CODEWITHSUNDEEP
pythonopenglpyqtgraphpyopenglqgraphicstextitem
Luiz Tauffer
Luiz Tauffer

Reputation: 632

How to add Axis features (labels, ticks, values) to a 3D plot with GLViewWidget of pyqtgraph?

I want to add axis info such as labels, ticks and values to a 3D scene created with the pyqtgraph.opengl.GLViewWidget module. There is already a very simple axis drawing option with GLAxisItem, but with this you can only control the length of the axes.

I've extended GLAxisItem to change the axis color, but can't see the way to include these other features.

Here's an example:

from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph.opengl as gl
import pyqtgraph as pg
import OpenGL.GL as ogl
import numpy as np

class CustomTextItem(gl.GLGraphicsItem.GLGraphicsItem):
    def __init__(self, X, Y, Z, text):
        gl.GLGraphicsItem.GLGraphicsItem.__init__(self)
        self.text = text
        self.X = X
        self.Y = Y
        self.Z = Z

    def setGLViewWidget(self, GLViewWidget):
        self.GLViewWidget = GLViewWidget

    def setText(self, text):
        self.text = text
        self.update()

    def setX(self, X):
        self.X = X
        self.update()

    def setY(self, Y):
        self.Y = Y
        self.update()

    def setZ(self, Z):
        self.Z = Z
        self.update()

    def paint(self):
        self.GLViewWidget.qglColor(QtCore.Qt.black)
        self.GLViewWidget.renderText(self.X, self.Y, self.Z, self.text)


class Custom3DAxis(gl.GLAxisItem):
    """Class defined to extend 'gl.GLAxisItem'."""
    def __init__(self, parent, color=(0,0,0,.6)):
        gl.GLAxisItem.__init__(self)
        self.parent = parent
        self.c = color

    def draw_labels(self):
        x,y,z = self.size()
        #X label
        self.xLabel = CustomTextItem(X=x/2, Y=-y/20, Z=-z/20, text="X")
        self.xLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.xLabel)
        #Y label
        self.yLabel = CustomTextItem(X=-x/20, Y=y/2, Z=-z/20, text="Y")
        self.yLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.yLabel)
        #Z label
        self.zLabel = CustomTextItem(X=-x/20, Y=-y/20, Z=z/2, text="Z")
        self.zLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.zLabel)

    def paint(self):
        self.setupGLState()
        if self.antialias:
            ogl.glEnable(ogl.GL_LINE_SMOOTH)
            ogl.glHint(ogl.GL_LINE_SMOOTH_HINT, ogl.GL_NICEST)
        ogl.glBegin(ogl.GL_LINES)

        x,y,z = self.size()
        #Draw Z
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(0, 0, z)
        #Draw Y
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(0, y, 0)
        #Draw X
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(x, 0, 0)
        #Draw labels
        self.draw_labels()
        ogl.glEnd()


app = QtGui.QApplication([])
fig1 = gl.GLViewWidget()
background_color = app.palette().color(QtGui.QPalette.Background)
fig1.setBackgroundColor(background_color)

n = 51
y = np.linspace(-10,10,n)
x = np.linspace(-10,10,100)
for i in range(n):
    yi = np.array([y[i]]*100)
    d = (x**2 + yi**2)**0.5
    z = 10 * np.cos(d) / (d+1)
    pts = np.vstack([x,yi,z]).transpose()
    plt = gl.GLLinePlotItem(pos=pts, color=pg.glColor((i,n*1.3)), width=(i+1)/10., antialias=True)
    fig1.addItem(plt)


axis = Custom3DAxis(fig1, color=(0.2,0.2,0.2,.6))
axis.setSize(x=12, y=12, z=12)
fig1.addItem(axis)
fig1.opts['distance'] = 40

fig1.show()

if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

It would be perfect if those features didn't change size with zooming.

--- Update ---

From here, I got how to create custom text items and extended my Custom3DAxis class to include X, Y and Z labels (code above is updated with it). I imagine that's the way to go to further include values and other things.

However, this solution causes the rendering to become very slow at each rotation/span (that is, at each scene update), just because of these 3 text items!

Does anyone have a clue on why is that? What should I do to avoid this?

Upvotes: 1

Views: 4143

Answers (2)

pnp. peeyush
pnp. peeyush

Reputation: 1

Ok bear with me, coz I've never written a class before in my life. But I did "borrow" your code and made some modifications to add more features.

Here is the modified GLTextItem file that I added to where all the 'GL item' files are kept in the pyQtGraph folder.

And here is the modified GLAxisItem file, I used your code and added some more features to the original GLAxisItem file in the pyQtGraph folder.

And here is the file that I'm using to debug both the axis and text item.

please take a look at these files and try to run them. I have a bug in GLAxisItem, there is a default label which is shown when no axis label is specified. But when I create the axis object and use the setAxisLabel() method to specify axis labels and their locations, the default text is still shown, it doesn't go away... any fix to this?

Here's the full repo link.

Upvotes: 0

Luiz Tauffer
Luiz Tauffer

Reputation: 632

Ok, I got a reasonable solution: creating text items for each label and value to be added. The slowing problem was caused because, in the questions code, more of the new items were being added (instead of just updating the initial ones) at each scene update. Here's a code that solves the question:

from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph.opengl as gl
import pyqtgraph as pg
import OpenGL.GL as ogl
import numpy as np

class CustomTextItem(gl.GLGraphicsItem.GLGraphicsItem):
    def __init__(self, X, Y, Z, text):
        gl.GLGraphicsItem.GLGraphicsItem.__init__(self)
        self.text = text
        self.X = X
        self.Y = Y
        self.Z = Z

    def setGLViewWidget(self, GLViewWidget):
        self.GLViewWidget = GLViewWidget

    def setText(self, text):
        self.text = text
        self.update()

    def setX(self, X):
        self.X = X
        self.update()

    def setY(self, Y):
        self.Y = Y
        self.update()

    def setZ(self, Z):
        self.Z = Z
        self.update()

    def paint(self):
        self.GLViewWidget.qglColor(QtCore.Qt.black)
        self.GLViewWidget.renderText(self.X, self.Y, self.Z, self.text)


class Custom3DAxis(gl.GLAxisItem):
    """Class defined to extend 'gl.GLAxisItem'."""
    def __init__(self, parent, color=(0,0,0,.6)):
        gl.GLAxisItem.__init__(self)
        self.parent = parent
        self.c = color

    def add_labels(self):
        """Adds axes labels."""
        x,y,z = self.size()
        #X label
        self.xLabel = CustomTextItem(X=x/2, Y=-y/20, Z=-z/20, text="X")
        self.xLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.xLabel)
        #Y label
        self.yLabel = CustomTextItem(X=-x/20, Y=y/2, Z=-z/20, text="Y")
        self.yLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.yLabel)
        #Z label
        self.zLabel = CustomTextItem(X=-x/20, Y=-y/20, Z=z/2, text="Z")
        self.zLabel.setGLViewWidget(self.parent)
        self.parent.addItem(self.zLabel)

    def add_tick_values(self, xticks=[], yticks=[], zticks=[]):
        """Adds ticks values."""
        x,y,z = self.size()
        xtpos = np.linspace(0, x, len(xticks))
        ytpos = np.linspace(0, y, len(yticks))
        ztpos = np.linspace(0, z, len(zticks))
        #X label
        for i, xt in enumerate(xticks):
            val = CustomTextItem(X=xtpos[i], Y=-y/20, Z=-z/20, text=str(xt))
            val.setGLViewWidget(self.parent)
            self.parent.addItem(val)
        #Y label
        for i, yt in enumerate(yticks):
            val = CustomTextItem(X=-x/20, Y=ytpos[i], Z=-z/20, text=str(yt))
            val.setGLViewWidget(self.parent)
            self.parent.addItem(val)
        #Z label
        for i, zt in enumerate(zticks):
            val = CustomTextItem(X=-x/20, Y=-y/20, Z=ztpos[i], text=str(zt))
            val.setGLViewWidget(self.parent)
            self.parent.addItem(val)

    def paint(self):
        self.setupGLState()
        if self.antialias:
            ogl.glEnable(ogl.GL_LINE_SMOOTH)
            ogl.glHint(ogl.GL_LINE_SMOOTH_HINT, ogl.GL_NICEST)
        ogl.glBegin(ogl.GL_LINES)

        x,y,z = self.size()
        #Draw Z
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(0, 0, z)
        #Draw Y
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(0, y, 0)
        #Draw X
        ogl.glColor4f(self.c[0], self.c[1], self.c[2], self.c[3])
        ogl.glVertex3f(0, 0, 0)
        ogl.glVertex3f(x, 0, 0)
        ogl.glEnd()


app = QtGui.QApplication([])
fig1 = gl.GLViewWidget()
background_color = app.palette().color(QtGui.QPalette.Background)
fig1.setBackgroundColor(background_color)

n = 51
y = np.linspace(-10,10,n)
x = np.linspace(-10,10,100)
for i in range(n):
    yi = np.array([y[i]]*100)
    d = (x**2 + yi**2)**0.5
    z = 10 * np.cos(d) / (d+1)
    pts = np.vstack([x,yi,z]).transpose()
    plt = gl.GLLinePlotItem(pos=pts, color=pg.glColor((i,n*1.3)), width=(i+1)/10., antialias=True)
    fig1.addItem(plt)


axis = Custom3DAxis(fig1, color=(0.2,0.2,0.2,.6))
axis.setSize(x=12, y=12, z=12)
# Add axes labels
axis.add_labels()
# Add axes tick values
axis.add_tick_values(xticks=[0,4,8,12], yticks=[0,6,12], zticks=[0,3,6,9,12])
fig1.addItem(axis)
fig1.opts['distance'] = 40

fig1.show()

if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

Upvotes: 4

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