本文主要是介绍QT 圆盘百分比，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
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/* 设置抗锯齿 */painter.setRenderHints(QPainter::Antialiasing, true);/* 最外层的圆 */QRect drawRect = event->rect();QRadialGradient gradient1(drawRect.center(),
drawRect.width() / 2,
drawRect.center());
gradient1.setColorAt(0, Qt::transparent);
gradient1.setColorAt(0.5, Qt::transparent);// 稍微增加透明部分的范围
gradient1.setColorAt(0.51, QColor("#00237f"));// 开始显示深蓝色
gradient1.setColorAt(0.58, QColor("#00237f"));// 保持深蓝色一段时间
gradient1.setColorAt(0.59, Qt::transparent);// 渐变回透明
gradient1.setColorAt(1, Qt::transparent);
painter.setBrush(gradient1);
painter.setPen(Qt::NoPen);
painter.drawEllipse(drawRect);
/* 里层的圆 */
QRadialGradient gradient2(drawRect.center(),
drawRect.width() / 2,
drawRect.center());
gradient2.setColorAt(0, Qt::transparent);
gradient2.setColorAt(0.420, Qt::transparent);
gradient2.setColorAt(0.421, QColor("#885881e3"));
gradient2.setColorAt(0.430, QColor("#5881e3"));
gradient2.setColorAt(0.440, QColor("#885881e3"));
gradient2.setColorAt(0.441, Qt::transparent);
gradient2.setColorAt(1, Qt::transparent);
painter.setBrush(gradient2);
painter.setPen(Qt::NoPen);
painter.drawEllipse(drawRect);
/* 数字 */
QFont font;
font.setPixelSize(drawRect.width() / 10);
painter.setPen(Qt::white);
painter.setFont(font);
painter.drawText(drawRect, Qt::AlignCenter,
QString::number(angleLength * 100 / 360) + "%");
/* 发光背景圆 */
painter.translate(drawRect.width() >> 1, drawRect.height() >> 1);
int radius = drawRect.width() / 2;
/* radius<< 1（左移1位）相当于radius*2 */
QRectF rect(-radius, -radius, radius << 1, radius << 1);
QRadialGradient gradient3(0, 0, radius);
gradient3.setColorAt(0, Qt::transparent);
gradient3.setColorAt(0.42, Qt::transparent);
gradient3.setColorAt(0.51, QColor("#500194d3"));
gradient3.setColorAt(0.55, QColor("#22c1f3f9"));
gradient3.setColorAt(0.58, QColor("#500194d3"));
gradient3.setColorAt(0.68, Qt::transparent);
gradient3.setColorAt(1.0, Qt::transparent);
painter.setBrush(gradient3);
QPainterPath path1;
path1.arcTo(rect, startAngle, -angleLength);
painter.setPen(Qt::NoPen);
painter.drawPath(path1);
/* 发光圆/弧 */
QRadialGradient gradient4(0, 0, radius);
gradient4.setColorAt(0, Qt::transparent);
gradient4.setColorAt(0.49, Qt::transparent);
gradient4.setColorAt(0.50, QColor("#4bf3f9"));
gradient4.setColorAt(0.59, QColor("#4bf3f9"));
gradient4.setColorAt(0.60, Qt::transparent);
gradient4.setColorAt(1.0, Qt::transparent);
painter.setBrush(gradient4);
QPainterPath path2;
path2.arcTo(rect, startAngle, -angleLength);
painter.setPen(Qt::NoPen);
painter.drawPath(path2);
/* 恢复状态 */
painter.restore();
/* 设置事件对象的accept标志 */
event->accept();
#include "arcgraph.h"ArcGraph::ArcGraph(QWidget *parent): QWidget(parent),startAngle(90),angleLength(100)
{this->setMinimumSize(100, 100);setAttribute(Qt::WA_TranslucentBackground, true);
}ArcGraph::~ArcGraph()
{
}void ArcGraph::setstartAngle(int angle)
{startAngle = angle;this->repaint();
}void ArcGraph::setangleLength(int length)
{angleLength = length;this->repaint();
}void ArcGraph::paintEvent(QPaintEvent *event)
{QPainter painter(this);/* 保存状态 */painter.save();/* 设置抗锯齿 */painter.setRenderHints(QPainter::Antialiasing, true);/* 最外层的圆 */QRect drawRect = event->rect();QRadialGradient gradient1(drawRect.center(),drawRect.width() / 2,drawRect.center());gradient1.setColorAt(0, Qt::transparent);gradient1.setColorAt(0.5, Qt::transparent);// 稍微增加透明部分的范围gradient1.setColorAt(0.51, QColor("#00237f"));// 开始显示深蓝色gradient1.setColorAt(0.58, QColor("#00237f"));// 保持深蓝色一段时间gradient1.setColorAt(0.59, Qt::transparent);// 渐变回透明gradient1.setColorAt(1, Qt::transparent);painter.setBrush(gradient1);painter.setPen(Qt::NoPen);painter.drawEllipse(drawRect);/* 里层的圆 */QRadialGradient gradient2(drawRect.center(),drawRect.width() / 2,drawRect.center());gradient2.setColorAt(0, Qt::transparent);gradient2.setColorAt(0.420, Qt::transparent);gradient2.setColorAt(0.421, QColor("#885881e3"));gradient2.setColorAt(0.430, QColor("#5881e3"));gradient2.setColorAt(0.440, QColor("#885881e3"));gradient2.setColorAt(0.441, Qt::transparent);gradient2.setColorAt(1, Qt::transparent);painter.setBrush(gradient2);painter.setPen(Qt::NoPen);painter.drawEllipse(drawRect);/* 数字 */QFont font;font.setPixelSize(drawRect.width() / 10);painter.setPen(Qt::white);painter.setFont(font);painter.drawText(drawRect, Qt::AlignCenter,QString::number(angleLength * 100 / 360) + "%");/* 发光背景圆 */painter.translate(drawRect.width() >> 1, drawRect.height() >> 1);int radius = drawRect.width() / 2;/* radius<< 1（左移1位）相当于radius*2 */QRectF rect(-radius, -radius, radius << 1, radius << 1);QRadialGradient gradient3(0, 0, radius);gradient3.setColorAt(0, Qt::transparent);gradient3.setColorAt(0.42, Qt::transparent);gradient3.setColorAt(0.51, QColor("#500194d3"));gradient3.setColorAt(0.55, QColor("#22c1f3f9"));gradient3.setColorAt(0.58, QColor("#500194d3"));gradient3.setColorAt(0.68, Qt::transparent);gradient3.setColorAt(1.0, Qt::transparent);painter.setBrush(gradient3);QPainterPath path1;path1.arcTo(rect, startAngle, -angleLength);painter.setPen(Qt::NoPen);painter.drawPath(path1);/* 发光圆/弧 */QRadialGradient gradient4(0, 0, radius);gradient4.setColorAt(0, Qt::transparent);gradient4.setColorAt(0.49, Qt::transparent);gradient4.setColorAt(0.50, QColor("#4bf3f9"));gradient4.setColorAt(0.59, QColor("#4bf3f9"));gradient4.setColorAt(0.60, Qt::transparent);gradient4.setColorAt(1.0, Qt::transparent);painter.setBrush(gradient4);QPainterPath path2;path2.arcTo(rect, startAngle, -angleLength);painter.setPen(Qt::NoPen);painter.drawPath(path2);/* 恢复状态 */painter.restore();/* 设置事件对象的accept标志 */event->accept();
}
#ifndef ARCGRAPH_H
#define ARCGRAPH_H#include <QWidget>
#include <QPainter>
#include <QPaintEvent>/* 蓝色科技感弧形视图 */
class ArcGraph : public QWidget
{Q_OBJECTpublic:ArcGraph(QWidget *parent = nullptr);~ArcGraph();void setstartAngle(int);void setangleLength(int);private:void paintEvent(QPaintEvent *event);int startAngle;int angleLength;
};
#endif // ARCGRAPH_H
应用：
ArcGraph *arcGraph=new ArcGraph;
arcGraph->setangleLength(als.toUInt() * 360 / 65535);
效果：
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