
C++
Raw Blame History

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qtriangulatingstroker_p.h"
#include <qmath.h>
QT_BEGIN_NAMESPACE
#define CURVE_FLATNESS Q_PI / 8
void QTriangulatingStroker::endCapOrJoinClosed(const qreal *start, const qreal *cur,
bool implicitClose, bool endsAtStart)
{
Q_ASSERT(start);
if (endsAtStart) {
join(start + 2);
} else if (implicitClose) {
join(start);
lineTo(start);
join(start+2);
} else {
endCap(cur);
}
int count = m_vertices.size();
// Copy the (x, y) values because QDataBuffer::add(const float& t)
// may resize the buffer, which will leave t pointing at the
// previous buffer's memory region if we don't copy first.
float x = m_vertices.at(count-2);
float y = m_vertices.at(count-1);
m_vertices.add(x);
m_vertices.add(y);
}
static inline void skipDuplicatePoints(const qreal **pts, const qreal *endPts)
{
while ((*pts + 2) < endPts && float((*pts)[0]) == float((*pts)[2])
&& float((*pts)[1]) == float((*pts)[3]))
{
*pts += 2;
}
}
void QTriangulatingStroker::process(const QVectorPath &path, const QPen &pen, const QRectF &, QPainter::RenderHints)
{
const qreal *pts = path.points();
const QPainterPath::ElementType *types = path.elements();
int count = path.elementCount();
m_vertices.reset();
if (count < 2)
return;
float realWidth = qpen_widthf(pen);
if (realWidth == 0)
realWidth = 1;
m_width = realWidth / 2;
bool cosmetic = pen.isCosmetic();
if (cosmetic) {
m_width = m_width * m_inv_scale;
}
m_join_style = qpen_joinStyle(pen);
m_cap_style = qpen_capStyle(pen);
m_miter_limit = pen.miterLimit() * qpen_widthf(pen);
// The curvyness is based on the notion that I originally wanted
// roughly one line segment pr 4 pixels. This may seem little, but
// because we sample at constantly incrementing B(t) E [0<t<1], we
// will get longer segments where the curvature is small and smaller
// segments when the curvature is high.
//
// To get a rough idea of the length of each curve, I pretend that
// the curve is a 90 degree arc, whose radius is
// qMax(curveBounds.width, curveBounds.height). Based on this
// logic we can estimate the length of the outline edges based on
// the radius + a pen width and adjusting for scale factors
// depending on if the pen is cosmetic or not.
//
// The curvyness value of PI/14 was based on,
// arcLength = 2*PI*r/4 = PI*r/2 and splitting length into somewhere
// between 3 and 8 where 5 seemed to be give pretty good results
// hence: Q_PI/14. Lower divisors will give more detail at the
// direct cost of performance.
// simplfy pens that are thin in device size (2px wide or less)
if (realWidth < 2.5 && (cosmetic || m_inv_scale == 1)) {
if (m_cap_style == Qt::RoundCap)
m_cap_style = Qt::SquareCap;
if (m_join_style == Qt::RoundJoin)
m_join_style = Qt::MiterJoin;
m_curvyness_add = 0.5;
m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;
m_roundness = 1;
} else if (cosmetic) {
m_curvyness_add = realWidth / 2;
m_curvyness_mul = float(CURVE_FLATNESS);
m_roundness = qMax<int>(4, realWidth * CURVE_FLATNESS);
} else {
m_curvyness_add = m_width;
m_curvyness_mul = CURVE_FLATNESS / m_inv_scale;
m_roundness = qMax<int>(4, realWidth * m_curvyness_mul);
}
// Over this level of segmentation, there doesn't seem to be any
// benefit, even for huge penWidth
if (m_roundness > 24)
m_roundness = 24;
m_sin_theta = qFastSin(Q_PI / m_roundness);
m_cos_theta = qFastCos(Q_PI / m_roundness);
const qreal *endPts = pts + (count<<1);
const qreal *startPts = nullptr;
Qt::PenCapStyle cap = m_cap_style;
if (!types) {
skipDuplicatePoints(&pts, endPts);
if ((pts + 2) == endPts)
return;
startPts = pts;
bool endsAtStart = float(startPts[0]) == float(endPts[-2])
&& float(startPts[1]) == float(endPts[-1]);
if (endsAtStart || path.hasImplicitClose())
m_cap_style = Qt::FlatCap;
moveTo(pts);
m_cap_style = cap;
pts += 2;
skipDuplicatePoints(&pts, endPts);
lineTo(pts);
pts += 2;
skipDuplicatePoints(&pts, endPts);
while (pts < endPts) {
join(pts);
lineTo(pts);
pts += 2;
skipDuplicatePoints(&pts, endPts);
}
endCapOrJoinClosed(startPts, pts-2, path.hasImplicitClose(), endsAtStart);
} else {
bool endsAtStart = false;
QPainterPath::ElementType previousType = QPainterPath::MoveToElement;
const qreal *previousPts = pts;
while (pts < endPts) {
switch (*types) {
case QPainterPath::MoveToElement: {
int end = (endPts - pts) / 2;
int nextMoveElement = 1;
bool hasValidLineSegments = false;
while (nextMoveElement < end && types[nextMoveElement] != QPainterPath::MoveToElement) {
if (!hasValidLineSegments) {
hasValidLineSegments =
float(pts[0]) != float(pts[nextMoveElement * 2]) ||
float(pts[1]) != float(pts[nextMoveElement * 2 + 1]);
}
++nextMoveElement;
}
/**
* 'LineToElement' may be skipped if it doesn't move the center point
* of the line. We should make sure that we don't end up with a lost
* 'MoveToElement' in the vertex buffer, not connected to anything. Since
* the buffer uses degenerate triangles trick to split the primitives,
* this spurious MoveToElement will create artifacts when rendering.
*/
if (!hasValidLineSegments) {
pts += 2 * nextMoveElement;
types += nextMoveElement;
continue;
}
if (previousType != QPainterPath::MoveToElement)
endCapOrJoinClosed(startPts, previousPts, path.hasImplicitClose(), endsAtStart);
startPts = pts;
skipDuplicatePoints(&startPts, endPts); // Skip duplicates to find correct normal.
if (startPts + 2 >= endPts)
return; // Nothing to see here...
endsAtStart = float(startPts[0]) == float(pts[nextMoveElement * 2 - 2])
&& float(startPts[1]) == float(pts[nextMoveElement * 2 - 1]);
if (endsAtStart || path.hasImplicitClose())
m_cap_style = Qt::FlatCap;
moveTo(startPts);
m_cap_style = cap;
previousType = QPainterPath::MoveToElement;
previousPts = pts;
pts+=2;
++types;
break; }
case QPainterPath::LineToElement:
if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])) {
if (previousType != QPainterPath::MoveToElement)
join(pts);
lineTo(pts);
previousType = QPainterPath::LineToElement;
previousPts = pts;
}
pts+=2;
++types;
break;
case QPainterPath::CurveToElement:
if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])
|| float(pts[0]) != float(pts[2]) || float(pts[1]) != float(pts[3])
|| float(pts[2]) != float(pts[4]) || float(pts[3]) != float(pts[5]))
{
if (float(m_cx) != float(pts[0]) || float(m_cy) != float(pts[1])) {
if (previousType != QPainterPath::MoveToElement)
join(pts);
}
cubicTo(pts);
previousType = QPainterPath::CurveToElement;
previousPts = pts + 4;
}
pts+=6;
types+=3;
break;
default:
Q_ASSERT(false);
break;
}
}
if (previousType != QPainterPath::MoveToElement)
endCapOrJoinClosed(startPts, previousPts, path.hasImplicitClose(), endsAtStart);
}
}
void QTriangulatingStroker::moveTo(const qreal *pts)
{
m_cx = pts[0];
m_cy = pts[1];
float x2 = pts[2];
float y2 = pts[3];
normalVector(m_cx, m_cy, x2, y2, &m_nvx, &m_nvy);
// To achieve jumps we insert zero-area tringles. This is done by
// adding two identical points in both the end of previous strip
// and beginning of next strip
bool invisibleJump = m_vertices.size();
switch (m_cap_style) {
case Qt::FlatCap:
if (invisibleJump) {
m_vertices.add(m_cx + m_nvx);
m_vertices.add(m_cy + m_nvy);
}
break;
case Qt::SquareCap: {
float sx = m_cx - m_nvy;
float sy = m_cy + m_nvx;
if (invisibleJump) {
m_vertices.add(sx + m_nvx);
m_vertices.add(sy + m_nvy);
}
emitLineSegment(sx, sy, m_nvx, m_nvy);
break; }
case Qt::RoundCap: {
QVarLengthArray<float> points;
arcPoints(m_cx, m_cy, m_cx + m_nvx, m_cy + m_nvy, m_cx - m_nvx, m_cy - m_nvy, points);
m_vertices.resize(m_vertices.size() + points.size() + 2 * int(invisibleJump));
int count = m_vertices.size();
int front = 0;
int end = points.size() / 2;
while (front != end) {
m_vertices.at(--count) = points[2 * end - 1];
m_vertices.at(--count) = points[2 * end - 2];
--end;
if (front == end)
break;
m_vertices.at(--count) = points[2 * front + 1];
m_vertices.at(--count) = points[2 * front + 0];
++front;
}
if (invisibleJump) {
m_vertices.at(count - 1) = m_vertices.at(count + 1);
m_vertices.at(count - 2) = m_vertices.at(count + 0);
}
break; }
default: break; // ssssh gcc...
}
emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
}
void QTriangulatingStroker::cubicTo(const qreal *pts)
{
const QPointF *p = (const QPointF *) pts;
QBezier bezier = QBezier::fromPoints(*(p - 1), p[0], p[1], p[2]);
QRectF bounds = bezier.bounds();
float rad = qMax(bounds.width(), bounds.height());
int threshold = qMin<float>(64, (rad + m_curvyness_add) * m_curvyness_mul);
if (threshold < 4)
threshold = 4;
qreal threshold_minus_1 = threshold - 1;
float vx = 0, vy = 0;
float cx = m_cx, cy = m_cy;
float x, y;
for (int i=1; i<threshold; ++i) {
qreal t = qreal(i) / threshold_minus_1;
QPointF p = bezier.pointAt(t);
x = p.x();
y = p.y();
normalVector(cx, cy, x, y, &vx, &vy);
emitLineSegment(x, y, vx, vy);
cx = x;
cy = y;
}
m_cx = cx;
m_cy = cy;
m_nvx = vx;
m_nvy = vy;
}
void QTriangulatingStroker::join(const qreal *pts)
{
// Creates a join to the next segment (m_cx, m_cy) -> (pts[0], pts[1])
normalVector(m_cx, m_cy, pts[0], pts[1], &m_nvx, &m_nvy);
switch (m_join_style) {
case Qt::BevelJoin:
break;
case Qt::SvgMiterJoin:
case Qt::MiterJoin: {
// Find out on which side the join should be.
int count = m_vertices.size();
float prevNvx = m_vertices.at(count - 2) - m_cx;
float prevNvy = m_vertices.at(count - 1) - m_cy;
float xprod = prevNvx * m_nvy - prevNvy * m_nvx;
float px, py, qx, qy;
// If the segments are parallel, use bevel join.
if (qFuzzyIsNull(xprod))
break;
// Find the corners of the previous and next segment to join.
if (xprod < 0) {
px = m_vertices.at(count - 2);
py = m_vertices.at(count - 1);
qx = m_cx - m_nvx;
qy = m_cy - m_nvy;
} else {
px = m_vertices.at(count - 4);
py = m_vertices.at(count - 3);
qx = m_cx + m_nvx;
qy = m_cy + m_nvy;
}
// Find intersection point.
float pu = px * prevNvx + py * prevNvy;
float qv = qx * m_nvx + qy * m_nvy;
float ix = (m_nvy * pu - prevNvy * qv) / xprod;
float iy = (prevNvx * qv - m_nvx * pu) / xprod;
// Check that the distance to the intersection point is less than the miter limit.
if ((ix - px) * (ix - px) + (iy - py) * (iy - py) <= m_miter_limit * m_miter_limit) {
m_vertices.add(ix);
m_vertices.add(iy);
m_vertices.add(ix);
m_vertices.add(iy);
}
// else
// Do a plain bevel join if the miter limit is exceeded or if
// the lines are parallel. This is not what the raster
// engine's stroker does, but it is both faster and similar to
// what some other graphics API's do.
break; }
case Qt::RoundJoin: {
QVarLengthArray<float> points;
int count = m_vertices.size();
float prevNvx = m_vertices.at(count - 2) - m_cx;
float prevNvy = m_vertices.at(count - 1) - m_cy;
if (m_nvx * prevNvy - m_nvy * prevNvx < 0) {
arcPoints(0, 0, m_nvx, m_nvy, -prevNvx, -prevNvy, points);
for (int i = points.size() / 2; i > 0; --i)
emitLineSegment(m_cx, m_cy, points[2 * i - 2], points[2 * i - 1]);
} else {
arcPoints(0, 0, -prevNvx, -prevNvy, m_nvx, m_nvy, points);
for (int i = 0; i < points.size() / 2; ++i)
emitLineSegment(m_cx, m_cy, points[2 * i + 0], points[2 * i + 1]);
}
break; }
default: break; // gcc warn--
}
emitLineSegment(m_cx, m_cy, m_nvx, m_nvy);
}
void QTriangulatingStroker::endCap(const qreal *)
{
switch (m_cap_style) {
case Qt::FlatCap:
break;
case Qt::SquareCap:
emitLineSegment(m_cx + m_nvy, m_cy - m_nvx, m_nvx, m_nvy);
break;
case Qt::RoundCap: {
QVarLengthArray<float> points;
int count = m_vertices.size();
arcPoints(m_cx, m_cy, m_vertices.at(count - 2), m_vertices.at(count - 1), m_vertices.at(count - 4), m_vertices.at(count - 3), points);
int front = 0;
int end = points.size() / 2;
while (front != end) {
m_vertices.add(points[2 * end - 2]);
m_vertices.add(points[2 * end - 1]);
--end;
if (front == end)
break;
m_vertices.add(points[2 * front + 0]);
m_vertices.add(points[2 * front + 1]);
++front;
}
break; }
default: break; // to shut gcc up...
}
}
void QTriangulatingStroker::arcPoints(float cx, float cy, float fromX, float fromY, float toX, float toY, QVarLengthArray<float> &points)
{
float dx1 = fromX - cx;
float dy1 = fromY - cy;
float dx2 = toX - cx;
float dy2 = toY - cy;
// while more than 180 degrees left:
while (dx1 * dy2 - dx2 * dy1 < 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.append(cx + dx1);
points.append(cy + dy1);
}
// while more than 90 degrees left:
while (dx1 * dx2 + dy1 * dy2 < 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.append(cx + dx1);
points.append(cy + dy1);
}
// while more than 0 degrees left:
while (dx1 * dy2 - dx2 * dy1 > 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.append(cx + dx1);
points.append(cy + dy1);
}
// remove last point which was rotated beyond [toX, toY].
if (!points.isEmpty())
points.resize(points.size() - 2);
}
static void qdashprocessor_moveTo(qreal x, qreal y, void *data)
{
((QDashedStrokeProcessor *) data)->addElement(QPainterPath::MoveToElement, x, y);
}
static void qdashprocessor_lineTo(qreal x, qreal y, void *data)
{
((QDashedStrokeProcessor *) data)->addElement(QPainterPath::LineToElement, x, y);
}
static void qdashprocessor_cubicTo(qreal, qreal, qreal, qreal, qreal, qreal, void *)
{
Q_ASSERT(0); // The dasher should not produce curves...
}
QDashedStrokeProcessor::QDashedStrokeProcessor()
: m_points(0), m_types(0),
m_dash_stroker(nullptr), m_inv_scale(1)
{
m_dash_stroker.setMoveToHook(qdashprocessor_moveTo);
m_dash_stroker.setLineToHook(qdashprocessor_lineTo);
m_dash_stroker.setCubicToHook(qdashprocessor_cubicTo);
}
void QDashedStrokeProcessor::process(const QVectorPath &path, const QPen &pen, const QRectF &clip, QPainter::RenderHints)
{
const qreal *pts = path.points();
const QPainterPath::ElementType *types = path.elements();
int count = path.elementCount();
bool cosmetic = pen.isCosmetic();
bool implicitClose = path.hasImplicitClose();
m_points.reset();
m_types.reset();
m_points.reserve(path.elementCount());
m_types.reserve(path.elementCount());
qreal width = qpen_widthf(pen);
if (width == 0)
width = 1;
m_dash_stroker.setDashPattern(pen.dashPattern());
m_dash_stroker.setStrokeWidth(cosmetic ? width * m_inv_scale : width);
m_dash_stroker.setDashOffset(pen.dashOffset());
m_dash_stroker.setMiterLimit(pen.miterLimit());
m_dash_stroker.setClipRect(clip);
float curvynessAdd, curvynessMul;
// simplify pens that are thin in device size (2px wide or less)
if (width < 2.5 && (cosmetic || m_inv_scale == 1)) {
curvynessAdd = 0.5;
curvynessMul = CURVE_FLATNESS / m_inv_scale;
} else if (cosmetic) {
curvynessAdd= width / 2;
curvynessMul= float(CURVE_FLATNESS);
} else {
curvynessAdd = width * m_inv_scale;
curvynessMul = CURVE_FLATNESS / m_inv_scale;
}
if (count < 2)
return;
bool needsClose = false;
if (implicitClose) {
if (pts[0] != pts[count * 2 - 2] || pts[1] != pts[count * 2 - 1])
needsClose = true;
}
const qreal *firstPts = pts;
const qreal *endPts = pts + (count<<1);
m_dash_stroker.begin(this);
if (!types) {
m_dash_stroker.moveTo(pts[0], pts[1]);
pts += 2;
while (pts < endPts) {
m_dash_stroker.lineTo(pts[0], pts[1]);
pts += 2;
}
} else {
while (pts < endPts) {
switch (*types) {
case QPainterPath::MoveToElement:
m_dash_stroker.moveTo(pts[0], pts[1]);
pts += 2;
++types;
break;
case QPainterPath::LineToElement:
m_dash_stroker.lineTo(pts[0], pts[1]);
pts += 2;
++types;
break;
case QPainterPath::CurveToElement: {
QBezier b = QBezier::fromPoints(*(((const QPointF *) pts) - 1),
*(((const QPointF *) pts)),
*(((const QPointF *) pts) + 1),
*(((const QPointF *) pts) + 2));
QRectF bounds = b.bounds();
float rad = qMax(bounds.width(), bounds.height());
int threshold = qMin<float>(64, (rad + curvynessAdd) * curvynessMul);
if (threshold < 4)
threshold = 4;
qreal threshold_minus_1 = threshold - 1;
for (int i=0; i<threshold; ++i) {
QPointF pt = b.pointAt(i / threshold_minus_1);
m_dash_stroker.lineTo(pt.x(), pt.y());
}
pts += 6;
types += 3;
break; }
default: break;
}
}
}
if (needsClose)
m_dash_stroker.lineTo(firstPts[0], firstPts[1]);
m_dash_stroker.end();
}
QT_END_NAMESPACE
Reference in New Issue View Git Blame Copy Permalink