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import numpy as np
from .. import gloo
from .visual import Visual
VERT_SHADER = """
attribute vec2 a_pos;
varying vec4 v_color;
void main() {
vec4 pos = vec4(a_pos, 0, 1);
if($is_vertical==1)
{
pos.y = $render_to_visual(pos).y;
}
else
{
pos.x = $render_to_visual(pos).x;
}
gl_Position = $transform(pos);
gl_PointSize = 10;
v_color = $color;
}
"""
FRAG_SHADER = """
varying vec4 v_color;
void main() {
gl_FragColor = v_color;
}
"""
class InfiniteLineVisual(Visual):
"""Infinite horizontal or vertical line for 2D plots.
Parameters
----------
pos : float
Position of the line along the axis.
color : list, tuple, or array
The color to use when drawing the line. If an array is given, it
must be of shape (1, 4) and provide one rgba color per vertex.
vertical:
True for drawing a vertical line, False for an horizontal line
"""
def __init__(self, pos=None, color=(1.0, 1.0, 1.0, 1.0),
vertical=True, **kwargs):
"""
"""
Visual.__init__(self, vcode=VERT_SHADER, fcode=FRAG_SHADER, **kwargs)
self._changed = {'pos': False, 'color': False}
self.pos_buf = gloo.VertexBuffer()
# The Visual superclass contains a MultiProgram, which is an object
# that behaves like a normal shader program (you can assign shader
# code, upload values, set template variables, etc.) but internally
# manages multiple ModularProgram instances, one per view.
# The MultiProgram is accessed via the `shared_program` property, so
# the following modifications to the program will be applied to all
# views:
self.shared_program['a_pos'] = self.pos_buf
self._program.vert['is_vertical'] = 1 if vertical else 0
self._need_upload = False
self._is_vertical = bool(vertical)
self._pos = np.zeros((2, 2), dtype=np.float32)
self._color = np.ones(4, dtype=np.float32)
# Visual keeps track of draw mode, index buffer, and GL state. These
# are shared between all views.
self._draw_mode = 'line_strip'
self.set_gl_state('translucent', depth_test=False)
self.set_data(pos=pos, color=color)
def set_data(self, pos=None, color=None):
"""Set the data
Parameters
----------
pos : float
Position of the line along the axis.
color : list, tuple, or array
The color to use when drawing the line. If an array is given, it
must be of shape (1, 4) and provide one rgba color per vertex.
"""
if pos is not None:
pos = float(pos)
xy = self._pos
if self._is_vertical:
xy[0, 0] = pos
xy[0, 1] = -1
xy[1, 0] = pos
xy[1, 1] = 1
else:
xy[0, 0] = -1
xy[0, 1] = pos
xy[1, 0] = 1
xy[1, 1] = pos
self._changed['pos'] = True
if color is not None:
color = np.array(color, dtype=np.float32)
if color.ndim != 1 or color.shape[0] != 4:
raise ValueError('color must be a 4 element float rgba tuple,'
' list or array')
self._color = color
self._changed['color'] = True
@property
def color(self):
return self._color
@property
def pos(self):
if self._is_vertical:
return self._pos[0, 0]
else:
return self._pos[0, 1]
def _compute_bounds(self, axis, view):
"""Return the (min, max) bounding values of this visual along *axis*
in the local coordinate system.
"""
is_vertical = self._is_vertical
pos = self._pos
if axis == 0 and is_vertical:
return (pos[0, 0], pos[0, 0])
elif axis == 1 and not is_vertical:
return (self._pos[0, 1], self._pos[0, 1])
return None
@property
def is_vertical(self):
return self._is_vertical
def _prepare_transforms(self, view=None):
program = view.view_program
transforms = view.transforms
program.vert['render_to_visual'] = transforms.get_transform('render',
'visual')
program.vert['transform'] = transforms.get_transform('visual',
'render')
def _prepare_draw(self, view=None):
"""This method is called immediately before each draw.
The *view* argument indicates which view is about to be drawn.
"""
if self._changed['pos']:
self.pos_buf.set_data(self._pos)
self._changed['pos'] = False
if self._changed['color']:
self._program.vert['color'] = self._color
self._changed['color'] = False