如何在合并时删除空格
我有一些代码需要3个不同的PDF字节数组并合并它们.这段代码效果很好.问题(有些人)认为每个PDF都被认为是一个完整的页面(如果打印),即使它上面只有4英寸的内容,因此垂直留下7英寸的空白区域.然后将中间文档放入其中,并且可以在其末尾处具有或不具有垂直空白空间.然后页脚也会放在自己的页面上.
这是代码:
byte[] Bytes = rv.LocalReport.Render("PDF", null, out MimeType, out Encoding, out Extension, out StreamIDs, out Warnings);
List<byte[]> MergeSets = // This is filled prior to this code
// Append any other pages to this primary letter
if (MergeSets.Count > 0) {
MemoryStream ms = new MemoryStream();
Document document = new Document();
PdfCopy copy = new PdfCopy(document, ms);
document.Open();
PdfImportedPage page;
PdfReader reader = new PdfReader(Bytes); // read the generated primary Letter
int pages = reader.NumberOfPages;
for (int i = 0; i < pages; ) {
page = copy.GetImportedPage(reader, ++i);
copy.AddPage(page);
} // foreach of the pages in the Cover Letter
// Now append the merge sets
foreach (byte[] ba in MergeSets) {
reader = new PdfReader(ba);
pages = reader.NumberOfPages;
for (int i = 0; i < pages; ) {
page = copy.GetImportedPage(reader, ++i);
copy.AddPage(page);
} // foreach of the pages in the current merge set
} // foreach of the sets of data
document.Close();
ServerSaved = SaveGeneratedLetter(ms.GetBuffer(), DateTime.Now.Year, hl.LetterName, SaveName);
} // if there is anything to merge
有没有办法合并每个页面来剪辑/删除/删除每个pdf末尾的垂直空白区域,以便它显示为一个无缝文档？
更新: 这是我试图合并的一些示例.pdf文件.
更新2:使用答案:
我已经将@ mkl的代码转换为C#,并且在这里.
工具类:
public class PdfVeryDenseMergeTool {
private Rectangle PageSize;
private float TopMargin;
private float BottomMargin;
private float Gap;
private Document Document = null;
private PdfWriter Writer = null;
private float YPosition = 0;
public PdfVeryDenseMergeTool(Rectangle size, float top, float bottom, float gap) {
this.PageSize = size;
this.TopMargin = top;
this.BottomMargin = bottom;
this.Gap = gap;
} // PdfVeryDenseMergeTool
public void Merge(MemoryStream outputStream, List<PdfReader> inputs) {
try {
this.OpenDocument(outputStream);
foreach (PdfReader reader in inputs) {
this.Merge(reader);
} // foreach of the PDF files to merge
} finally {
this.CloseDocument();
} // try-catch-finally
} // Merge
public void OpenDocument(MemoryStream outputStream) {
this.Document = new Document(PageSize, 36, 36, this.TopMargin, this.BottomMargin);
this.Writer = PdfWriter.GetInstance(Document, outputStream);
this.Document.Open();
this.NewPage();
} // OpenDocument
public void CloseDocument() {
try {
this.Document.Close();
} finally {
this.Document = null;
this.Writer = null;
this.YPosition = 0;
} // try-finally
} // CloseDocument
public void NewPage() {
this.Document.NewPage();
this.YPosition = PageSize.GetTop(this.TopMargin);
} // Merge
public void Merge(PdfReader reader) {
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
for (int pageIndex = 1; pageIndex <= reader.NumberOfPages; pageIndex++) {
this.Merge(reader, parser, pageIndex);
} // foreach of the pages of the current PDF
} // Merge
public void Merge(PdfReader reader, PdfReaderContentParser parser, int pageIndex) {
PdfImportedPage importedPage = Writer.GetImportedPage(reader, pageIndex);
PdfContentByte directContent = Writer.DirectContent;
PageVerticalAnalyzer finder = parser.ProcessContent(pageIndex, new PageVerticalAnalyzer());
if (finder.VerticalFlips.Count < 2)
return;
Rectangle pageSizeToImport = reader.GetPageSize(pageIndex);
int startFlip = finder.VerticalFlips.Count - 1;
bool first = true;
while (startFlip > 0) {
if (!first)
this.NewPage();
float freeSpace = this.YPosition - PageSize.GetBottom(BottomMargin);
int endFlip = startFlip + 1;
while ((endFlip > 1) && (finder.VerticalFlips[startFlip] - finder.VerticalFlips[endFlip - 2] < freeSpace))
endFlip -= 2;
if (endFlip < startFlip) {
float height = finder.VerticalFlips[startFlip] - finder.VerticalFlips[endFlip];
directContent.SaveState();
directContent.Rectangle(0, this.YPosition - height, pageSizeToImport.Width, height);
directContent.Clip();
directContent.NewPath();
this.Writer.DirectContent.AddTemplate(importedPage, 0, this.YPosition - (finder.VerticalFlips[startFlip] - pageSizeToImport.Bottom));
directContent.RestoreState();
this.YPosition -= height + this.Gap;
startFlip = endFlip - 1;
} else if (!first) {
throw new ArgumentException(string.Format("Page {0} content too large", pageIndex));
} // if
first = false;
} // while
} // Merge
} // PdfVeryDenseMergeTool
RenderListener类:
更新3:修复了1行代码及其工作原理:查看代码中的注释
public class PageVerticalAnalyzer : IRenderListener {
public PageVerticalAnalyzer() { }
public List<float> VerticalFlips = new List<float>();
public void AddVerticalUseSection(float from, float to) {
if (to < from) {
float temp = to;
to = from;
from = temp;
}
int i = 0;
int j = 0;
for (i = 0; i < VerticalFlips.Count; i++) {
float flip = VerticalFlips[i];
if (flip < from)
continue;
for (j = i; j < VerticalFlips.Count; j++) {
flip = VerticalFlips[j];
if (flip < to)
continue;
break;
}
break;
} // foreach of the vertical flips
bool fromOutsideInterval = i % 2 == 0;
bool toOutsideInterval = j % 2 == 0;
while (j-- > i)
VerticalFlips.RemoveAt(j); // This was the problem line with just .Remove(j)
if (toOutsideInterval)
VerticalFlips.Insert(i, to);
if (fromOutsideInterval)
VerticalFlips.Insert(i, from);
} // AddVerticalUseSection
public void BeginTextBlock() { /* Do nothing */ }
public void EndTextBlock() { /* Do nothing */ }
public void RenderImage(ImageRenderInfo renderInfo) {
Matrix ctm = renderInfo.GetImageCTM();
List<float> YCoords = new List<float>(4) { 0, 0, 0, 0 };
for (int x = 0; x < 2; x++) {
for (int y = 0; y < 2; y++) {
Vector corner = new Vector(x, y, 1).Cross(ctm);
YCoords[2 * x + y] = corner[Vector.I2];
}
}
YCoords.Sort();
AddVerticalUseSection(YCoords[0], YCoords[3]);
} // RenderImage
public void RenderText(TextRenderInfo renderInfo) {
LineSegment ascentLine = renderInfo.GetAscentLine();
LineSegment descentLine = renderInfo.GetDescentLine();
List<float> YCoords = new List<float>(4) {
ascentLine.GetStartPoint()[Vector.I2],
ascentLine.GetEndPoint()[Vector.I2],
descentLine.GetStartPoint()[Vector.I2],
descentLine.GetEndPoint()[Vector.I2],
};
YCoords.Sort();
AddVerticalUseSection(YCoords[0], YCoords[3]);
} // RenderText
} // PageVericalAnalyzer
用于收集文件和运行工具的代码:
public void TestMergeDocuments() {
PdfVeryDenseMergeTool tool = new PdfVeryDenseMergeTool(iTextSharp.text.PageSize.A4, 18, 18, 10);
List<byte[]> Files = new List<byte[]>();
// Code to load each of the 3 files I need into this byte array list
using (MemoryStream ms = new MemoryStream()) {
List<PdfReader> files = new List<PdfReader>();
foreach (byte[] ba in Files) {
files.Add(new PdfReader(ba));
} // foreach of the sets of data
tool.Merge(ms, files);
// Save the file using: ms.GetBuffer()
} // using the memory stream
} // TestMergeDocuments
以下示例工具已经PdfDenseMergeTool根据该答案的工具的想法实施,OP已经评论说它接近[他]需要的.就像PdfDenseMergeTool这个工具一样,用Java/iText实现,我比C#/ iTextSharp更喜欢它.由于OP 已经翻译 PdfDenseMergeTool成C#/ iTextSharp,在这里翻译这个工具也不应该是一个太大的问题.
PdfVeryDenseMergeTool
此工具类似于PdfDenseMergeTool从多个PdfReader实例中获取页面的页面内容,并尝试密集地合并它们,即,如果有足够的可用空间,则将多个源页面的内容放到单个目标页面上.与之前的工具相比,此工具甚至可以拆分源页面内容,以实现更密集的合并.
就像其他工具一样,PdfVeryDenseMergeTool不考虑矢量图形因为iText(Sharp)解析API只转发文本和位图图像
该PdfVeryDenseMergeTool拆分源的网页,无法完全贴合到目标页面,在未通过文字的字形或位图图形的边框相交的水平线.
工具类:
Run Code Online (Sandbox Code Playgroud)public class PdfVeryDenseMergeTool { public PdfVeryDenseMergeTool(Rectangle size, float top, float bottom, float gap) { this.pageSize = size; this.topMargin = top; this.bottomMargin = bottom; this.gap = gap; } public void merge(OutputStream outputStream, Iterable<PdfReader> inputs) throws DocumentException, IOException { try { openDocument(outputStream); for (PdfReader reader: inputs) { merge(reader); } } finally { closeDocument(); } } void openDocument(OutputStream outputStream) throws DocumentException { final Document document = new Document(pageSize, 36, 36, topMargin, bottomMargin); final PdfWriter writer = PdfWriter.getInstance(document, outputStream); document.open(); this.document = document; this.writer = writer; newPage(); } void closeDocument() { try { document.close(); } finally { this.document = null; this.writer = null; this.yPosition = 0; } } void newPage() { document.newPage(); yPosition = pageSize.getTop(topMargin); } void merge(PdfReader reader) throws IOException { PdfReaderContentParser parser = new PdfReaderContentParser(reader); for (int page = 1; page <= reader.getNumberOfPages(); page++) { merge(reader, parser, page); } } void merge(PdfReader reader, PdfReaderContentParser parser, int page) throws IOException { PdfImportedPage importedPage = writer.getImportedPage(reader, page); PdfContentByte directContent = writer.getDirectContent(); PageVerticalAnalyzer finder = parser.processContent(page, new PageVerticalAnalyzer()); if (finder.verticalFlips.size() < 2) return; Rectangle pageSizeToImport = reader.getPageSize(page); int startFlip = finder.verticalFlips.size() - 1; boolean first = true; while (startFlip > 0) { if (!first) newPage(); float freeSpace = yPosition - pageSize.getBottom(bottomMargin); int endFlip = startFlip + 1; while ((endFlip > 1) && (finder.verticalFlips.get(startFlip) - finder.verticalFlips.get(endFlip - 2) < freeSpace)) endFlip -=2; if (endFlip < startFlip) { float height = finder.verticalFlips.get(startFlip) - finder.verticalFlips.get(endFlip); directContent.saveState(); directContent.rectangle(0, yPosition - height, pageSizeToImport.getWidth(), height); directContent.clip(); directContent.newPath(); writer.getDirectContent().addTemplate(importedPage, 0, yPosition - (finder.verticalFlips.get(startFlip) - pageSizeToImport.getBottom())); directContent.restoreState(); yPosition -= height + gap; startFlip = endFlip - 1; } else if (!first) throw new IllegalArgumentException(String.format("Page %s content sections too large.", page)); first = false; } } Document document = null; PdfWriter writer = null; float yPosition = 0; final Rectangle pageSize; final float topMargin; final float bottomMargin; final float gap; }
此工具使用自定义RenderListener功能与iText解析器API一起使用:
Run Code Online (Sandbox Code Playgroud)public class PageVerticalAnalyzer implements RenderListener { @Override public void beginTextBlock() { } @Override public void endTextBlock() { } /* * @see RenderListener#renderText(TextRenderInfo) */ @Override public void renderText(TextRenderInfo renderInfo) { LineSegment ascentLine = renderInfo.getAscentLine(); LineSegment descentLine = renderInfo.getDescentLine(); float[] yCoords = new float[]{ ascentLine.getStartPoint().get(Vector.I2), ascentLine.getEndPoint().get(Vector.I2), descentLine.getStartPoint().get(Vector.I2), descentLine.getEndPoint().get(Vector.I2) }; Arrays.sort(yCoords); addVerticalUseSection(yCoords[0], yCoords[3]); } /* * @see RenderListener#renderImage(ImageRenderInfo) */ @Override public void renderImage(ImageRenderInfo renderInfo) { Matrix ctm = renderInfo.getImageCTM(); float[] yCoords = new float[4]; for (int x=0; x < 2; x++) for (int y=0; y < 2; y++) { Vector corner = new Vector(x, y, 1).cross(ctm); yCoords[2*x+y] = corner.get(Vector.I2); } Arrays.sort(yCoords); addVerticalUseSection(yCoords[0], yCoords[3]); } /** * This method marks the given interval as used. */ void addVerticalUseSection(float from, float to) { if (to < from) { float temp = to; to = from; from = temp; } int i=0, j=0; for (; i<verticalFlips.size(); i++) { float flip = verticalFlips.get(i); if (flip < from) continue; for (j=i; j<verticalFlips.size(); j++) { flip = verticalFlips.get(j); if (flip < to) continue; break; } break; } boolean fromOutsideInterval = i%2==0; boolean toOutsideInterval = j%2==0; while (j-- > i) verticalFlips.remove(j); if (toOutsideInterval) verticalFlips.add(i, to); if (fromOutsideInterval) verticalFlips.add(i, from); } final List<Float> verticalFlips = new ArrayList<Float>(); }
它是这样使用的:
Run Code Online (Sandbox Code Playgroud)PdfVeryDenseMergeTool tool = new PdfVeryDenseMergeTool(PageSize.A4, 18, 18, 5); tool.merge(output, inputs);
适用于OP的样本文件
Header.pdf
Body.pdf
Footer.pdf
它会产生
如果将目标文档页面大小定义为A5 landscape:
Run Code Online (Sandbox Code Playgroud)PdfVeryDenseMergeTool tool = new PdfVeryDenseMergeTool(new RectangleReadOnly(595,421), 18, 18, 5); tool.merge(output, inputs);
它产生了这个:
谨防!这只是概念的证明,并没有考虑所有可能性.例如,没有正确处理具有非平凡旋转值的源页面或目标页面的情况.因此,它尚未准备好用于生产.
当前(5.5.6 SNAPSHOT)iText版本的改进
目前针对5.5.6的iText开发版增强了解析器功能,也可以发送矢量图形信号.因此,我扩展了PageVerticalAnalyzer使用它:
Run Code Online (Sandbox Code Playgroud)public class PageVerticalAnalyzer implements ExtRenderListener { @Override public void beginTextBlock() { } @Override public void endTextBlock() { } @Override public void clipPath(int rule) { } ... static class SubPathSection { public SubPathSection(float x, float y, Matrix m) { float effectiveY = getTransformedY(x, y, m); pathFromY = effectiveY; pathToY = effectiveY; } void extendTo(float x, float y, Matrix m) { float effectiveY = getTransformedY(x, y, m); if (effectiveY < pathFromY) pathFromY = effectiveY; else if (effectiveY > pathToY) pathToY = effectiveY; } float getTransformedY(float x, float y, Matrix m) { return new Vector(x, y, 1).cross(m).get(Vector.I2); } float getFromY() { return pathFromY; } float getToY() { return pathToY; } private float pathFromY; private float pathToY; } /* * Beware: The implementation is not correct as it includes the control points of curves * which may be far outside the actual curve. * * @see ExtRenderListener#modifyPath(PathConstructionRenderInfo) */ @Override public void modifyPath(PathConstructionRenderInfo renderInfo) { Matrix ctm = renderInfo.getCtm(); List<Float> segmentData = renderInfo.getSegmentData(); switch (renderInfo.getOperation()) { case PathConstructionRenderInfo.MOVETO: subPath = null; case PathConstructionRenderInfo.LINETO: case PathConstructionRenderInfo.CURVE_123: case PathConstructionRenderInfo.CURVE_13: case PathConstructionRenderInfo.CURVE_23: for (int i = 0; i < segmentData.size()-1; i+=2) { if (subPath == null) { subPath = new SubPathSection(segmentData.get(i), segmentData.get(i+1), ctm); path.add(subPath); } else subPath.extendTo(segmentData.get(i), segmentData.get(i+1), ctm); } break; case PathConstructionRenderInfo.RECT: float x = segmentData.get(0); float y = segmentData.get(1); float w = segmentData.get(2); float h = segmentData.get(3); SubPathSection section = new SubPathSection(x, y, ctm); section.extendTo(x+w, y, ctm); section.extendTo(x, y+h, ctm); section.extendTo(x+w, y+h, ctm); path.add(section); case PathConstructionRenderInfo.CLOSE: subPath = null; break; default: } } /* * @see ExtRenderListener#renderPath(PathPaintingRenderInfo) */ @Override public Path renderPath(PathPaintingRenderInfo renderInfo) { if (renderInfo.getOperation() != PathPaintingRenderInfo.NO_OP) { for (SubPathSection section : path) addVerticalUseSection(section.getFromY(), section.getToY()); } path.clear(); subPath = null; return null; } List<SubPathSection> path = new ArrayList<SubPathSection>(); SubPathSection subPath = null; ... }
一个简单的测试(VeryDenseMerging.java方法testMergeOnlyGraphics)合并这些文件
进入这个:
但再次提防:这仅仅是概念的证明.特别modifyPath()需要改进,实施不正确,因为它包括可能远远超出实际曲线的曲线控制点.