Qt 制作验证码
#include <QRandomGenerator>
#include <QPainterPath>
#include <QPainter>// 生成随机数
int r(int a,int b=0){return b ? QRandomGenerator::global()->bounded(a, b): QRandomGenerator::global()->bounded(a);
}// 生成随机多边形路径
QPainterPath createRandomPolygon(int width, int height) {QPainterPath path;int points = r(1, 7);QPointF center(r(width),r(height));for (int i = 0; i < points; ++i) {qreal radius = 1.0*r(3, 20);qreal angle = 2 * M_PI * i / points;QPointF pt = center + QPointF(radius * cos(angle), radius * sin(angle));if (i == 0) path.moveTo(pt);else path.lineTo(pt);}path.closeSubpath();return path;
}void MainWindow::genRandomPixmap()
{// 生成随机4位数QString numberStr = QString::number(r(1000, 10000));// 创建画布QPixmap pixmap(ui->lbCode->size());pixmap.fill(Qt::white);QPainter painter(&pixmap);painter.setRenderHint(QPainter::Antialiasing);// 字体设置QFont baseFont("Arial", 23, QFont::Bold);painter.setFont(baseFont);// 动态计算字符间距（考虑旋转扩展）QFontMetrics fm(baseFont);int charSpacing = fm.horizontalAdvance('0') * 1.4; // 基础间距// 计算安全绘制区域auto w = pixmap.width();auto h = pixmap.height();// 绘制每个字符for (int i = 0; i < numberStr.size(); ++i) {painter.save();// 随机颜色（避免过浅）QColor textColor(r(10, 210), r(10, 210),r(10, 210) );painter.setPen(textColor);// 获取字符尺寸QRect charRect = fm.boundingRect(numberStr[i]);// 生成随机变换参数qreal angle = r(-30, 30);qreal centerX = i*charSpacing + (charRect.width() >> 1) + 11;qreal centerY = h >> 1;qreal scaleX = 1.0 + 0.01*r(-15, 15); // X缩放qreal scaleY = 1.0 + 0.01*r(-15, 15); // Y缩放qreal shearX = 0.1*r(-5, 5); // X倾斜qreal shearY = 0.1*r(-1,1); // Y倾斜// 设置变换（以字符中心为旋转点）QTransform transform;transform.translate(centerX, centerY);transform.rotate(angle);transform.scale(scaleX, scaleY); // 缩放transform.shear(shearX, shearY); // 倾斜transform.translate(-charRect.width()/2, charRect.height()>> 1); // 对齐基线painter.setTransform(transform);// 添加位置抖动（限制在安全区）QPointF offset(r(-2,2), r(-2,2) );painter.drawText(offset, QString(numberStr[i]));painter.restore();}// 增强效果// 添加干扰线（可选）for (int i = 0; i <5; ++i) {painter.setPen(QColor(r(240), r(240), r(240), r(150, 250)));painter.drawLine(r(w), r(h),r(w), r(h));}// 添加随机多边形（可选）for (int i = 0; i <5; ++i) {QPainterPath path = createRandomPolygon(w, h);painter.setPen(QColor(r(240), r(240), r(240), r(150, 250)));painter.drawPath(path);}ui->lbCode->setPixmap(pixmap);
}
