LCP CA correction now usable on more RAW types

see issue 1421

rtengine/imagedata.cc

@@ -172,10 +172,22 @@ void ImageData::extractInfo () {
         focal_len = exif->getTag ("FocalLength")->toDouble ();
     if (exif->getTag ("FocalLengthIn35mmFilm"))
         focal_len35mm = exif->getTag ("FocalLengthIn35mmFilm")->toDouble ();
-    rtexif::Tag* pDst=exif->getTag("SubjectDistance");  // EXIF, set by Adobe. MakerNote ones are scattered and partly encrypted
+
+    // Focus distance from EXIF or XMP. MakerNote ones are scattered and partly encrypted
+    int num=-3, denom=-3;
+
+    // First try, offical EXIF. Set by Adobe on some DNGs
+    rtexif::Tag* pDst=exif->getTag("SubjectDistance");  
     if (pDst) {
         int num, denom;
         pDst->toRational(num,denom);
+    } else {
+        // Second try, XMP data
+        char sXMPVal[64];
+        if (root->getXMPTagValue("aux:ApproximateFocusDistance",sXMPVal)) { sscanf(sXMPVal,"%d/%d",&num,&denom); }
+    }
+
+    if (num!=-3) {
         if ((denom==1 && num>=10000) || num<0 || denom<0) 
             focus_dist=10000;  // infinity
         else if (denom>0) {

rtexif/rtexif.cc

@@ -213,6 +213,51 @@ Tag* TagDirectory::findTag (const char* name) const {
 	  return NULL;
 }
 
+// Searches a simple value, as either attribute or element
+// only for simple values, not for entries with special chars or free text
+bool TagDirectory::getXMPTagValue(const char* name, char* value) const {
+    *value=0;
+
+    if (!getTag("ApplicationNotes")) return false;
+    char *sXMP = (char*)getTag("ApplicationNotes")->getValue();
+
+    // Check for full word
+    char *pos=sXMP;
+
+    bool found=false;
+    do {
+        pos=strstr(pos,name);
+        if (pos) {
+            char nextChar=*(pos+strlen(name));
+            if (nextChar==' ' || nextChar=='>' || nextChar=='=') 
+                found=true;
+            else
+                pos+=strlen(name);
+        }
+    } while (pos && !found);
+    if (!found) return false;
+
+    char *posTag =strchr(pos,'>');
+    char *posAttr=strchr(pos,'"');
+
+    if (!posTag && !posAttr) return false;
+
+    if (posTag && (!posAttr || posTag<posAttr)) {
+        // Tag
+        pos=strchr(posTag+1,'<');
+        strncpy(value,posTag+1,pos-posTag-1);
+        value[pos-posTag-1]=0;
+        return true;
+    } else
+    if (posAttr && (!posTag || posAttr<posTag)) {
+        // Attribute
+        pos=strchr(posAttr+1,'"');
+        strncpy(value,posAttr+1,pos-posAttr-1);
+        value[pos-posAttr-1]=0;
+        return true;
+    } else return false;
+}
+
 void TagDirectory::keepTag (int ID) {
     for (size_t i=0; i<tags.size(); i++)
         if (tags[i]->getID()==ID) tags[i]->setKeep(true);

rtexif/rtexif.h

@@ -83,6 +83,7 @@ class TagDirectory {
     virtual Tag*     getTag        (const char* name) const;
     virtual Tag*     getTag        (int ID) const;
     virtual Tag*     findTag       (const char* name) const;
+    bool             getXMPTagValue(const char* name, char* value) const;
 
     void             keepTag       (int ID);
     virtual void     addTag        (Tag* a);