opencv python 中cv2.putText()函数的用法

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虽然用啦很多次，还是决定记录一下

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一、快速使用

cv2.putText(image, text, (5,50 ), cv2.FONT_HERSHEY_SIMPLEX, 0.75, (0, 0, 255), 2)

位置参数说明：

• 图片
• 要添加的文字
• 文字添加到图片上的位置
• 字体的类型
• 字体大小
• 字体颜色
• 字体粗细

二、官方文档

def putText(img, text, org, fontFace, fontScale, color, thickness=None, lineType=None, bottomLeftOrigin=None): # real signature unknown; restored from __doc__
    """
    putText(img, text, org, fontFace, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]]]) -> img
    .   @brief Draws a text string.
    .   
    .   The function cv::putText renders the specified text string in the image. Symbols that cannot be rendered
    .   using the specified font are replaced by question marks. See #getTextSize for a text rendering code
    .   example.
    .   
    .   @param img Image.
    .   @param text Text string to be drawn.
    .   @param org Bottom-left corner of the text string in the image.
    .   @param fontFace Font type, see #HersheyFonts.
    .   @param fontScale Font scale factor that is multiplied by the font-specific base size.
    .   @param color Text color.
    .   @param thickness Thickness of the lines used to draw a text.
    .   @param lineType Line type. See #LineTypes
    .   @param bottomLeftOrigin When true, the image data origin is at the bottom-left corner. Otherwise,
    .   it is at the top-left corner.
    """
    pass

三、使用举例

下面举例把文字添加到摄像头中

import cv2
cap = cv2.VideoCapture(0)
while (1):  
    ret, img = cap.read()
    start = time.time()
    result = discern(img)
    end = time.time()
    seconds = end - start  # 处理一帧所用的时间
    fps = 1 / seconds  # 一秒钟可以处理多少帧
    fps = "%.2f fps"%fps
    print(fps)

    # 图片 添加的文字 位置 字体 字体大小 字体颜色 字体粗细
    cv2.putText(result, fps, (5,50 ), cv2.FONT_HERSHEY_SIMPLEX, 0.75, (0, 0, 255), 2)
    cv2.imshow("image", result)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
cap.release()  
cv2.destroyAllWindows()  

结果如下（ps:还是不要漏出自己的丑照，免得影响你们学习）

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