implement GLPainterItem

examples/GLPainterItem.py

@@ -0,0 +1,94 @@
+"""
+Demonstrate using QPainter on a subclass of GLGraphicsItem.
+"""
+## Add path to library (just for examples; you do not need this)
+import initExample
+
+import pyqtgraph as pg
+import pyqtgraph.opengl
+from pyqtgraph.Qt import QtCore, QtGui
+import OpenGL.GL as GL
+
+SIZE = 32
+
+class GLPainterItem(pg.opengl.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().opts
+        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 = pg.opengl.GLViewWidget()
+glv.show()
+glv.setWindowTitle('pyqtgraph example: GLPainterItem')
+glv.setCameraPosition(distance=50, elevation=90, azimuth=0)
+
+griditem = pg.opengl.GLGridItem()
+griditem.setSize(SIZE, SIZE)
+griditem.setSpacing(1, 1)
+glv.addItem(griditem)
+
+axisitem = pg.opengl.GLAxisItem()
+axisitem.setSize(SIZE/2, SIZE/2, 1)
+glv.addItem(axisitem)
+
+paintitem = GLPainterItem()
+glv.addItem(paintitem)
+
+if __name__ == '__main__':
+    pg.exec()

examples/utils.py

@@ -74,6 +74,7 @@ examples_ = OrderedDict([
         ('Mesh', 'GLMeshItem.py'),
         ('Image', 'GLImageItem.py'),
         ('Text', 'GLTextItem.py'),
+        ('Painter', 'GLPainterItem.py'),
     ])),
     ('Widgets', OrderedDict([
         ('PlotWidget', 'PlotWidget.py'),