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scene_scroll_test
from scene import *
from math import exp
from threading import Thread
import datetime
# example scrolling scene with inertial scrolling
# basic scrolling example was by Dalorbi on the forums at:
# http://omz-software.com/pythonista/forums/discussion/213/scrolling-in-scene-module/p1
# inertial scrolling added on by hroe
class MyScene (Scene):
def setup(self):
self.dx = self.size.w / 2
self.dy = self.size.h / 2 + 10
self.xy_velocity = None
self.velocity_decay_timescale_seconds = 0.4
self.max_retained_touch_points = 6
self.min_velocity_points_per_second = 50
self.cur_touch = None
def draw(self):
if self.xy_velocity is not None and self.cur_touch is None:
self.dx += self.xy_velocity[0] * self.dt
self.dy += self.xy_velocity[1] * self.dt
decay = exp( - self.dt / self.velocity_decay_timescale_seconds )
self.xy_velocity = (self.xy_velocity[0] * decay, self.xy_velocity[1] * decay)
if ((abs(self.xy_velocity[0]) <= self.min_velocity_points_per_second) and
(abs(self.xy_velocity[1]) <= self.min_velocity_points_per_second)):
self.xy_velocity = None
background(0, 0, 0)
translate(self.dx, self.dy)
fill(1, 1, 1)
stroke(1, 1, 1)
stroke_weight(3)
for x in range(-3000,3100,100):
line(x,-3000,x,3000)
text(str(x), font_size = 30, x = x, y = 0, alignment = 5)
for y in range(-3000,3100,100):
line(-3000,y,3000,y)
text(str(y), font_size = 30, x = 0, y = y, alignment = 5)
for i in range(-3000,3000,100):
image('PC_Grass_Block',i,-125)
def touch_began(self, touch):
if self.cur_touch is None:
self.cur_touch = touch.touch_id
self.xy_velocity = None
self.touch_log = []
def touch_moved(self, touch):
if touch.touch_id == self.cur_touch:
self.dx += touch.location.x - touch.prev_location.x
self.dy += touch.location.y - touch.prev_location.y
self.touch_log.append((datetime.datetime.utcnow(), touch.location))
self.touch_log = self.touch_log[-self.max_retained_touch_points:]
def touch_ended(self, touch):
if touch.touch_id == self.cur_touch:
self.xy_velocity = None
if len(self.touch_log) >= 2:
dt = (self.touch_log[-1][0] - self.touch_log[0][0]).total_seconds()
if dt > 0:
x_velocity = (self.touch_log[-1][1].x - self.touch_log[0][1].x) / dt
y_velocity = (self.touch_log[-1][1].y - self.touch_log[0][1].y) / dt
self.xy_velocity = (x_velocity, y_velocity)
self.cur_touch = None
run(MyScene())
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