1、概述
源码放在文章末尾

该项目实现了屏幕拾色器的功能，可以根据鼠标指定的位置识别当前位置的颜色

项目功能包含：
鼠标按下实时采集鼠标处的颜色。
实时显示颜色值。
支持16进制格式和rgb格式。
实时显示预览颜色。
根据背景色自动计算合适的前景色。

下面是demo演示：

项目部分代码如下所示：

#pragma execution_character_set("utf-8")#include "colorwidget.h"
#include "qmutex.h"
#include "qgridlayout.h"
#include "qlabel.h"
#include "qlineedit.h"
#include "qapplication.h"
#include "qtimer.h"
#include "qevent.h"
#include "qdebug.h"#if (QT_VERSION >= QT_VERSION_CHECK(5,0,0))
#include "qscreen.h"
#define deskGeometry qApp->primaryScreen()->geometry()
#define deskGeometry2 qApp->primaryScreen()->availableGeometry()
#else
#include "qdesktopwidget.h"
#define deskGeometry qApp->desktop()->geometry()
#define deskGeometry2 qApp->desktop()->availableGeometry()
#endifColorWidget *ColorWidget::instance = 0;
ColorWidget *ColorWidget::Instance()
{if (!instance) {static QMutex mutex;QMutexLocker locker(&mutex);if (!instance) {instance = new ColorWidget;}}return instance;
}ColorWidget::ColorWidget(QWidget *parent) : QWidget(parent)
{gridLayout = new QGridLayout(this);gridLayout->setSpacing(6);gridLayout->setContentsMargins(11, 11, 11, 11);verticalLayout = new QVBoxLayout();verticalLayout->setSpacing(0);labColor = new QLabel(this);labColor->setText("+");labColor->setStyleSheet("background-color: rgb(255, 107, 107);color: rgb(250, 250, 250);");labColor->setAlignment(Qt::AlignCenter);QFont font;font.setPixelSize(35);font.setBold(true);labColor->setFont(font);QSizePolicy sizePolicy(QSizePolicy::Preferred, QSizePolicy::Expanding);sizePolicy.setHorizontalStretch(0);sizePolicy.setVerticalStretch(0);sizePolicy.setHeightForWidth(labColor->sizePolicy().hasHeightForWidth());labColor->setSizePolicy(sizePolicy);labColor->setMinimumSize(QSize(80, 70));labColor->setMaximumSize(QSize(80, 70));labColor->setCursor(QCursor(Qt::CrossCursor));labColor->setFrameShape(QFrame::StyledPanel);labColor->setFrameShadow(QFrame::Sunken);verticalLayout->addWidget(labColor);label = new QLabel(this);label->setMinimumSize(QSize(0, 18));label->setStyleSheet("background-color: rgb(0, 0, 0);color: rgb(200, 200, 200);");label->setAlignment(Qt::AlignCenter);verticalLayout->addWidget(label);gridLayout->addLayout(verticalLayout, 0, 0, 3, 1);labWeb = new QLabel(this);gridLayout->addWidget(labWeb, 0, 1, 1, 1);txtWeb = new QLineEdit(this);gridLayout->addWidget(txtWeb, 0, 2, 1, 1);labRgb = new QLabel(this);gridLayout->addWidget(labRgb, 1, 1, 1, 1);txtRgb = new QLineEdit(this);gridLayout->addWidget(txtRgb, 1, 2, 1, 1);labPoint = new QLabel(this);gridLayout->addWidget(labPoint, 2, 1, 1, 1);txtPoint = new QLineEdit(this);gridLayout->addWidget(txtPoint, 2, 2, 1, 1);label->setText("当前颜色");labWeb->setText("web值:");labRgb->setText("rgb值:");labPoint->setText("坐标值:");this->setLayout(gridLayout);this->setWindowTitle("屏幕拾色器");this->setFixedSize(300, 108);cp = QApplication::clipboard();pressed = false;timer = new QTimer(this);timer->setInterval(100);connect(timer, SIGNAL(timeout()), this, SLOT(showColorValue()));timer->start();
}ColorWidget::~ColorWidget()
{
}void ColorWidget::mousePressEvent(QMouseEvent *e)
{if (labColor->rect().contains(e->pos())) {pressed = true;}
}void ColorWidget::mouseReleaseEvent(QMouseEvent *)
{pressed = false;
}void ColorWidget::showColorValue()
{if (!pressed) {return;}int x = QCursor::pos().x();int y = QCursor::pos().y();txtPoint->setText(tr("x:%1  y:%2").arg(x).arg(y));#if (QT_VERSION >= QT_VERSION_CHECK(5,0,0))QScreen *screen = qApp->primaryScreen();QPixmap pixmap = screen->grabWindow(0, x, y, 2, 2);
#elseQPixmap pixmap = QPixmap::grabWindow(qApp->desktop()->winId(), x, y, 2, 2);
#endifint red, green, blue;QString strDecimalValue, strHex;if (pixmap.isNull()) {return;}QImage image = pixmap.toImage();if (image.valid(0, 0)) {QColor color = image.pixel(0, 0);red = color.red();green = color.green();blue = color.blue();QString strRed = tr("%1").arg(red & 0xFF, 2, 16, QChar('0'));QString strGreen = tr("%1").arg(green & 0xFF, 2, 16, QChar('0'));QString strBlue = tr("%1").arg(blue & 0xFF, 2, 16, QChar('0'));strDecimalValue = tr("%1, %2, %3").arg(red).arg(green).arg(blue);strHex = tr("#%1%2%3").arg(strRed.toUpper()).arg(strGreen.toUpper()).arg(strBlue.toUpper());}//根据背景色自动计算合适的前景色QColor color(red, green, blue);double gray = (0.299 * color.red() + 0.587 * color.green() + 0.114 * color.blue()) / 255;QColor textColor = gray > 0.5 ? Qt::black : Qt::white;QString str = tr("background:rgb(%1);color:%2").arg(strDecimalValue).arg(textColor.name());labColor->setStyleSheet(str);txtRgb->setText(strDecimalValue);txtWeb->setText(strHex);
}

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