.. currentmodule:: mayavi.mlab
.. note::
This section is only a reference describing the function, please see
the chapter on :ref:`simple-scripting-with-mlab` for an introduction to
mlab and how to interact with and assemble the functions of `mlab`.
Please see the section on :ref:`running-mlab-scripts` for
instructions on running the examples.
Camera handling functions
=========================
move
~~~~
.. function:: move(forward=None, right=None, up=None)
Translates the camera and focal point together.
The arguments specify the relative distance to translate the
camera and focal point, so as to produce the appearence of
moving the camera without changing the effective field of view.
If called with no arguments, the function returns the absolute
position of the camera and focal pointon a cartesian coordinate
system.
Note that the arguments specify relative motion, although the
return value with no arguments is in an absolute coordinate system.
**Keyword arguments**:
:forward: float, optional. The distance in space to translate the
camera forward (if positive) or backward (if negative)
:right: float, optional. The distance in space to translate the
camera to the right (if positive) or left (if negative)
:up: float, optional. The distance in space to translate the
camera up (if positive) or down (if negative)
**Returns**:
If no arguments are supplied (or all are None), returns a
tuple (camera_position, focal_point_position)
otherwise, returns None
**Examples**:
Get the current camera position::
>>> cam,foc = move()
>>> cam
array([-0.06317079, -0.52849738, -1.68316389])
>>> foc
array([ 1.25909623, 0.15692708, -0.37576693])
Translate the camera::
>>> move(3,-1,-1.2)
>>> move()
(array([ 2.93682921, -1.52849738, -2.88316389]),
array([ 4.25909623, -0.84307292, -1.57576693]))
Return to the starting position::
>>> move(-3,1,1.2)
>>> move()
(array([-0.06317079, -0.52849738, -1.68316389]),
array([ 1.25909623, 0.15692708, -0.37576693]))
**See also**
:mlab.yaw: yaw the camera (tilt left-right)
:mlab.pitch: pitch the camera (tilt up-down)
:mlab.roll: control the absolute roll angle of the camera
:mlab.view: set the camera position relative to the focal point instead
of in absolute space
pitch
~~~~~
.. function:: pitch(degrees)
Rotates the camera about the axis corresponding to the
"right" direction of the current view. Note that this will
change the location of the focal point (although not the
camera location).
This angle is relative to the current direction - the
angle is NOT an absolute angle in a fixed coordinate
system.
**See also**
:mlab.yaw: relative rotation about the "up" direction
:mlab.roll: absolute roll angle (i.e. "up" direction)
:mlab.move: relative translation of the camera and focal
point
roll
~~~~
.. function:: roll(roll=None, figure=None)
Sets or returns the absolute roll angle of the camera.
**See also**
:mlab.view: control the position and direction of the camera
view
~~~~
.. function:: view(azimuth=None, elevation=None, distance=None, focalpoint=None, roll=None, reset_roll=True, figure=None)
Sets/Gets the view point for the camera::
view(azimuth=None, elevation=None, distance=None, focalpoint=None,
roll=None, reset_roll=True, figure=None)
If called with no arguments this returns the current view of the
camera. To understand how this function works imagine the surface
of a sphere centered around the visualization. The `azimuth`
argument specifies the angle "phi" on the x-y plane which varies
from 0-360 degrees. The `elevation` argument specifies the angle
"theta" from the z axis and varies from 0-180 degrees. The
`distance` argument is the radius of the sphere and the
`focalpoint`, the center of the sphere.
Note that if the `elevation` is close to zero or 180, then the
`azimuth` angle refers to the amount of rotation of a standard x-y
plot with respect to the x-axis. Thus, specifying ``view(0,0)``
will give you a typical x-y plot with x varying from left to right
and y from bottom to top.
**Keyword arguments**:
:azimuth: float, optional. The azimuthal angle (in degrees, 0-360),
i.e. the angle subtended by the position vector on a sphere
projected on to the x-y plane with the x-axis.
:elevation: float, optional. The zenith angle (in degrees, 0-180),
i.e. the angle subtended by the position vector and the z-axis.
:distance: float or 'auto', optional.
A positive floating point number representing the distance from
the focal point to place the camera. New in Mayavi 3.4.0: if
'auto' is passed, the distance is computed to have a best fit of
objects in the frame.
:focalpoint: array_like or 'auto', optional.
An array of 3 floating point numbers representing the focal point
of the camera. New in Mayavi 3.4.0: if 'auto' is passed, the
focal point is positioned at the center of all objects in the
scene.
:roll: float, optional
Controls the roll, ie the rotation of the camera around its axis.
:reset_roll: boolean, optional.
If True, and 'roll' is not specified, the roll orientation of the
camera is reset.
:figure: The Mayavi figure to operate on. If None is passed, the
current one is used.
**Returns**:
If no arguments are supplied it returns a tuple of 4 values
``(azimuth, elevation, distance, focalpoint)``, representing the
current view. Note that these can be used later on to set the view.
If arguments are supplied it returns `None`.
**Examples**:
Get the current view::
>>> v = view()
>>> v
(45.0, 45.0, 25.02794981, array([ 0.01118028, 0. , 4.00558996]))
Set the view in different ways::
>>> view(45, 45)
>>> view(240, 120)
>>> view(distance=20)
>>> view(focalpoint=(0,0,9))
Set the view to that saved in `v` above::
>>> view(*v)
**See also**
:mlab.roll: control the roll angle of the camera, ie the direction
pointing up
yaw
~~~
.. function:: yaw(degrees)
Rotates the camera about the axis corresponding to the
"up" direction of the current view. Note that this will
change the location of the focal point (although not the
camera location).
This angle is relative to the current direction - the
angle is NOT an absolute angle in a fixed coordinate
system.
**See also**
:mlab.pitch: relative rotation about the "right" direction
:mlab.roll: absolute roll angle (i.e. "up" direction)
:mlab.move: relative translation of the camera and focal
point