forked from Mirrors/apostrophe
111 lines
3.7 KiB
Python
111 lines
3.7 KiB
Python
class TextViewScroller:
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def __init__(self, text_view, scrolled_window):
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super().__init__()
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self.text_view = text_view
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self.scrolled_window = scrolled_window
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self.smooth_scroller = None
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def can_scroll(self):
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vap = self.scrolled_window.get_vadjustment().props
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return vap.upper > vap.page_size
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def get_scroll_scale(self):
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vap = self.scrolled_window.get_vadjustment().props
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if vap.upper > vap.page_size:
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return vap.value / (vap.upper - vap.page_size)
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else:
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return 0
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def set_scroll_scale(self, scale):
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vap = self.scrolled_window.get_vadjustment().props
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vap.value = (vap.upper - vap.page_size) * scale
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def scroll_to_mark(self, mark, center):
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"""Scrolls until mark is visible, if needed."""
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target_pos = self.get_target_pos_for_mark(mark, center)
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if target_pos:
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self.scrolled_window.get_vadjustment().set_value(target_pos)
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def smooth_scroll_to_mark(self, mark, center):
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"""Smoothly scrolls until mark is visible, if needed."""
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if self.smooth_scroller and self.smooth_scroller.is_started:
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self.smooth_scroller.end()
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target_pos = self.get_target_pos_for_mark(mark, center)
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if target_pos:
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source_pos = self.scrolled_window.get_vadjustment().props.value
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self.smooth_scroller = SmoothScroller(self.scrolled_window, source_pos, target_pos)
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self.smooth_scroller.start()
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def get_target_pos_for_mark(self, mark, center):
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margin = 32
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mark_iter = self.text_view.get_buffer().get_iter_at_mark(mark)
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mark_rect = self.text_view.get_iter_location(mark_iter)
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vap = self.scrolled_window.get_vadjustment().props
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pos_y = mark_rect.y + mark_rect.height + self.text_view.props.top_margin
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pos_viewport_y = pos_y - vap.value
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target_pos = None
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if center:
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if pos_viewport_y != vap.page_size / 2:
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target_pos = pos_y - (vap.page_size / 2)
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elif pos_viewport_y > vap.page_size - margin:
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target_pos = pos_y - vap.page_size + margin
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elif pos_viewport_y < margin:
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target_pos = pos_y - margin - mark_rect.height
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return target_pos
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class SmoothScroller:
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def __init__(self, scrolled_window, source_pos, target_pos):
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super().__init__()
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self.scrolled_window = scrolled_window
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self.source_pos = source_pos
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self.target_pos = target_pos
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self.duration = max(100, (target_pos - source_pos) / 50) * 1000
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self.is_started = False
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self.is_setup = False
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self.start_time = 0
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self.end_time = 0
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self.tick_callback_id = 0
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def start(self):
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self.is_started = True
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self.tick_callback_id = self.scrolled_window.add_tick_callback(self.on_tick)
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def end(self):
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self.scrolled_window.remove_tick_callback(self.tick_callback_id)
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self.is_started = False
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def setup(self, time):
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self.start_time = time
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self.end_time = time + self.duration
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self.is_setup = True
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def on_tick(self, widget, frame_clock):
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def ease_out_cubic(value):
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return pow(value - 1, 3) + 1
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now = frame_clock.get_frame_time()
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if not self.is_setup:
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self.setup(now)
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if now < self.end_time:
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time = float(now - self.start_time) / float(self.end_time - self.start_time)
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else:
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time = 1
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self.end()
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time = ease_out_cubic(time)
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pos = self.source_pos + (time * (self.target_pos - self.source_pos))
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widget.get_vadjustment().props.value = pos
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return True
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