Plotly：如何去除用 add_annotation() 创建的箭头尾部后面的间隙？

Question

我正在使用 plotly.graph_objects.Figure.add_annotation() 函数将箭头添加到我的图中 - 请参阅下面的简单示例代码：

import plotly.graph_objects as go

fig = go.Figure()

fig.add_annotation(ax = 3, axref = 'x', ay = 2, ayref = 'y',
                   x = 4, xref = 'x', y = 2, yref = 'y',
                   arrowhead = 3)

fig.add_shape(x0 = 1, x1 = 3, xref = 'x',
              y0 = 1, y1 = 3, yref = 'y')

fig.add_shape(x0 = 4, x1 = 6, xref = 'x',
              y0 = 1, y1 = 3, yref = 'y')

fig.update_layout(xaxis_range = [0, 7], yaxis_range = [0, 4])

fig.show()

呈现以下图像：

如您所见，左侧矩形和箭头尾部之间有一个小间隙。 有没有办法消除这个间隙，使箭头完全按照参数 ax 和 ay 的指定开始？ 我试过查看 documentation 看看是否还有add_annotation() 函数的其他相关参数，但没找到线索。

Answer 1

应该这样做：

xanchor = 'right'

完整代码：

import plotly.graph_objects as go

fig = go.Figure()

fig.add_annotation(ax = 3, axref = 'x', ay = 2, ayref = 'y',
                   x = 4, xref = 'x', y = 2, yref = 'y',
                   arrowhead = 3,
                   xanchor = 'right')

fig.add_shape(x0 = 1, x1 = 3, xref = 'x',
              y0 = 1, y1 = 3, yref = 'y')

fig.add_shape(x0 = 4, x1 = 6, xref = 'x',
              y0 = 1, y1 = 3, yref = 'y')

fig.update_layout(xaxis_range = [0, 7], yaxis_range = [0, 4])

fig.show()

解释：

根据 documentation、

xanchor – Sets the text box’s horizontal position anchor This anchor binds the x position to the “left”, “center” or “right” of the annotation. For example, if x is set to 1, xref to “paper” and xanchor to “right” then the right-most portion of the annotation lines up with the right-most edge of the plotting area. If “auto”, the anchor is equivalent to “center” for data- referenced annotations or if there is an arrow, whereas for paper-referenced with no arrow, the anchor picked corresponds to the closest side.

即使没有实际的注释文本，(place-holder) 文本字段仍会呈现（默认情况下锚定到 'center'），这就是推动箭头尾部的原因。将 xanchor 设置为 'right' 可确保箭头从预期位置开始，同时将空文本字段推到其左侧。

Plotly：如何去除用 add_annotation() 创建的箭头尾部后面的间隙？

Plotly: How to remove the gap behind the tail of an arrow created with add_annotation()?

python

graphics

visualization

plotly

plotly-python

完整代码：

解释：