PyCairo – Setting Context Color

18 Feb, 2022
In this article, we will see how we can set context colors in pycairo Python. Pycairo is a Python module providing bindings for the Cairo graphics library. This library is used for creating SVG i.e vector files in python. The easiest and quickest way to open an SVG file to view it (read only) is with a modern web browser like Chrome, Firefox, Edge, or Internet Explorer—nearly all of them should provide some sort of rendering support for the SVG format. Color can be set using RGBA model, RGBA stands for red green blue alpha. While it is sometimes described as a color space, it is actually the three-channel RGB color model supplemented with a fourth alpha channel.
In order to this we will use set_source_rgba method with the Context object
Syntax: context.set_source_rgba(0, 0, 0, 1)
Argument: It takes color format in RGBA model
Return: It returns None  
Example 1 :
Python
# importing pycairoimport cairo  # creating a SVG surface# here geek007 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek007.svg", 700, 700) as surface:      # creating a cairo context object for SVG surface    # using Context method    context = cairo.Context(surface)      # setting color of the context    context.set_source_rgba(0, 0, 0, 1)      # setting of line width    context.set_line_width(4)      # move the context to x,y position    context.move_to(40, 30)      # creating a rectangle(square)    context.rectangle(100, 100, 100, 100)      # stroke out the color and width property    context.stroke()    # printing message when file is savedprint("File Saved")
Setting color of the context
 context.set_source_rgba (0, 0, 0, 1)
Output :
Example 2 :
Python3
# importing pycairoimport cairo  # creating a SVG surface # here geek007 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek007.svg", 700, 700) as surface:          # creating a cairo context object for SVG surface    #using Context method    context = cairo.Context(surface)          # setting color of the context    context.set_source_rgba(4, 0, 4, 0.5)          # setting of line width    context.set_line_width(40)        # move the context to x,y position    context.move_to(40, 30)            #creating a rectangle(square)    context.rectangle(100, 100, 100, 100)          # stroke out the color and width property    context.stroke()            # printing message when file is savedprint("File Saved")
Setting color of the context
   context.set_source_rgba (4, 0, 4, 0.5)
Output :
Example 3 :
Python3
# importing pycairoimport cairo  # creating a SVG surface# here geek007 is file name & 700, 700 is dimensionwith cairo.SVGSurface("geek007.svg", 700, 700) as surface:      # creating a cairo context object for SVG surface    # using Context method    context = cairo.Context(surface)      # setting color of the context    context.set_source_rgba(180, 150, 0, 0.5)      # setting of line width    context.set_line_width(40)      # move the context to x,y position    context.move_to(40, 30)      # creating a rectangle(square)    context.rectangle(100, 100, 100, 100)      # stroke out the color and width property    context.stroke()    # printing message when file is savedprint("File Saved")
Setting color of the context
context.set_source_rgba (180, 150, 0, 0.5)
Output :
saurabh1990aror
Python-PyCairo
Python
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