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"""
Demonstrate using QPainter on a subclass of GLGraphicsItem.
"""
import OpenGL.GL as GL
import pyqtgraph as pg
from pyqtgraph.opengl import GLAxisItem, GLGraphicsItem, GLGridItem, GLViewWidget
from pyqtgraph.Qt import QtCore, QtGui
SIZE = 32
class GLPainterItem(GLGraphicsItem.GLGraphicsItem):
def __init__(self, **kwds):
super().__init__()
glopts = kwds.pop('glOptions', 'additive')
self.setGLOptions(glopts)
def compute_projection(self):
modelview = GL.glGetDoublev(GL.GL_MODELVIEW_MATRIX)
projection = GL.glGetDoublev(GL.GL_PROJECTION_MATRIX)
mvp = projection.T @ modelview.T
mvp = QtGui.QMatrix4x4(mvp.ravel().tolist())
# note that QRectF.bottom() != QRect.bottom()
rect = QtCore.QRectF(self.view().rect())
ndc_to_viewport = QtGui.QMatrix4x4()
ndc_to_viewport.viewport(rect.left(), rect.bottom(), rect.width(), -rect.height())
return ndc_to_viewport * mvp
def paint(self):
self.setupGLState()
painter = QtGui.QPainter(self.view())
self.draw(painter)
painter.end()
def draw(self, painter):
painter.setPen(QtCore.Qt.GlobalColor.white)
painter.setRenderHints(QtGui.QPainter.RenderHint.Antialiasing | QtGui.QPainter.RenderHint.TextAntialiasing)
rect = self.view().rect()
af = QtCore.Qt.AlignmentFlag
painter.drawText(rect, af.AlignTop | af.AlignRight, 'TR')
painter.drawText(rect, af.AlignBottom | af.AlignLeft, 'BL')
painter.drawText(rect, af.AlignBottom | af.AlignRight, 'BR')
opts = self.view().cameraParams()
lines = []
center = opts['center']
lines.append(f"center : ({center.x():.1f}, {center.y():.1f}, {center.z():.1f})")
for key in ['distance', 'fov', 'elevation', 'azimuth']:
lines.append(f"{key} : {opts[key]:.1f}")
xyz = self.view().cameraPosition()
lines.append(f"xyz : ({xyz.x():.1f}, {xyz.y():.1f}, {xyz.z():.1f})")
info = "\n".join(lines)
painter.drawText(rect, af.AlignTop | af.AlignLeft, info)
project = self.compute_projection()
hsize = SIZE // 2
for xi in range(-hsize, hsize+1):
for yi in range(-hsize, hsize+1):
if xi == -hsize and yi == -hsize:
# skip one corner for visual orientation
continue
vec3 = QtGui.QVector3D(xi, yi, 0)
pos = project.map(vec3).toPointF()
painter.drawEllipse(pos, 1, 1)
pg.mkQApp("GLPainterItem Example")
glv = GLViewWidget()
glv.show()
glv.setWindowTitle('pyqtgraph example: GLPainterItem')
glv.setCameraPosition(distance=50, elevation=90, azimuth=0)
griditem = GLGridItem()
griditem.setSize(SIZE, SIZE)
griditem.setSpacing(1, 1)
glv.addItem(griditem)
axisitem = GLAxisItem()
axisitem.setSize(SIZE/2, SIZE/2, 1)
glv.addItem(axisitem)
paintitem = GLPainterItem()
glv.addItem(paintitem)
if __name__ == '__main__':
pg.exec()
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