Port PdfFormField from develop

Add AppearanceResources and AppearanceXObject
Those classes will save font names from default resources.
Update javadoc for PdfAcroForm#setGenerateAppearance()

Update PdfFormField#setDefaultAppearance()
Save original font and fontSize for /DA.
Do not override /DA if inherited is the same.

Use font from /DA for button
Actually /DA has no any sense for button.
But let's keep this behaviour as backward compatibility.

Fix backward compatibility issue in PdfFormField
Remove redundant comparing in setDefaultAppearance

DEVSIX-1916

Author: pavel-alay

forms/src/main/java/com/itextpdf/forms/PdfAcroForm.java

@@ -578,6 +578,8 @@ public boolean isGenerateAppearance() {
      * If generateAppearance is set to <code>true</code>, then
      * <code>NeedAppearances</code> is set to <code>false</code>. This does not
      * apply vice versa.
+     * <p>
+     * Note, this method does not change default behaviour of {@link PdfFormField#setValue(String)} method.
      *
      * @param generateAppearance a boolean
      */

forms/src/main/java/com/itextpdf/forms/fields/AppearanceResources.java

@@ -0,0 +1,57 @@
+package com.itextpdf.forms.fields;
+
+import com.itextpdf.kernel.font.PdfFont;
+import com.itextpdf.kernel.pdf.PdfDictionary;
+import com.itextpdf.kernel.pdf.PdfDocument;
+import com.itextpdf.kernel.pdf.PdfIndirectReference;
+import com.itextpdf.kernel.pdf.PdfName;
+import com.itextpdf.kernel.pdf.PdfResources;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * AppearanceResources allows to register font names that will be used as resource name.
+ * Preserving existed font names in default resources of AcroForm is the only goal of this class.
+ * <p>
+ * Shall be used only in {@link PdfFormField}.
+ *
+ * @see AppearanceXObject
+ */
+class AppearanceResources extends PdfResources {
+
+    private static final long serialVersionUID = -1991503804376023468L;
+
+    private Map<PdfIndirectReference, PdfName> drFonts = new HashMap<>();
+
+    AppearanceResources() {
+        super();
+    }
+
+    AppearanceResources(PdfDictionary pdfObject) {
+        super(pdfObject);
+    }
+
+    AppearanceResources addFontFromDefaultResources(PdfName name, PdfFont font) {
+        if (name != null && font != null && font.getPdfObject().getIndirectReference() != null) {
+            //So, most likely it's a document PdfFont
+            drFonts.put(font.getPdfObject().getIndirectReference(), name);
+        }
+        return this;
+    }
+
+    @Override
+    public PdfName addFont(PdfDocument pdfDocument, PdfFont font) {
+        PdfName fontName = null;
+        if (font != null && font.getPdfObject().getIndirectReference() != null) {
+            fontName = drFonts.get(font.getPdfObject().getIndirectReference());
+        }
+
+        if (fontName != null) {
+            addResource(font.getPdfObject(), PdfName.Font, fontName);
+            return fontName;
+        } else {
+            return super.addFont(pdfDocument, font);
+        }
+    }
+}

forms/src/main/java/com/itextpdf/forms/fields/AppearanceXObject.java

@@ -0,0 +1,49 @@
+package com.itextpdf.forms.fields;
+
+import com.itextpdf.kernel.font.PdfFont;
+import com.itextpdf.kernel.geom.Rectangle;
+import com.itextpdf.kernel.pdf.PdfDictionary;
+import com.itextpdf.kernel.pdf.PdfName;
+import com.itextpdf.kernel.pdf.PdfResources;
+import com.itextpdf.kernel.pdf.PdfStream;
+import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
+
+/**
+ * AppearanceXObject allows font names registration. Those names will be used as resource name
+ * for a particular {@link PdfFont}.
+ * <p>
+ * Preserving existed font names in default resources of AcroForm is the only goal of this class.
+ * <p>
+ * Shall be used only in {@link PdfFormField}.
+ */
+class AppearanceXObject extends PdfFormXObject {
+
+    private static final long serialVersionUID = 6098843657444897565L;
+
+    AppearanceXObject(PdfStream pdfStream) {
+        super(pdfStream);
+    }
+
+    AppearanceXObject(Rectangle bBox) {
+        super(bBox);
+    }
+
+    void addFontFromDR(PdfName fontName, PdfFont font) {
+        if (fontName != null && font != null) {
+            ((AppearanceResources) getResources()).addFontFromDefaultResources(fontName, font);
+        }
+    }
+
+    @Override
+    public PdfResources getResources() {
+        if (this.resources == null) {
+            PdfDictionary resourcesDict = getPdfObject().getAsDictionary(PdfName.Resources);
+            if (resourcesDict == null) {
+                resourcesDict = new PdfDictionary();
+                getPdfObject().put(PdfName.Resources, resourcesDict);
+            }
+            this.resources = new AppearanceResources(resourcesDict);
+        }
+        return resources;
+    }
+}

forms/src/main/java/com/itextpdf/forms/fields/PdfFormField.java

@@ -101,7 +101,7 @@ This file is part of the iText (R) project.
 /**
  * This class represents a single field or field group in an {@link com.itextpdf.forms.PdfAcroForm
  * AcroForm}.
- * <p>
+ *
  * <br><br>
  * To be able to be wrapped with this {@link PdfObjectWrapper} the {@link PdfObject}
  * must be indirect.
@@ -795,7 +795,7 @@ public static PdfButtonFormField createPushButton(PdfDocument doc, Rectangle rec
         field.font = font;
         field.fontSize = fontSize;
 
-        PdfFormXObject xObject = field.drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), caption, font, fontSize);
+        PdfFormXObject xObject = field.drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), caption, font, null, fontSize);
         annot.setNormalAppearance(xObject.getPdfObject());
 
         PdfDictionary mk = new PdfDictionary();
@@ -1513,8 +1513,7 @@ public PdfString getDefaultAppearance() {
      */
     public PdfFormField setDefaultAppearance(String defaultAppearance) {
         byte[] b = defaultAppearance.getBytes(StandardCharsets.UTF_8);
-        int len = b.length;
-        for (int k = 0; k < len; ++k) {
+        for (int k = 0; k < b.length; ++k) {
             if (b[k] == '\n')
                 b[k] = 32;
         }
@@ -1805,7 +1804,10 @@ public boolean regenerateField() {
 
                 Object[] fontAndSize = getFontAndSize(asNormal);
                 PdfFont localFont = (PdfFont) fontAndSize[0];
-                float fontSize = normalizeFontSize((float) fontAndSize[1], localFont, bBox, value);
+                PdfName localFontName = (PdfName) fontAndSize[2];
+                // Save it for Default Appearance.
+                this.fontSize = (float) fontAndSize[1];
+                float fontSize = normalizeFontSize(this.fontSize, localFont, bBox, value);
 
                 //Apply Page rotation
                 int pageRotation = 0;
@@ -1886,14 +1888,14 @@ public boolean regenerateField() {
                     bBox = new PdfArray(rect);
                 }
                 //Create appearance
-                PdfFormXObject appearance = null;
+                AppearanceXObject appearance;
                 if (asNormal != null) {
-                    appearance = new PdfFormXObject(asNormal);
+                    appearance = new AppearanceXObject(asNormal);
                     appearance.setBBox(new PdfArray(new float[]{0, 0, bBox.toRectangle().getWidth(), bBox.toRectangle().getHeight()}));
+                } else {
+                    appearance = new AppearanceXObject(new Rectangle(0, 0, bBox.toRectangle().getWidth(), bBox.toRectangle().getHeight()));
                 }
-                if (appearance == null) {
-                    appearance = new PdfFormXObject(new Rectangle(0, 0, bBox.toRectangle().getWidth(), bBox.toRectangle().getHeight()));
-                }
+                appearance.addFontFromDR(localFontName, localFont);
                 appearance.put(PdfName.Matrix, matrix);
                 //Create text appearance
                 if (PdfName.Tx.equals(type)) {
@@ -1943,20 +1945,19 @@ public boolean regenerateField() {
                             apDic = widgets.get(0).getPdfObject().getAsDictionary(PdfName.AP);
                         }
                     }
-                    if (img != null) {
-                        appearance = drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), value, null, 0);
-                    } else if (form != null) {
-                        appearance = drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), value, null, 0);
+                    if (img != null || form != null) {
+                        appearance = drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), value, null, null, 0);
                     } else {
                         PdfStream asNormal = null;
                         if (apDic != null) {
                             asNormal = apDic.getAsStream(PdfName.N);
                         }
                         Object[] fontAndSize = getFontAndSize(asNormal);
                         PdfFont localFont = (PdfFont) fontAndSize[0];
+                        PdfName localFontName = (PdfName) fontAndSize[2];
                         float fontSize = (float) fontAndSize[1];
-                        appearance = drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), value, localFont, fontSize);
-                        appearance.getResources().addFont(getDocument(), localFont);
+                        appearance = drawPushButtonAppearance(rect.getWidth(), rect.getHeight(), value,
+                                localFont, localFontName, fontSize);
                     }
 
                     if (apDic == null) {
@@ -2032,6 +2033,7 @@ private PdfObject getAcroFormKey(PdfName key, int type) {
     private float normalizeFontSize(float fs, PdfFont localFont, PdfArray bBox, String value) {
         if (fs == 0) {
             if (isMultiline()) {
+                //We do not support autosize with multiline.
                 fontSize = DEFAULT_FONT_SIZE;
             } else {
                 float height = bBox.toRectangle().getHeight() - borderWidth * 2;
@@ -2457,7 +2459,21 @@ protected static PdfArray processOptions(String[] options) {
         return array;
     }
 
+    /**
+     * Generate default appearance, /DA key.
+     *
+     * @param font     preferred font. If {@link #getFont()} is not null, it will be used instead.
+     * @param fontSize preferred font size. If {@link PdfFormField#fontSize} is valid,
+     *                 it will be used instead.
+     * @return generated string
+     */
     protected String generateDefaultAppearanceString(PdfFont font, float fontSize, Color color, PdfResources res) {
+        if (this.fontSize >= 0) {
+            fontSize = this.fontSize;
+        }
+        if (this.font != null) {
+            font = this.font;
+        }
         PdfStream stream = new PdfStream();
         PdfCanvas canvas = new PdfCanvas(stream, res, getDocument());
         canvas.setFontAndSize(font, fontSize);
@@ -2479,7 +2495,7 @@ protected String generateDefaultAppearanceString(PdfFont font, int fontSize, Pdf
     }
 
     protected Object[] getFontAndSize(PdfDictionary asNormal) throws IOException {
-        Object[] fontAndSize = new Object[2];
+        Object[] fontAndSize = new Object[3];
         PdfDictionary normalResources = null;
         PdfDictionary defaultResources = null;
         PdfDocument document = getDocument();
@@ -2494,6 +2510,7 @@ protected Object[] getFontAndSize(PdfDictionary asNormal) throws IOException {
             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);
@@ -3036,12 +3053,34 @@ protected void drawPdfA2CheckAppearance(float width, float height, String value,
      * @param font     a {@link PdfFont}
      * @param fontSize the size of the font
      * @return a new {@link PdfFormXObject}
+     * @deprecated Will be removed in 7.2.
+     * @see #drawPushButtonAppearance(float, float, String, PdfFont, PdfName, float)
      */
-    protected PdfFormXObject drawPushButtonAppearance(float width, float height, String text, PdfFont font, float fontSize) {
-        PdfStream stream = new PdfStream().makeIndirect(getDocument());
-        PdfCanvas canvas = new PdfCanvas(stream, new PdfResources(), getDocument());
+    @Deprecated
+    protected PdfFormXObject drawPushButtonAppearance(float width, float height, String text,
+                                                      PdfFont font, float fontSize) {
+        return drawPushButtonAppearance(width, height, text, font, null, fontSize);
 
-        PdfFormXObject xObject = new PdfFormXObject(new Rectangle(0, 0, width, height));
+    }
+
+    /**
+     * Draws the appearance for a push button.
+     *
+     * @param width    the width of the pushbutton
+     * @param height   the width of the pushbutton
+     * @param text     the text to display on the button
+     * @param font     a {@link PdfFont}
+     * @param fontName fontName in DR.
+     * @param fontSize the size of the font
+     * @return a new {@link PdfFormXObject}
+     */
+    protected PdfFormXObject drawPushButtonAppearance(float width, float height, String text,
+                                                      PdfFont font, PdfName fontName, float fontSize) {
+        PdfStream stream = (PdfStream) new PdfStream().makeIndirect(getDocument());
+        AppearanceResources resources = new AppearanceResources().addFontFromDefaultResources(fontName, font);
+        PdfCanvas canvas = new PdfCanvas(stream, resources, getDocument());
+
+        AppearanceXObject xObject = new AppearanceXObject(new Rectangle(0, 0, width, height));
         if (backgroundColor == null) {
             backgroundColor = ColorConstants.LIGHT_GRAY;
         }
@@ -3056,7 +3095,8 @@ protected PdfFormXObject drawPushButtonAppearance(float width, float height, Str
             xObject.getResources().addForm(form);
         } else {
             drawButton(canvas, 0, 0, width, height, text, font, fontSize);
-            setDefaultAppearance(generateDefaultAppearanceString(font, fontSize, color, new PdfResources()));
+            xObject.addFontFromDR(fontName, font);
+            setDefaultAppearance(generateDefaultAppearanceString(font, fontSize, color, resources));
             xObject.getResources().addFont(getDocument(), font);
         }
         xObject.getPdfObject().getOutputStream().writeBytes(stream.getBytes());