PDFJet-Open-source:如何在Cell对象中设置多行文本

Question

我使用PDFJet-Open-Source库来构建pdf.所以,我有几个问题:

1)如何将多行文本放在Cell中？

问题描述:目前我遇到的问题是我不能将多行文本放在Cell对象中.我尝试设置文本,"text1 \n text2..."但它没有任何影响.不幸的是,开源版本没有TextColumn和Paragraph类.

2)什么是CompositeTextLine以及如何使用它？

问题描述:也许我有错误的想象力,但我尝试做以下事情:

...
CompositeTextLine ctl = new CompositTextLine(0,0);
ctl.addComponent(new TextLine(f1,"MyText1"));
ctl.addComponent(new TextLine(f1,"MyText2"));
ctl.addComponent(new TextLine(f1,"MyText3"));
Cell cell = new Cell(f1);
cell.setCompositeTextLine(ctl);
...

我希望看到Cell中有几行,但我什么都没看到.此外,如果我添加该行table.wrapAroundCellText(),我有NullPointerException.如果我打电话ctl.drawOn(page),我只是观察:"MyText1 MyText2 MyText3"没有换行.

更新:我发现了TextBox类,所以,如果我写:

TextBox textbox = new TextBox(f1);
textbox.setText("First Line \n Second Line");
textbox.drawOn(page);

它将构建我想要的东西:

First Line
Second Line

但我仍然对(1)和(2)的描述以及其中一些变体的可能性感兴趣,比如"如何在Cell中设置TextBox(或图像等),而不仅仅是单行？"

最后一个,请有人,请参考我在Java或C++中实现"文本对齐"算法.

Answer 1

我可以在同样的问题,我结束了延长电池使用WordUtils从Apache的百科全书lang3:

public class MultilineCell extends Cell {

    private final int characterCount;

    public MultilineCell(Font font, String content, int characterCount) {
        super(font, content);
        this.characterCount = characterCount;
    }

    @Override
    public String getText() {
        return WrapUtil.wrap(super.getText(), this.characterCount);
    }

    @Override
    public float getHeight() {
        float height = this.font.getBodyHeight();

        String text = getText();
        if (text != null) {
            String[] wrappedTexts = text.split(System.getProperty("line.separator"));

            if (wrappedTexts.length > 1) {
                return (height * wrappedTexts.length) + this.top_padding + this.bottom_padding;
            }
        }
        return height + this.top_padding + this.bottom_padding;
    }

    @Override
    protected void paint(Page page, float x, float y, float w, float h) throws Exception {
        page.setPenColor(this.getPenColor());
        page.setPenWidth(this.lineWidth);

        drawBorders(page, x, y, w, h);
        drawText(page, x, y, w);
    }

    private void drawBorders(
            Page page,
            float x,
            float y,
            float cell_w,
            float cell_h) throws Exception {

        if (getBorder(Border.TOP) &&
                getBorder(Border.BOTTOM) &&
                getBorder(Border.LEFT) &&
                getBorder(Border.RIGHT)) {
            page.drawRect(x, y, cell_w, cell_h);
        }
        else {
            if (getBorder(Border.TOP)) {
                page.moveTo(x, y);
                page.lineTo(x + cell_w, y);
                page.strokePath();
            }
            if (getBorder(Border.BOTTOM)) {
                page.moveTo(x, y + cell_h);
                page.lineTo(x + cell_w, y + cell_h);
                page.strokePath();
            }
            if (getBorder(Border.LEFT)) {
                page.moveTo(x, y);
                page.lineTo(x, y + cell_h);
                page.strokePath();
            }
            if (getBorder(Border.RIGHT)) {
                page.moveTo(x + cell_w, y);
                page.lineTo(x + cell_w, y + cell_h);
                page.strokePath();
            }
        }

    }

    private void drawText(
            Page page,
            float x,
            float y,
            float cell_w) throws IOException {

        String wrappedText = WrapUtil.wrap(super.getText(), this.characterCount);
        String[] lines = wrappedText.split(System.getProperty("line.separator"));

        float x_text = x + this.left_padding;
        float y_text = y + this.font.getAscent() + this.top_padding;

        for (String line : lines) {
            page.drawString(this.font, line, x_text, y_text);
            y_text += this.font.getBodyHeight();
        }
    }
}

您可以像使用Cell一样实例化和添加MultilineCell:

List<Cell> rowCells = new ArrayList<Cell>();
rowCells.add(new MultilineCell(font, c.getString(reasonIdx), 42));

我知道扩展不是一个很好的解决方案,并且复制drawBorders()更糟糕,但在这种情况下,如果你不想分叉PDFJet,它是唯一的解决方案.

然而,这会破坏autoAdjustColumnWidths:宽度是在整个文本上计算的,而不是最长的行.因此,如果您打算使用此方法,无论是子类Table,fork PDFJet,还是只提取此方法(后者的唯一缺点是我无法解决单元格填充):

/**
 * Auto adjusts the widths of all columns so that they are just wide enough to hold the text without truncation.
 */
private static void autoAdjustColumnWidths(List<List<Cell>> tableData) {
    // Find the maximum text width for each column
    float[] max_col_widths = new float[tableData.get(0).size()];
    for (int i = 0; i < tableData.size(); i++) {
        List<Cell> row = tableData.get(i);
        for (int j = 0; j < row.size(); j++) {
            Cell cell = row.get(j);
            if (cell.getColSpan() == 1) {
                float cellWidth = 0f;
                if (cell.getImage() != null) {
                    cellWidth = cell.getImage().getWidth();
                }
                if (cell.getText() != null) {
                    // Is this a multiline cell? If so, measure the widest line
                    if (cell.getText().contains(MultilineCell.NEW_LINE)) {
                        String[] lines = cell.getText().split(MultilineCell.NEW_LINE);
                        for (String line : lines) {
                            if (cell.getFont().stringWidth(cell.getFallbackFont(), line) > cellWidth) {
                                cellWidth = cell.getFont().stringWidth(cell.getFallbackFont(), line);
                            }
                        }
                    }
                    // Standard (single-line) cell, measure whole text
                    else {
                        if (cell.getFont().stringWidth(cell.getFallbackFont(), cell.getText()) > cellWidth) {
                            cellWidth = cell.getFont().stringWidth(cell.getFallbackFont(), cell.getText());
                        }
                    }
                }
                cell.setWidth(cellWidth + 2f /*cell.left_padding*/ + 2f/*cell.right_padding*/);
                if (max_col_widths[j] == 0f ||
                        cell.getWidth() > max_col_widths[j]) {
                    max_col_widths[j] = cell.getWidth();
                }
            }
        }
    }

    for (int i = 0; i < tableData.size(); i++) {
        List<Cell> row = tableData.get(i);
        for (int j = 0; j < row.size(); j++) {
            Cell cell = row.get(j);
            cell.setWidth(max_col_widths[j]);
        }
    }
}

PDFJet是一个有趣的库,顺便说一下:受保护的字段,每个其他方法抛出异常,并且这些类绝对不是为扩展而设计的,即使它不是最终的.