我们有一个 WPF 应用程序，它允许用户按照自己的意愿输入和设置文本样式。然后将它们的文本转换为 XPS 以使用 ABCPdf 插入到 PDF 中。
我们最近切换到 .Net 4，现在 XPS 生成有时会生成格式错误的 XPS。
生成格式错误的 XPS 的唯一时间是用户使用重叠两个字符的字体(例如 Sevillana、available on Google Fonts)。在 .Net 4 中，字符重叠，而在 .Net 3.5 中，它们不重叠。从 another SO question 我了解到这是因为 .Net 4.0 改变了它的字体渲染引擎。
.Net 3.5:
.Net 4.0 :(注意“d”和“A”是如何重叠的)
看起来 .Net 4 没有考虑撇号的间距，甚至否定它。如果我删除撇号，间距会变宽。我创建了一个简单的测试项目来演示这个问题:https://github.com/tbroust-trepia/wpf-4-font-rendering
我们将 FlowDocument 保存到 XPS 的方法与 creating an XPS Document from a FlowDocument and attach it on the fly 中的几乎相同(我怀疑原始开发人员只是复制/粘贴了该代码)；它只是将 XPS 保存到文件而不是流中。
The MS tool IsXPS 表示特定节点无效。事实上，在 Documents\1\Pages\1.fpage 中，Indices 的值为 ;,-16;,84;;;;,30 。我可以看到“0.-16”并不是一个真正的数字。
所以，我有很多问题:
编辑
I have opened a bug at Microsoft ，但我对那里的期望并不高。我想我会尝试修改生成的XPS。它很脏，但可能有用。
最佳答案
在等待 MS 为所欲为时，我找到了修复损坏的 XPS 的方法。
Warning: dirty hack ahead
public class XpsFile
{
/// <summary>
/// Regex to validate XPS "indices" property (gotten from ABCPDF)
/// </summary>
private static readonly string IndicesRegex = @"(((\(([1-9][0-9]*)(:([1-9][0-9]*))?\))?([0-9]+))?(,(\+?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?)?(,((\-|\+)?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?)?(,((\-|\+)?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?))?)?)?)(;((\(([1-9][0-9]*)(:([1-9][0-9]*))?\))?([0-9]+))?(,(\+?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?)?(,((\-|\+)?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?)?(,((\-|\+)?(([0-9]+(\.[0-9]+)?)|(\.[0-9]+))((e|E)(\-|\+)?[0-9]+)?))?)?)?)*";
/// <summary>
/// Fixes the XPS problems it encounters and knows about
/// </summary>
public static void FixXps(string filePath)
{
// first we'll load the XPS file
using (var currentPackage = Package.Open(filePath, FileMode.Open))
{
var pageUri = new Uri("/Documents/1/Pages/1.fpage", UriKind.Relative);
// check that the file we'll modify exists
if (!currentPackage.PartExists(pageUri))
{
throw new Exception(string.Format("Unable to find first page in XPS {0} - unable to fix this XPS !", filePath));
}
// assume the broken part is in the first page
var firstPage = currentPackage.GetPart(pageUri);
var relationships = firstPage.GetRelationships();
var pageContent = XDocument.Load(firstPage.GetStream());
// then we'll look up each glyph and check if their "Indices" property is valid
XNamespace ns = pageContent.Root.GetDefaultNamespace();
var glyphs = (from g in pageContent.Descendants(ns + "Glyphs")
where g.Attribute("Indices") != null
select g).ToList();
for (var i = 0; i < glyphs.Count(); i ++)
{
glyphs[i] = FixGlyph(glyphs[i]);
}
// remove the current (corrupted) file from the package
currentPackage.DeletePart(pageUri);
// add the new (shiny) file to the package
var newPage = currentPackage.CreatePart(pageUri, "application/vnd.ms-package.xps-fixedpage+xml", CompressionOption.NotCompressed);
using (var ms = new MemoryStream())
{
// we need to remove XML declaration, so we need to use the XmlWriter
var settings = new XmlWriterSettings();
settings.Indent = false;
settings.NewLineChars = string.Empty;
settings.NewLineHandling = NewLineHandling.Replace;
settings.OmitXmlDeclaration = true;
using (var xw = XmlWriter.Create(ms, settings))
{
pageContent.WriteTo(xw);
}
ms.Seek(0, SeekOrigin.Begin);
CopyStream(newPage.GetStream(), ms);
}
// now we need to re-create the relationships between the Page file and the fonts
foreach (var relation in relationships)
{
newPage.CreateRelationship(relation.TargetUri, relation.TargetMode, relation.RelationshipType, relation.Id);
}
}
}
/// <summary>
/// Tries to load the XPS, and returns false if it fails
/// </summary>
public static bool IsValidXps(string filePath)
{
try
{
using (var xpsOld = new XpsDocument(filePath, FileAccess.Read))
{
var unused = xpsOld.GetFixedDocumentSequence();
}
return true;
}
catch (System.Windows.Markup.XamlParseException)
{
return false;
}
}
/// <summary>
/// Writes the whole content of a stream into another
/// </summary>
/// <remarks>
/// http://stackoverflow.com/a/18885954/2354542
/// </remarks>
private static void CopyStream(Stream target, Stream source)
{
const int bufSize = 0x1000;
byte[] buf = new byte[bufSize];
int bytesRead = 0;
while ((bytesRead = source.Read(buf, 0, bufSize)) > 0)
{
target.Write(buf, 0, bytesRead);
}
}
/// <summary>
/// Fixes the glyph, if necessary
/// </summary>
private static XElement FixGlyph(XElement g)
{
var matchAttribute = Regex.Match(g.Attribute("Indices").Value, IndicesRegex);
if (!matchAttribute.Success)
{
return g;
}
var hasProblem = false;
foreach (var token in matchAttribute.Value.Split(";".ToCharArray()))
{
if (token == ",")
{
hasProblem = true;
break;
}
}
if (hasProblem)
{
// the Indices attribute is not well-formed: let's try to fix the one(s) that are wrong
var fixedTokens = new List<string>();
foreach (var token in g.Attribute("Indices").Value.Split(";".ToCharArray()))
{
var newToken = token;
var matchToken = Regex.Match(token, @",(-\d+)");
if (matchToken.Success) // negative number, yay ! it's not allowed :-(
{
newToken = ",0"; // it should be zero, I believe
}
fixedTokens.Add(newToken);
}
g.Attribute("Indices").Value = string.Join(";", fixedTokens);
}
return g;
}
}
关于c# - XPS 编写器因 .Net 4/字体渲染错误而失败？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/23246254/