In this article, we will learn how we can draw different line caps types using PyCairo in python. The line caps are endpoints of lines.
Steps of Implementation :
- Import the Pycairo module.
- Create a SVG surface object and add context to it.
- Setting color of the context & line width
- Setting of line cap style using set_line_cap( )
- Creating a line.
There are three different types line cap styles in PyCairo.
1. set_line_cap ( cairo.LINE_CAP_BUTT )
Example :
Python3
# importing pycairoimport cairo# creating a SVG surface# here geek94 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek94.svg", 700, 700) as surface: # creating a cairo context object for SVG surface # using Context method context = cairo.Context(surface) context.set_source_rgba(0, 0, 0, 1) context.set_line_width(12) context.set_line_cap(cairo.LINE_CAP_BUTT) context.move_to(30, 50) context.line_to(150, 50) # stroke out the color and width property context.stroke() # printing message when file is saved print("File Saved") |
Output :
2. set_line_cap ( cairo.LINE_CAP_ROUND )
Example :
Python3
# importing pycairoimport cairo# creating a SVG surface# here geek94 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek94.svg", 700, 700) as surface: # creating a cairo context object for SVG surface # using Context method context = cairo.Context(surface) context.set_source_rgba(0, 0, 0, 1) context.set_line_width(12) context.set_line_cap(cairo.LINE_CAP_ROUND) context.move_to(30, 50) context.line_to(150, 50) # stroke out the color and width property context.stroke() # printing message when file is saved print("File Saved") |
Output :
3. set_line_cap ( cairo.LINE_CAP_SQUARE )
Example :
Python
# importing pycairoimport cairo# creating a SVG surface# here geek94 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek94.svg", 700, 700) as surface: # creating a cairo context object for SVG surface # using Context method context = cairo.Context(surface) context.set_source_rgba(0, 0, 0, 1) context.set_line_width(12) context.set_line_cap(cairo.LINE_CAP_SQUARE) context.move_to(30, 50) context.line_to(150, 50) # stroke out the color and width property context.stroke() # printing message when file is saved print("File Saved") |
Output:
Note: A line with cairo.LINE_CAP_SQUARE cap used has a different size than a line with cairo.LINE_CAP_BUTT cap. If the line is z units wide, the line with cairo.LINE_CAP_SQUARE cap will be exactly z units greater in size; z/2 units at the beginning and z/2 units at the end.
All three type of line caps can be seen in the below python Example, and the output of each line cap can also be compared
Python3
# importing pycairoimport cairo# creating a SVG surface# here geek94 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek94.svg", 700, 700) as surface: # creating a cairo context object for SVG surface # using Context method context = cairo.Context(surface) context.set_source_rgba(0, 0, 0, 1) context.set_line_width(12) # Setting line cap style context.set_line_cap(cairo.LINE_CAP_SQUARE) context.move_to(30, 50) context.line_to(150, 50) # stroke out the color and width property context.stroke() # Setting line cap style context.set_line_cap(cairo.LINE_CAP_ROUND) context.move_to(30, 90) context.line_to(150, 90) context.stroke() # Setting line cap style context.set_line_cap(cairo.LINE_CAP_SQUARE) context.move_to(30, 130) context.line_to(150, 130) context.stroke() # printing message when file is saved print("File Saved") |
Output :
