新增平滑曲线demo
feiyangqingyun
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1a00016148
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982ee44840
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@ -35,6 +35,7 @@ SUBDIRS += screenwidget #屏幕截图控件
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SUBDIRS += imageswitch #图片开关控件
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SUBDIRS += netserver #网络中转服务器
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SUBDIRS += base64 #图片文字base64互换
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SUBDIRS += smoothcurve #平滑曲线
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win32 {
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SUBDIRS += ffmpegdemo #视频流播放ffmpeg内核
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@ -47,6 +47,7 @@
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| 40 | mpvdemo | 视频流播放mpv内核 |
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| 41 | miniblink | miniblink示例 |
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| 42 | base64 | 图片文字base64互换 |
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| 43 | smoothcurve | 平滑曲线 |
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### 二、学习群
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1. **Qt交流大会群 853086607(雨田哥)**
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@ -97,3 +98,4 @@
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@ -0,0 +1,68 @@
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#include "frmsmoothcurve.h"
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#include "ui_frmsmoothcurve.h"
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#include "smoothcurve.h"
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#include "qpainter.h"
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#include "qdatetime.h"
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#include "qdebug.h"
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frmSmoothCurve::frmSmoothCurve(QWidget *parent) : QWidget(parent), ui(new Ui::frmSmoothCurve)
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{
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ui->setupUi(this);
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//初始化随机数种子
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qsrand(QDateTime::currentDateTime().toMSecsSinceEpoch());
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//随机生成曲线上的点
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int x = -300;
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while (x < 300) {
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datas << QPointF(x, qrand() % 300 - 100);
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x += qMin(qrand() % 30 + 5, 300);
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}
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//根据曲线上的点创建平滑曲线
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smoothCurve = SmoothCurve::createSmoothCurve(datas);
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// 直接连接点的创建非平滑曲线曲线
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smoothCurve2.moveTo(datas[0]);
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for (int i = 1; i < datas.size(); ++i) {
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smoothCurve2.lineTo(datas[i]);
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}
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connect(ui->showKnotsCheckBox, SIGNAL(clicked(bool)), this, SLOT(update()));
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connect(ui->showSmoothCurveCheckBox, SIGNAL(clicked(bool)), this, SLOT(update()));
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}
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frmSmoothCurve::~frmSmoothCurve()
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{
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delete ui;
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}
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void frmSmoothCurve::paintEvent(QPaintEvent *)
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{
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QPainter painter(this);
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painter.setRenderHint(QPainter::Antialiasing);
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painter.translate(width() / 2, height() / 2);
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painter.scale(1, -1);
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//画坐标轴
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painter.setPen(QColor(180, 180, 180));
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painter.drawLine(-250, 0, 250, 0);
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painter.drawLine(0, 150, 0, -150);
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//被选中时显示平滑曲线,否则显示非平滑曲线
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painter.setPen(QPen(QColor(80, 80, 80), 2));
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if (ui->showSmoothCurveCheckBox->isChecked()) {
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painter.drawPath(smoothCurve);
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} else {
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painter.drawPath(smoothCurve2);
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}
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//如果曲线上的点可见则显示出来
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if (ui->showKnotsCheckBox->isChecked()) {
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painter.setPen(Qt::black);
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painter.setBrush(Qt::gray);
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foreach (QPointF p, datas) {
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painter.drawEllipse(p, 3, 3);
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}
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}
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}
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@ -0,0 +1,31 @@
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#ifndef FRMSMOOTHCURVE_H
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#define FRMSMOOTHCURVE_H
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#include <QWidget>
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#include <QList>
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#include <QPointF>
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#include <QPainterPath>
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namespace Ui {
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class frmSmoothCurve;
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}
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class frmSmoothCurve : public QWidget
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{
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Q_OBJECT
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public:
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explicit frmSmoothCurve(QWidget *parent = 0);
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~frmSmoothCurve();
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protected:
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void paintEvent(QPaintEvent *event);
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private:
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Ui::frmSmoothCurve *ui;
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QVector<QPointF> datas; //曲线上的点
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QPainterPath smoothCurve; //平滑曲线
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QPainterPath smoothCurve2; //直接连接点的非平滑曲线
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};
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#endif // FRMSMOOTHCURVE_H
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@ -0,0 +1,62 @@
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<?xml version="1.0" encoding="UTF-8"?>
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<ui version="4.0">
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<class>frmSmoothCurve</class>
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<widget class="QWidget" name="frmSmoothCurve">
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<property name="geometry">
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<rect>
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<x>0</x>
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<y>0</y>
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<width>714</width>
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<height>523</height>
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</rect>
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</property>
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<property name="windowTitle">
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<string>Widget</string>
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</property>
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<layout class="QGridLayout" name="gridLayout">
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<item row="0" column="2">
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<spacer name="verticalSpacer">
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<property name="orientation">
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<enum>Qt::Vertical</enum>
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</property>
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<property name="sizeHint" stdset="0">
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<size>
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<width>20</width>
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<height>473</height>
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</size>
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</property>
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</spacer>
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</item>
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<item row="1" column="0">
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<widget class="QCheckBox" name="showKnotsCheckBox">
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<property name="text">
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<string>显示坐标点</string>
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</property>
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</widget>
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</item>
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<item row="1" column="1">
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<spacer name="horizontalSpacer">
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<property name="orientation">
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<enum>Qt::Horizontal</enum>
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</property>
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<property name="sizeHint" stdset="0">
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<size>
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<width>549</width>
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<height>20</height>
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</size>
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</property>
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</spacer>
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</item>
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<item row="1" column="2">
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<widget class="QCheckBox" name="showSmoothCurveCheckBox">
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<property name="text">
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<string>平滑</string>
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</property>
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</widget>
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</item>
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</layout>
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</widget>
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<layoutdefault spacing="6" margin="11"/>
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<resources/>
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<connections/>
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</ui>
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@ -0,0 +1,31 @@
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#pragma execution_character_set("utf-8")
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#include "frmsmoothcurve.h"
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#include <QApplication>
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#include <QTextCodec>
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int main(int argc, char *argv[])
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{
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QApplication a(argc, argv);
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a.setFont(QFont("Microsoft Yahei", 9));
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#if (QT_VERSION <= QT_VERSION_CHECK(5,0,0))
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#if _MSC_VER
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QTextCodec *codec = QTextCodec::codecForName("gbk");
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#else
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QTextCodec *codec = QTextCodec::codecForName("utf-8");
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#endif
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QTextCodec::setCodecForLocale(codec);
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QTextCodec::setCodecForCStrings(codec);
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QTextCodec::setCodecForTr(codec);
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#else
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QTextCodec *codec = QTextCodec::codecForName("utf-8");
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QTextCodec::setCodecForLocale(codec);
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#endif
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frmSmoothCurve w;
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w.setWindowTitle("平滑曲线");
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w.show();
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return a.exec();
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}
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@ -0,0 +1,96 @@
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#include "smoothcurve.h"
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QPainterPath SmoothCurve::createSmoothCurve(const QVector<QPointF> &points)
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{
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QPainterPath path;
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int len = points.size();
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if (len < 2) {
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return path;
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}
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QVector<QPointF> firstControlPoints;
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QVector<QPointF> secondControlPoints;
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calculateControlPoints(points, &firstControlPoints, &secondControlPoints);
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path.moveTo(points[0].x(), points[0].y());
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for (int i = 0; i < len - 1; ++i) {
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path.cubicTo(firstControlPoints[i], secondControlPoints[i], points[i + 1]);
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}
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return path;
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}
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void SmoothCurve::calculateFirstControlPoints(double *&result, const double *rhs, int n)
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{
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result = new double[n];
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double *tmp = new double[n];
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double b = 2.0;
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result[0] = rhs[0] / b;
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for (int i = 1; i < n; i++) {
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tmp[i] = 1 / b;
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b = (i < n - 1 ? 4.0 : 3.5) - tmp[i];
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result[i] = (rhs[i] - result[i - 1]) / b;
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}
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for (int i = 1; i < n; i++) {
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result[n - i - 1] -= tmp[n - i] * result[n - i];
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}
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delete tmp;
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}
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void SmoothCurve::calculateControlPoints(const QVector<QPointF> &datas,
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QVector<QPointF> *firstControlPoints,
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QVector<QPointF> *secondControlPoints)
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{
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int n = datas.size() - 1;
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for (int i = 0; i < n; ++i) {
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firstControlPoints->append(QPointF());
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secondControlPoints->append(QPointF());
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}
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if (n == 1) {
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(*firstControlPoints)[0].rx() = (2 * datas[0].x() + datas[1].x()) / 3;
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(*firstControlPoints)[0].ry() = (2 * datas[0].y() + datas[1].y()) / 3;
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(*secondControlPoints)[0].rx() = 2 * (*firstControlPoints)[0].x() - datas[0].x();
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(*secondControlPoints)[0].ry() = 2 * (*firstControlPoints)[0].y() - datas[0].y();
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return;
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}
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double *xs = 0;
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double *ys = 0;
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double *rhsx = new double[n];
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double *rhsy = new double[n];
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for (int i = 1; i < n - 1; ++i) {
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rhsx[i] = 4 * datas[i].x() + 2 * datas[i + 1].x();
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rhsy[i] = 4 * datas[i].y() + 2 * datas[i + 1].y();
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}
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rhsx[0] = datas[0].x() + 2 * datas[1].x();
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rhsx[n - 1] = (8 * datas[n - 1].x() + datas[n].x()) / 2.0;
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rhsy[0] = datas[0].y() + 2 * datas[1].y();
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rhsy[n - 1] = (8 * datas[n - 1].y() + datas[n].y()) / 2.0;
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calculateFirstControlPoints(xs, rhsx, n);
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calculateFirstControlPoints(ys, rhsy, n);
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for (int i = 0; i < n; ++i) {
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(*firstControlPoints)[i].rx() = xs[i];
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(*firstControlPoints)[i].ry() = ys[i];
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if (i < n - 1) {
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(*secondControlPoints)[i].rx() = 2 * datas[i + 1].x() - xs[i + 1];
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(*secondControlPoints)[i].ry() = 2 * datas[i + 1].y() - ys[i + 1];
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} else {
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(*secondControlPoints)[i].rx() = (datas[n].x() + xs[n - 1]) / 2;
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(*secondControlPoints)[i].ry() = (datas[n].y() + ys[n - 1]) / 2;
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}
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}
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delete xs;
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delete ys;
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delete rhsx;
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delete rhsy;
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}
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@ -0,0 +1,27 @@
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#ifndef SMOOTHCURVE_H
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#define SMOOTHCURVE_H
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#include <QObject>
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#include <QVector>
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#include <QPointF>
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#include <QPainterPath>
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#ifdef quc
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class Q_DECL_EXPORT SmoothCurve : public QObject
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#else
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class SmoothCurve : public QObject
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#endif
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{
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public:
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//创建平滑曲线路径
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static QPainterPath createSmoothCurve(const QVector<QPointF> &points);
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private:
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static void calculateFirstControlPoints(double *&result, const double *rhs, int n);
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static void calculateControlPoints(const QVector<QPointF> &datas,
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QVector<QPointF> *firstControlPoints,
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QVector<QPointF> *secondControlPoints);
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};
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#endif // SMOOTHCURVE_H
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@ -0,0 +1,23 @@
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#-------------------------------------------------
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#
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# Project created by QtCreator 2017-01-09T09:29:12
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#
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#-------------------------------------------------
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QT += core gui
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greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
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TARGET = smoothcurve
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TEMPLATE = app
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DESTDIR = $$PWD/../bin
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CONFIG += warn_off
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SOURCES += main.cpp
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SOURCES += frmsmoothcurve.cpp
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SOURCES += smoothcurve.cpp
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HEADERS += frmsmoothcurve.h
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HEADERS += smoothcurve.h
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FORMS += frmsmoothcurve.ui
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