selenium实现chrome分屏截图的合并

selenium的截图功能在chrome下无法实现，但是可以操作滚动条来一屏一屏的截图，然后再合并成一张图，解决方案如下：

def test_capture(url, w_pix,h_pix):
    try:
        self.driver.set_window_size(w_pix,h_pix)
        self.driver.get(url)
        self.driver.implicitly_wait(5)
        i = 0
        img_list = []
        while i<30:
            js="var q=document.body.scrollTop="+ str(i*wap_pixs[pix][1])+";"
            self.driver.execute_script(js)
            time.sleep(1)
            js1 = "return document.body.scrollHeight-document.body.scrollTop"
            s= self.driver.execute_script(js1)
            if h_pix >= s:
                break
            else:
                self.driver.save_screenshot(str(i)+‘.png‘)
                img_list.append(str(i)+‘.png‘)
            i += 1
        image_merge(img_list)　　except:　　　　print ‘error‘

from PIL import Imagedef image_merge(images, output_dir=‘‘, output_name=‘merge.jpg‘, restriction_max_width=None, restriction_max_height=None):
    """垂直合并多张图片
    images - 要合并的图片路径列表
    ouput_dir - 输出路径
    output_name - 输出文件名
    restriction_max_width - 限制合并后的图片最大宽度，如果超过将等比缩小
    restriction_max_height - 限制合并后的图片最大高度，如果超过将等比缩小
    """
    def image_resize(img, size=(1500, 1100)):
        """调整图片大小
        """
        try:
            if img.mode not in (‘L‘, ‘RGB‘):
                img = img.convert(‘RGB‘)
            img = img.resize(size)
        except Exception, e:
            pass
        return img

    max_width = 0
    total_height = 0
    # 计算合成后图片的宽度（以最宽的为准）和高度
    for img_path in images:
        if os.path.exists(img_path):
            img = Image.open(img_path)
            width, height = img.size
            if width > max_width:
                max_width = width
            total_height += height  

    # 产生一张空白图
    new_img = Image.new(‘RGB‘, (max_width, total_height), 255)
    # 合并
    x = y = 0
    for img_path in images:
        if os.path.exists(img_path):
            img = Image.open(img_path)
            width, height = img.size
            new_img.paste(img, (x, y))
            y += height  

    if restriction_max_width and max_width >= restriction_max_width:
        # 如果宽带超过限制
        # 等比例缩小
        ratio = restriction_max_height / float(max_width)
        max_width = restriction_max_width
        total_height = int(total_height * ratio)
        new_img = image_resize(new_img, size=(max_width, total_height))  

    if restriction_max_height and total_height >= restriction_max_height:
        # 如果高度超过限制
        # 等比例缩小
        ratio = restriction_max_height / float(total_height)
        max_width = int(max_width * ratio)
        total_height = restriction_max_height
        new_img = image_resize(new_img, size=(max_width, total_height))  

    if not os.path.exists(output_dir):
        os.makedirs(output_dir)
    save_path = ‘%s/%s‘ % (output_dir, output_name)
    new_img.save(save_path)
    for img_path in images:
        os.remove(img_path)
    return save_path 

大致就这么个思路