本节对应的视频讲解：B_站_视_频

https://www.bilibili.com/video/BV1qd4y1s7xk

布局完成后，就可以修改控件的名称，以及添加初始化数据

1. 变量命名

先修改各控件显示的的名称，做到 “见名知义”，方便写代码

修改完控件名称后的效果如下：

2. 初始化数据

为各个控件添加初始化数据

2.1 形状

为 cboShape 控件，添加形状

首先，在 paintwidget.h 中定义一个枚举类型，表示形状的类型，如下：

enum Shape {
    _Point,         //
    _Line,          //

    _Rect,          //
    _RoundedRect,   //
    _Ellipse,       //

    _Polyline,      //
    _Polygon,       //

    _Arc,           //
    _Pie,           //
    _Chord,         //

    _Path,          //

    _Text,          //
    _Pixmap
};

然后，在 widget.cpp 的构造中，添加如下初始化代码：

Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
{
    ui->setupUi(this);

    // 1. 形状
    ui->cboShape->addItem("Point", static_cast<int>(_Point));
    ui->cboShape->addItem("Line", static_cast<int>(_Line));

    ui->cboShape->addItem("Rectangle", static_cast<int>(_Rect));
    ui->cboShape->addItem("Rounded Rectangle", static_cast<int>(_RoundedRect));
    ui->cboShape->addItem("Ellipse", static_cast<int>(_Ellipse));

    ui->cboShape->addItem("Arc", static_cast<int>(_Arc));
    ui->cboShape->addItem("Pie", static_cast<int>(_Pie));
    ui->cboShape->addItem("Chord", static_cast<int>(_Chord));

    ui->cboShape->addItem("Polyline", static_cast<int>(_Polyline));
    ui->cboShape->addItem("Polygon", static_cast<int>(_Polygon));

    ui->cboShape->addItem("Path", static_cast<int>(_Path));

    ui->cboShape->addItem("Text", static_cast<int>(_Text));
    ui->cboShape->addItem("Pixmap", static_cast<int>(_Pixmap));
}

2.2 画笔

初始化画笔的属性

Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
{
    ui->setupUi(this);

    // 2. 线宽
    ui->sbPenWidth->setRange(1, 10);

    // 3. 线型
    // 3.1 线型-实线、虚线、点画线等
    ui->cboPenStyle->addItem("Solid", static_cast<int>(Qt::SolidLine));
    ui->cboPenStyle->addItem("Dash", static_cast<int>(Qt::DashLine));
    ui->cboPenStyle->addItem("Dot", static_cast<int>(Qt::DotLine));
    ui->cboPenStyle->addItem("Dash Dot", static_cast<int>(Qt::DashDotLine));
    ui->cboPenStyle->addItem("Dash Dot Dot", static_cast<int>(Qt::DashDotDotLine));
    ui->cboPenStyle->addItem("None", static_cast<int>(Qt::NoPen));

    // 3.2 线型-线的端点的样式
    ui->cboPenCap->addItem("Flat", static_cast<int>(Qt::FlatCap));
    ui->cboPenCap->addItem("Square", static_cast<int>(Qt::SquareCap));
    ui->cboPenCap->addItem("Round", static_cast<int>(Qt::RoundCap));

    // 3.3 连接-两根线的连接处的样式
    ui->cboPenJoin->addItem("Miter", static_cast<int>(Qt::MiterJoin));
    ui->cboPenJoin->addItem("Bevel", static_cast<int>(Qt::BevelJoin));
    ui->cboPenJoin->addItem("Round", static_cast<int>(Qt::RoundJoin));
}

2.3 画刷

初始化画刷的属性

Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget)
{
    ui->setupUi(this);
    
    // 4. 画刷
    ui->cboBrushStyle->addItem(tr("Linear Gradient"), static_cast<int>(Qt::LinearGradientPattern));
    ui->cboBrushStyle->addItem(tr("Radial Gradient"), static_cast<int>(Qt::RadialGradientPattern));
    ui->cboBrushStyle->addItem(tr("Conical Gradient"), static_cast<int>(Qt::ConicalGradientPattern));
    ui->cboBrushStyle->addItem(tr("Texture"), static_cast<int>(Qt::TexturePattern));
    ui->cboBrushStyle->addItem(tr("Solid"), static_cast<int>(Qt::SolidPattern));
    ui->cboBrushStyle->addItem(tr("Horizontal"), static_cast<int>(Qt::HorPattern));
    ui->cboBrushStyle->addItem(tr("Vertical"), static_cast<int>(Qt::VerPattern));
    ui->cboBrushStyle->addItem(tr("Cross"), static_cast<int>(Qt::CrossPattern));
    ui->cboBrushStyle->addItem(tr("Backward Diagonal"), static_cast<int>(Qt::BDiagPattern));
    ui->cboBrushStyle->addItem(tr("Forward Diagonal"), static_cast<int>(Qt::FDiagPattern));
    ui->cboBrushStyle->addItem(tr("Diagonal Cross"), static_cast<int>(Qt::DiagCrossPattern));
    ui->cboBrushStyle->addItem(tr("Dense 1"), static_cast<int>(Qt::Dense1Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 2"), static_cast<int>(Qt::Dense2Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 3"), static_cast<int>(Qt::Dense3Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 4"), static_cast<int>(Qt::Dense4Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 5"), static_cast<int>(Qt::Dense5Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 6"), static_cast<int>(Qt::Dense6Pattern));
    ui->cboBrushStyle->addItem(tr("Dense 7"), static_cast<int>(Qt::Dense7Pattern));
    ui->cboBrushStyle->addItem(tr("None"), static_cast<int>(Qt::NoBrush));
}