I. Introduction

The update and iteration speed of the operating system is very fast. Basically, a new version will be released every three to five years. The WIN10 operating system is still a relatively successful system. It is said that the market share is getting larger and larger. XP’s share is already very small, and WIN7’s share is It is also gradually decreasing. In the latest WIN10 system, there is a calendar control in the lower right corner, which comes with a lunar calendar. This localization is quite good. When you move the mouse up, there is a halo background effect. The experience is very pleasing to the eye, so I plan to I can imitate it using Qt.
There are two technical difficulties in this control. One is to automatically arrange the day and date according to the current month. This needs to be automatically calculated. The second difficulty is to draw the halo background. You need to use the image overlay mode setCompositionMode in the painter to set the image overlay mode. In the future, you can overlap multiple drawings and combine them according to set rules, such as drawing a halo background behind you.

2. Functions implemented

1: Background color can be set
2: Halo color can be set
3: Text color can be set
4: The selected date background can be set
5: The halo follows the mouse movement

3. Effect drawing

4. Header file code

#ifndef SHADOWCALENDAR_H
#define SHADOWCALENDAR_H

/**
 * 光晕日历控件 作者:雨田哥(QQ:3246214072) 整理:feiyangqingyun(QQ:517216493) 2019-10-07
 * 1:可设置背景颜色
 * 2:可设置光晕颜色
 * 3:可设置文字颜色
 * 4:可设置选中日期背景
 * 5:光晕跟随鼠标移动
 */

#include <QWidget>
#include <QDate>

#ifdef quc
#if (QT_VERSION < QT_VERSION_CHECK(5,7,0))
#include <QtDesigner/QDesignerExportWidget>
#else
#include <QtUiPlugin/QDesignerExportWidget>
#endif

class QDESIGNER_WIDGET_EXPORT ShadowCalendar : public QWidget
#else
class ShadowCalendar : public QWidget
#endif

{
    Q_OBJECT
    Q_PROPERTY(QColor bgColor READ getBgColor WRITE setBgColor)
    Q_PROPERTY(QColor textColor READ getTextColor WRITE setTextColor)
    Q_PROPERTY(QColor shadowColor READ getShadowColor WRITE setShadowColor)
    Q_PROPERTY(QColor selectColor READ getSelectColor WRITE setSelectColor)

public:
    struct DateItem {
        int year;
        int month;
        int day;

        DateItem()
        {
            year = -1;
            month = -1;
            day = -1;
        }
    };

    explicit ShadowCalendar(QWidget *parent = 0);
    ~ShadowCalendar();

public:
    void updateCalendar(const QDate &selectDate);

protected:
    void leaveEvent(QEvent *);
    void mouseMoveEvent(QMouseEvent *);
    void paintEvent(QPaintEvent *);

private:
    QColor bgColor;             //背景颜色
    QColor textColor;           //文字颜色
    QColor shadowColor;         //光晕颜色
    QColor selectColor;         //选中颜色

    QDate selectDate;           //今天日期
    DateItem dateItem[6][7];    //日期数组

public:
    QColor getBgColor()         const;
    QColor getTextColor()       const;
    QColor getShadowColor()     const;
    QColor getSelectColor()     const;

    QSize sizeHint()            const;
    QSize minimumSizeHint()     const;

public Q_SLOTS:
    //设置背景颜色+文字颜色+光晕颜色+选中颜色
    void setBgColor(const QColor &bgColor);
    void setTextColor(const QColor &textColor);
    void setShadowColor(const QColor &shadowColor);
    void setSelectColor(const QColor &selectColor);
};

#endif // SHADOWCALENDAR_H

As a benefit for this article, you can receive a Qt development learning package and technical videos for free, including (C++ language basics, introduction to Qt programming, QT signal and slot mechanism, QT interface development-image drawing, QT network, QT database programming, QT project practice , QT embedded development, Quick module, etc.) ↓↓↓↓↓↓See below↓↓Click at the bottom of the article to receive the fee↓↓

5. Core code

void ShadowCalendar::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing);

    int sw = 336;
    int sh = 336;
    qreal scaleX = this->width() * 1.0 / sw;
    qreal scaleY = this->height() * 1.0 / sh;

    painter.scale(scaleX, scaleY);
    painter.setPen(Qt::NoPen);
    painter.fillRect(0, 0, sw, sh, bgColor);

    qreal iw = sw / 7.0;
    qreal ih = sh / 7.0;

    //mask
    QPointF globalpoint = this->mapFromGlobal(QCursor::pos());
    const QPointF &point = QPointF(globalpoint.x() / scaleX, globalpoint.y() / scaleY);

    //绘制光晕背景
    if (this->underMouse()) {
        int effectradius = 58;
        painter.setCompositionMode(QPainter::CompositionMode_DestinationIn);
        QRadialGradient radialGrad(point, effectradius);
        radialGrad.setColorAt(0, QColor(0, 0, 0, 120));
        radialGrad.setColorAt(1, QColor(0, 0, 0, 255));
        painter.setBrush(radialGrad);
        painter.drawEllipse(point, effectradius, effectradius);

        painter.setCompositionMode(QPainter::CompositionMode_DestinationOver);
        painter.setBrush(Qt::NoBrush);

        for (int row = 0; row < 6; row++) {
            for (int column = 0; column < 7; column++) {
                QRectF rect = QRectF(column * iw, (row + 1) * ih, iw, ih).adjusted(3, 3, -3, -3);
                if (rect.contains(point)) {
                    painter.save();
                    painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
                    painter.setPen(QPen(QColor(220, 220, 220, 160), 2));
                    painter.drawRoundedRect(rect, 2, 2);
                    painter.restore();
                    continue;
                } else {
                    painter.setPen(QPen(shadowColor, 2));
                }

                painter.drawRoundedRect(rect, 2, 2);
            }
        }

        //绘制圆形的光晕底层背景
        painter.fillRect(0, 0, sw, sh, QColor(200, 200, 200, 50));
    }

    //绘制头部中文数字,先设置图像叠加模式为源在上面
    painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
    painter.setPen(textColor);
    QStringList listHead;
    listHead << "一" << "二" << "三" << "四" << "五" << "六" << "日";
    for (int i = 0; i < 7; i++) {
        painter.drawText(i * iw, 0, iw, ih, Qt::AlignCenter, listHead.at(i));
    }

    //绘制日期
    for (int row = 0; row < 6; row++) {
        for (int column = 0; column < 7; column++) {
            if (dateItem[row][column].day > 0) {
                QRectF rect = QRectF(column * iw, (row + 1) * ih, iw, ih).adjusted(3, 3, -3, -3);

                //如果是选中的日期则突出绘制背景
                if (QDate::currentDate() == QDate(dateItem[row][column].year, dateItem[row][column].month, dateItem[row][column].day)) {
                    painter.setPen(QPen(selectColor, 2));
                    painter.setBrush(Qt::NoBrush);

                    //如果和光晕效果重叠则边框高亮
                    if (rect.contains(point)) {
                        painter.setPen(QPen(selectColor.lighter(), 2));
                    }

                    //绘制圆角边框
                    painter.drawRoundedRect(rect, 2, 2);

                    //绘制里边背景
                    painter.setPen(Qt::NoPen);
                    painter.setBrush(selectColor);
                    painter.drawRoundedRect(rect.adjusted(4, 4, -4, -4), 2, 2);
                }

                painter.setPen(textColor);
                painter.drawText(rect, Qt::AlignCenter, QString::number(dateItem[row][column].day));
            }
        }
    }
}

6. Control introduction

More than 160 exquisite controls, covering various dashboards, progress bars, progress balls, compasses, curves, rulers, thermometers, navigation bars, navigation bars, flatui, highlight buttons, sliding selectors, lunar calendar, etc. Far exceeds the number of controls integrated by qwt.
Each class can be independently formed into a separate control, with zero coupling. Each control has a header file and an implementation file, and does not rely on other files. It is convenient for a single control to be integrated into the project in the form of source code, with less code. The control classes of qwt are interlocking and highly coupled. If you want to use one of the controls, you must include all the code.
All written in pure Qt, drawn by QWidget+QPainter, supports any Qt version from Qt4.6 to Qt5.13, supports compilers such as mingw, msvc, gcc, etc., and supports any operating system such as windows+linux+mac+embedded linux, etc., without garbled code , can be directly integrated into Qt Creator and used like the built-in controls. Most effects only need to set a few properties, which is extremely convenient.
Each control has a corresponding separate DEMO containing the source code of the control for easy reference and use. It also provides an integrated DEMO used by all controls.
The source code of each control has detailed Chinese comments and is written in accordance with unified design specifications, making it easy to learn how to write custom controls.
The default color matching of each control and the color matching corresponding to the demo are very exquisite.
More than 130 visible controls and 6 invisible controls.
Some controls provide multiple style choices and multiple indicator style choices.
All controls adapt to form stretch changes.
Integrated custom control attribute designer, supports drag and drop design, WYSIWYG, supports import and export of xml format.
Comes with activex control demo, all controls can be run directly in the IE browser.
Integrate fontawesome graphic fonts + hundreds of graphic fonts collected by Alibaba iconfont, and enjoy the fun brought by graphic fonts.
All controls finally generate a dynamic library file (dll or so, etc.), which can be directly integrated into qtcreator for drag and drop design.
There is already a qml version, and a pyqt version will be considered later if there is great demand from users.
The custom control plug-in is open to dynamic library use (free forever), without any backdoors or restrictions, so please feel free to use it.
Currently, 32 versions of dll have been provided, among which the version qt_5_7_0_mingw530_32 will always be guaranteed to be the latest and complete.
Controls are added and improved from time to time, and the SDK is updated from time to time. Suggestions are welcome, thank you!
For introductory Qt books, we recommend Huo Yafei's "Quick Start with Qt Creator" and "Introduction to Qt5 Programming". For advanced Qt books, we recommend the official "C++ GUI Qt4 Programming".
I highly recommend the series of self-cultivation and planning books for programmers, "The Big Talk Programmer", "Programmer's Growth Course", and "The Worry-Relieving Programmer", which will benefit you a lot and will last a lifetime!
SDK address: https://gitee.com/feiyangqingyun/QUCSDK https://github.com/feiyangqingyun/qucsdk

Original link: https://www.cnblogs.com/feiyangqingyun/p/11646186.html