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Share a recent wave of Get a python painting method.

Let's get off to a happy start!

Related documents

Baidu web download link: https://pan.baidu.com/s/1ZBs4-DpVxXvoisAllwHV5Q

Password: 9nei

Develop tools

Python version: 3.6.4

Related modules:

cv2 module;

numpy module;

pywin32 module;

bs4 module;

and some Python's own modules.

other:

potrace

Environment construction

Install Python and add it to the environment variable, and pip installs the relevant modules that are required.

Resources

1.http://www.html-js.com/article/1628

2.https://zh.wikipedia.org/wiki/%E5%8F%AF%E7%B8%AE%E6%94%BE%E5%90%91%E9%87%8F%E5%9C%96%E5%BD%A2

3.https://www.cnblogs.com/hnfxs/p/3148483.html

Take a quick look

Modify the path to the picture you want to draw:

Run the main.py file in the cmd window.

The effect is as follows:

Introduction to the principle

I. Implementation steps

First read the original image:

Secondly, the number of colors of the original image is reduced to the specified number by the K mean cluster, the larger the K value, the slower the operation, but the better the effect:

Each time you remove a color from the clustering results and use potrace to convert it to a graphic in SVG format, parse the format and draw it with Python's own gallery:

Two .SVG format

SVG, which scales vector graphics, is a graphics format based on a scalable markup language (XML) that describes 2D vector graphics. SVG mainly supports the following display objects:

1. Vector display objects, basic vector display objects include rectangles, circles, ellipses, polygons, straight lines, arbitrary curves, etc

2. Embedded external images, including PNG, JPEG, SVG, etc

3. Text object.

For more technical details on SVG, please refer to:

http://www.w3school.com.cn/svg/svg_intro.asp

Iii. Turtle Library

Here's a recommended document for the Turtle library:

https://www.rddoc.com/doc/Python/3.6.0/zh/library/turtle/

Bezier curve

The Bezier curve is used for drawing, which is briefly described here.

The mathematical basis of the Bezier curve is the Bernstein polynomial, named after the French engineer Pierre Bézier.

Bezier curve control is simple but has strong description ability, so it is widely used in the field of industrial design, and bezier curve also plays an important role in vector graphics. Some of our most common vector drawing software today (e.g. Flash, CorelDraw, PS, etc.) provides the ability to plot Bezier curves.

Linear formula:

Given points P0, P1, the linear Bezier curve is a straight line between two points, determined as follows:

It's actually linear interpolation.

Secondary formula:

Given points P0, P1, and P2, the path of the second-order Bezier curve is determined as follows:

n-side formula:

Given points P0 to Pn, the path of the n-order Bezier curve is determined as follows:

How the Bezier curve is drawn (in the second order):

Suppose the three points in the plane that are not collinear are shown in the following illustration:

Select a little D on AB and A little E on BC to make:

AD:AB=BE:BC。

Connect DE:

Select a little F on the DE so that:

AD:AB=BE:BC=DF:DE

To ensure that the proportional relationship between AD, AB, BE, BC, DF, and DE remains unchanged, and that the D-point moves from point A to point B, the curve of all point F is the second-order Bezier curve:

The n-order Bezier curve is drawn in a similar way, for example, in the third and fourth orders:

That's all~

Complete source code and required tools are available in the relevant files, please download and use them yourself.

more

The code is correct as of 2018-07-31.

Still quite interesting, the original picture is best not too big, otherwise the generation speed is very slow very slow very slow.