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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Show an image using gloo, with on-mouseover cross-section visualizations.
"""
import numpy as np
from vispy import app
from vispy.gloo import set_viewport, clear, set_state, Program
# Image
def func(x, y):
return (1-x/2+x**5+y**3)*np.exp(-x**2-y**2)
x = np.linspace(-3.0, 3.0, 512).astype(np.float32)
y = np.linspace(-3.0, 3.0, 512).astype(np.float32)
X, Y = np.meshgrid(x, y)
idxs = func(X, Y)
# Image normalization
vmin, vmax = idxs.min(), idxs.max()
idxs = (idxs - vmin) / (vmax - vmin)
# Colormaps
colormaps = np.ones((16, 512, 4)).astype(np.float32)
values = np.linspace(0, 1, 512)[1:-1]
# Hot colormap
colormaps[0, 0] = 0, 0, 1, 1 # Low values (< vmin)
colormaps[0, -1] = 0, 1, 0, 1 # High values (> vmax)
colormaps[0, 1:-1, 0] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 1.00, 1.00, 1.00])
colormaps[0, 1:-1, 1] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 0.00, 1.00, 1.00])
colormaps[0, 1:-1, 2] = np.interp(values, [0.00, 0.33, 0.66, 1.00],
[0.00, 0.00, 0.00, 1.00])
# Grey colormap
colormaps[1, 0] = 0, 0, 1, 1 # Low values (< vmin)
colormaps[1, -1] = 0, 1, 0, 1 # High values (> vmax)
colormaps[1, 1:-1, 0] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
colormaps[1, 1:-1, 1] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
colormaps[1, 1:-1, 2] = np.interp(values, [0.00, 1.00],
[0.00, 1.00])
# Jet colormap
# ...
lines_vertex = """
attribute vec2 position;
attribute vec4 color;
varying vec4 v_color;
void main()
{
gl_Position = vec4(position, 0.0, 1.0 );
v_color = color;
}
"""
lines_fragment = """
varying vec4 v_color;
void main()
{
gl_FragColor = v_color;
}
"""
image_vertex = """
attribute vec2 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0 );
v_texcoord = texcoord;
}
"""
image_fragment = """
uniform float vmin;
uniform float vmax;
uniform float cmap;
uniform float n_colormaps;
uniform sampler2D image;
uniform sampler2D colormaps;
varying vec2 v_texcoord;
void main()
{
float value = texture2D(image, v_texcoord).r;
float index = (cmap+0.5) / n_colormaps;
if( value < vmin ) {
gl_FragColor = texture2D(colormaps, vec2(0.0,index));
} else if( value > vmax ) {
gl_FragColor = texture2D(colormaps, vec2(1.0,index));
} else {
value = (value-vmin)/(vmax-vmin);
value = 1.0/512.0 + 510.0/512.0*value;
gl_FragColor = texture2D(colormaps, vec2(value,index));
}
}
"""
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, size=(512, 512),
keys='interactive')
self.image = Program(image_vertex, image_fragment, 4)
self.image['position'] = (-1, -1), (-1, +1), (+1, -1), (+1, +1)
self.image['texcoord'] = (0, 0), (0, +1), (+1, 0), (+1, +1)
self.image['vmin'] = +0.0
self.image['vmax'] = +1.0
self.image['cmap'] = 0 # Colormap index to use
self.image['colormaps'] = colormaps
self.image['n_colormaps'] = colormaps.shape[0]
self.image['image'] = idxs.astype('float32')
self.image['image'].interpolation = 'linear'
set_viewport(0, 0, *self.physical_size)
self.lines = Program(lines_vertex, lines_fragment)
self.lines["position"] = np.zeros((4+4+514+514, 2), np.float32)
color = np.zeros((4+4+514+514, 4), np.float32)
color[1:1+2, 3] = 0.25
color[5:5+2, 3] = 0.25
color[9:9+512, 3] = 0.5
color[523:523+512, 3] = 0.5
self.lines["color"] = color
set_state(clear_color='white', blend=True,
blend_func=('src_alpha', 'one_minus_src_alpha'))
self.show()
def on_resize(self, event):
set_viewport(0, 0, *event.physical_size)
def on_draw(self, event):
clear(color=True, depth=True)
self.image.draw('triangle_strip')
self.lines.draw('line_strip')
def on_mouse_move(self, event):
x, y = event.pos
w, h = self.size
# Make sure the mouse isn't outside of the viewport.
x = max(0, min(x, w - 1))
y = max(0, min(y, h - 1))
yf = 1 - y/(h/2.)
xf = x/(w/2.) - 1
x_norm = int((x*512)//w)
y_norm = int((y*512)//h)
P = np.zeros((4+4+514+514, 2), np.float32)
x_baseline = P[:4]
y_baseline = P[4:8]
x_profile = P[8:522]
y_profile = P[522:]
x_baseline[...] = (-1, yf), (-1, yf), (1, yf), (1, yf)
y_baseline[...] = (xf, -1), (xf, -1), (xf, 1), (xf, 1)
x_profile[1:-1, 0] = np.linspace(-1, 1, 512)
x_profile[1:-1, 1] = yf + 0.15 * idxs[y_norm, :]
x_profile[0] = x_profile[1]
x_profile[-1] = x_profile[-2]
y_profile[1:-1, 0] = xf + 0.15 * idxs[:, x_norm]
y_profile[1:-1, 1] = np.linspace(-1, 1, 512)
y_profile[0] = y_profile[1]
y_profile[-1] = y_profile[-2]
self.lines["position"] = P
self.update()
if __name__ == '__main__':
canvas = Canvas()
app.run()
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