解释下这段代码record_list = [] screen_width = 1024 screen_height = 768 interest_time_start_offset = 1200 interest_time_duration = 3000 while row_index <= fix_record.max_row: row_start = fix_record[row_index][0].value if row_start is None: break if row_start.startswith("trail"): record_list.clear() record_list.append(fix_record[row_index][0].value) record_list.append(images_info[image_index + 1][0].value) img_width = float(images_info[image_index + 1][1].value) img_height = float(images_info[image_index + 1][2].value) object1_xmin = float(images_info[image_index + 1][3].value) / img_width * screen_width object1_ymin = float(images_info[image_index + 1][4].value) / img_height * screen_height object1_xmax = float(images_info[image_index + 1][5].value) / img_width * screen_width object1_ymax = float(images_info[image_index + 1][6].value) / img_height * screen_height if images_info[image_index + 1][7].value is None: object2_xmin = -1.0 object2_ymin = -1.0 object2_xmax = -1.0 object2_ymax = -1.0 else: object2_xmin = float(images_info[image_index + 1][7].value) / img_width * screen_width object2_ymin = float(images_info[image_index + 1][8].value) / img_height * screen_height object2_xmax = float(images_info[image_index + 1][9].value) / img_width * screen_width object2_ymax = float(images_info[image_index + 1][10].value) / img_height * screen_height image_index += 1 row_index += 1 start_time = -1 end_time = -1 interest_duration_start = -1 interest_duration_end = -1 object1_attention_time = -1 object2_attention_time = -1 object1_times = 0 object2_times = 0

这段代码定义了一些变量和一个 while 循环。变量包括一个空列表 record_list，屏幕宽度和高度，以及一些时间偏移值和持续时间。while 循环的作用是遍历一个名为 fix_record 的数据集，如果该数据集中的某一行以 "trail" 开头，则将该行的信息存储在 record_list 中，并计算出对象1和对象2在屏幕上的位置和出现的次数等信息。最后通过递增 image_index 和 row_index 来继续遍历数据集。这段代码的具体功能和作用需要结合上下文才能确定。