Avoid failing with exception in case form field /DA key is malformed

Also avoid using DR font name if custom font was explicitly set;
if text field is created without specifying font and font-size, rely on inherited DA first.

ITXT-CR-669

Autoported commit.
Original commit hash: [6e8b824838]

Author: yulian-gaponenko

itext.tests/itext.forms.tests/itext/forms/PdfFormFieldTest.cs

@@ -120,6 +120,28 @@ public virtual void FormFieldTest03() {
             }
         }
 
+        /// <exception cref="System.IO.IOException"/>
+        /// <exception cref="System.Exception"/>
+        [NUnit.Framework.Test]
+        public virtual void FormFieldTest04() {
+            String filename = destinationFolder + "formFieldTest04.pdf";
+            PdfDocument pdfDoc = new PdfDocument(new PdfReader(sourceFolder + "formFieldFile.pdf"), new PdfWriter(filename
+                ));
+            PdfAcroForm form = PdfAcroForm.GetAcroForm(pdfDoc, true);
+            PdfPage page = pdfDoc.GetFirstPage();
+            Rectangle rect = new Rectangle(210, 490, 150, 22);
+            PdfTextFormField field = PdfFormField.CreateText(pdfDoc, rect, "TestField", "some value in courier font", 
+                PdfFontFactory.CreateFont(StandardFonts.COURIER), 10);
+            form.AddField(field, page);
+            pdfDoc.Close();
+            CompareTool compareTool = new CompareTool();
+            String errorMessage = compareTool.CompareByContent(filename, sourceFolder + "cmp_formFieldTest04.pdf", destinationFolder
+                , "diff_");
+            if (errorMessage != null) {
+                NUnit.Framework.Assert.Fail(errorMessage);
+            }
+        }
+
         /// <exception cref="System.IO.IOException"/>
         [NUnit.Framework.Test]
         public virtual void UnicodeFormFieldTest() {
@@ -432,5 +454,29 @@ public virtual void FillFormWithDefaultResourcesUpdateFont() {
                 NUnit.Framework.Assert.Fail(errorMessage);
             }
         }
+
+        /// <exception cref="System.IO.IOException"/>
+        /// <exception cref="System.Exception"/>
+        [NUnit.Framework.Test]
+        public virtual void FormRegenerateWithInvalidDefaultAppearance01() {
+            String testName = "formRegenerateWithInvalidDefaultAppearance01";
+            String outPdf = destinationFolder + testName + ".pdf";
+            String cmpPdf = sourceFolder + "cmp_" + testName + ".pdf";
+            String srcPdf = sourceFolder + "invalidDA.pdf";
+            PdfWriter writer = new PdfWriter(outPdf);
+            PdfReader reader = new PdfReader(srcPdf);
+            PdfDocument pdfDoc = new PdfDocument(reader, writer);
+            PdfAcroForm form = PdfAcroForm.GetAcroForm(pdfDoc, true);
+            IDictionary<String, PdfFormField> fields = form.GetFormFields();
+            fields.Get("Text1").SetValue("New field value");
+            fields.Get("Text2").SetValue("New field value");
+            fields.Get("Text3").SetValue("New field value");
+            pdfDoc.Close();
+            CompareTool compareTool = new CompareTool();
+            String errorMessage = compareTool.CompareByContent(outPdf, cmpPdf, destinationFolder, "diff_");
+            if (errorMessage != null) {
+                NUnit.Framework.Assert.Fail(errorMessage);
+            }
+        }
     }
 }

itext.tests/itext.forms.tests/resources/itext/forms/PdfFormFieldTest/cmp_formFieldTest03.pdf

@@ -496,12 +496,7 @@ public static PdfTextFormField CreateText(PdfDocument doc, Rectangle rect, Strin
         /// <see cref="PdfTextFormField"/>
         /// </returns>
         public static PdfTextFormField CreateText(PdfDocument doc, Rectangle rect, String name, String value) {
-            try {
-                return CreateText(doc, rect, name, value, PdfFontFactory.CreateFont(), (float)DEFAULT_FONT_SIZE);
-            }
-            catch (System.IO.IOException e) {
-                throw new PdfException(e);
-            }
+            return CreateText(doc, rect, name, value, null, -1);
         }
 
         /// <summary>
@@ -658,12 +653,7 @@ public static PdfTextFormField CreateMultilineText(PdfDocument doc, Rectangle re
         /// </returns>
         public static PdfTextFormField CreateMultilineText(PdfDocument doc, Rectangle rect, String name, String value
             ) {
-            try {
-                return CreateText(doc, rect, name, value, PdfFontFactory.CreateFont(), (float)DEFAULT_FONT_SIZE, true);
-            }
-            catch (System.IO.IOException e) {
-                throw new PdfException(e);
-            }
+            return CreateText(doc, rect, name, value, null, -1, true);
         }
 
         /// <summary>
@@ -3274,71 +3264,59 @@ protected internal virtual Object[] GetFontAndSize(PdfDictionary asNormal) {
             if (asNormal != null) {
                 normalResources = asNormal.GetAsDictionary(PdfName.Resources);
             }
+            PdfDictionary daFontDict = null;
+            PdfName daFontName = null;
+            Object[] dab = new Object[3];
             if (defaultResources != null || normalResources != null) {
                 PdfDictionary normalFontDic = normalResources != null ? normalResources.GetAsDictionary(PdfName.Font) : null;
                 PdfDictionary defaultFontDic = defaultResources != null ? defaultResources.GetAsDictionary(PdfName.Font) : 
                     null;
                 PdfString defaultAppearance = GetDefaultAppearance();
                 if ((normalFontDic != null || defaultFontDic != null) && defaultAppearance != null) {
-                    Object[] dab = SplitDAelements(defaultAppearance.ToUnicodeString());
-                    PdfName fontName = new PdfName(dab[DA_FONT].ToString());
-                    fontAndSize[2] = fontName;
-                    PdfDictionary requiredFontDictionary = null;
-                    if (normalFontDic != null && null != normalFontDic.GetAsDictionary(fontName)) {
-                        requiredFontDictionary = normalFontDic.GetAsDictionary(fontName);
-                    }
-                    else {
-                        if (defaultFontDic != null) {
-                            requiredFontDictionary = defaultFontDic.GetAsDictionary(fontName);
+                    dab = SplitDAelements(defaultAppearance.ToUnicodeString());
+                    Object fontNameObj = dab[DA_FONT];
+                    if (fontNameObj != null) {
+                        daFontName = new PdfName(fontNameObj.ToString());
+                        // according to spec, DA font shall be taken from the DR
+                        if (defaultFontDic != null && null != defaultFontDic.GetAsDictionary(daFontName)) {
+                            daFontDict = defaultFontDic.GetAsDictionary(daFontName);
+                        }
+                        else {
+                            if (normalFontDic != null) {
+                                // search normal appearance as a fall back in case it was not found in DR
+                                daFontDict = normalFontDic.GetAsDictionary(daFontName);
+                            }
                         }
-                    }
-                    if (font != null) {
-                        fontAndSize[0] = font;
-                    }
-                    else {
-                        PdfFont dicFont = document != null ? document.GetFont(requiredFontDictionary) : PdfFontFactory.CreateFont(
-                            requiredFontDictionary);
-                        fontAndSize[0] = dicFont;
-                    }
-                    if (fontSize >= 0) {
-                        fontAndSize[1] = fontSize;
-                    }
-                    else {
-                        fontAndSize[1] = dab[DA_SIZE];
-                    }
-                    if (color == null) {
-                        color = (Color)dab[DA_COLOR];
-                    }
-                }
-                else {
-                    if (font != null) {
-                        fontAndSize[0] = font;
-                    }
-                    else {
-                        fontAndSize[0] = PdfFontFactory.CreateFont();
-                    }
-                    if (fontSize >= 0) {
-                        fontAndSize[1] = fontSize;
-                    }
-                    else {
-                        fontAndSize[1] = (float)DEFAULT_FONT_SIZE;
                     }
                 }
             }
+            if (font != null) {
+                fontAndSize[0] = font;
+            }
             else {
-                if (font != null) {
-                    fontAndSize[0] = font;
+                if (daFontDict != null) {
+                    PdfFont daFont = document != null ? document.GetFont(daFontDict) : PdfFontFactory.CreateFont(daFontDict);
+                    fontAndSize[0] = daFont;
+                    fontAndSize[2] = daFontName;
                 }
                 else {
                     fontAndSize[0] = PdfFontFactory.CreateFont();
                 }
-                if (fontSize >= 0) {
-                    fontAndSize[1] = fontSize;
+            }
+            if (fontSize >= 0) {
+                fontAndSize[1] = fontSize;
+            }
+            else {
+                if (dab[DA_SIZE] != null) {
+                    fontAndSize[1] = dab[DA_SIZE];
                 }
                 else {
                     fontAndSize[1] = (float)DEFAULT_FONT_SIZE;
                 }
             }
+            if (color == null) {
+                color = (Color)dab[DA_COLOR];
+            }
             return fontAndSize;
         }
 
@@ -3407,7 +3385,7 @@ protected internal static Object[] SplitDAelements(String da) {
                     }
                 }
             }
-            catch (System.IO.IOException) {
+            catch (Exception) {
             }
             return ret;
         }

itext.tests/itext.forms.tests/resources/itext/forms/PdfFormFieldTest/cmp_formFieldTest04.pdf

@@ -1 +1 @@
-6a3d9021cfabe03aaf5ee7851ce08968e95af1a4
+6e8b824838790fba08afbe516ae8c9b8d43120f4