Recreate Wuhan University’s Cherry Blossom Bloom with Python and OpenCV

Wuhan University launched a "Cherry Blossom Cloud Live" stream from March 16 to 25, inviting viewers to watch the blossoms online. A student, Zhu Yongchun, wrote a Python script that simulates the blooming process, and the code was later open‑sourced.

The script explains that each image consists of pixels, each represented by an RGB array (a, b, c) where values range from 0 to 255. More pixels yield higher resolution, while too few cause visible jagged edges.

Using OpenCV, frames are saved as JPEG files:

cv2.imwrite("pic/frame%d.jpg" % count, image)  # save frame as JPEG file

A blank canvas is created with Pillow, a font is selected, and a nested loop writes colored text onto the canvas based on pixel values:

blank = Image.new("RGB", [len(img[0]), len(img)], "white")
drawObj = ImageDraw.Draw(blank)
font = ImageFont.truetype("C:/Windows/Fonts/msyhbd.ttc", size=n-1)
for i in range(0, len(img), n):
    for j in range(0, len(img[i]), n):
        text = "武汉加油"
        drawObj.ink = img[i][j][0] + img[i][j][1]*256 + img[i][j][2]*256*256
        drawObj.text([j, i], text[int(j/n) % len(text)], font=font)
        print("完成处理——", i, j)
blank.save("new/" + pic + ".jpeg")

Finally, the generated images are compiled into a video using OpenCV’s VideoWriter:

def picvideo(path, size):
    fps = 24
    file_path = "video/new.mp4"
    fourcc = cv2.VideoWriter_fourcc('D','I','V','X')
    video = cv2.VideoWriter(file_path, fourcc, fps, size)
    for item in os.listdir(path):
        if item.endswith('.jpg'):
            img = cv2.imread(os.path.join(path, item))
            video.write(img)
    video.release()

Running the script produces a time‑lapse video that visualizes the full cherry blossom opening process, which can be shared or streamed online.