# USAGE
# python click_and_crop.py
# 依次展示 ./src 目录下的文件，裁剪后保存到 ./dst 目录

import cv2
import os

# 初始化参考点列表和布尔值标志：是否正在执行裁剪
refPt = []
cropping = False


# 点击并裁剪ROI区域
# -events 鼠标事件（如按下鼠标左键，释放鼠标左键，鼠标移动等）
# -x x坐标
# -y y坐标
# -flages params 其他参数
def click_and_crop(event, x, y, flags, param):
    # 获取全局变量的引用
    global refPt, cropping

    # 如果鼠标左被单击，记录（x,y）坐标并显示裁剪正在进行
    if event == cv2.EVENT_LBUTTONDOWN:
        refPt = [(x, y)]
        cropping = True
    # 检测鼠标左键是否释放
    elif event == cv2.EVENT_LBUTTONUP:
        # 记录结束（x,y）坐标，并显示裁剪结束
        refPt.append((x, y))
        cropping = False

        draw = image.copy()
        cv2.rectangle(draw, refPt[0], refPt[1], (0, 255, 0), 2)
        cv2.imshow("image", draw)

std_width :int = 1280
std_height :int = 720
std_ratio = std_width / std_height

cv2.namedWindow("image")
cv2.setMouseCallback("image", click_and_crop)

for filename in os.listdir("./src"):
    if not filename.endswith(".png"):
        continue

    print(filename)
    image = cv2.imread("./src/" + filename)
    
    cur_ratio = image.shape[1] / image.shape[0]

    if cur_ratio >= std_ratio: # 说明是宽屏或默认16:9，按照高度计算缩放
        dsize_width :int = (int)(cur_ratio * std_height)
        dsize_height :int= std_height
    else:                       # 否则可能是偏正方形的屏幕，按宽度计算
        dsize_width :int = std_width
        dsize_height :int = std_width / cur_ratio;

    dsize = (dsize_width, dsize_height)
    image = cv2.resize(image, dsize)

    while True:
        cv2.imshow("image", image)
        key = cv2.waitKey(0) & 0xFF
        if key == ord("s"):
            break
        elif key == ord("q"):
            exit()

    # 如果参考点列表里有俩个点，则裁剪区域并展示
    if len(refPt) == 2:
        left = refPt[0][0]
        right = refPt[1][0]
        top = refPt[0][1]
        bottom = refPt[1][1]

        roi = image[top:bottom, left:right]
        
        horizontal_expansion = 100
        vertical_expansion = 100

        filename_x :int = (int)(left - horizontal_expansion / 2)
        if filename_x < 0:
            filename_x = 0
        filename_y :int = (int)(top - vertical_expansion / 2)
        if filename_y < 0:
            filename_y = 0
        filename_w :int = (right - left) + horizontal_expansion
        if filename_x + filename_w > dsize_width:
            filename_w = dsize_width - filename_x
        filename_h : int = (bottom - top) + vertical_expansion
        if filename_y + filename_h > dsize_height:
            filename_h = dsize_height - filename_y
        
        dst_filename :str = f'{filename}_{filename_x},{filename_y},{filename_w},{filename_h}.png'

        print('dst:', dst_filename)
        cv2.imwrite('./dst/' + dst_filename, roi)

    refPt = []
    cropping = False

# 关闭所有打开的窗口
cv2.destroyAllWindows()