如何在qt creator中画一颗心

Question

我需要在qt creator上画一颗心，但是我在使用drawArc时遇到了问题。我知道我以错误的方式使用它，但我不知道该怎么做。请帮忙？这就是用 c++ 画心的代码。

HeartDrawableStrategy::draw(QPainter &painter, QRect &rect, double xRatio, double yRatio, QPoint &pos, int size,)
{
    //Define the heart points
    int newPointX = pos.x();
    int newPointY = pos.y()+size/4;
    QPoint leftPoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    newPointX = pos.x()+size/2;
    newPointY = pos.y() + size;
    QPoint bottomCenterPoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    newPointX = pos.x() + size;
    newPointY = pos.y() + size/4;
    QPoint rightPoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    newPointX = pos.x() + size/2;
    newPointY = pos.y() + size/4;
    QPoint middlePoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    newPointX = pos.x() + size/4;
    newPointY = pos.y();
    QPoint topLeftPoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    newPointX = pos.x() + (size*3/4);
    newPointY = pos.y();
    QPoint topRightPoint = QPoint(newPointX*xRatio, newPointY*yRatio);

    //Draw the heart
    QLine line = QLine(leftPoint, bottomCenterPoint);
    painter.drawLine(line);

    line = QLine(bottomCenterPoint, rightPoint);
    painter.drawLine(line);

    line = QLine(leftPoint, middlePoint);
    painter.drawArc(line);

    line = QLine(middlePoint, rightPoint);
    painter.drawArc(line);

}

Answer 1

您当前创建了一个 QLine，并尝试用它创建一个圆弧。这不行。

根据 QT Doc 您需要 X 方向的起点、Y 方向的起点、宽度、高度、起始角度和跨度角度。像那样:

painter.drawArc(x, y, width, height, startAngle, spanAngle);

X 和 Y 是左上角，startAngle 和 spanAngle 必须指定为 1/16 度，即一个完整的圆等于 5760 (16 * 360)。角度的正值表示逆时针方向，负值表示顺时针方向。零度在 3 点钟位置。

下面的代码：

painter.drawArc(10, 20, 80, 60, (30 * 16), (120 * 16);

会画这个:

如何在qt creator中画一颗心

How to draw a heart in qt creator

c++

qt

draw