63 lines
1.3 KiB
Python
63 lines
1.3 KiB
Python
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import math
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import cairo
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class SnowflakeLayout:
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_BASE_RADIUS = 65
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_CHILDREN_FACTOR = 1
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_FLAKE_DISTANCE = 6
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_BORDER = 20
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def __init__(self):
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self._root = None
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self._children = []
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def set_root(self, icon):
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self._root = icon
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def add_child(self, icon):
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self._children.append(icon)
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self._layout()
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def remove_child(self, icon):
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self._children.remove(icon)
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self._layout()
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def _layout_root(self):
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[width, height] = self._root.get_size_request()
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matrix = cairo.Matrix(1, 0, 0, 1, 0, 0)
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matrix.translate(self._cx, self._cy)
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self._root.set_transform(matrix)
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def _layout_child(self, child, index):
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r = self._r
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if (len(self._children) > 10):
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r += SnowflakeLayout._FLAKE_DISTANCE * (index % 3)
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angle = 2 * math.pi / len(self._children) * index
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x = self._cx + math.cos(angle) * r
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y = self._cy + math.sin(angle) * r
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matrix = cairo.Matrix(1, 0, 0, 1, 0, 0)
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matrix.translate(x, y)
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child.set_transform(matrix)
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def _layout(self):
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self._r = SnowflakeLayout._BASE_RADIUS + \
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SnowflakeLayout._CHILDREN_FACTOR * len(self._children)
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c = self._r + SnowflakeLayout._BORDER + \
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SnowflakeLayout._FLAKE_DISTANCE * 2
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self._cx = c
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self._cy = c
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self._layout_root()
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index = 0
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for child in self._children:
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self._layout_child(child, index)
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index += 1
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