鲁达 ## 一、前言
导航按钮控件，主要用于各种漂亮精美的导航条，我们经常在web中看到导航条都非常精美，都是html+css+js实现的，还自带动画过度效果，Qt提供的qss其实也是无敌的，支持基本上所有的CSS2属性，配合QPainter这个无敌大法工具，没有什么不能绘制的。这个控件总结了大部分的导航条样式，比如左侧+右侧+顶部+底部，线条指示器，倒三角指示器等。还可以在导航条前面加上图标等，就显得更加有特色。有了此控件，再也不用担心没有精美的导航了。总之这个控件在我的很多的项目中都在用，而且很多Qt界的朋友也在用，反响很热烈很好。
主要功能：
1. 可设置文字的左侧+右侧+顶部+底部间隔
2. 可设置文字对齐方式
3. 可设置显示倒三角/倒三角边长/倒三角位置/倒三角颜色
4. 可设置显示图标/图标间隔/图标尺寸/正常状态图标/悬停状态图标/选中状态图标
5. 可设置显示边框线条/线条宽度/线条间隔/线条位置/线条颜色
6. 可设置正常背景颜色/悬停背景颜色/选中背景颜色
7. 可设置正常文字颜色/悬停文字颜色/选中文字颜色
8. 可设置背景颜色为画刷颜色
## 二、代码思路
void NavButton::paintEvent(QPaintEvent *) { //绘制准备工作,启用反锯齿 QPainter painter(this); (QPainter::Antialiasing | QPainter::TextAntialiasing); //绘制背景 drawBg(&painter); //绘制文字 drawText(&painter); //绘制图标 drawIcon(&painter); //绘制边框线条 drawLine(&painter); //绘制倒三角 drawTriangle(&painter); } void NavButton::drawBg(QPainter *painter) { painter->save(); painter->setPen(Qt::NoPen); int width = this->width(); int height = this->height(); QRect bgRect; if (linePosition == LinePosition_Left) { bgRect = QRect(lineSpace, 0, width - lineSpace, height); } else if (linePosition == LinePosition_Right) { bgRect = QRect(0, 0, width - lineSpace, height); } else if (linePosition == LinePosition_Top) { bgRect = QRect(0, lineSpace, width, height - lineSpace); } else if (linePosition == LinePosition_Bottom) { bgRect = QRect(0, 0, width, height - lineSpace); } //如果画刷存在则取画刷 QBrush bgBrush; if (isChecked()) { bgBrush = checkBgBrush; } else if (hover) { bgBrush = hoverBgBrush; } else { bgBrush = normalBgBrush; } if (bgBrush != Qt::NoBrush) { painter->setBrush(bgBrush); } else { //根据当前状态选择对应颜色 QColor bgColor; if (isChecked()) { bgColor = checkBgColor; } else if (hover) { bgColor = hoverBgColor; } else { bgColor = normalBgColor; } painter->setBrush(bgColor); } painter->drawRect(bgRect); painter->restore(); } void NavButton::drawText(QPainter *painter) { painter->save(); painter->setBrush(Qt::NoBrush); //根据当前状态选择对应颜色 QColor textColor; if (isChecked()) { textColor = checkTextColor; } else if (hover) { textColor = hoverTextColor; } else { textColor = normalTextColor; } QRect textRect = QRect(paddingLeft, paddingTop, width() - paddingLeft - paddingRight, height() - paddingTop - paddingBottom); painter->setPen(textColor); painter->drawText(textRect, textAlign | Qt::AlignVCenter, text()); painter->restore(); } void NavButton::drawIcon(QPainter *painter) { if (!showIcon) { return; } painter->save(); QPixmap pix; if (isChecked()) { pix = iconCheck; } else if (hover) { pix = iconHover; } else { pix = iconNormal; } if (!()) { //等比例平滑缩放图标 pix = (iconSize, Qt::KeepAspectRatio, Qt::SmoothTransformation); painter->drawPixmap(iconSpace, (height() - iconSize.height()) / 2, pix); } painter->restore(); } void NavButton::drawLine(QPainter *painter) { if (!showLine) { return; } if (!isChecked()) { return; } painter->save(); QPen pen; (lineWidth); (lineColor); painter->setPen(pen); //根据线条位置设置线条坐标 QPoint pointStart, pointEnd; if (linePosition == LinePosition_Left) { pointStart = QPoint(0, 0); pointEnd = QPoint(0, height()); } else if (linePosition == LinePosition_Right) { pointStart = QPoint(width(), 0); pointEnd = QPoint(width(), height()); } else if (linePosition == LinePosition_Top) { pointStart = QPoint(0, 0); pointEnd = QPoint(width(), 0); } else if (linePosition == LinePosition_Bottom) { pointStart = QPoint(0, height()); pointEnd = QPoint(width(), height()); } painter->drawLine(pointStart, pointEnd); painter->restore(); } void NavButton::drawTriangle(QPainter *painter) { if (!showTriangle) { return; } //选中或者悬停显示 if (!hover && !isChecked()) { return; } painter->save(); painter->setPen(Qt::NoPen); painter->setBrush(triangleColor); //绘制在右侧中间,根据设定的倒三角的边长设定三个点位置 int width = this->width(); int height = this->height(); int midWidth = width / 2; int midHeight = height / 2; QPolygon pts; if (trianglePosition == TrianglePosition_Left) { (3, triangleLen, midHeight, 0, midHeight - triangleLen, 0, midHeight + triangleLen); } else if (trianglePosition == TrianglePosition_Right) { (3, width - triangleLen, midHeight, width, midHeight - triangleLen, width, midHeight + triangleLen); } else if (trianglePosition == TrianglePosition_Top) { (3, midWidth, triangleLen, midWidth - triangleLen, 0, midWidth + triangleLen, 0); } else if (trianglePosition == TrianglePosition_Bottom) { (3, midWidth, height - triangleLen, midWidth - triangleLen, height, midWidth + triangleLen, height); } painter->drawPolygon(pts); painter->restore(); }## 三、效果图
## 四、开源主页
**以上作品完整源码下载都在开源主页，会持续不断更新作品数量和质量，欢迎各位关注。**
1. 国内站点：[]()
2. 国际站点：[]()
3. 个人主页：[]()
4. 知乎主页：[]()