一.颜色绘制

1.看一下三色图

其代码行式

2.绘制基本图形及代码

整体代码

"""
Example to show how to draw basic shapes using OpenCV
"""

# Import required packages:
import cv2
import numpy as np
import matplotlib.pyplot as plt


def show_with_matplotlib(img, title):
    """Shows an image using matplotlib capabilities"""

    # Convert BGR image to RGB:
    img_RGB = img[:, :, ::-1]

    # Show the image using matplotlib:
    plt.imshow(img_RGB)
    plt.title(title)
    plt.show()


# Dictionary containing some colors:
colors = {'blue': (255, 0, 0), 'green': (0, 255, 0), 'red': (0, 0, 255), 'yellow': (0, 255, 255),
          'magenta': (255, 0, 255), 'cyan': (255, 255, 0), 'white': (255, 255, 255), 'black': (0, 0, 0),
          'gray': (125, 125, 125), 'rand': np.random.randint(0, high=256, size=(3,)).tolist(),
          'dark_gray': (50, 50, 50), 'light_gray': (220, 220, 220)}

# We create the canvas to draw: 400 x 400 pixels, 3 channels, uint8 (8-bit unsigned integers)
# We set the background to black using np.zeros():
image = np.zeros((400, 400, 3), dtype="uint8")

# If you want another background color you can do the following:
image[:] = colors['light_gray']

# Show image:
show_with_matplotlib(image, '')

# 1. We are going to see how cv2.line() works:
cv2.line(image, (0, 0), (400, 400), colors['green'], 3)
cv2.line(image, (0, 400), (400, 0), colors['blue'], 3)
cv2.line(image, (200, 0), (200, 400), colors['red'], 10)
cv2.line(image, (0, 200), (400, 200), colors['yellow'], 10)

# Show image:
show_with_matplotlib(image, 'cv2.line()')

# Clean the canvas to draw again:
image[:] = colors['light_gray']

# 2. We are going to see how cv2.rectangle() works:
cv2.rectangle(image, (10, 50), (60, 300), colors['green'], 3)
cv2.rectangle(image, (80, 50), (130, 300), colors['blue'], -1)
cv2.rectangle(image, (150, 50), (350, 100), colors['red'], -1)
cv2.rectangle(image, (150, 150), (350, 300), colors['cyan'], 10)

# Show image:
show_with_matplotlib(image, 'cv2.rectangle()')

下面展示一些效果其相关代码 内联代码片。

绘制直线是用2个坐标连成一条直线，固然有2个坐标参数

cv2.line(image, (0, 0), (400, 400), colors['green'], 3)
cv2.line(image, (0, 400), (400, 0), colors['blue'], 3)
cv2.line(image, (200, 0), (200, 400), colors['red'], 10)
cv2.line(image, (0, 200), (400, 200), colors['yellow'], 10)

绘制矩形就是用一个坐标x轴的起点，另一个坐标x轴的终点的直线为宽，一个坐标y轴的起点，另一个坐标y轴的终点的直线为长围成的矩形

cv2.rectangle(image, (10, 50), (60, 300), colors['green'], 3)
cv2.rectangle(image, (80, 50), (130, 300), colors['blue'], -1)
cv2.rectangle(image, (150, 50), (350, 100), colors['red'], -1)
cv2.rectangle(image, (150, 150), (350, 300), colors['cyan'], 10)

绘制圆形
下面代码中，第一个参数是选圆心的坐标，第二个参数是选半经，第三个参数是选颜色，第四个参数是厚度

cv2.circle(image, (50, 50), 20, colors['green'], 3)
cv2.circle(image, (100, 100), 30, colors['blue'], -1)
cv2.circle(image, (200, 200), 40, colors['magenta'], 10)
cv2.circle(image, (300, 300), 40, colors['cyan'], -1)