此示例演示如何使用运算符decode_bar_code_rectangle2.
通过简单的分割提取条形码区域并将返回的矩形2参数传递给操作者decode_bar_code_rectangle2.

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总代码：

* Initialize variables
*初始化变量
Directory := 'barcode/ean13/'
TeaBoxRegExp := '.*tea_box.*'
* 
* Initialize settings
*初始化设置
dev_update_window ('off')
dev_set_draw ('margin')
* 
* Get list of tea_box*-image files
*获取图像文件列表
list_image_files (Directory, 'default', [], ImageFiles)
ImageFilesTea := regexp_select(ImageFiles,[TeaBoxRegExp,'ignore_case'])
*读取图片
read_image (Image, ImageFilesTea[0])
* 
* Prepare graphics window and bar code model
*准备图形窗口和条形码模型
dev_close_window ()
dev_open_window_fit_image (Image, 0, 0, -1, -1, WindowHandle)
set_display_font (WindowHandle, 14, 'mono', 'true', 'false')
dev_set_line_width (2)
create_bar_code_model ([], [], BarCodeHandle)
* 
* Decode tea_box*-images
*解码茶盒图像
for ImageIndex := 0 to |ImageFilesTea| - 1 by 1
    read_image (Image, ImageFilesTea[ImageIndex])
    dev_display (Image)
    * 
    * segment and determine the bar code region
    **分段并确定条形码区域
    threshold (Image, RegionThresh, 56, 255)
    connection (RegionThresh, RegThreshConn)
    select_shape_std (RegThreshConn, RegionBC, 'max_area', 100)
    * 
    * create input parameters for decode_bar_code_rectangle2
    *为创建decode_bar_code_rectangle2输入参数
    smallest_rectangle2 (RegionBC, Row, Column, Phi, Length1, Length2)
    gen_rectangle2 (Rectangle2BC, Row, Column, Phi, Length1, Length2)
    dev_set_color ('magenta')
    dev_display (Rectangle2BC)
    * 
    * decode_bar_code_rectangle2 directly uses the passed rectangle2 parameters as ROI
    * decode_bar_code_rectangle2 直接使用传递的矩形2参数作为ROI


    decode_bar_code_rectangle2 (Image, BarCodeHandle, 'EAN-13', Row, Column, Phi, Length1, Length2, Decoded)
    get_bar_code_object (SymbolRegions, BarCodeHandle, 'all', 'symbol_regions')
    dev_set_color ('lime green')
    dev_display (SymbolRegions)
    disp_message (WindowHandle, 'Found bar code: ' + Decoded, 'window', 5, 5, 'black', 'true')
    if (ImageIndex < |ImageFilesTea| - 1)
        disp_continue_message (WindowHandle, 'black', 'true')
        stop ()
    endif
endfor
clear_bar_code_model (BarCodeHandle)
* 

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逐段分析：

*初始化变量
Directory := 'barcode/ean13/'
TeaBoxRegExp := '.*tea_box.*'

*初始化设置
dev_update_window ('off')
dev_set_draw ('margin')

*获取图像文件列表
list_image_files (Directory, 'default', [], ImageFiles)
ImageFilesTea := regexp_select(ImageFiles,[TeaBoxRegExp,'ignore_case'])

*读取图片
read_image (Image, ImageFilesTea[0])

*准备图形窗口和条形码模型
dev_close_window ()
dev_open_window_fit_image (Image, 0, 0, -1, -1, WindowHandle)
set_display_font (WindowHandle, 14, 'mono', 'true', 'false')
dev_set_line_width (2)

*创建条形码模型句柄
create_bar_code_model ([], [], BarCodeHandle)

*解码图像
for ImageIndex := 0 to |ImageFilesTea| - 1 by 1
    *读取图片
    read_image (Image, ImageFilesTea[ImageIndex])
    dev_display (Image)
    
    *分段并确定条形码区域
    *阈值分割
    threshold (Image, RegionThresh, 56, 255)

    *联通区域
    connection (RegionThresh, RegThreshConn)

    *根绝最大面积特征选择
    select_shape_std (RegThreshConn, RegionBC, 'max_area', 100)

    *求最小外接矩形
    smallest_rectangle2 (RegionBC, Row, Column, Phi, Length1, Length2)

    *生成外接矩形
    gen_rectangle2 (Rectangle2BC, Row, Column, Phi, Length1, Length2)
    
    *设置颜色
    dev_set_color ('magenta')

    *显示矩形
    dev_display (Rectangle2BC)

    * decode_bar_code_rectangle2 直接使用传递的矩形2参数作为ROI
    *解码矩形内的条形码符号。
    decode_bar_code_rectangle2 (Image, BarCodeHandle, 'EAN-13', Row, Column, Phi, Length1, Length2, Decoded)

    *获得条形码的区域
    get_bar_code_object (SymbolRegions, BarCodeHandle, 'all', 'symbol_regions')
    dev_set_color ('lime green')
    dev_display (SymbolRegions)

    *显示信息
    disp_message (WindowHandle, 'Found bar code: ' + Decoded, 'window', 5, 5, 'black', 'true')

    *判断条形码是否循环完
    if (ImageIndex < |ImageFilesTea| - 1)
        disp_continue_message (WindowHandle, 'black', 'true')
        stop ()
    endif
endfor

*释放条形码阅读器分配的内存
clear_bar_code_model (BarCodeHandle)

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主要算子解释：

decode_bar_code_rectangle2(Image : : BarCodeHandle, CodeType, Row, Column, Phi, Length1, Length2 : DecodedDataStrings)

功能：解码矩形内的条形码符号。直接扫描提供的区域，以查找条形码。

BarCodeHandle：条形码模型的句柄

CodeType：条形码模型的句柄

Row：中心的行索引

Column：中心的列索引

Phi：矩形的弧度方向

Length1：沿条形码读取方向的矩形长度的一半

Length2 ：垂直于条形码读取方向的矩形长度的一半

DecodedDataStrings：所有成功解码条形码的数据字符串