如何使用QOpenGLWidget呈现文本

问题描述

在旧版本的Qt中有，其中有一个很好的函数。现在我使用类，并且缺少渲染文本的功能。

In older version of Qt there was QGLWidget, with a nice function called renderText. Now I'm using QOpenGLWidget class and the functionality for rendering text is missing.

有没有简单的方法使用QOpenGLWidget来呈现文本？我不想从头开始用OpenGL构建整个文本渲染...

Is there a easy way to render text using QOpenGLWidget? I won't like to build the whole text rendering with OpenGL from scratch...

推荐答案

到什么@jaba写。我也注意到一些图形损坏，除非我在方法结束时调用painter.end（）。

I ended up doing a solution similar to what @jaba wrote. I also noticed some graphical corruption unless I called painter.end() at the end of the method.

void MapCanvas::renderText(double x, double y, double z, const QString &str, const QFont & font = QFont()) {
    // Identify x and y locations to render text within widget
    int height = this->height();
    GLdouble textPosX = 0, textPosY = 0, textPosZ = 0;
    project(x, y, 0f, &textPosX, &textPosY, &textPosZ);
    textPosY = height - textPosY; // y is inverted

    // Retrieve last OpenGL color to use as a font color
    GLdouble glColor[4];
    glGetDoublev(GL_CURRENT_COLOR, glColor);
    QColor fontColor = QColor(glColor[0], glColor[1], glColor[2], glColor[3]);

    // Render text
    QPainter painter(this);
    painter.setPen(fontColor);
    painter.setFont(font);
    painter.drawText(textPosX, textPosY, text);
    painter.end();
}

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