PyCairo – Setting Context Color

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 pycairo
import cairo

# creating a SVG surface
# here geek007 is file name & 700, 700 is dimension
with 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 saved
print("File Saved")

Setting color of the context

 context.set_source_rgba (0, 0, 0, 1)

Output :

Example 2 :

Python3

# importing pycairo
import cairo

# creating a SVG surface
# here geek007 is file name & 700, 700 is dimension
with 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 saved
print("File Saved")

Setting color of the context

   context.set_source_rgba (4, 0, 4, 0.5)

Output :

Example 3 :

Python3

# importing pycairo
import cairo

# creating a SVG surface
# here geek007 is file name & 700, 700 is dimension
with 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 saved
print("File Saved")

Setting color of the context

context.set_source_rgba (180, 150, 0, 0.5)

Output :