我实现了以下代码:
void TestGlPlot::resizeGL(int width, int height)
{
setupViewport(width, height);
}
void TestGlPlot::setupViewport(int width, int height)
{
/* Prevent divide by zero --------------------------------------------------------------------*/
if (height == 0) height = 1;
/* Calculate aspect ratio --------------------------------------------------------------------*/
float aspectRatio = (float)width / (float)height;
/* Set viewport to cover the window ----------------------------------------------------------*/
glViewport(0, 0, width, height);
/* Set aspect ratio --------------------------------------------------------------------------*/
glMatrixMode(GL_PROJECTION); /* switch to projection matrix */
glLoadIdentity();
/*
if (width >= height)
{
gluOrtho2D(-0.5*aspectRatio, 0.5*aspectRatio, 0.0, 1.0);
}
else
{
gluOrtho2D(-0.5, 0.5, 0.0*aspectRatio, 1.0*aspectRatio);
}
glMatrixMode(GL_MODELVIEW);
*/
gluOrtho2D(-1, 1, 0.0, 1.0);
glMatrixMode(GL_MODELVIEW);
}
void TestGlPlot::paintEvent(QPaintEvent *event) {
makeCurrent();
setupViewport(width(), height());
glMatrixMode(GL_MODELVIEW);
/* Set white background ----------------------------------------------------------------------*/
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(255,255,255,0);
/* Paint OpenGL events -----------------------------------------------------------------------*/
glColor4f(1.0, 0.0, 0.0, 1.0);
/* light grey */
glColor4f(0.0, 0.0, 0.0, 0.3);
gluPartialDisk(plainQuad, 0.1, 1, 20, 4, -60, 120);
/* Paint QPainter events ---------------------------------------------------------------------*/
QPainter painter(this);
/* Draw grey border around plot --------------------------------------------------------------*/
painter.setPen(QColor("#808080"));
painter.drawRect(0, 0, width()-1, height()-1);
painter.setFont(font);
/* Translate coordinate system to (0,0) center -----------------------------------------------*/
QMatrix m;
m.translate(width()*0.5, height()*0.5);
painter.setMatrix(m);
/* Left side descriptions for radius ---------------------------------------------------------*/
painter.drawText(-0.17*width(), 0.38*height(), tr("100m"));
painter.drawText(-0.27*width(), 0.28*height(), tr("200m"));
painter.drawText(-0.37*width(), 0.18*height(), tr("300m"));
painter.drawText(-0.47*width(), 0.08*height(), tr("400m"));
painter.drawText(0.45*width(), -0.01*height(), tr("60°"));
painter.drawText(0.26*width(), -0.38*height(), tr("30°"));
painter.drawText(-0.47*width(), -0.01*height(), tr("300°"));
painter.drawText(-0.28*width(), -0.38*height(), tr("330°"));
painter.end();
}
我尝试了不同的方法来调整大小处理(保持 partialDisk 对象的形状而不拉伸(stretch)它),但每种方法都失败了。我还想保留单位圆的坐标处理(这样我就可以标准化我的测量并将它们绘制成极坐标图)。
最佳答案
为了保持纵横比,您通常有几种选择:
在您的代码中,您几乎已经实现了方法 2,但是您的 aspectRatio < 1 case 错误,应该是
if (width >= height)
gluOrtho2D(-0.5f*aspectRatio, 0.5f*aspectRatio, 0.0f, 1.0f);
else
gluOrtho2D(-0.5f, 0.5f, 0.0, 1.0/aspectRatio);
关于opengl - 在 OpenGL 中调整大小时保持纵横比,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16498784/