PyCairo – 如何获得 SVG 单元？

在本文中，我们将看到如何使用Python在 pycairo 中获取 SVG 单元。 SVG unit用于描述SVG规范中坐标和长度有效的单位

Pycairo是一个Python模块，为 cairo 图形库提供绑定。这个库用于在Python中创建SVG即矢量文件。打开 SVG 文件以查看它（只读）的最简单快捷的方法是使用现代网络浏览器，如 Chrome、Firefox、Edge 或 Internet Explorer——几乎所有这些都应该为 SVG 格式提供某种渲染支持.

These are the following SVG units in Pycairo

1. USER User unit, a value in the current coordinate system. If used in the root element for the initial coordinate systems it corresponds to pixels
2. EM The size of the element’s font
3. EX The x-height of the element’s font
4. PX Pixels (1px = 1/96^th of 1in)
5. IN Inches (1in = 2.54cm = 96px)
6. CM Centimeters (1cm = 96px/2.54)
7. MM Millimeters (1mm = 1/10^th of 1cm)
8. PT Points (1pt = 1/72^th of 1in)
9. PC Picas (1pc = 1/6^th of 1in)
10. PERCENT Percent, a value that is some fraction of another reference value.

In order to use the we will use get_document_unit with SVG surface object

Syntax : get_document_unit()

Argument : It takes no argument

Return : It returns SVG unit but when printed it shows value associated with it.

Python3

# importing pycairo
import cairo
  
# creating a SVG surface
# here geek95 is file name & 700, 700 is dimension
with cairo.SVGSurface("geek95.svg", 700, 700) as surface:
    # creating a cairo context object
    context = cairo.Context(surface)
  
    # creating a rectangle(square)
    context.rectangle(100, 100, 100, 100)
  
    # setting color of the context
    context.set_source_rgba(0.4, 1, 0.4, 1)
  
    # stroke out the color and width property
    context.stroke()
  
    # getting the svg unit
    value = surface.get_document_unit()
  
# printing the SVG unit
print("SVG unit= " + str(value))

输出：

SVG unit= 7