A better solution for Itext 7 Text fitting - optimization

Question

I have a project that used Itext 5 and worked as intended.
Program had to put userInput in certain 'Chunks' inside paragraphs. Paragraphs have unmovable (chunks)words per line, and the userInput should scale in the space reserved for the userInput inside paragraph.
Old Project had the following code(made as example)
public class Oldway {
static final transient Font bold2 = FontFactory.getFont("Times-Roman", 10.0f, 1);
public static void main(String[] args) {
Document document = new Document();
document.setPageSize(PageSize.A4);
try {
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(new File("itext5.pdf")));
document.open();
Paragraph title = new Paragraph("Title of doc");
title.setAlignment(1);
document.add(title);
Paragraph dec= new Paragraph();
Chunk ch01 = new Chunk("Prev text ");
dec.add(ch01);
Chunk ch02 = new Chunk(getEmptySpace(42));
dec.add(ch02);
Chunk ch03 = new Chunk(" next Text");
dec.add(ch03);
document.add(dec);
float y = writer.getVerticalPosition(false);
float x2 = document.left() + ch01.getWidthPoint();
float x3 = x2 + ch02.getWidthPoint();
getPlainFillTest("Text to insert", document, y, x3, x2, writer, false);
document.close();
writer.flush();
} catch (FileNotFoundException | DocumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static Chunk getEmptySpace(int size) {
Chunk ch = new Chunk();
for(int i = 0;i<=size;i++) {
ch.append("\u00a0");
}
return new Chunk(ch);
}
public static void getPlainFillTest(String str,Document document,float y, float x1pos,
float x2pos, PdfWriter writer,boolean withTab) {
if(str.isEmpty() || str.isBlank()) {
str = "________";
}
Rectangle rec2 = null;
if(!withTab)
rec2 = new Rectangle(x2pos, y, x1pos-2,y+10);
else {
rec2 = new Rectangle(x2pos+35, y, x1pos+33,y+10);
}
BaseFont bf = bold2.getBaseFont();
PdfContentByte cb = writer.getDirectContent();
float fontSize = getMaxFontSize(bf, str,(int)rec2.getWidth(), (int)rec2.getHeight());
Phrase phrase = new Phrase(str, new Font(bf, fontSize));
ColumnText.showTextAligned(cb, Element.ALIGN_CENTER, phrase,
// center horizontally
(rec2.getLeft() + rec2.getRight()) / 2,
// shift baseline based on descent
rec2.getBottom() - bf.getDescentPoint(str, fontSize),0);
cb.saveState();//patrulaterul albastru
cb.setColorStroke(Color.BLUE);
cb.rectangle(rec2.getLeft(), rec2.getBottom(), rec2.getWidth(), rec2.getHeight());
cb.stroke();
cb.restoreState();
}
//stackoverflow solution
private static float getMaxFontSize(BaseFont bf, String text, int width, int height){
// avoid infinite loop when text is empty
if(text.isEmpty()){
return 0.0f;
}
float fontSize = 0.1f;
while(bf.getWidthPoint(text, fontSize) < width){
fontSize += 0.1f;
}
float maxHeight = measureHeight(bf, text, fontSize);
while(maxHeight > height){
fontSize -= 0.1f;
maxHeight = measureHeight(bf, text, fontSize);
};
return fontSize;
}
public static float measureHeight(BaseFont baseFont, String text, float fontSize)
{
float ascend = baseFont.getAscentPoint(text, fontSize);
float descend = baseFont.getDescentPoint(text, fontSize);
return ascend - descend;
}}
Now I'm trying to do the same thing in IText 7 and ...is not that easy!
I manage to create a working code, but its messy, and some things don't get the right coordinates. The Itext7 code(made as example):
public class Newway {
public static void main(String[] args) {
PdfWriter writer;
try {
writer = new PdfWriter(new File("test2.pdf"));
PdfDocument document = new PdfDocument(writer);
document.getDocumentInfo().addCreationDate();
document.getDocumentInfo().setTitle("Title");
document.setDefaultPageSize(PageSize.A4);
Document doc = new Document(document);
doc.setFontSize(12);
Paragraph par = new Paragraph();
Text ch01 = new Text("Prev Text ");
par.add(ch01);
Paragraph space = new Paragraph();
space.setMaxWidth(40);
for(int i=0;i<40;i++) {
par.add("\u00a0");
space.add("\u00a0");
}
Text ch02 = new Text(" next text");
par.add(ch02);
doc.add(par);
Paragraph linePara = new Paragraph().add("Test from UserInput")
.setTextAlignment(TextAlignment.CENTER).setBorder(new DottedBorder(1));
float width = doc.getPageEffectiveArea(PageSize.A4).getWidth();
float height = doc.getPageEffectiveArea(PageSize.A4).getHeight();
IRenderer primul = ch01.createRendererSubTree().setParent(doc.getRenderer());
IRenderer spaceR = space.createRendererSubTree().setParent(doc.getRenderer());
LayoutResult primulResult = primul.layout(new LayoutContext(new LayoutArea(1, new Rectangle(width,height))));
LayoutResult layoutResult = spaceR.layout(new LayoutContext(new LayoutArea(1, new Rectangle(width,height))));
Rectangle primulBox = ((TextRenderer) primul).getInnerAreaBBox();
Rectangle rect = ((ParagraphRenderer) spaceR).getInnerAreaBBox();
float rwidth = rect.getWidth();
float rheight = rect.getHeight();
float x = primulBox.getWidth()+ doc.getLeftMargin();
float y = rect.getY()+(rheight*2.05f);//rect.getY() is never accurate, is always below the paragraph. WHY ??
Rectangle towr = new Rectangle(x, y, rwidth, rheight*1.12f);//rheight on default is way too small
PdfCanvas pdfcanvas = new PdfCanvas(document.getFirstPage());
Canvas canvas = new Canvas(pdfcanvas, towr);
//from theinternet
float fontSizeL = 1;
float fontSizeR = 14;
while (Math.abs(fontSizeL - fontSizeR) > 1e-1) {
float curFontSize = (fontSizeL + fontSizeR) / 2;
linePara.setFontSize(curFontSize);
// It is important to set parent for the current element renderer to a root renderer
IRenderer renderer = linePara.createRendererSubTree().setParent(canvas.getRenderer());
LayoutContext context = new LayoutContext(new LayoutArea(1, towr));
if (renderer.layout(context).getStatus() == LayoutResult.FULL) {
// we can fit all the text with curFontSize
fontSizeL = curFontSize;
} else {
fontSizeR = curFontSize;
}
}
canvas.add(linePara);
new PdfCanvas(document.getFirstPage()).rectangle(towr).setStrokeColor(ColorConstants.BLACK).stroke();
canvas.close();
doc.close();
writer.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}
The questions are
Is there a better, more elegant way to do this ?
Why rect.getY() is always below the paragraph? and how do I get Y to match the Paragraph real Y coorinate ?
Why the default 'rheight' is always too small? but (rheight*1.1f) works ?
(Optional) How do I set tab() space size in IText 7 ?

Answer 1

This way is quite good because it's taking into account all the possible model element settings and implications of the layout process. Your iText 5 alternative was good enough for basic case of Latin-based text without any modifications on the visual side. The iText 7 code you have is much more flexible and will still work if you use more complex layout settings, complex scripts etc. Also I see the iText 5 code is 105 lines in your example while the iText 7 code is 80 lines.
You are adding some magic +(rheight*2.05f); here while in reality what you are missing here is that when you draw via Canvas you don't have your margins defined anymore, so what you really need instead of rect.getY()+(rheight*2.05f); is rect.getY() + doc.getBottomMargin()
The issue comes from the fact that you are calculating rheight as renderer.getInnerAreaBBox() while this calculation does not take into account default margins that are applied to a paragraph. Margins are included into the occupied area but not the inner area bbox. To fix that, use renderer.getOccupiedArea().getBBox() instead. In this case there is not need to multiply rheight by a coefficient anymore.
The visual result is slightly different now but there is no magic constants anymore. Depending on what you are trying to really achieve you can tune the code further (add some margins here and there etc). But the code adapts well to the change in the user text.
Visual result before:
Visual result after:
Resultant code:
PdfWriter writer;
try {
writer = new PdfWriter(new File("test2.pdf"));
PdfDocument document = new PdfDocument(writer);
document.getDocumentInfo().addCreationDate();
document.getDocumentInfo().setTitle("Title");
document.setDefaultPageSize(PageSize.A4);
Document doc = new Document(document);
doc.setFontSize(12);
Paragraph par = new Paragraph();
Text ch01 = new Text("Prev Text ");
par.add(ch01);
Paragraph space = new Paragraph();
space.setMaxWidth(40);
for(int i=0;i<40;i++) {
par.add("\u00a0");
space.add("\u00a0");
}
Text ch02 = new Text(" next text");
par.add(ch02);
doc.add(par);
Paragraph linePara = new Paragraph().add("Test from UserInput")
.setTextAlignment(TextAlignment.CENTER).setBorder(new DottedBorder(1));
float width = doc.getPageEffectiveArea(PageSize.A4).getWidth();
float height = doc.getPageEffectiveArea(PageSize.A4).getHeight();
IRenderer primul = ch01.createRendererSubTree().setParent(doc.getRenderer());
IRenderer spaceR = space.createRendererSubTree().setParent(doc.getRenderer());
LayoutResult primulResult = primul.layout(new LayoutContext(new LayoutArea(1, new Rectangle(width,height))));
LayoutResult layoutResult = spaceR.layout(new LayoutContext(new LayoutArea(1, new Rectangle(width,height))));
Rectangle primulBox = ((TextRenderer) primul).getInnerAreaBBox();
Rectangle rect = ((ParagraphRenderer) spaceR).getOccupiedArea().getBBox();
float rwidth = rect.getWidth();
float rheight = rect.getHeight();
float x = primulBox.getWidth()+ doc.getLeftMargin();
float y = rect.getY() + doc.getBottomMargin();
Rectangle towr = new Rectangle(x, y, rwidth, rheight);
PdfCanvas pdfcanvas = new PdfCanvas(document.getFirstPage());
Canvas canvas = new Canvas(pdfcanvas, towr);
//from theinternet
float fontSizeL = 1;
float fontSizeR = 14;
while (Math.abs(fontSizeL - fontSizeR) > 1e-1) {
float curFontSize = (fontSizeL + fontSizeR) / 2;
linePara.setFontSize(curFontSize);
// It is important to set parent for the current element renderer to a root renderer
IRenderer renderer = linePara.createRendererSubTree().setParent(canvas.getRenderer());
LayoutContext context = new LayoutContext(new LayoutArea(1, towr));
if (renderer.layout(context).getStatus() == LayoutResult.FULL) {
// we can fit all the text with curFontSize
fontSizeL = curFontSize;
} else {
fontSizeR = curFontSize;
}
}
canvas.add(linePara);
new PdfCanvas(document.getFirstPage()).rectangle(towr).setStrokeColor(ColorConstants.BLACK).stroke();
canvas.close();
doc.close();
writer.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}