win下使用exists匹配图像的时候，总是会把分辨率转换成（1024,0），导致识别不到

[rurutiazhou]

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bug描述：
我attach了一个windows的窗口，在脚本里使用exists方法截取了窗体内的一部分图像，在脚本运行的时候，log里显示，总是把我的窗体的分辨率转换成（1024,0），导致匹配失败：

[05:21:25][INFO]<airtest.core.api> Try finding:
Template(C:\Users\lucy.zhou\Desktop\集成用例脚本\v5_student_test_1.air\tpl1721024590314.png)
[05:21:26][DEBUG]<airtest.core.api> resize: (484, 108)->(1, 1), resolution: (1024, 768)=>(1024, 0)
[05:21:26][DEBUG]<airtest.core.api> try match with _find_template
[05:21:26][DEBUG]<airtest.core.api> 'error: in template match, found im_search bigger than im_source.'
[05:21:26][DEBUG]<airtest.core.api> try match with _find_sift_in_predict_area
[05:21:26][DEBUG]<airtest.core.api> try match with _find_sift
[05:21:26][DEBUG]<airtest.core.api> match result: None

**```Traceback (most recent call last):**
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\cli\runner.py", line 66, in runTest
    six.reraise(*sys.exc_info())
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\six.py", line 693, in reraise
    raise value
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\cli\runner.py", line 62, in runTest
    exec(compile(code.encode("utf-8"), pyfilepath, 'exec'), self.scope)
  File "C:\Users\lucy.zhou\Desktop\集成用例脚本\v5_student_test_1.air\v5_student_test_1.py", line 47, in <module>
    existsExamNo = exists(Template(r"tpl1721024590314.png", record_pos=(0.046, 0.002), resolution=(1024, 768)))
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\utils\logwraper.py", line 72, in wrapper
    res = f(*args, **kwargs)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\core\api.py", line 408, in exists
    pos = loop_find(v, timeout=ST.FIND_TIMEOUT_TMP)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\utils\logwraper.py", line 72, in wrapper
    res = f(*args, **kwargs)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\core\cv.py", line 59, in loop_find
    try_log_screen(screen)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\utils\logwraper.py", line 72, in wrapper
    res = f(*args, **kwargs)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\core\cv.py", line 83, in try_log_screen
    aircv.imwrite(filepath, screen)
  File "C:\UItestFramwork\Common\python3.7\lib\site-packages\airtest\aircv\aircv.py", line 29, in imwrite
    cv2.imencode('.jpg', img)[1].tofile(filename)
cv2.error: OpenCV(3.4.2) C:\projects\opencv-python\opencv\modules\imgcodecs\src\grfmt_base.cpp:145: error: (-10:Unknown error code -10) Raw image encoder error: Empty JPEG image (DNL not supported) in function 'cv::BaseImageEncoder::throwOnEror'

**python 版本:** `python3.5`

**airtest 版本:** `1.2.17`