Itext 7 Text fitting 更好的解决方案
A better solution for Itext 7 Text fitting
我有一个使用 Itext 5 并按预期工作的项目。
程序必须将 userInput 放在某些 'Chunks' 段落内。段落每行有不可移动的（块）字，并且 userInput 应该缩放 space 为段落内的 userInput 保留。
旧项目有以下代码（作为示例制作）
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();
}
//Whosebug 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;
}}
现在我正尝试在 IText 7 中做同样的事情，但...并不那么容易！
我设法创建了一个工作代码，但它很乱，有些东西没有得到正确的坐标。 Itext7代码（作为例子制作）：
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();
}
}}
问题是
- 有没有更好、更优雅的方法来做到这一点？
- 为什么rect.getY()总是在段落下面？以及如何让 Y 与段落实际 Y 坐标相匹配？
- 为什么默认值 'rheight' 总是太小？但是 (rheight*1.1f) 有效吗？
- （可选）如何在 IText 7 中设置 tab() space 大小？
这种方式非常好，因为它考虑了所有可能的模型元素设置和布局过程的影响。您的 iText 5 替代方案对于基于拉丁语的文本的基本情况已经足够好了，而无需在视觉方面进行任何修改。你拥有的 iText 7 代码更加灵活，如果你使用更复杂的布局设置、复杂的脚本等，它仍然可以工作。我还看到 iText 5 代码在你的示例中是 105 行，而 iText 7 代码是 80 行。
你在这里添加了一些魔法 +(rheight*2.05f); 而实际上你在这里缺少的是当你通过 Canvas 绘制时你没有定义你的边距，所以你真正需要的而不是 rect.getY()+(rheight*2.05f); 是 rect.getY() + doc.getBottomMargin()
问题出在您将 rheight 计算为 renderer.getInnerAreaBBox() 而此计算未考虑应用于段落的默认页边距。边距包含在占用区域中，但不包含在内部区域 bbox 中。要解决此问题，请改用 renderer.getOccupiedArea().getBBox()。在这种情况下，不再需要将 rheight 乘以系数。
现在的视觉效果略有不同，但不再有魔术常量。根据您真正想要实现的目标，您可以进一步调整代码（在这里和那里添加一些边距等）。但是代码很好地适应了用户文本的变化。
之前的视觉结果：
之后的视觉效果：
结果代码：
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();
}
我有一个使用 Itext 5 并按预期工作的项目。 程序必须将 userInput 放在某些 'Chunks' 段落内。段落每行有不可移动的（块）字，并且 userInput 应该缩放 space 为段落内的 userInput 保留。 旧项目有以下代码（作为示例制作）
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();
}
//Whosebug 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;
}}
现在我正尝试在 IText 7 中做同样的事情，但...并不那么容易！ 我设法创建了一个工作代码，但它很乱，有些东西没有得到正确的坐标。 Itext7代码（作为例子制作）：
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();
}
}}
问题是
- 有没有更好、更优雅的方法来做到这一点？
- 为什么rect.getY()总是在段落下面？以及如何让 Y 与段落实际 Y 坐标相匹配？
- 为什么默认值 'rheight' 总是太小？但是 (rheight*1.1f) 有效吗？
- （可选）如何在 IText 7 中设置 tab() space 大小？
这种方式非常好，因为它考虑了所有可能的模型元素设置和布局过程的影响。您的 iText 5 替代方案对于基于拉丁语的文本的基本情况已经足够好了，而无需在视觉方面进行任何修改。你拥有的 iText 7 代码更加灵活，如果你使用更复杂的布局设置、复杂的脚本等，它仍然可以工作。我还看到 iText 5 代码在你的示例中是 105 行，而 iText 7 代码是 80 行。
你在这里添加了一些魔法
+(rheight*2.05f);而实际上你在这里缺少的是当你通过Canvas绘制时你没有定义你的边距，所以你真正需要的而不是rect.getY()+(rheight*2.05f);是rect.getY() + doc.getBottomMargin()问题出在您将
rheight计算为renderer.getInnerAreaBBox()而此计算未考虑应用于段落的默认页边距。边距包含在占用区域中，但不包含在内部区域 bbox 中。要解决此问题，请改用renderer.getOccupiedArea().getBBox()。在这种情况下，不再需要将rheight乘以系数。
现在的视觉效果略有不同，但不再有魔术常量。根据您真正想要实现的目标，您可以进一步调整代码（在这里和那里添加一些边距等）。但是代码很好地适应了用户文本的变化。
之前的视觉结果：
之后的视觉效果：
结果代码：
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();
}