# Drawing flag of Japan | Image processing in Python

This is an **example of image processing in python** – here we are going to learn how to **draw a flag of Japan in python?**

Submitted by Ankit Rai, on June 11, 2019

Read basics of the drawing/image processing in python: Drawing flag of Thailand

The **national flag of Japan** is a rectangular white banner bearing a crimson-red disc at its center. This flag is officially called Nisshōki but is more commonly known in Japan as Hinomaru. It embodies the country's sobriquet: Land of the Rising Sun.

**Steps:**

First, we make a matrix of dimensions 300 X 600 X 3. Where the number of pixels of rows is 300, the number of pixels of columns is 600 and 3 represent the number of dimensions of the color coding in BGR format.

- Paint the complete image with white color. BGR code for White is (255,255,255).
- Apply loop on rows and columns and implement the equation of the circle such that we get a circle in the center of the flag and color it crimson glory using RGB format.

**Equation of circle:**

((x-h)^2 - (y-k)^2)=r^2

Where (h, k) are the centres, (x, y) are co-ordinates of x-axis and y-axis and r is the radius of the circle.

bgrcode for crimson glory color is (45, 0, 188).

## Python code to draw flag of Japan

# import numpy library as np import numpy as np # import open-cv library import cv2 # import sqrt function from the math module from math import sqrt # here image is of class 'uint8', the range of values # that each colour component can have is [0 - 255] # create a zero matrix of order 300x600 of 3-dimensions flag = np.zeros((300, 600, 3),np.uint8) # take coordinate of the circle center_x, center_y = 150, 300 # take radius of the circle radius = 50 # fill whole pixels of dimensions # with White color flag[:, :, :] = 255; # Draw a circle with crimson glory color # loop for rows i.e. for x-axis for i in range(101,201) : # loop for columns i.e. for y-axis for j in range(251, 351) : #applying the equation of circle to make the circle in the center. distance = sqrt((center_x - i)**2 + (center_y - j)**2) if distance <= radius : # fill the circle with crimson glory # color using RGB color representation. flag[i, j, 0] = 45 flag[i, j, 1] = 0 flag[i, j, 2] = 188 # Show the image formed cv2.imshow("Japan Flag",flag);

**Output**

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