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| #include <QApplication>
#include <QWidget>
#include <QPainter>
#include <QPen>
#include <QBrush>
#include <QFont>
#include <QGradient>
#include <QTransform>
#include <QRandomGenerator>
#include <QLabel>
#include <QVBoxLayout>
// 自定义绘图窗口
class PaintDemo : public QWidget {
Q_OBJECT
public:
PaintDemo(QWidget *parent = nullptr) : QWidget(parent) {
setWindowTitle("Qt绘图演示");
setMinimumSize(800, 600);
}
protected:
void paintEvent(QPaintEvent *event) override {
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing); // 抗锯齿
painter.setRenderHint(QPainter::TextAntialiasing);
int w = width();
int h = height();
// ========== 1. 基本几何图形 ==========
// 画线
QPen linePen(Qt::red, 3);
painter.setPen(linePen);
painter.drawLine(20, 20, 200, 20);
painter.drawText(20, 40, "直线");
// 画矩形
QBrush rectBrush(Qt::blue);
painter.setBrush(rectBrush);
painter.drawRect(20, 60, 100, 60);
painter.drawText(130, 90, "矩形");
// 画椭圆
QBrush ellipseBrush(QColor(0, 200, 0));
painter.setBrush(ellipseBrush);
painter.drawEllipse(20, 140, 100, 60);
painter.drawText(130, 170, "椭圆");
// 画圆
QColor circleColor(200, 0, 200);
painter.setBrush(circleColor);
painter.drawEllipse(20, 200, 60, 60);
painter.drawText(90, 230, "圆");
// 画多边形
QVector<QPointF> triangle;
triangle << QPointF(20, 280) << QPointF(100, 280) << QPointF(60, 320);
painter.setBrush(QColor(255, 165, 0));
painter.drawPolygon(triangle);
painter.drawText(110, 305, "三角形");
// ========== 2. 渐变填充 ==========
// 线性渐变
QLinearGradient linearGrad(20, 350, 200, 350);
linearGrad.setColorAt(0, Qt::red);
linearGrad.setColorAt(0.5, Qt::yellow);
linearGrad.setColorAt(1, Qt::green);
painter.setBrush(linearGrad);
painter.drawRect(20, 350, 180, 50);
painter.drawText(210, 380, "线性渐变");
// 径向渐变
QRadialGradient radialGrad(100, 450, 50, 100, 450);
radialGrad.setColorAt(0, Qt::white);
radialGrad.setColorAt(0.5, Qt::cyan);
radialGrad.setColorAt(1, Qt::blue);
painter.setBrush(radialGrad);
painter.drawEllipse(50, 400, 100, 100);
painter.drawText(160, 455, "径向渐变");
// ========== 3. 文本绘制 ==========
painter.setPen(Qt::black);
QFont titleFont("Arial", 16, QFont::Bold);
painter.setFont(titleFont);
painter.drawText(w/2 + 50, 30, "Qt绘图示例 🖌️");
QFont normalFont("Consolas", 12);
painter.setFont(normalFont);
painter.setPen(Qt::darkBlue);
painter.drawText(w/2 + 50, 60, "字体: Consolas, 12pt");
// 带背景的文本
QRectF textRect(w/2 + 50, 80, 200, 40);
painter.fillRect(textRect, QColor(255, 255, 200));
painter.drawRect(textRect);
painter.drawText(textRect, Qt::AlignCenter, "带背景的文本 📝");
// ========== 4. 变换操作 ==========
painter.save(); // 保存画笔状态
// 平移
painter.translate(w/2 + 50, 160);
painter.setBrush(Qt::darkMagenta);
painter.drawRect(-30, -30, 60, 60);
painter.drawText(0, 50, "平移");
painter.restore(); // 恢复画笔状态
// 旋转
painter.save();
painter.translate(w/2 + 150, 160);
painter.rotate(45);
painter.setBrush(Qt::darkCyan);
painter.drawRect(-30, -30, 60, 60);
painter.drawText(0, 50, "旋转45°");
painter.restore();
// 缩放
painter.save();
painter.translate(w/2 + 250, 160);
painter.scale(1.5, 0.8);
painter.setBrush(Qt::darkYellow);
painter.drawRect(-30, -30, 60, 60);
painter.drawText(0, 50, "缩放1.5x");
painter.restore();
// ========== 5. 高级绘图: 画家的艺术 🎨 ==========
// 绘制饼图
painter.save();
painter.translate(100, h - 180);
QVector<QPair<QString, double>> data = {
{"苹果", 30},
{"香蕉", 25},
{"橙子", 20},
{"葡萄", 15},
{"其他", 10}
};
QVector<QColor> colors = {
Qt::red, Qt::yellow, Qt::orange, Qt::darkMagenta, Qt::gray
};
double total = 0;
for (auto &item : data) total += item.second;
double startAngle = 0;
int centerX = 80, centerY = 80, radius = 70;
for (int i = 0; i < data.size(); ++i) {
double spanAngle = (data[i].second / total) * 360 * 16; // 16分之一度
painter.setBrush(colors[i]);
painter.drawPie(-radius, -radius, radius*2, radius*2,
startAngle, spanAngle);
startAngle += spanAngle;
}
// 绘制图例
painter.setPen(Qt::black);
painter.setBrush(Qt::NoBrush);
for (int i = 0; i < data.size(); ++i) {
int legendY = 100 + i * 20;
painter.setBrush(colors[i]);
painter.drawRect(w/2 - 80, legendY - 10, 15, 15);
painter.drawText(w/2 - 55, legendY + 3,
QString("%1: %2%").arg(data[i].first).arg(data[i].second, 0, 'f', 0));
}
painter.restore();
// ========== 6. 贝塞尔曲线 ==========
painter.save();
painter.translate(w/2 + 50, h - 180);
QPainterPath path;
path.moveTo(0, 100);
path.cubicTo(50, 0, 150, 200, 200, 100);
painter.setPen(QPen(Qt::blue, 3));
painter.setBrush(Qt::NoBrush);
painter.drawPath(path);
// 绘制控制点
painter.setBrush(Qt::red);
painter.drawEllipse(0, 95, 10, 10); // 起点
painter.drawEllipse(50, -5, 10, 10); // 控制点1
painter.drawEllipse(150, 195, 10, 10); // 控制点2
painter.drawEllipse(195, 95, 10, 10); // 终点
painter.setPen(Qt::black);
painter.drawText(0, 130, "贝塞尔曲线");
painter.restore();
// ========== 7. 绘制时钟 ==========
painter.save();
painter.translate(w - 120, h - 120);
// 表盘
painter.setBrush(Qt::white);
painter.setPen(QPen(Qt::black, 3));
painter.drawEllipse(-80, -80, 160, 160);
// 刻度
for (int i = 0; i < 12; ++i) {
painter.save();
painter.rotate(i * 30);
painter.drawLine(0, -70, 0, -60);
painter.restore();
}
// 时针
QDateTime now = QDateTime::currentDateTime();
double hourAngle = (now.time().hour() % 12 + now.time().minute() / 60.0) * 30;
painter.save();
painter.rotate(hourAngle);
painter.setPen(QPen(Qt::black, 5));
painter.drawLine(0, 0, 0, -40);
painter.restore();
// 分针
double minuteAngle = now.time().minute() * 6;
painter.save();
painter.rotate(minuteAngle);
painter.setPen(QPen(Qt::darkBlue, 3));
painter.drawLine(0, 0, 0, -55);
painter.restore();
// 秒针
double secondAngle = now.time().second() * 6;
painter.save();
painter.rotate(secondAngle);
painter.setPen(QPen(Qt::red, 2));
painter.drawLine(0, 0, 0, -60);
painter.restore();
painter.restore();
painter.setPen(Qt::darkGray);
painter.drawText(w - 200, h - 10, "🕐 当前时间");
}
};
int main(int argc, char *argv[]) {
QApplication app(argc, argv);
PaintDemo window;
window.show();
return app.exec();
}
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