86 lines
3.5 KiB
Python
86 lines
3.5 KiB
Python
"""RectTransform - 一个轻量级的 Unity-like RectTransform 实现（Python 层 MVP）
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提供 anchors/pivot/anchored_position/size_delta 的数据结构和
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把相对锚点映射到像素矩形的计算方法。
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此实现不修改底层 C++ LUI，而是在 Python 层计算并把结果应用到
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`LUIObject` 的 `left/top/width/height` 属性上。
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"""
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from typing import Tuple
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class RectTransform(object):
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def __init__(self,
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anchor_min=(0.5, 0.5),
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anchor_max=(0.5, 0.5),
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pivot=(0.5, 0.5),
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anchored_position=(0.0, 0.0),
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size_delta=(100.0, 30.0)):
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# 值域: anchor/pivot 为 0..1，anchored_position/size_delta 为像素
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self.anchor_min = tuple(anchor_min)
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self.anchor_max = tuple(anchor_max)
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self.pivot = tuple(pivot)
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self.anchored_position = tuple(anchored_position)
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self.size_delta = tuple(size_delta)
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def compute_pixel_rect(self, parent_rect: Tuple[float, float, float, float]):
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"""
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将 RectTransform 转换为相对于父节点的像素矩形 (left, top, width, height)
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parent_rect: (parent_left, parent_top, parent_width, parent_height)
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"""
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p_left, p_top, p_w, p_h = parent_rect
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a_min_x = self.anchor_min[0]
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a_min_y = self.anchor_min[1]
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a_max_x = self.anchor_max[0]
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a_max_y = self.anchor_max[1]
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# 计算锚框的像素坐标（left/top 和 right/bottom）
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anchor_left = p_left + a_min_x * p_w
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anchor_right = p_left + a_max_x * p_w
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anchor_top = p_top + a_min_y * p_h
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anchor_bottom = p_top + a_max_y * p_h
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# 宽高
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if abs(a_max_x - a_min_x) < 1e-6:
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# 固定锚点 -> 使用 size_delta.x
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width = float(self.size_delta[0])
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# anchored_position.x 表示相对于锚点框的位置（像素）
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left = anchor_left + float(self.anchored_position[0]) - self.pivot[0] * width
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else:
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# 拉伸到锚框再加上 size_delta.x
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width = (anchor_right - anchor_left) + float(self.size_delta[0])
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# anchored_position.x 表示锚框内的像素偏移
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left = anchor_left + float(self.anchored_position[0])
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if abs(a_max_y - a_min_y) < 1e-6:
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height = float(self.size_delta[1])
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# 注意：engine 中 top 增大表示向下，所以 anchored_position.y 保持像素系
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top = anchor_top + float(self.anchored_position[1]) - self.pivot[1] * height
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else:
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height = (anchor_bottom - anchor_top) + float(self.size_delta[1])
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top = anchor_top + float(self.anchored_position[1])
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return (left, top, width, height)
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def apply_to_lui(self, lui_obj, parent_rect: Tuple[float, float, float, float]):
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"""计算并应用到给定的 LUIObject（设置 left/top/width/height）"""
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left, top, width, height = self.compute_pixel_rect(parent_rect)
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try:
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lui_obj.left = left
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lui_obj.top = top
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lui_obj.width = width
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lui_obj.height = height
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except Exception:
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# 忽略不能设置的属性，调用者应保证对象支持这些属性
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pass
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def to_dict(self):
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return {
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'anchor_min': tuple(self.anchor_min),
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'anchor_max': tuple(self.anchor_max),
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'pivot': tuple(self.pivot),
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'anchored_position': tuple(self.anchored_position),
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'size_delta': tuple(self.size_delta),
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}
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