[jira] [Commented] (FOP-2918) Surrogate pairs not handled in U+10800-U+1083F

[Kelly H Wilkerson (Jira)]

    [ 
https://issues.apache.org/jira/browse/FOP-2918?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17158838#comment-17158838
 ] 

Kelly H Wilkerson commented on FOP-2918:
----------------------------------------

I'm not sure if this is the right place to make the change, but a change that 
does work is to correct add an additional check for a high surrogate in 
org.apache.fop.layoutmgr.inline.TextLayoutManager.  

I think it's sufficient to guard against a break mid surrogate pair when the 
bidi levels change (first diff) but added another option (second diff) that 
would prevent a word break after any high surrogate char no matter which cause.

{code:java}
--- 
a/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
+++ 
b/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
@@ -776,6 +776,7 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
         boolean inWord = false;
         boolean inWhitespace = false;
         char ch = 0;
+        char prevChar = 0;
         int level = -1;
         int prevLevel = -1;
         boolean retainControls = false;
@@ -814,7 +815,8 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
                 if (breakOpportunity
                      || GlyphMapping.isSpace(ch)
                      || CharUtilities.isExplicitBreak(ch)
-                     || ((prevLevel != -1) && (level != prevLevel))) {
+                     || ((prevLevel != -1) && (level != prevLevel) && 
!Character.isHighSurrogate(prevChar))
+                   ) {
                     // this.foText.charAt(lastIndex) == 
CharUtilities.SOFT_HYPHEN
                     prevMapping = processWord(alignment, sequence, 
prevMapping, ch,
                         breakOpportunity, true, prevLevel, retainControls);
@@ -870,6 +872,7 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
             inWhitespace = ch == CharUtilities.SPACE
                     && foText.getWhitespaceTreatment() != 
Constants.EN_PRESERVE;
             prevLevel = level;
+            prevChar = ch;
             nextStart++;
         }
 {code}



{code:java}
--- 
a/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
+++ 
b/fop-core/src/main/java/org/apache/fop/layoutmgr/inline/TextLayoutManager.java
@@ -776,6 +776,7 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
         boolean inWord = false;
         boolean inWhitespace = false;
         char ch = 0;
+        char prevChar = 0;
         int level = -1;
         int prevLevel = -1;
         boolean retainControls = false;
@@ -811,10 +812,11 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
                             + "}");
             }
             if (inWord) {
-                if (breakOpportunity
+                if ((breakOpportunity
                      || GlyphMapping.isSpace(ch)
                      || CharUtilities.isExplicitBreak(ch)
-                     || ((prevLevel != -1) && (level != prevLevel))) {
+                    || ((prevLevel != -1) && (level != prevLevel)))
+                   && !Character.isHighSurrogate(prevChar)) {
                     // this.foText.charAt(lastIndex) == 
CharUtilities.SOFT_HYPHEN
                     prevMapping = processWord(alignment, sequence, 
prevMapping, ch,
                         breakOpportunity, true, prevLevel, retainControls);
@@ -870,6 +872,7 @@ public class TextLayoutManager extends 
LeafNodeLayoutManager {
             inWhitespace = ch == CharUtilities.SPACE
                     && foText.getWhitespaceTreatment() != 
Constants.EN_PRESERVE;
             prevLevel = level;
+            prevChar = ch;
             nextStart++;
         }
{code}


> Surrogate pairs not handled in U+10800-U+1083F
> ----------------------------------------------
>
>                 Key: FOP-2918
>                 URL: https://issues.apache.org/jira/browse/FOP-2918
>             Project: FOP
>          Issue Type: Bug
>          Components: renderer/pdf
>    Affects Versions: 2.4
>         Environment: Windows 10
>            Reporter: Jan Driesen
>            Priority: Major
>         Attachments: NotoSansCypriot-Regular.ttf, fop.xconf, input.fo
>
>
> Fop is not properly handling surrogate pairs for characters in Unicode Block 
> 'Cypriot Syllabary' when rendering PDF.
> It tries to resolve the individual surrogate entities. This results in errors 
> saying the glyphs cannot be found.
> The attached test shows a font that supports characters in this range, and an 
> FO file holding the surrogate characters to be rendered.
> Similar issues arise with fonts "MPH 2b Damas" 
> ([https://fedoraproject.org/wiki/MPH_2B_Damase_fonts]) and "Segoe UI 
> Historic" 
> ([https://docs.microsoft.com/en-us/typography/font-list/segoe_ui_historic),] 
> but the error may differ. [I am unsure whether licensing allows me to add 
> these)
> Some fonts (Damas & Noto) result in a "String index out of range". Other 
> fonts (Segoe) deliver a "ill-formed UTF-16 sequence, contains isolated high 
> surrogate at end of sequence" FOPException.
> We expected this to work thanks to FOP-1969 (fop 2.3).



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