How to draw a rectangle around multiline text

问题:

I am trying to draw a rectangle around multiline text in iText.

The user will be able to enter some lines of text. The font size of the text might be different and it can be formatted (bold, underlined...).

I use this code to draw the text:

ColumnText ct = new ColumnText(cb);
Phrase phrase = new Phrase("Some String\nOther string etc...\n test");
ct.setSimpleColumn(myText......);
ct.addElement(phrase);
ct.go();

I know how to draw a rectangle, but I am not able to draw a rectangle outlining this text.

回答1:

It sounds as if you are missing only a single piece of the puzzle to meet your requirement. That piece is called getYLine().

Please take a look at the DrawRectangleAroundText example. This example draws the same paragraph twice. The first time, it adds a rectangle that probably looks like the solution you already have. The second time, it adds a rectangle the way you want it to look:

The first time, we add the text like this:

ColumnText ct = new ColumnText(cb);
ct.setSimpleColumn(120f, 500f, 250f, 780f);
Paragraph p = new Paragraph("This is a long paragraph that doesn't"
        + "fit the width we defined for the simple column of the" 
        + "ColumnText object, so it will be distributed over several"
        + "lines (and we don't know in advance how many).");
ct.addElement(p);
ct.go();

You define your column using the coordinates:

llx = 120;
lly = 500;
urx = 250;
ury = 780;

This is a rectangle with lower left corner (120, 500), a width of 130 and a height of 380. Hence you draw a rectangle like this:

cb.rectangle(120, 500, 130, 280);
cb.stroke();

Unfortunately, that rectangle is too big.

Now let's add the text once more at slightly different coordinates:

ct = new ColumnText(cb);
ct.setSimpleColumn(300f, 500f, 430f, 780f);
ct.addElement(p);
ct.go();

Instead of using (300, 500) as lower left corner for the rectangle, we ask the ct object for its current Y position using the getYLine() method:

float endPos = ct.getYLine() - 5;

As you can see, I subtract 5 user units, otherwise the bottom line of my rectangle will coincide with the baseline of the final line of text and that doesn't look very nice. Now I can use the endPos value to draw my rectangle like this:

cb.rectangle(300, endPos, 130, 780 - endPos);
cb.stroke();