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#!/usr/bin/env python3
"""A simple Qt-based virtual chalkboard program.
Draw with left-click, erase with right-click drag. Hold down the middle mouse button and drag to
pick a different colour (white, blue, red, green).
Keyboard shortcuts:
C: Erase the current board
N: Add a new board and switch to it
->: Next board
<-: Previous board
S: Save the current session to disk
U: Save a picture of the current board to the disk (c.f. the `--path` argument)
L: Switch to "laser" mode (bright red draw, disappears after a few seconds)
The usual setup is to mount a folder from some webserver on the local machine (e.g. with SSHFS) and
use the `U` key to periodically save screenshots of the current board to that folder; this way,
students can page between boards, access them in breakout rooms, and you float between breakout
rooms and still use the board. An HTML file is generated in the screenshot folder which is suitable
for displaying the images in a browser.
For example, I would mount the folder "/var/www/html/cb" on my webserver running
"https://unsuspicious.services" to "./cb" on the local machine using SSHFS, then invoke BTNS using:
./btns2.py -p ./cb -s "https://unsuspicious.services/cb" <filename>
(the filename is auto-generated if not given). The `-p` argument says to store screenshots in
"./cb" and the `-s` argument takes some text to display in the upper right corner to remind
students where to access it.
"""
import argparse
import base64
import datetime as dt
import io
import math
import os
import shutil
import sys
import threading
import time
import traceback as tb
import xml.etree.ElementTree as et
from PIL import ImageDraw, Image, ImageChops, ImageQt
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
## Default/only pen colours available
DEFAULT_COLOURS = (
QColor(255, 255, 255), ## White
QColor(0x64, 0xA5, 0xFF), ## Blue
QColor(0xFF, 0x64, 0x64), ## Red
QColor(0x83, 0xF7, 0x83), ## Green
)
BXW = "{https://unsuspicious.services/btns}"
HTML_TEMPLATE = """<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>BTNS v2</title>
</head>
<body>
<!-- Don't be so nosy, get back to work! -->
<div style="width: 80%; margin: 0 auto">
<h1>Chalkboards</h1>
{items}
</div>
</body>
</html>
"""
HTML_ITEM_TEMPLATE = """ <h2>{name}</h2>
<img width="100%" src="{src}"/>"""
## A small piece of H*goromo chalk
CURSOR = Image.open(io.BytesIO(base64.b64decode("""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""")))
## A small chalkboard eraser
ERASER = ImageQt.ImageQt(Image.open(io.BytesIO(base64.b64decode("""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"""))))
def make_cursor(colour=(255, 255, 255)):
"""Construct a new cursor by multiplying `CURSOR` with the given colour."""
other = Image.new("RGBA", (32, 32), colour)
image = ImageQt.ImageQt(ImageChops.multiply(other, CURSOR))
return QCursor(QPixmap.fromImage(image), 2, 29)
class LoadError(Exception):
pass
def xml_indent(elem, indent=4, level=0):
"""Pretty-indent the XML tree."""
i = "\n" + level*(indent*' ')
if elem:
if not elem.text or not elem.text.strip():
elem.text = i + (' '*indent)
if not elem.tail or not elem.tail.strip():
elem.tail = i
for elem in elem:
xml_indent(elem, indent=indent, level=level+1)
if not elem.tail or not elem.tail.strip():
elem.tail = i
else:
if level and (not elem.tail or not elem.tail.strip()):
elem.tail = i
class IncrementalSplineMask:
"""Class for constructing (carindal) cubic splines incrementally, i.e. adding a control point,
rendering, adding a control point, rendering, etc.
:param resolution: Parameter controlling the number of points to compute between each control
point, e.g. 0.1 for 10, 0.5 for 2.
:param tension: Controls the "smoothness" of the resulting path; this will depend on how
frequently points are added/rendered.
:param width: Width of the spline; used for image export and detecting when multiple splines
intersect. If you are rendering the spline elsewhere, that width should match
this one.
"""
@staticmethod
def _spline_points(p_0, m_0, p_1, m_1, resolution):
points = [p_0]
t = resolution
while t < 1:
h_00 = 2*(t**3) - 3*(t**2) + 1
h_10 = t**3 - 2*(t**2) + t
h_01 = -2*(t**3) + 3*(t**2)
h_11 = t**3 - t**2
points.append(tuple((int(z+0.5) for z in (h_00*c_0 + h_10*s_0 + h_01*c_1 + h_11*s_1 for c_0, s_0, c_1, s_1 in zip(p_0, m_0, p_1, m_1)))))
t += resolution
points.append(p_1)
return points
@staticmethod
def _bbox(points):
minx = None
miny = None
maxx = None
maxy = None
for x, y in points:
if minx is None or x < minx:
minx = x
if miny is None or y < miny:
miny = y
if maxx is None or x > maxx:
maxx = x
if maxy is None or y > maxy :
maxy = y
return math.floor(minx), math.floor(miny), math.ceil(maxx), math.ceil(maxy)
@staticmethod
def _overlap(x0, y0, x1, y1, x2, y2, x3, y3):
"""Compute the overlap between the two rectangles.
We assume x0 <= x1, y0 <= y1, and likewise for the other points.
"""
if None in (x0, y0, x1, y1, x2, y2, x3, y3) or x1 < x2 or x3 < x0 or y1 < y2 or y3 < y0:
## No overlap, return 4 for convenience
return None, None, None, None
minx = max(x0, x2)
maxx = min(x1, x3)
miny = max(y0, y2)
maxy = min(y1, y3)
return minx, miny, maxx, maxy
@staticmethod
def composite(background, *splines, size=None):
"""Return a composite image of the given splines.
:param size: The desired size; if not given, it is computed from the bounding boxes of the
splines.
"""
maxx = max((i.maxx for i in splines if i.maxx is not None))
maxy = max((i.maxy for i in splines if i.maxy is not None))
if size is not None:
maxx = max(maxx, size[0])
maxy = max(maxy, size[1])
composite = Image.new("RGBA", (maxx+1, maxy+1), color=background)
draw = ImageDraw.Draw(composite)
for spline in splines:
if spline.maxx is None:
continue
draw.bitmap((spline.minx, spline.miny), spline.current, spline.colour)
return composite
def _update_bounds(self, temp_coords):
## It is simpler to include the temporary coordinates in the calculations, rather than try
## to save some memory by maintaining different sizes for the current and permanent images
minx, miny, maxx, maxy = self._bbox(self.coords + temp_coords)
if (minx, miny, maxx, maxy) == (self.minx, self.miny, self.maxx, self.maxy):
return
## Allocate and copy the PREVIOUS image data; when this is called, that's all we care about
new = Image.new("1", (maxx-minx+1, maxy-miny+1))
bix, biy, bax, bay = self._overlap(minx, miny, maxx, maxy, self.minx, self.miny, self.maxx, self.maxy)
if bix is not None:
prev = self.previous.crop((bix-self.minx, biy-self.miny, bax-self.minx, bay-self.miny))
new.paste(self.previous, (bix-minx, biy-miny))
self.minx, self.miny, self.maxx, self.maxy = minx, miny, maxx, maxy
self.previous = new
self.current = None
def _fix_coords(self, coords):
return [(x-self.minx, y-self.miny) for x, y in coords]
def add_points(self, *points):
"""Add points to the spline.
Updates the spline's mask image and returns two lists of points: `new` and `rest`. `rest`
contains the points corresponding to the previous spline control points, EXCEPT for the
last segment: this segment changed with the addition of the current control point(s). `new`
contains all of the added/changed points; `rest + new` is the complete spline.
"""
rest = []
new_points = []
prev = None
if self.points:
prev = self.points[-1]
for n, this_pt in enumerate(points, 1):
self.points.append(this_pt)
if self.last_pt is None:
## No points
self.last_pt = this_pt
new_points.append(this_pt)
continue
m_0 = self.last_last_m
if self.last_last_pt is None:
## Two points
m_1 = tuple(((a-b)*self.tension for a, b in zip(this_pt, self.last_pt)))
else:
m_1 = tuple(((a-c)*self.tension for a, c in zip(this_pt, self.last_last_pt)))
## We can't compute this one properly yet
m_2 = tuple(((a-b)*self.tension for a, b in zip(this_pt, self.last_pt)))
p_0 = self.last_last_pt
p_1 = self.last_pt
p_2 = this_pt
if m_0 is not None:
## This segment will not change: we have all the data needed to draw it
this_points = self._spline_points(p_0, m_0, p_1, m_1, self.resolution)
new_points.extend(this_points if not new_points else this_points[1:])
if n == len(points):
## This segment will change if another point is added, since we have only one side.
## Since we have no other points to add in this call, we need to compute the
## temporary values so they can be drawn until another point is added
rest = self._spline_points(p_1, m_1, p_2, m_2, self.resolution)
## Swap out variables
self.last_last_pt = self.last_pt
self.last_pt = this_pt
self.last_last_m = m_1
## Update our coordinates and mask image
self.coords.extend(new_points if not self.coords else new_points[1:])
self._update_bounds(rest)
## Now draw the actual things
previous_draw = ImageDraw.Draw(self.previous)
if new_points:
previous_draw.line(self._fix_coords(new_points), fill=1, width=self.width)
self.current = self.previous.copy()
current_draw = ImageDraw.Draw(self.current)
current_draw.line(self._fix_coords(rest), fill=1, width=self.width)
return new_points, rest
def overlaps(self, other):
"""Check if two splines overlap.
We do this in a simple way: first check bounding boxes, then compute the logical AND of
the mask images of the two splines and check if there are any non-zero pixels.
"""
## This is slightly tricky: first, we compute the overlap images
bix, biy, bax, bay = self._overlap(self.minx, self.miny, self.maxx, self.maxy, other.minx, other.miny, other.maxx, other.maxy)
if bix is None:
return None
## There is overlap; create two images that contain our and their overlap
ours = self.current.crop((bix-self.minx, biy-self.miny, bax-self.minx+1, bay-self.miny+1))
theirs = other.current.crop((bix-other.minx, biy-other.miny, bax-other.minx+1, bay-other.miny+1))
## Compute the overlap of the result
a = ImageChops.logical_and(ours, theirs)
a = a.getbbox()
return a is not None
def __init__(self, resolution=0.1, tension=0.1, width=1, colour=(255, 0, 0)):
self.resolution = resolution
self.tension = tension
self.width = width
self.colour = colour
self.last_pt = None
self.last_last_pt = None
self.last_last_m = None
self.points = []
self.minx = None
self.miny = None
self.maxx = None
self.maxy = None
## Current image, including the last segment, which will change on the next control point
self.current = None
## Previous image, storing all parts of the spline that will not change
self.previous = None
self.coords = []
def qcolor_to_hex(colour):
return ("#%02x%02x%02x%02x" % colour.getRgb()).upper()
def hex_to_qcolor(s):
r = int(s[1:3], 16)
g = int(s[3:5], 16)
b = int(s[5:7], 16)
if len(s) > 7:
a = int(s[7:9], 16)
return QColor(r, g, b, a)
class SerializablePen(QPen):
def serialize(self):
e = et.Element(BXW+"pen")
e.set("width", str(self.width()))
e.set("cap", str(self.capStyle()))
e.set("join", str(self.joinStyle()))
e.set("style", str(self.style()))
e.set("colour", str(qcolor_to_hex(self.color())))
return e
@classmethod
def deserialize(cls, e):
if e.tag != BXW+"pen":
raise LoadError("Invalid pen tag!")
width = res_or_none(int, e.get("width"))
join = res_or_none(int, e.get("join"))
cap = res_or_none(int, e.get("cap"))
colour = e.get("colour")
style = res_or_none(int, e.get("style"))
if None in (width, join, cap, colour, style):
raise LoadError("Invalid pen properties!")
try:
colour = hex_to_qcolor(colour)
except:
raise LoadError("Invalid pen colour!")
return cls(colour, width, style=style, cap=cap, join=join)
def res_or_none(func, s):
try:
return func(s)
except:
return None
class Path(IncrementalSplineMask):
def serialize(self):
e = et.Element(BXW+"path")
e.set("id", str(self.id))
e.set("resolution", str(self.resolution))
e.set("tension", str(self.tension))
pen = self.pen.serialize()
e.insert(0, pen)
for n, p in enumerate(self.points, 1):
se = et.Element(BXW+"point")
se.set("x", str(p[0]))
se.set("y", str(p[1]))
e.insert(n, se)
return e
@classmethod
def deserialize(cls, e):
if e.tag != BXW+"path":
raise LoadError("Invalid path tag!")
id_ = res_or_none(int, e.get("id"))
if id_ is None:
raise LoadError("Invalid path id!")
resolution = res_or_none(float, e.get("resolution"))
if resolution is None:
raise LoadError("Invalid path resolution!")
tension = res_or_none(float, e.get("resolution"))
if tension is None:
raise LoadError("Invalid path tension!")
points = []
pen = None
for point in e:
if pen is None:
pen = SerializablePen.deserialize(point)
continue
if point.tag != BXW+"point":
raise LoadError("Invalid point tag!")
x = res_or_none(int, point.get("x"))
y = res_or_none(int, point.get("y"))
if x is None or y is None:
raise LoadError("Invalid point coordinates!")
points.append((x, y))
if pen is None:
raise LoadError("Path must have a pen!")
elif not points:
raise LoadError("Path must not be empty!")
path = cls(id=id_, pen=pen, resolution=resolution, tension=tension)
path.add_points(*points)
return path
def __init__(self, id, pen, *args, **kwargs):
super().__init__(*args, **kwargs)
self.id = id
self.pen = pen
class Board(QGraphicsScene):
def start_path(self, pen, x, y, erase=False, laser=False):
if not laser:
self.changed = True
else:
self.laser_timer.stop()
self.path = Path(id=self.current_id, pen=pen)
self.current_id += 1
self.erase = erase
self.laser = laser
self.path_items = []
def move_to(self, x, y):
good, rest = self.path.add_points((x, y))
if not self.erase:
if not self.laser:
self.changed = True
self.laser_timer.stop()
if len(good)+len(rest) > 1:
for _ in range(self.last_path_items):
self.removeItem(self.path_items.pop(-1))
new = good+rest
self.last_path_items = len(rest)-1
for i in range(len(new)-1):
self.path_items.append(self.addLine(*new[i], *new[i+1], self.path.pen))
else:
for n, (path, group) in enumerate(self.paths):
if path.overlaps(self.path):
self.changed = True
self.removeItem(group)
self.paths.pop(n)
break
def finish_path(self):
if self.path is None:
return
if not self.laser:
self.changed = True
if self.path.coords is not None and self.path.coords and not self.erase:
group = self.createItemGroup(self.path_items)
if not self.laser:
self.paths.append((self.path, group))
else:
self.laser_paths.append((self.path, group))
self.laser_timer.start(1500)
self.transitive.append(group)
self.path = None
self.path_items = []
self.last_path_items = 0
def _add_path(self, path):
items = []
for i in range(len(path.coords)-1):
items.append(self.addLine(*path.coords[i], *path.coords[i+1], path.pen))
group = self.createItemGroup(items)
self.paths.append((path, group))
def _remove_laser(self):
for _, group in self.laser_paths:
self.removeItem(group)
self.laser_paths = []
def serialize(self):
e = et.Element(BXW+"board")
e.set("id", str(self.id))
e.set("current-id", str(self.current_id))
e.set("background", qcolor_to_hex(self.backgroundBrush().color()))
e.set("text-colour", qcolor_to_hex(self.text_colour))
for n, (path, _) in enumerate(self.paths):
se = path.serialize()
e.insert(n, se)
return e
@classmethod
def deserialize(cls, e, *args, **kwargs):
if e.tag != BXW+"board":
raise LoadError("Invalid board tag", e.tag)
id_ = res_or_none(int, e.get("id"))
if id_ is None:
raise LoadError("Invalid board id!")
current_id = res_or_none(int, e.get("current-id"))
if current_id is None:
raise LoadError("Invalid board current id!")
background = res_or_none(hex_to_qcolor, e.get("background"))
if background is None:
raise LoadError("Invalid board background!")
text_colour = res_or_none(hex_to_qcolor, e.get("text-colour"))
if text_colour is None:
raise LoadError("Invalid board text colour!")
self = cls(id_, background, text_colour, *args, current_id=current_id, **kwargs)
for path in e:
path = Path.deserialize(path)
self._add_path(path)
return self
def show_menu(self, pens, x, y):
"""Show the colour menu."""
menu_radius = 150
delta = 360 / len(pens)
angle = 90 - delta/2
for pen in pens:
e = self.addEllipse(x-menu_radius, y-menu_radius, 2*menu_radius, 2*menu_radius, pen=pen, brush=pen.brush())
e.setStartAngle(int(angle*16))
e.setSpanAngle(int(delta*16 + 1))
self.menu[e] = pen
angle += delta
def finish_menu(self, x, y):
"""Hide the colour menu."""
item = self.itemAt(x, y, QTransform())
pen = None
if item in self.menu:
pen = self.menu[item]
for item in self.menu:
self.removeItem(item)
self.menu = {}
return pen
def clear(self):
"""Clear the board."""
self.finish_path()
for path, group in self.paths:
self.removeItem(group)
self.paths = []
def set_size(self, width, height):
self.setSceneRect(0, 0, width, height)
self.parent_width = width
self.parent_height = height
self._fix_message_pos()
def _fix_message_pos(self):
br = self.message.boundingRect()
self.message.setPos(QPoint(self.parent_width//2, self.parent_height-5) - br.center() - QPoint(0, int(br.height())//2))
def show_message(self, text, length=1500):
"""Show a message in the bottom centre for the given time (in ms)."""
self.message.setPlainText(text)
self._fix_message_pos()
self.message.show()
self.message_timer.start(length)
def to_image(self):
"""Save the board to a QImage."""
image = QImage(int(self.width()), int(self.height()), QImage.Format_ARGB32)
painter = QPainter(image)
painter.setRenderHints(QPainter.HighQualityAntialiasing);
## Hide everything (mainly text, menus) that shouldn't be visible in the saved image
for t in self.transitive:
t.hide()
self.render(painter)
for t in self.transitive:
t.show()
return image
def _hide_message(self):
self.message.hide()
def __init__(self, id, background, text_colour, *args, current_id=0, show_number=True, site_text=None, **kwargs):
super().__init__(*args, **kwargs)
self.setBackgroundBrush(background)
self.id = id
self.current_id = current_id
self.paths = []
self.path = None
self.path_items = []
self.last_path_items = 0
self.erase = False
self.laser = False
self.laser_timer = QTimer()
self.laser_timer.setSingleShot(True)
self.laser_timer.timeout.connect(self._remove_laser)
self.laser_paths = []
self.changed = False
self.text_colour = text_colour
self.text_font = QFont()
self.text_font.setPointSize(20)
self.parent_width = None
self.parent_height = None
## This list contains everything that needs to be disabled for screenshots
self.transitive = []
if show_number:
## Show the board number permanently, TODO
self.number = self.addText("-1/-1", self.text_font)
self.transitive.append(self.number)
if site_text is not None:
## Show some text, usually pointing to somewhere students can view it
self.site = self.addText(site_text, self.text_font)
self.site.setPos(5, 5)
self.site.show()
self.site.setDefaultTextColor(self.text_colour)
self.transitive.append(self.site)
self.message = self.addText("No message yet!", self.text_font)
self.message.setDefaultTextColor(self.text_colour)
self.message.hide()
self.transitive.append(self.message)
self.message_timer = QTimer()
self.message_timer.timeout.connect(self._hide_message)
self.message_timer.setSingleShot(True)
self.menu = {}
class Room(QGraphicsView):
def release_pen(self, x, y):
self.board.finish_path()
def release_erase(self, x, y):
self.board.finish_path()
self.setCursor(self.cursor)
def set_pen(self, pen):
self.pen = pen
self.cursor = make_cursor(pen.brush().color().getRgb()[0:3])
self.laser = False
self.setCursor(self.cursor)
def release_menu(self, x, y):
pen = self.board.finish_menu(x, y)
if pen is not None:
self.set_pen(pen)
def down_pen(self, x, y):
self.board.start_path(self.pen if not self.laser else self.laser_pen, x, y, erase=(self.down == 2), laser=self.laser)
def down_erase(self, x, y):
self.down_pen(x, y)
self.setCursor(self.eraser_cursor)
def down_menu(self, x, y):
self.board.show_menu(self.pens, x, y)
def move_pen(self, x, y):
now = time.monotonic()
## Restrict the update speed or it will look jagged
if self.last_time is not None and now-self.last_time < 1/24:
if not (None in (self.last_used_x, self.last_used_y)) and (x-self.last_used_x)**2 + (y-self.last_used_y)**2 < 50:
return
self.last_time = now
self.last_used_x = x
self.last_used_y = y
self.board.move_to(x, y)
move_erase = move_pen
def clear(self):
self.board.clear()
self.board.show_message("Cleared!")
def keyPressEvent(self, ev):
if ev.key() == Qt.Key_C:
self.clear()
elif ev.key() == Qt.Key_N:
self.append_board()
elif ev.key() == Qt.Key_Right:
self.next_board()
elif ev.key() == Qt.Key_Left:
self.previous_board()
elif ev.key() == Qt.Key_S:
self.save()
self.board.show_message("Saved!")
elif ev.key() == Qt.Key_U and self.site_path is not None:
self.to_site(self.site_path)
elif ev.key() == Qt.Key_L:
self.toggle_laser()
def toggle_laser(self):
if self.laser:
self.set_pen(self.pen)
else:
self.laser = True
self.unsetCursor()
def mouseMoveEvent(self, ev):
x, y = ev.x(), ev.y()
b1 = bool(ev.buttons() & Qt.LeftButton)
b2 = bool(ev.buttons() & Qt.RightButton)
b3 = bool(ev.buttons() & Qt.MiddleButton)
button = max(1*b1, 2*b2, 3*b3)
buttons = (0, b1, b2, b3)
if self.down is not None and not buttons[self.down]:
if self.down == 1:
self.release_pen(x, y)
elif self.down == 2:
self.release_erase(x, y)
else:
self.release_menu(x, y)
self.down = None
elif self.down is None and button:
self.down = button
if self.down == 1:
self.down_pen(x, y)
elif self.down == 2:
self.down_erase(x, y)
else:
self.down_menu(x, y)
elif self.down is not None and buttons[self.down]:
if x == self.last_x and y == self.last_y:
return
if self.down == 1:
self.move_pen(x, y)
elif self.down == 2:
self.move_erase(x, y)
self.last_x = x
self.last_y = y
def mousePressEvent(self, ev):
self.mouseMoveEvent(ev)
def mouseReleaseEvent(self, ev):
self.mouseMoveEvent(ev)
def resizeEvent(self, ev):
self.set_size(ev.size().width(), ev.size().height())
def set_size(self, width, height):
if self.board is None:
return
self.board.set_size(width, height)
self.setSceneRect(0, 0, width, height)
def serialize(self):
e = et.Element(BXW+"room")
e.set("active-board", str(self.board.id))
e.set("created", self.created.isoformat())
e.set("current-id", str(self.current_id))
for n, board in enumerate(self.boards):
se = board.serialize()
e.insert(n, se)
return e
@classmethod
def deserialize(cls, e, *args, **kwargs):
if e.tag != BXW+"room":
raise LoadError("Invalid room tag!")
created = res_or_none(dt.datetime.fromisoformat, e.get("created"))
active_board = res_or_none(int, e.get("active-board"))
current_id = res_or_none(int, e.get("current-id"))
if None in (created, active_board, current_id):
raise LoadError("Invalid room!")
room = cls(*args, current_id=current_id, created=created, **kwargs)
boards = []
for board in e:
board = Board.deserialize(board, show_number=self.show_number, site_text=self.site_text)
boards.append(board)
room.boards = boards
room.set_active_board_by_id(active_board)
return room
def set_active_board(self, idx, save=True):
idx = idx % len(self.boards)
if idx == self.board_idx:
return
do_save = save and self.board is not None and self.board.changed
self.board = self.boards[idx]
self.board.changed = False
self.board_idx = idx
self.setScene(self.board)
self.set_size(self.width(), self.height())
self.board.show_message("Board %d/%d" % (self.board_idx+1, len(self.boards)))
if do_save:
self.save()
def set_active_board_by_id(self, id):
for n, board in enumerate(self.boards):
if board.id == id:
self.set_active_board(n)
else:
return False
return True
def append_board(self, activate=True):
board = Board(self.current_id, background=self.default_background, text_colour=self.pens[0].brush().color(), show_number=self.show_number, site_text=self.site_text)
self.current_id += 1
self.boards.append(board)
if activate:
self.set_active_board(len(self.boards)-1, save=self.autosave)
def next_board(self):
self.set_active_board(self.board_idx+1, save=self.autosave)
def previous_board(self):
self.set_active_board(self.board_idx-1, save=self.autosave)
def save(self, filename=None):
if filename is None:
filename = self.filename
et.register_namespace("", BXW.strip("{}"))
root = self.serialize()
xml_indent(root)
tree = et.ElementTree(element=root)
tree.write(filename, encoding="unicode")
@classmethod
def load(cls, filename, *args, **kwargs):
tree = et.parse(filename)
root = tree.getroot()
return cls.deserialize(root, *args, **kwargs)
def to_site(self, path):
images = []
for n, board in enumerate(self.boards, 1):
images.append((n, board.to_image()))
class TheThread(QThread):
actual_start = pyqtSignal()
def run(this):
with self.to_site_lock:
this.actual_start.emit()
items = []
for id, image in images:
name = "Board %d" % id
src = "%s_%03d.png" % (self.created_name, id)
items.append(HTML_ITEM_TEMPLATE.format(name=name, src=src))
image.save(os.path.join(path, src))
os.chmod(os.path.join(path, src), 0o744)
html = HTML_TEMPLATE.format(items='\n'.join(items))
with open(os.path.join(path, "index.html"), 'w') as f:
f.write(html)
os.chmod(os.path.join(path, "index.html"), 0o744)
def message1():
self.board.show_message("Uploading...")
def message2():
self.board.show_message("Uploaded!")
self.to_site_threads.pop(0)
thread = TheThread()
self.to_site_threads.append(thread)
thread.actual_start.connect(message1)
thread.finished.connect(message2)
thread.start()
def __init__(self, *args, filename=None, default_background=QColor(0x2D, 0x2D, 0x2D), width=4, current_id=0, created=None, pens=None, site_path=None, site_text=None, show_number=True, **kwargs):
self.board = None
self.board_idx = -1
self.boards = []
super().__init__(self.board, *args, **kwargs)
if pens is None:
pens = [SerializablePen(colour, width, join=Qt.RoundJoin, cap=Qt.RoundCap) for colour in DEFAULT_COLOURS]
self.default_background = default_background
self.current_id = current_id
self.setAlignment(Qt.AlignTop | Qt.AlignLeft)
self.down = None
self.last_time = None
self.pens = pens
self.pen = self.pens[0]
self.laser_pen = QPen(QColor(255, 0, 0), width)
self.laser = False
self.setWindowTitle("BTNS v2")
self.last_x = None
self.last_y = None
self.last_used_x = None
self.last_used_y = None
self.cursor = None
self.eraser_cursor = QCursor(QPixmap.fromImage(ERASER), 4, 30)
self.setRenderHints(QPainter.HighQualityAntialiasing)
self.setMouseTracking(True)
self.setStyleSheet("border: 0px")
self.autosave = True
self.to_site_lock = threading.Lock()
self.to_site_threads = []
self.site_path = site_path
self.site_text = site_text
self.show_number = show_number
if created is None:
self.created = dt.datetime.now()
self.append_board()
else:
self.created = created
self.created_name = self.created.isoformat().replace(':', '_').replace('.', '_')
if filename is None:
self.filename = self.created_name + ".xml"
else:
self.filename = filename
self.set_pen(self.pen)
if __name__ == "__main__":
parser = argparse.ArgumentParser(
description="Ben's Terrible Notetaking Software, v2",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=__doc__
)
parser.add_argument("file", nargs="?", default=None, help="Room file to load")
parser.add_argument("-n", "--show-numbers", action="store_true", default=False, help="Show board numbers")
parser.add_argument("-s", "--site", action="store", default="https://unsuspicious.services/cb", help="Text to show in the bottom corner")
parser.add_argument("-p", "--path", action="store", default="cb", help="Folder to store screenshots in (for uploading)")
args = parser.parse_args()
app = QApplication(sys.argv)
if args.file and os.path.isfile(args.file):
shutil.copyfile(args.file, args.file+".bak")
w = Room.load(args.file, show_number=args.show_numbers, site_path=args.path, site_text=args.site)
else:
w = Room(filename=args.file, show_number=args.show_numbers, site_path=args.path, site_text=args.site)
w.show()
sys.exit(app.exec())
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