itext 在工作期间如何找出坐标文本？

Question

我想知道添加到页面的文本的坐标。并对本文应用一些 canvas。（例如自定义下划线或删除线或三角形内的文本）

我只需要某些词

List<String> listString = new ArraList();

PdfDocument pdfDoc = new PdfDocument(new PdfWriter(DEST));

Document doc = new Document(pdfDoc, PageSize.A4);
for(String s:listString)
   //**underlineWord** hidden it will be removed
 if( s.contains("**underlineWord**")){
     s.replace("**underlineWord**","");
    Text text = new Text(s)
    Float[] coords = getCoords(text)
     Canvas canvas = new Canvas(...);
     setCustomUderline(coords)
 }


 doc.add(new Paragraph(text) );

我知道 PdfCanvasProcessor，但我不使用它，因为我不知道某些单词，（包含 **underlineWord**）

Answer 1

在 iText7 中，您可以使用自定义 Renderer 实现此类任务。该技术显示在 DashedUnderline example:

PdfDocument pdfDoc = new PdfDocument(new PdfWriter(DEST));
Document doc = new Document(pdfDoc);
doc.add(new Paragraph("This text is not underlined"));
Text text1 = new Text("This text is underlined with a solid line");
text1.setUnderline(1, -3);
doc.add(new Paragraph(text1));
Text text2 = new Text("This text is underlined with a dashed line");
text2.setNextRenderer(new DashedLineTextRenderer(text2));
doc.add(new Paragraph(text2));
doc.close();

即您只需将自定义 Renderer 设置为有问题的 Text 位。在手头的示例中，自定义 Renderer class 是

protected class DashedLineTextRenderer extends TextRenderer {
    public DashedLineTextRenderer(Text textElement) {
        super(textElement);
    }

    @Override
    public void draw(DrawContext drawContext) {
        super.draw(drawContext);
        Rectangle rect = this.getOccupiedAreaBBox();
        PdfCanvas canvas = drawContext.getCanvas();
        canvas
                .saveState()
                .setLineDash(3, 3)
                .moveTo(rect.getLeft(), rect.getBottom() - 3)
                .lineTo(rect.getRight(), rect.getBottom() - 3)
                .stroke()
                .restoreState();
    }
}

如您所见，您可以覆盖 draw 以首先调用 super 实现以正常绘制文本。之后，您可以通过调用 getOccupiedAreaBBox 检索用于绘制文本的区域并将其用于您的任务，无论是装饰文本还是仅将位置存储在某处。

如果你想知道为什么这个例子在eventssub-package...这个例子对应一个iText5的例子，在iText5你实现通过将通用标记设置为有问题的 Chunk 并在页面事件侦听器的 onGenericTag 方法中侦听该通用标记来完成这样的任务，请参见示例。

在您提问的评论中

Can i do it with table? (draw border with help canvas)

是的，您再次为此使用相关的渲染器，例如请参阅 DottedLineCell example:

PdfDocument pdfDoc = new PdfDocument(new PdfWriter(dest));
Document doc = new Document(pdfDoc);
doc.add(new Paragraph("Table event"));
Table table = new Table(UnitValue.createPercentArray(3)).useAllAvailableWidth();
table.setNextRenderer(new DottedLineTableRenderer(table, new Table.RowRange(0, 2)));
table.addCell(new Cell().add(new Paragraph("A1")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("A2")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("A3")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("B1")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("B2")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("B3")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("C1")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("C2")).setBorder(Border.NO_BORDER));
table.addCell(new Cell().add(new Paragraph("C3")).setBorder(Border.NO_BORDER));
doc.add(table);
doc.add(new Paragraph("Cell event"));
table = new Table(UnitValue.createPercentArray(1)).useAllAvailableWidth();
Cell cell = new Cell().add(new Paragraph("Test"));
cell.setNextRenderer(new DottedLineCellRenderer(cell));
cell.setBorder(Border.NO_BORDER);
table.addCell(cell.setBorder(Border.NO_BORDER));
doc.add(table);

doc.close();

此处第一个 table 展示了如何在关闭标准 table 单元格边框后使用 table 渲染器执行此操作，而第二个 table 展示了如何执行此操作使用单元格渲染器。

自定义渲染器class是

private class DottedLineTableRenderer extends TableRenderer {
    public DottedLineTableRenderer(Table modelElement, Table.RowRange rowRange) {
        super(modelElement, rowRange);
    }

    @Override
    public void drawChildren(DrawContext drawContext) {
        super.drawChildren(drawContext);
        PdfCanvas canvas = drawContext.getCanvas();
        canvas.setLineDash(3f, 3f);
        // first horizontal line
        CellRenderer[] cellRenderers = rows.get(0);
        canvas.moveTo(cellRenderers[0].getOccupiedArea().getBBox().getLeft(),
                cellRenderers[0].getOccupiedArea().getBBox().getTop());
        canvas.lineTo(cellRenderers[cellRenderers.length - 1].getOccupiedArea().getBBox().getRight(),
                cellRenderers[cellRenderers.length - 1].getOccupiedArea().getBBox().getTop());

        for (int i = 0; i < rows.size(); i++) {
            cellRenderers = rows.get(i);
            // horizontal lines
            canvas.moveTo(cellRenderers[0].getOccupiedArea().getBBox().getX(),
                    cellRenderers[0].getOccupiedArea().getBBox().getY());
            canvas.lineTo(cellRenderers[cellRenderers.length - 1].getOccupiedArea().getBBox().getRight(),
                    cellRenderers[cellRenderers.length - 1].getOccupiedArea().getBBox().getBottom());
            // first vertical line
            Rectangle cellRect = cellRenderers[0].getOccupiedArea().getBBox();
            canvas.moveTo(cellRect.getLeft(), cellRect.getBottom());
            canvas.lineTo(cellRect.getLeft(), cellRect.getTop());
            // vertical lines
            for (int j = 0; j < cellRenderers.length; j++) {
                cellRect = cellRenderers[j].getOccupiedArea().getBBox();
                canvas.moveTo(cellRect.getRight(), cellRect.getBottom());
                canvas.lineTo(cellRect.getRight(), cellRect.getTop());
            }
        }
        canvas.stroke();
    }
}

和

private class DottedLineCellRenderer extends CellRenderer {
    public DottedLineCellRenderer(Cell modelElement) {
        super(modelElement);
    }

    @Override
    public void draw(DrawContext drawContext) {
        super.draw(drawContext);
        drawContext.getCanvas().setLineDash(3f, 3f);
        drawContext.getCanvas().rectangle(this.getOccupiedArea().getBBox());
        drawContext.getCanvas().stroke();
    }
}

分别。

正如 Alexey Subach in 所解释的那样，Renderer 的完整自定义也应该 覆盖 getNextRenderer() 方法。 特别是如果一个区域break 可能发生在有问题的对象中，这是必要的，否则自定义仅在 OP 观察到的第一个区域有效。

itext 在工作期间如何找出坐标文本？

How during work itext find out coordinates text?

java

itext

itext7