PyCairo - Drawing Bezier curve

PyCairo - Drawing Bezier curve

To draw a Bezier curve using PyCairo, you need to use the curve_to method of the Context class. A Bezier curve is defined by four points: the starting point, two control points, and an ending point. The curve_to method requires the coordinates of these three control points (the second, third, and fourth points), with the assumption that the starting point is the current point of the context.

Here's an example of how to draw a Bezier curve using PyCairo:

Step 1: Install PyCairo

If you haven't installed PyCairo, you can do so via pip:

pip install pycairo

Step 2: Create a Surface and Context

Before drawing, you need to create a Surface and a Context. For this example, let's create an image surface:

import cairo # Create an image surface WIDTH, HEIGHT = 800, 600 surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, WIDTH, HEIGHT) ctx = cairo.Context(surface)

Step 3: Draw a Bezier Curve

# Set the starting point ctx.move_to(100, 300) # Draw a Bezier curve # curve_to(x1, y1, x2, y2, x3, y3) ctx.curve_to(200, 100, 400, 500, 600, 300) # Set line width and color ctx.set_line_width(3) ctx.set_source_rgb(0, 0, 0) # Black # Stroke the curve ctx.stroke()

In the curve_to method, (200, 100) and (400, 500) are the control points, and (600, 300) is the end point of the Bezier curve.

Step 4: Save the Image

Finally, save the image to a file:

surface.write_to_png("bezier_curve.png")

When you run this script, it will create an image file named bezier_curve.png with a Bezier curve drawn on it.

Customization

You can adjust the coordinates used in move_to and curve_to to change the shape and position of the Bezier curve. Experimenting with different control points will give you a variety of curve shapes. The line width and color can also be customized using set_line_width and set_source_rgb.

More Tags

react-leaflet searching ilmerge android-6.0-marshmallow c99 ethernet xcode7 resources audio-recording elasticsearch

More Programming Guides

Other Guides

More Programming Examples