画布错误地在表itext7中绘制了高度单元

Question

i draw table as it: Draw custom borders for table with more flexibility in itext7

But i But with big data the table is badly drawn height cell in table.

 PdfDocument pdfDoc = new PdfDocument(new PdfWriter("_testPd/dashed_underline.pdf"));
        Document doc = new Document(pdfDoc, PageSize.A5);

        Table table = new Table(3).useAllAvailableWidth().setFixedLayout();
        table.addCell("Highway System that runs east from the Indiana state line near Lake Michigan through the southern Lower Peninsula to Detroit, then n");
        table.addCell("Highway System that runs east from the Indiana state line near Lake Michigan through the southern Lower Peninsula to Detroit, then n");
        table.addCell("Highway System that runs east from the Indiana state line near Lake Michigan through the southern Lower Peninsula to Detroit, then n");

        table.addCell("Pell morbi tristique senectus et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. Aenean ultricies mi vitae est. Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, commodo vitae, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui. Donec non enim in turpis pulvinar facilisis. Ut felis. Praesent dapibus, neque id cursus faucibus, tortor neque egestas augue, eu vulputate magna eros eu erat. Aliquam erat volutpat. Nam dui mi, tincidunt quis, accumsan porttitor, facilisis luctus, metus");



        table.setNextRenderer(new CustomTableRenderer(table));


        doc.add(table);

        doc.close();

also one example:

  Table table = new Table(3);
    table.addCell("hello1 ");
    table.addCell("hello2 ");
    table.addCell("hello3 ");
    table.addCell("hello4\nWord ");
    table.addCell("hello5 ");

Answer 1

There is a minor mistake in your custom renderer: the items of heights list represent rows from the highest to the lowest, but you're drawing the borders from the lowest to the highest.

The following code should be used to draw horizontal lines:

        // Draw horizontal lines
        float curY = getOccupiedAreaBBox().getTop();
        for (int i = 0; i <= heights.size(); i++) {
            canvas.moveTo(getOccupiedAreaBBox().getLeft() - 3, curY);
            canvas.lineTo(getOccupiedAreaBBox().getRight() + 3, curY + r.nextInt(4));
            if (i < heights.size()) {
                float curHeight = heights.get(i);
                curY -= curHeight;
            }
        }