PDFBox-删除不可见文本（通过剪辑/填充路径问题）

Question

链接到示例PDF：单击此处。在这里，您可以看到左侧的许多标签被剪裁（因为一些剪裁说明）

当我使用PDFTextStripper时，它会打印示例PDF文件中实际剪切/隐藏的所有文本。我已经尝试过这里描述的解决方案，但它甚至值得，因为它删除了顶部的许多文本，以及每行开头的一些文本。是否有其他方法可以使用PDFBox仅显示可见字符，并跳过所有重叠字符？或者有没有其他工具可以只返回可见文本？提前谢谢。

Answer 1

OP引用的这个答案中的PDFVisibleTextStripper不起作用的原因是，在覆盖的进程中，字符基线end的末尾的计算没有考虑页面旋转。但是，如果您改变这种方法，只测试每个字符基线的开始而忽略末尾，它对手头的文档非常有效：

@Override
protected void processTextPosition(TextPosition text) {
    Matrix textMatrix = text.getTextMatrix();
    Vector start = textMatrix.transform(new Vector(0, 0));

    PDGraphicsState gs = getGraphicsState();
    Area area = gs.getCurrentClippingPath();
    if (area == null || area.contains(start.getX(), start.getY()))
        super.processTextPosition(text);
}

使用此processTextPosition覆盖文本提取的结果（使用SortByPosition设置为true）：

Profit & Loss 12 Month Recap
Property: 8151 W. 183rd Street
Monthly recap 05/01/16 - 04/30/17  (cash basis)
MAY 16 JUN 16 JUL 16 AUG 16 SEP 16 OCT 16 NOV 16 DEC 16 JAN 17 FEB 17 MAR 17 APR 17 TOTAL
INCOME
    4000 RENTAL INCOME
        4001 Base Rent 343,002.59 38,045.11 38,045.11 38,045.11 66,081.36 122,153.86 66,081.36 38,045.11 0.00 76,090.22 38,598.49 66,634.74 930,823.06
        4004 Prepaid Rent Inco -165,742.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 38,045.11 -38,045.11 0.00 0.00 -165,742.50
        4000 Total RENTAL INC 177,260.09 38,045.11 38,045.11 38,045.11 66,081.36 122,153.86 66,081.36 38,045.11 38,045.11 38,045.11 38,598.49 66,634.74 765,080.56
    4200 INCOME CHARGEB
        4205 Property Tax Reco 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 4,250.00 3,696.62 4,250.00 50,446.62
        4210 CAM Recoveries 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 4,750.00 57,000.00
        4200 Total INCOME CH 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 9,000.00 8,446.62 9,000.00 107,446.62
    4600 OTHER INCOME
        4610 Late / NSF Fees 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1,394.72 3,828.61 0.00 0.00 0.00 5,223.33
        4600 Total OTHER INC 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1,394.72 3,828.61 0.00 0.00 0.00 5,223.33
TOTAL INCOME 186,260.09 47,045.11 47,045.11 47,045.11 75,081.36 131,153.86 75,081.36 48,439.83 50,873.72 47,045.11 47,045.11 75,634.74 877,750.51
EXPENSE
    6000 PROFESSIONAL FE
        6010 Professional Fees 0.00 0.00 0.00 2,500.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2,500.00
        6020 Legal Fees 0.00 0.00 0.00 4,592.71 0.00 1,466.33 1,703.35 2,006.00 0.00 685.96 4,368.50 0.00 14,822.85
        6000 Total PROFESSIO 0.00 0.00 0.00 7,092.71 0.00 1,466.33 1,703.35 2,006.00 0.00 685.96 4,368.50 0.00 17,322.85
    6100 UTILITIES
        6105 Water & Sewer 0.00 0.00 0.00 21.21 0.00 0.00 25.81 0.00 0.00 31.91 0.00 0.00 78.93
        6110 Electricity 1,000.91 358.23 390.43 350.71 353.69 0.00 666.39 381.97 486.85 449.62 480.21 486.81 5,405.82
        6125 Trash Removal 229.54 231.34 232.56 232.78 231.66 240.94 240.94 241.40 241.40 518.97 259.18 0.00 2,900.71
        6100 Total UTILITIES 1,230.45 589.57 622.99 604.70 585.35 240.94 933.14 623.37 728.25 1,000.50 739.39 486.81 8,385.46
    6200 REPAIR & MAINTEN
        6210 Field & Grounds - 3,094.00 0.00 0.00 2,313.84 1,009.50 0.00 1,439.58 1,302.75 600.00 0.00 0.00 1,909.73 11,669.40
        6211 Irrigation / Sprinkle 0.00 0.00 0.00 0.00 0.00 1,121.08 350.00 0.00 0.00 0.00 0.00 0.00 1,471.08
        6215 Landscape / Lawn 565.71 565.71 565.71 565.71 565.71 565.71 1,165.71 0.00 0.00 0.00 0.00 495.00 5,054.97
        6220 Sanitary Sewers 0.00 0.00 0.00 950.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 950.00
        6221 Storm Drains 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2,500.00 0.00 2,500.00
        6223 Snow Removal 1,365.00 3,440.00 0.00 0.00 0.00 0.00 0.00 1,350.00 4,440.00 4,106.00 790.00 2,340.00 17,831.00
        6228 Ceiling Tiles 0.00 0.00 0.00 0.00 53.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 53.30
        6231 Building - General 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 634.65 634.65
        6233 Roof / Flashing 1,840.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 764.00 0.00 2,604.00
        6234 Electrical Repairs 0.00 0.00 0.00 395.00 0.00 0.00 960.00 90.00 0.00 0.00 0.00 0.00 1,445.00
        6236 Plumbing Repairs 0.00 0.00 3,316.59 0.00 2,315.95 0.00 930.00 812.17 0.00 0.00 0.00 0.00 7,374.71
        6237 Fire & Life Safety 0.00 0.00 0.00 0.00 0.00 150.00 0.00 0.00 660.00 0.00 0.00 1,550.00 2,360.00
        6238 Lighting Supplies 0.00 0.00 0.00 0.00 0.00 0.00 875.00 193.05 0.00 0.00 0.00 0.00 1,068.05
Profit & Loss 12 Month Recap          05/02/17 11:13 AM Page 1 of rentmanager.com - property management systems   rev.12.180
MAY 16 JUN 16 JUL 16 AUG 16 SEP 16 OCT 16 NOV 16 DEC 16 JAN 17 FEB 17 MAR 17 APR 17 TOTAL
        6240 Lock & Key 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 14.59 0.00 0.00 0.00 14.59
        6242 HVAC Expense 4,375.00 0.00 1,370.00 2,043.25 0.00 0.00 0.00 415.00 1,326.00 1,835.00 0.00 0.00 11,364.25
        6251 Pest Control 0.00 71.07 0.00 71.07 0.00 0.00 71.07 71.07 0.00 71.07 0.00 71.07 426.42
        6200 Total REPAIR & M 11,239.71 4,076.78 5,252.30 6,338.87 3,944.46 1,836.79 5,791.36 4,234.04 7,040.59 6,012.07 4,054.00 7,000.45 66,821.42
    6300 JANITORIAL
        6310 Janitorial Services 1,935.00 1,935.00 1,935.00 1,935.00 1,935.00 0.00 3,870.00 1,935.00 1,935.00 1,935.00 1,995.00 1,995.00 23,340.00
        6320 Janitorial Supplies 79.74 260.01 79.74 90.84 113.14 0.00 170.58 0.00 365.61 90.84 0.00 153.01 1,403.51
        6300 Total JANITORIAL 2,014.74 2,195.01 2,014.74 2,025.84 2,048.14 0.00 4,040.58 1,935.00 2,300.61 2,025.84 1,995.00 2,148.01 24,743.51
    6400 PAYROLL
        6410 P/R Salaries - Offi 2,167.72 2,190.43 2,213.14 2,213.14 1,512.40 2,342.28 2,224.93 2,107.58 2,107.58 2,107.58 2,190.78 2,344.16 25,721.72
        6412 P/R Taxes - Office 179.87 167.56 169.30 169.30 115.70 179.18 170.21 161.23 238.16 231.10 199.89 196.42 2,177.92
        6420 Employee Insuran 76.06 76.14 76.22 199.23 104.30 161.06 152.29 137.91 139.14 139.14 143.91 175.02 1,580.42
        6421 Employee Benefit 3.54 2.40 87.37 141.59 35.59 114.13 111.50 110.15 89.47 107.81 114.80 49.60 967.95
        6423 Workers Compens 42.50 42.94 37.74 32.10 21.93 33.96 32.26 30.56 30.56 30.56 31.76 33.98 400.85
        6400 Total PAYROLL 2,469.69 2,479.47 2,583.77 2,755.36 1,789.92 2,830.61 2,691.19 2,547.43 2,604.91 2,616.19 2,681.14 2,799.18 30,848.86
    6500 TAXES INSURANCE
        6510 Real Estate Tax E 69,570.07 0.00 0.00 0.00 0.00 69,570.07 0.00 0.00 0.00 0.00 0.00 0.00 139,140.14
        6520 Insurance Expens 2,078.00 2,704.50 0.00 2,704.50 0.00 0.00 2,704.50 0.00 0.00 2,704.50 0.00 0.00 12,896.00
        6500 Total TAXES INSU 71,648.07 2,704.50 0.00 2,704.50 0.00 69,570.07 2,704.50 0.00 0.00 2,704.50 0.00 0.00 152,036.14
    6600 Property Manageme 9,575.44 8,381.70 2,117.03 2,117.03 2,117.03 3,378.66 5,901.92 3,378.66 2,179.79 2,000.00 3,829.06 2,117.03 47,093.35
    6650 Receiver Fees 6,625.00 6,125.00 0.00 0.00 6,875.00 0.00 7,062.50 8,375.00 0.00 0.00 8,875.00 0.00 43,937.50
    6700 GENERAL & ADMIN
        6710 PM / Work Order S 95.00 95.00 95.00 95.00 95.00 95.00 95.00 95.00 95.00 95.00 95.00 95.00 1,140.00
        6720 Postage / Messen 63.58 0.00 7.59 9.64 20.63 5.98 6.99 0.00 17.38 7.21 14.36 10.98 164.34
        6725 Office Supplies 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 148.88 148.88
        6735 Office Equipment 0.00 0.00 0.00 0.00 0.00 0.00 0.00 218.40 0.00 0.00 0.00 0.00 218.40
        6740 Telephone 21.33 0.00 11.54 15.00 21.12 8.76 9.77 0.00 13.19 11.96 3.14 7.88 123.69
        6760 Auto Mileage & Ex 100.44 0.00 68.75 140.24 104.14 61.29 142.59 29.00 56.04 0.00 23.14 0.00 725.63
        6770 Leasing & Maint. O 0.00 0.00 0.00 0.00 0.00 0.00 75.00 0.00 0.00 0.00 0.00 0.00 75.00
        6780 Bank Fees 129.45 0.00 0.00 105.91 87.62 0.00 53.61 0.00 120.92 56.46 77.49 79.74 711.20
        6700 Total GENERAL & 409.80 95.00 182.88 365.79 328.51 171.03 382.96 342.40 302.53 170.63 213.13 342.48 3,307.14
TOTAL EXPENSE 105,212.90 26,647.03 12,773.71 24,004.80 17,688.41 79,494.43 31,211.50 23,441.90 15,156.68 17,215.69 26,755.22 14,893.96 394,496.23
NOI 81,047.19 20,398.08 34,271.40 23,040.31 57,392.95 51,659.43 43,869.86 24,997.93 35,717.04 29,829.42 20,289.89 60,740.78 483,254.28
N/O EXPENSE
    7100 NON-OPERATING E
        7110 Lease Commissio 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 33,203.00 0.00 0.00 0.00 33,203.00
        7130 Professional Fees 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1,276.00 0.00 0.00 1,276.00
        7100 Total NON-OPER 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 33,203.00 1,276.00 0.00 0.00 34,479.00
TOTAL N/O EXPENSE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 33,203.00 1,276.00 0.00 0.00 34,479.00
NET INCOME 81,047.19 20,398.08 34,271.40 23,040.31 57,392.95 51,659.43 43,869.86 24,997.93 2,514.04 28,553.42 20,289.89 60,740.78 448,775.28
Profit & Loss 12 Month Recap          05/02/17 11:13 AM Page 2 of rentmanager.com - property management systems   rev.12.180

乍一看，唯一缺少的可见文本是两个页面页脚的总页数。

正如OP在评论中所说

似乎应该在deleteCharsInPath（）中应用同样的东西

实际上，deleteCharsInPath也应该更改为：

void deleteCharsInPath() {
    for (List<TextPosition> list : charactersByArticle) {
        List<TextPosition> toRemove = new ArrayList<>();
        for (TextPosition text : list) {
            Matrix textMatrix = text.getTextMatrix();
            Vector start = textMatrix.transform(new Vector(0, 0));
            if (linePath.contains(start.getX(), start.getY())) {
                toRemove.add(text);
            }
        }
        if (toRemove.size() != 0) {
            System.out.println("Removed " + toRemove.size() + " TextPosition objects as they are being covered.");
            list.removeAll(toRemove);
        }
    }
}

OP提供了另一个文档，其中即使是上面更正的PDFVisibleTextStripper也无法正确识别可见字符。

原因是PDFBox文本剥离将原点移动到裁剪框的左下角的另一个规范化。

修补PDFVisibleTextStripper方法以再次添加左下方的裁剪框坐标值，从而可以很好地提取可见文本。

覆盖processPage允许我们读取左下方的裁剪框坐标：

float lowerLeftX = 0;
float lowerLeftY = 0;

@Override
public void processPage(PDPage page) throws IOException {
    PDRectangle pageSize = page.getCropBox();

    lowerLeftX = pageSize.getLowerLeftX();
    lowerLeftY = pageSize.getLowerLeftY();

    super.processPage(page);
}

processTextPosition和deleteCharsInPath需要考虑这些值：

@Override
protected void processTextPosition(TextPosition text) {
    Matrix textMatrix = text.getTextMatrix();
    Vector start = textMatrix.transform(new Vector(0, 0));

    PDGraphicsState gs = getGraphicsState();
    Area area = gs.getCurrentClippingPath();
    if (area == null || area.contains(lowerLeftX + start.getX(), lowerLeftY + start.getY()))
        super.processTextPosition(text);
}

[...]

void deleteCharsInPath() {
    for (List<TextPosition> list : charactersByArticle) {
        List<TextPosition> toRemove = new ArrayList<>();
        for (TextPosition text : list) {
            Matrix textMatrix = text.getTextMatrix();
            Vector start = textMatrix.transform(new Vector(0, 0));
            if (linePath.contains(lowerLeftX + start.getX(), lowerLeftY + start.getY())) {
                toRemove.add(text);
            }
        }
        if (toRemove.size() != 0) {
            System.out.println("Removed " + toRemove.size() + " TextPosition objects as they are being covered.");
            list.removeAll(toRemove);
        }
    }
}

现在，新文件的提取结果也可以了。；）