Vispy pres minimal

vispy_pres.py

import itertools
import os
import hashlib

import numpy as np
import vispy
from vispy import app
from vispy import scene
from vispy import gloo

# Shorthands
from vispy.scene.visuals import Text
from vispy.scene.visuals import Image

class Presentation(scene.SceneCanvas):
    """ Presentation canvas.
    """
    
    def __init__(self, title='A presentation', **kwargs):
        self._current_slide = 0
        self._slides = []
        scene.SceneCanvas.__init__(self, title=title, bgcolor='white', **kwargs)
        self.size = 800, 600
        refresh = lambda x: self.update()
        self._timer = app.Timer(1/30, connect=refresh, start=True)
        
        # Create toplevel viewbox that we can use to see whole presentation
        self._top_vb = scene.widgets.ViewBox(parent=self.scene, border_color=None)
        #self._top_vb.camera = scene.cameras.PerspectiveCamera('perspective')
        #self._top_vb.camera.fov = 80
        self._top_vb.camera = scene.cameras.TurntableCamera()
        self._top_vb.camera.center = -2000, -200, -2000
        self._top_vb.camera.width = 15000
        self._top_vb.camera.azimuth = -60
        self._top_vb.camera._update_camera_pos()  # todo: camera must do this
        self._top_vb.size = self.size
        
        self.show_text = True
    
    def on_initialize(self, event):
        gloo.set_state('translucent',
        #blend=True,
                       #blend_func=('src_alpha', 'one_minus_src_alpha'),
                       depth_test=False)

    def on_resize(self, event):
        gloo.set_viewport(0, 0, *self.size)
        for slide in self._slides:
            expand = self.size[0] / self.size[1]
            slide.camera.rect = -0.5*(expand-1), 0, expand, 1
            slide.size = self.size
    
    def add_slide(self, title=None, cls=None):
        # todo: make _children a list or ordered set
        # Create super viewbox
        super_vb = scene.widgets.ViewBox(parent= self._top_vb.scene, border_color='b')
        super_vb.transform = scene.transforms.AffineTransform()
        for i in range(len(self._slides)):
            super_vb.transform.rotate(-10, (0, 1, 0))
            super_vb.transform.translate((1000, 0))
        super_vb.size = self.size
        super_vb.camera = scene.cameras.BaseCamera()  # Null camera
        
        # Create slide itself
        cls = cls or Slide
        slide = cls(parent=super_vb.scene, border_color=None)
        slide.camera.interactive = False
        slide.camera.invert_y = False
        expand = self.size[0] / self.size[1]
        slide.camera.rect = 0, 0, 1, 1  # overwritten on resize
        self._slides.append(slide)
        slide.size = self.size
        slide.clip_method = 'viewport'
        slide.events.add(key_press=None)
        slide.scene._systems['draw'] = DrawingSystem()
        if title:
            slide.set_title(title)
        # Select this slide now?
        if len(self._slides) == 1:
            self.scene = self._slides[-1].superviewbox.scene
        return slide
    
    def on_key_press(self, event):
        if event.key == vispy.keys.HOME:
            self.scene = self._top_vb.parent
        elif event.key in (vispy.keys.LEFT, vispy.keys.RIGHT, vispy.keys.END, vispy.keys.SPACE):
            for child in self._slides[self._current_slide].scene.children:
                if hasattr(child, 'on_leave_slide'): child.on_leave_slide()
            M = {vispy.keys.LEFT:-1, vispy.keys.RIGHT:1, vispy.keys.SPACE:1}
            self._current_slide += M.get(event.key, 0)
            self._current_slide = max(min(self._current_slide, len(self._slides)-1), 0)
            self.scene = self._slides[self._current_slide].superviewbox.scene
            for child in self._slides[self._current_slide].scene.children:
                if hasattr(child, 'on_enter_slide'): child.on_enter_slide()
        elif event.text.lower() == 'f':
            self.fullscreen = not self.fullscreen
            self.on_resize(None)
        else:
            self._slides[self._current_slide].events.key_press(event)
        self.show_text = self.scene is not self._top_vb.parent


class Slide(scene.widgets.ViewBox):
    """ Representation of a slide in the presentation in the form of a viewbox.
    """
    
    @property
    def superviewbox(self):
        return self.parent.parent
    
    def set_title(self, text):
        text = Text(text, parent=self.scene, pos=(0.5, 0.1), 
                    font_size=26, bold=True, color='#002233', 
                    font_manager=font_manager)
        return text
    
    def add_text(self, text, pos, size=20, anchor_x='left', **kwargs):
        text = Text(text, parent=self.scene, pos=pos, font_size=size, 
                    anchor_x=anchor_x, anchor_y='center',
                    font_manager=font_manager, **kwargs)
        return text

class DrawingSystem(scene.systems.DrawingSystem):
    def _process_entity(self, event, entity, force_recurse=False):
        if (not pres.show_text) and isinstance(entity, scene.visuals.Text):
            return
        else:
            scene.systems.DrawingSystem._process_entity(self, event, entity, force_recurse)


# For more efficient fonts
font_manager = scene.visuals.text.text.FontManager()

pres = Presentation(show=True)

## Introduction


slide = pres.add_slide()
# slide.add_image('vispylogo.png', (0.42, 0.05), 0.16)
slide.add_text("Introducing Vispy's high level modules:", (0.5, 0.5), 24, 'center', color='k', bold=True)
slide.add_text("easy yet powerful visualization for everyone", (0.5, 0.6), 24, 'center', color='k', bold=True)
slide.add_text("EuroScipy - August 29, 2014", (0.5, 0.8), 20, 'center', color='b', bold=True)
t1 = slide.add_text("Almar Klein", (0.5, 0.9), 20, 'center', color='k')