放置、几何锚点与路径定位#

用途与概念#

定位关系需要明确自身选哪个点、目标选哪个点、额外移动多少。默认九点属于布局框，圆角矩形和椭圆的框角通常不在轮廓上。需要轮廓点时使用 path 或 ink.boundary 查询并显式索引候选。

最小完整示例#

此文件包含画布及必要定义，可直接运行 laymesh validate 或 laymesh render，不依赖前文未声明的变量。

1# Minimal complete example: path.at2page=canvas(size=(100mm,75mm),background="#ffffff")3curve=page.add(path(commands=[move_to(0mm,0mm),cubic_to(0mm,0mm,0mm,35mm,50mm,35mm),cubic_to(65mm,35mm,70mm,0mm,75mm,0mm),line_to(82mm,12mm)],border_color="#0072b2",border_width=0.7mm),offset=(8mm,15mm))4route=curve.path.subpaths[0]5dot=ellipse(size=(2mm,2mm),fill="#e36b70")6point=route.at(fraction=0.5)7page.add(dot,anchor=center,target=point)

# Minimal complete example: path.at
page=canvas(size=(100mm,75mm),background="#ffffff")
curve=page.add(path(commands=[move_to(0mm,0mm),cubic_to(0mm,0mm,0mm,35mm,50mm,35mm),cubic_to(65mm,35mm,70mm,0mm,75mm,0mm),line_to(82mm,12mm)],border_color="#0072b2",border_width=0.7mm),offset=(8mm,15mm))
route=curve.path.subpaths[0]
dot=ellipse(size=(2mm,2mm),fill="#e36b70")
point=route.at(fraction=0.5)
page.add(dot,anchor=center,target=point)

1# Minimal complete example: path.at2page=canvas(size=(100mm,75mm),background="#ffffff")3curve=page.add(path(commands=[move_to(0mm,0mm),cubic_to(0mm,0mm,0mm,35mm,50mm,35mm),cubic_to(65mm,35mm,70mm,0mm,75mm,0mm),line_to(82mm,12mm)],border_color="#0072b2",border_width=0.7mm),offset=(8mm,15mm))4route=curve.path.subpaths[0]5dot=ellipse(size=(2mm,2mm),fill="#e36b70")6point=route.at(fraction=0.5)7page.add(dot,anchor=center,target=point)

# Minimal complete example: path.at
page=canvas(size=(100mm,75mm),background="#ffffff")
curve=page.add(path(commands=[move_to(0mm,0mm),cubic_to(0mm,0mm,0mm,35mm,50mm,35mm),cubic_to(65mm,35mm,70mm,0mm,75mm,0mm),line_to(82mm,12mm)],border_color="#0072b2",border_width=0.7mm),offset=(8mm,15mm))
route=curve.path.subpaths[0]
dot=ellipse(size=(2mm,2mm),fill="#e36b70")
point=route.at(fraction=0.5)
page.add(dot,anchor=center,target=point)

依赖文件

examples/manual/path-at.lay

参数与默认行为#

裸几何长度使用画布单位，裸字号和描边宽度使用 pt。显式调用参数优先于继承和主题默认值；下面的接口参考逐项列出允许类型、可选值与默认来源。

组合用法#

将曲线的弧长中点用作文字 target，并将 rotation 设置为该点的 tangent_angle。需要沿线与法线偏移时使用 offset_space=target；尖角先选择 incoming 或 outgoing。

7panel = rect(size=(72 mm, 45 mm), fill="#e6f2f3", border_color="#087f8c", border_width=0.5 mm)8placed = page.add(panel, target=page.top_left, offset=(24 mm, 26 mm))9dot = ellipse(size=(4 mm, 4 mm), fill="#df6e70")10page.add(dot, anchor=center, target=placed.top_left)11page.add(dot, anchor=center, target=placed.top_center)12page.add(dot, anchor=center, target=placed.top_right)13page.add(dot, anchor=center, target=placed.middle_left)14page.add(dot, anchor=center, target=placed.center)15page.add(dot, anchor=center, target=placed.middle_right)16page.add(dot, anchor=center, target=placed.bottom_left)17page.add(dot, anchor=center, target=placed.bottom_center)18page.add(dot, anchor=center, target=placed.bottom_right)

panel = rect(size=(72 mm, 45 mm), fill="#e6f2f3", border_color="#087f8c", border_width=0.5 mm)
placed = page.add(panel, target=page.top_left, offset=(24 mm, 26 mm))
dot = ellipse(size=(4 mm, 4 mm), fill="#df6e70")
page.add(dot, anchor=center, target=placed.top_left)
page.add(dot, anchor=center, target=placed.top_center)
page.add(dot, anchor=center, target=placed.top_right)
page.add(dot, anchor=center, target=placed.middle_left)
page.add(dot, anchor=center, target=placed.center)
page.add(dot, anchor=center, target=placed.middle_right)
page.add(dot, anchor=center, target=placed.bottom_left)
page.add(dot, anchor=center, target=placed.bottom_center)
page.add(dot, anchor=center, target=placed.bottom_right)

1# Gallery: positioning / anchors2page = canvas(name="Nine anchors", size=(120 mm, 80 mm), background="#f7f9fc")3font = "DejaVu Sans"4heading = text(content="Nine anchors", font_family=font, font_size=14 pt, color="#203864")5page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))6# BEGIN DEMO7panel = rect(size=(72 mm, 45 mm), fill="#e6f2f3", border_color="#087f8c", border_width=0.5 mm)8placed = page.add(panel, target=page.top_left, offset=(24 mm, 26 mm))9dot = ellipse(size=(4 mm, 4 mm), fill="#df6e70")10page.add(dot, anchor=center, target=placed.top_left)11page.add(dot, anchor=center, target=placed.top_center)12page.add(dot, anchor=center, target=placed.top_right)13page.add(dot, anchor=center, target=placed.middle_left)14page.add(dot, anchor=center, target=placed.center)15page.add(dot, anchor=center, target=placed.middle_right)16page.add(dot, anchor=center, target=placed.bottom_left)17page.add(dot, anchor=center, target=placed.bottom_center)18page.add(dot, anchor=center, target=placed.bottom_right)19# END DEMO

# Gallery: positioning / anchors
page = canvas(name="Nine anchors", size=(120 mm, 80 mm), background="#f7f9fc")
font = "DejaVu Sans"
heading = text(content="Nine anchors", font_family=font, font_size=14 pt, color="#203864")
page.add(heading, target=page.top_left, offset=(7 mm, 5 mm))
# BEGIN DEMO
panel = rect(size=(72 mm, 45 mm), fill="#e6f2f3", border_color="#087f8c", border_width=0.5 mm)
placed = page.add(panel, target=page.top_left, offset=(24 mm, 26 mm))
dot = ellipse(size=(4 mm, 4 mm), fill="#df6e70")
page.add(dot, anchor=center, target=placed.top_left)
page.add(dot, anchor=center, target=placed.top_center)
page.add(dot, anchor=center, target=placed.top_right)
page.add(dot, anchor=center, target=placed.middle_left)
page.add(dot, anchor=center, target=placed.center)
page.add(dot, anchor=center, target=placed.middle_right)
page.add(dot, anchor=center, target=placed.bottom_left)
page.add(dot, anchor=center, target=placed.bottom_center)
page.add(dot, anchor=center, target=placed.bottom_right)
# END DEMO

依赖文件

examples/gallery/positioning/anchors.lay

常见错误与限制#

候选集合不能直接传给 target。空集合索引报错；连续重合和无限个最近点不会被随意抽样。self 只在 anchor 中绑定，未放置的素材不能充当目标实例。

逐项功能说明#

instance-data#

在已放置图表中选择原始数据坐标点。轴变换、断轴、实例变换及组重放都重新解析此引用；点必须处于有效可见数据域。

返回：anchor

最小完整源码 · 组合源码 · 全部参数

instance-axis#

按名称选择图表轴的数值起端、物理中点或数值终端。保留旧变换语义；新几何查询可通过 axes[name].spine.path 选轴线。

返回：anchor

最小完整源码 · 组合源码 · 全部参数

add#

将素材放置到画布或组合中，使用 anchor 对齐素材锚点、target 指定目标、offset 设置偏移。同一素材可以重复放置，各实例可独立设置尺寸与样式。

返回：已放置实例；可读取测量尺寸并引用其锚点继续定位。

必需输入：material.

最小完整源码 · 组合源码 · 全部参数

ray#

创建有起点和非零方向的查询射线。origin 与目标路径必须在同一容器；direction 在路径所选测量空间中解释。

返回：ray

必需输入：origin, direction.

最小完整源码 · 组合源码 · 全部参数

path-at#

按弧长比例或距离选点；先选 segments[i] 才能使用原始参数 t。默认按放置后的路径测量。

返回：path_anchor

最小完整源码 · 组合源码 · 全部参数

path-nearest#

返回所有全局最近路径位置，按子路径、源段和参数排序。必须索引；无限多个最近点报错。

返回：anchor_collection

必需输入：to.

最小完整源码 · 组合源码 · 全部参数

path-extrema#

返回所选空间中的局部坐标极值，不含普通端点或常量区间。

返回：anchor_collection

最小完整源码 · 组合源码 · 全部参数

path-inflections#

返回曲率改变符号且方向平滑的拐点。

返回：anchor_collection

最小完整源码 · 组合源码 · 全部参数

path-corners#

返回方向不平滑的连接节点；方向需 with_side 明确选择。

返回：anchor_collection

最小完整源码 · 组合源码 · 全部参数

path-intersections#

返回与射线相交的全部路径位置；自交处保留不同路径位置，连续重合报错。

返回：anchor_collection

必需输入：ray.

最小完整源码 · 组合源码 · 全部参数

path-between#

沿原路径顺序选择两个路径锚点间的连续区间；端点必须来自同一实例和子路径。

返回：geometry_path

最小完整源码 · 组合源码 · 全部参数

path-in_space#

切换弧长、最近点和特征查询的测量空间；结果仍是当前容器中的锚点。

返回：geometry_path

最小完整源码 · 组合源码 · 全部参数

anchor-with_side#

选择尖角的 incoming 或 outgoing 方向；正法线为沿遍历方向的左侧。

返回：path_anchor

最小完整源码 · 组合源码 · 全部参数

详细行为与补充示例#

三种几何视图#

视图	含义	用途
`bounds`	原有布局框的轴对齐外接矩形，不计描边	排版、对齐与间距
`path`	闭合图形的边界或线条的逻辑中心线	连接、曲线标注与节点定位
`ink`	填充和描边形成的区域，包含端帽、虚线及箭头头部	贴住绘制边缘与计算占用范围

placed.top_left 等九点简写保留原语义，等同于 placed.bounds.top_left。path.bounds 和 ink.bounds 是对应几何的紧致外接框；框角不保证位于图形上。圆角矩形、椭圆的框角和边界点应分别选取：

1page.add(dot, anchor=center, target=placed.bounds.top_left)2page.add(dot, anchor=center,3         target=placed.path.nearest(to=placed.bounds.top_left)[0])4page.add(dot, anchor=center,5         target=placed.ink.boundary.nearest(to=placed.bounds.top_left)[0])

page.add(dot, anchor=center, target=placed.bounds.top_left)
page.add(dot, anchor=center,
         target=placed.path.nearest(to=placed.bounds.top_left)[0])
page.add(dot, anchor=center,
         target=placed.ink.boundary.nearest(to=placed.bounds.top_left)[0])

箭头的 path 包含完整逻辑中心线，末端不会被箭头头部截短。线条的 path.bounds 可以零高度，ink.bounds 计入线宽、端帽及箭头头部。本轮仅支持原生矢量几何；图片与文字继续使用 bounds，不提取像素或字形轮廓。

节点、曲线段与沿途选点#

1route = curve.path.subpaths[0]2route.start3route.end4route.nodes[2]5route.segments[1].controls[0]  # 控制点可能不在曲线上，没有路径方向6route.at(fraction=0.5)         # 整条子路径的弧长一半7route.at(distance=10 mm)      # 从起点量出的弧长8route.segments[1].at(t=0.5)   # 原始曲线段参数，不等同于弧长一半9route.between(route.nodes[1], route.nodes[3]).at(fraction=0.5)

route = curve.path.subpaths[0]
route.start
route.end
route.nodes[2]
route.segments[1].controls[0]  # 控制点可能不在曲线上，没有路径方向
route.at(fraction=0.5)         # 整条子路径的弧长一半
route.at(distance=10 mm)      # 从起点量出的弧长
route.segments[1].at(t=0.5)   # 原始曲线段参数，不等同于弧长一半
route.between(route.nodes[1], route.nodes[3]).at(fraction=0.5)

节点与段索引遵循原始几何定义，不随渲染细分数量改变；一个 arc_to 仍是一个逻辑段。多个子路径上的连续遍历操作须先选择 subpaths[i]。闭合路径保留起点与遍历方向，start 和 end 的坐标可以重合；跨闭合接缝必须显式写 between(..., wrap=true)。between 两端必须来自同一实例、同一几何路径和同一子路径，不能混用重合实例的点。

默认在当前容器中测量：不等比缩放会改变弧长、最近点及极值位置。route.in_space("local") 按原始局部几何测量，in_space("parent") 恢复容器测量；所有结果仍转换为当前容器中的锚点。直接访问外接框时，九点遵循所选测量空间的矩形。

搜索始终返回集合#

1route.nearest(to=another.bounds.center)[0]2route.extrema(axis="y")[0]3route.inflections()[0]4route.corners()[0]5route.intersections(ray(origin=another.bounds.center, direction=(1, 0)))[0]

route.nearest(to=another.bounds.center)[0]
route.extrema(axis="y")[0]
route.inflections()[0]
route.corners()[0]
route.intersections(ray(origin=another.bounds.center, direction=(1, 0)))[0]

即使只有一个候选，也必须显式索引后才能传给 target。无结果返回空集合，索引越界报 E_INDEX；可用 len(candidates) 检查数量，或 for point in candidates 逐一放置。候选按子路径、原始段、段内参数排序；相邻段共享节点去重，自交处不同路径位置保留各自身份。连续重合、无限多个全局最近点报告 E_GEOMETRY，不会擅自采样成有限候选。

extrema 返回所选空间中的局部坐标极值，普通端点和常量区间不算孤立极值；inflections 返回曲率改变符号的平滑拐点；corners 返回方向不平滑的连接节点。射线只取正向部分，方向 (dx,dy) 在路径所选测量空间中解释，方向不能为零。

自身锚点、方向与偏移#

1point = placed.path.at(fraction=0.5)2page.add(curve, anchor=self.path.start, target=point,3         offset=(2 mm, 3 mm), offset_space="target",4         rotation=point.tangent_angle)

point = placed.path.at(fraction=0.5)
page.add(curve, anchor=self.path.start, target=point,
         offset=(2 mm, 3 mm), offset_space="target",
         rotation=point.tangent_angle)

self 是本次素材的符号根，仅在 anchor 中绑定，尺寸与变换完成后才解析；自身选择器不能依赖另一个实例。旧九点与 anchor="start"/"end" 保留原有变换语义。

路径锚点提供 tangent、normal（两个无单位分量）及 tangent_angle。正法线是沿遍历方向的左侧；在页面坐标中向右的切线对应向上的正法线。尖角或尖点方向不唯一时，用 point.with_side("incoming") 或 with_side("outgoing") 选择，未指定时方向查询报 E_ANCHOR_DIRECTION。start/end 分别采用出射/入射方向；单纯定位无需方向。

参数	含义	默认
`anchor`	布局锚点名称或 `self` 几何选择器	`top_left`
`target`	同一容器中的已放置实例锚点	当前容器左上角
`offset`	两个物理长度分量	`(0 mm, 0 mm)`
`offset_space`	`container` 为容器横纵方向；`target` 为目标切线、左法线方向	`container`
`rotation`	围绕实例中心旋转，也接受 `point.tangent_angle`	`0deg`

图表内部部件#

1chart.plot_area.bounds.top_left2chart.axes["x"].bounds.bottom_center   # 完整轴组件：轴线、刻度与标题3chart.axes["x"].spine.path.at(fraction=0.5)4chart.axes["x"].label.bounds.center5chart.axes["x"].min                    # 数值范围最小端6chart.axes["x"].max                    # 数值范围最大端7chart.data(x=2, y=1.8)

chart.plot_area.bounds.top_left
chart.axes["x"].bounds.bottom_center   # 完整轴组件：轴线、刻度与标题
chart.axes["x"].spine.path.at(fraction=0.5)
chart.axes["x"].label.bounds.center
chart.axes["x"].min                    # 数值范围最小端
chart.axes["x"].max                    # 数值范围最大端
chart.data(x=2, y=1.8)

轴组件的九点简写对应完整组件布局框；轴线通过 spine 单独选择。横向、纵向和 top/bottom/left/right 侧的轴都使用同一模型。min/max 根据数值域而非页面方向命名，反向轴不会交换数值含义。断轴的 spine.path 有多条子路径，连续遍历需先选一条。旧 plot_* 与 axis(name="x",anchor="center") 写法保留原变换语义。

实例身份、部件与选点条件保存在引用中；组重放和图表重新排版后，会重新计算路径、部件、数据锚点及直接读取的 tangent_angle 等测量值。

完整接口清单 · 单位与尺寸 · 旋转与图层 · 组与复用

geometry-model#

类型参考列出全部视图成员和方法，源码身份与测量空间规则见上文；复合路径连续遍历前先选 .subpaths[i]。

下例分别读取实例、布局框、真实路径及绘制区域；同一个九点接口也能用于图表区域、完整坐标轴、标签、刻度和指数标签。红点标记布局框，蓝点标记绘制边界，黄色点标记控制点和轴标签。控制点须通过 .segments[i].controls[j] 选取；它提供位置，但通常不在曲线上。

1# Views retain their own meaning even though they share the nine-point API.2page=canvas(size=(145mm,120mm),background="#ffffff")3function mark_frame(view,color) {4    for location in [view.top_left,view.top_center,view.top_right,5                     view.middle_left,view.center,view.middle_right,6                     view.bottom_left,view.bottom_center,view.bottom_right] {7        page.add(ellipse(size=(1.5mm,1.5mm),fill=color),anchor=center,target=location)8    }9}10curve=page.add(path(commands=[move_to(0mm,20mm),11    cubic_to(15mm,-5mm,40mm,40mm,60mm,20mm)],12    border_color="#0072b2",border_width=1mm),offset=(15mm,12mm))13marked=mark_frame(curve,"#df6e70")14layout=curve.bounds

# Views retain their own meaning even though they share the nine-point API.
page=canvas(size=(145mm,120mm),background="#ffffff")
function mark_frame(view,color) {
    for location in [view.top_left,view.top_center,view.top_right,
                     view.middle_left,view.center,view.middle_right,
                     view.bottom_left,view.bottom_center,view.bottom_right] {
        page.add(ellipse(size=(1.5mm,1.5mm),fill=color),anchor=center,target=location)
    }
}
curve=page.add(path(commands=[move_to(0mm,20mm),
    cubic_to(15mm,-5mm,40mm,40mm,60mm,20mm)],
    border_color="#0072b2",border_width=1mm),offset=(15mm,12mm))
marked=mark_frame(curve,"#df6e70")
layout=curve.bounds

1# Views retain their own meaning even though they share the nine-point API.2page=canvas(size=(145mm,120mm),background="#ffffff")3function mark_frame(view,color) {4    for location in [view.top_left,view.top_center,view.top_right,5                     view.middle_left,view.center,view.middle_right,6                     view.bottom_left,view.bottom_center,view.bottom_right] {7        page.add(ellipse(size=(1.5mm,1.5mm),fill=color),anchor=center,target=location)8    }9}10curve=page.add(path(commands=[move_to(0mm,20mm),11    cubic_to(15mm,-5mm,40mm,40mm,60mm,20mm)],12    border_color="#0072b2",border_width=1mm),offset=(15mm,12mm))13marked=mark_frame(curve,"#df6e70")14layout=curve.bounds15marked=mark_frame(layout,"#df6e70")16page.add(rect(size=(layout.width,layout.height),border_color="#df6e70",17              border_width=0.15mm),target=layout.top_left)18marked=mark_frame(curve.path,"#009e88")19marked=mark_frame(curve.path.bounds,"#009e88")20painted=curve.ink21marked=mark_frame(painted.bounds,"#287dc3")22boundary=painted.boundary23page.add(ellipse(size=(2mm,2mm),fill="#287dc3"),anchor=center,24         target=boundary.nearest(to=layout.top_left)[0])25 26# List indices refer to original subpaths, segments, nodes and controls.27route=curve.path.subpaths[0]28same_route=route.path29segment=route.segments[0]30node=route.nodes[1]31control=segment.controls[0]32all_controls=segment.controls33for location in [route.start,route.end,node,control,all_controls[1]] {34    page.add(ellipse(size=(2mm,2mm),fill="#e69f00"),anchor=center,target=location)35}36point=segment.at(t=0.5)37coordinate=(point.x,point.y)38page.add(text("t = 0.5",font_size=6pt),offset=(coordinate[0]+2mm,coordinate[1]-4mm))39direction=point.tangent40left_normal=point.normal41page.add(line(length=7mm,line_color="#009e88"),anchor=self.path.start,42         target=point,rotation=point.tangent_angle)43page.add(ellipse(size=(2mm,2mm),fill="#009e88"),anchor=center,44         target=point,offset=(left_normal[0]*5mm,left_normal[1]*5mm))45page.add(ellipse(size=(2mm,2mm),fill="#009e88"),anchor=center,46         target=point,offset=(direction[0]*5mm,direction[1]*5mm))47box_point=layout.top_left48page.add(text("Bounds / path / ink",font_size=9pt),49         offset=(box_point.x,box_point.y-5mm))50 51# Plot areas, complete axes, labels, ticks and exponent labels are components.52p=plot(size=(105mm,50mm),x=axis(range=(0,4000),notation=offset,53       exponent=3,label="Time"),y=axis(range=(0,5),label="Signal"))54p.line(x=[0,1000,2000,3000,4000],y=[1,2,4,3,4])55chart=page.add(p,offset=(15mm,65mm))56area=chart.plot_area57marked=mark_frame(area,"#df6e70")58marked=mark_frame(area.bounds,"#df6e70")59axes=chart.axes60horizontal=axes["x"]61marked=mark_frame(horizontal,"#009e88")62marked=mark_frame(horizontal.bounds,"#009e88")63marked=mark_frame(horizontal.label,"#e69f00")64marked=mark_frame(horizontal.exponent,"#e69f00")65tick=horizontal.ticks[0]66marked=mark_frame(tick,"#e69f00")67for location in [horizontal.min,horizontal.max,68                 horizontal.spine.path.at(fraction=0.5)] {69    page.add(ellipse(size=(2mm,2mm),fill="#287dc3"),anchor=center,target=location)70}

# Views retain their own meaning even though they share the nine-point API.
page=canvas(size=(145mm,120mm),background="#ffffff")
function mark_frame(view,color) {
    for location in [view.top_left,view.top_center,view.top_right,
                     view.middle_left,view.center,view.middle_right,
                     view.bottom_left,view.bottom_center,view.bottom_right] {
        page.add(ellipse(size=(1.5mm,1.5mm),fill=color),anchor=center,target=location)
    }
}
curve=page.add(path(commands=[move_to(0mm,20mm),
    cubic_to(15mm,-5mm,40mm,40mm,60mm,20mm)],
    border_color="#0072b2",border_width=1mm),offset=(15mm,12mm))
marked=mark_frame(curve,"#df6e70")
layout=curve.bounds
marked=mark_frame(layout,"#df6e70")
page.add(rect(size=(layout.width,layout.height),border_color="#df6e70",
              border_width=0.15mm),target=layout.top_left)
marked=mark_frame(curve.path,"#009e88")
marked=mark_frame(curve.path.bounds,"#009e88")
painted=curve.ink
marked=mark_frame(painted.bounds,"#287dc3")
boundary=painted.boundary
page.add(ellipse(size=(2mm,2mm),fill="#287dc3"),anchor=center,
         target=boundary.nearest(to=layout.top_left)[0])

# List indices refer to original subpaths, segments, nodes and controls.
route=curve.path.subpaths[0]
same_route=route.path
segment=route.segments[0]
node=route.nodes[1]
control=segment.controls[0]
all_controls=segment.controls
for location in [route.start,route.end,node,control,all_controls[1]] {
    page.add(ellipse(size=(2mm,2mm),fill="#e69f00"),anchor=center,target=location)
}
point=segment.at(t=0.5)
coordinate=(point.x,point.y)
page.add(text("t = 0.5",font_size=6pt),offset=(coordinate[0]+2mm,coordinate[1]-4mm))
direction=point.tangent
left_normal=point.normal
page.add(line(length=7mm,line_color="#009e88"),anchor=self.path.start,
         target=point,rotation=point.tangent_angle)
page.add(ellipse(size=(2mm,2mm),fill="#009e88"),anchor=center,
         target=point,offset=(left_normal[0]*5mm,left_normal[1]*5mm))
page.add(ellipse(size=(2mm,2mm),fill="#009e88"),anchor=center,
         target=point,offset=(direction[0]*5mm,direction[1]*5mm))
box_point=layout.top_left
page.add(text("Bounds / path / ink",font_size=9pt),
         offset=(box_point.x,box_point.y-5mm))

# Plot areas, complete axes, labels, ticks and exponent labels are components.
p=plot(size=(105mm,50mm),x=axis(range=(0,4000),notation=offset,
       exponent=3,label="Time"),y=axis(range=(0,5),label="Signal"))
p.line(x=[0,1000,2000,3000,4000],y=[1,2,4,3,4])
chart=page.add(p,offset=(15mm,65mm))
area=chart.plot_area
marked=mark_frame(area,"#df6e70")
marked=mark_frame(area.bounds,"#df6e70")
axes=chart.axes
horizontal=axes["x"]
marked=mark_frame(horizontal,"#009e88")
marked=mark_frame(horizontal.bounds,"#009e88")
marked=mark_frame(horizontal.label,"#e69f00")
marked=mark_frame(horizontal.exponent,"#e69f00")
tick=horizontal.ticks[0]
marked=mark_frame(tick,"#e69f00")
for location in [horizontal.min,horizontal.max,
                 horizontal.spine.path.at(fraction=0.5)] {
    page.add(ellipse(size=(2mm,2mm),fill="#287dc3"),anchor=center,target=location)
}

依赖文件

examples/manual/geometry-members.lay

point.x 与 point.y 返回当前容器中的物理坐标；point.tangent 和 point.normal 返回两个无量纲分量，分别可用 [0] 和 [1] 读取。乘以物理长度可计算偏移，正法线始终在遍历方向左侧。target=point 保留锚点引用；数值二元组可用于 offset。重新放置后的依赖关系见组合源码。

几何视图类型

workflow#

本流程的完整源码与可执行验证文件列在功能覆盖清单。组合使用时请遵循本页的输入条件与限制。