BUG: Generate static appearance for fields

pypdf/_reader.py

@@ -69,11 +69,11 @@
 from .constants import CatalogDictionary as CD
 from .constants import (
     CheckboxRadioButtonAttributes,
-    FieldDictionaryAttributes,
     GoToActionArguments,
 )
 from .constants import Core as CO
 from .constants import DocumentInformationAttributes as DI
+from .constants import FieldDictionaryAttributes as FA
 from .constants import PageAttributes as PG
 from .constants import PagesAttributes as PA
 from .constants import TrailerKeys as TK
@@ -542,7 +542,7 @@ def get_fields(
             default, the mapping name is used for keys.
             ``None`` if form data could not be located.
         """
-        field_attributes = FieldDictionaryAttributes.attributes_dict()
+        field_attributes = FA.attributes_dict()
         field_attributes.update(CheckboxRadioButtonAttributes.attributes_dict())
         if retval is None:
             retval = {}
@@ -626,6 +626,26 @@ def _build_field(
             self._write_field(fileobj, field, field_attributes)
             fileobj.write("\n")
         retval[key] = Field(field)
+        obj = retval[key].indirect_reference.get_object()  # to get the full object
+        if obj.get(FA.FT, "") == "/Ch":
+            retval[key][NameObject("/_States_")] = obj[NameObject(FA.Opt)]
+        if obj.get(FA.FT, "") == "/Btn" and "/AP" in obj:
+            #  Checkbox
+            retval[key][NameObject("/_States_")] = ArrayObject(
+                list(obj["/AP"]["/N"].keys())
+            )
+            if "/Off" not in retval[key]["/_States_"]:
+                retval[key][NameObject("/_States_")].append(NameObject("/Off"))
+        elif obj.get(FA.FT, "") == "/Btn" and obj.get(FA.Ff, 0) & FA.FfBits.Radio != 0:
+            states = []
+            for k in obj.get(FA.Kids, {}):
+                k = k.get_object()
+                for s in list(k["/AP"]["/N"].keys()):
+                    if s not in states:
+                        states.append(s)
+                retval[key][NameObject("/_States_")] = ArrayObject(states)
+            if obj.get(FA.Ff, 0) & FA.FfBits.NoToggleToOff != 0:
+                del retval[key]["/_States_"][retval[key]["/_States_"].index("/Off")]
 
     def _check_kids(
         self, tree: Union[TreeObject, DictionaryObject], retval: Any, fileobj: Any
@@ -636,20 +656,20 @@ def _check_kids(
                 self.get_fields(kid.get_object(), retval, fileobj)
 
     def _write_field(self, fileobj: Any, field: Any, field_attributes: Any) -> None:
-        field_attributes_tuple = FieldDictionaryAttributes.attributes()
+        field_attributes_tuple = FA.attributes()
         field_attributes_tuple = (
             field_attributes_tuple + CheckboxRadioButtonAttributes.attributes()
         )
 
         for attr in field_attributes_tuple:
             if attr in (
-                FieldDictionaryAttributes.Kids,
-                FieldDictionaryAttributes.AA,
+                FA.Kids,
+                FA.AA,
             ):
                 continue
             attr_name = field_attributes[attr]
             try:
-                if attr == FieldDictionaryAttributes.FT:
+                if attr == FA.FT:
                     # Make the field type value more clear
                     types = {
                         "/Btn": "Button",
@@ -659,12 +679,12 @@ def _write_field(self, fileobj: Any, field: Any, field_attributes: Any) -> None:
                     }
                     if field[attr] in types:
                         fileobj.write(f"{attr_name}: {types[field[attr]]}\n")
-                elif attr == FieldDictionaryAttributes.Parent:
+                elif attr == FA.Parent:
                     # Let's just write the name of the parent
                     try:
-                        name = field[attr][FieldDictionaryAttributes.TM]
+                        name = field[attr][FA.TM]
                     except KeyError:
-                        name = field[attr][FieldDictionaryAttributes.T]
+                        name = field[attr][FA.T]
                     fileobj.write(f"{attr_name}: {name}\n")
                 else:
                     fileobj.write(f"{attr_name}: {field[attr]}\n")

pypdf/_writer.py

@@ -32,7 +32,6 @@
 import decimal
 import enum
 import hashlib
-import logging
 import re
 import struct
 import uuid
@@ -72,10 +71,10 @@
     deprecation_with_replacement,
     logger_warning,
 )
+from .constants import AnnotationDictionaryAttributes as AA
+from .constants import CatalogAttributes as CA
 from .constants import (
-    AnnotationDictionaryAttributes,
     CatalogDictionary,
-    FieldDictionaryAttributes,
     FieldFlag,
     FileSpecificationDictionaryEntries,
     GoToActionArguments,
@@ -84,9 +83,11 @@
     TypFitArguments,
     UserAccessPermissions,
 )
-from .constants import CatalogAttributes as CA
 from .constants import Core as CO
 from .constants import EncryptionDictAttributes as ED
+from .constants import (
+    FieldDictionaryAttributes as FA,
+)
 from .constants import PageAttributes as PG
 from .constants import PagesAttributes as PA
 from .constants import StreamAttributes as SA
@@ -127,9 +128,6 @@
     ZoomArgType,
 )
 
-logger = logging.getLogger(__name__)
-
-
 OPTIONAL_READ_WRITE_FIELD = FieldFlag(0)
 ALL_DOCUMENT_PERMISSIONS = UserAccessPermissions((2**31 - 1) - 3)
 
@@ -332,7 +330,20 @@ def _add_page(
         pages[NameObject(PA.COUNT)] = NumberObject(page_count + 1)
         return page
 
-    def set_need_appearances_writer(self) -> None:
+    def set_need_appearances_writer(self, state: bool = True) -> None:
+    """
+    Sets the "NeedAppearances" flag in the PDF writer.
+
+    The "NeedAppearances" flag indicates whether the appearance dictionary
+    for form fields should be automatically generated by the PDF viewer or
+    if the embedded appearence should be used.
+
+    Args:
+        state: The actual value of the NeedAppearances flag.
+
+    Returns:
+        None
+    """
         # See 12.7.2 and 7.7.2 for more information:
         # http://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf
         try:
@@ -343,9 +354,13 @@ def set_need_appearances_writer(self) -> None:
                 ] = self._add_object(DictionaryObject())
 
             need_appearances = NameObject(InteractiveFormDictEntries.NeedAppearances)
-            self._root_object[CatalogDictionary.ACRO_FORM][need_appearances] = BooleanObject(True)  # type: ignore
-        except Exception as exc:
-            logger.error("set_need_appearances_writer() catch : %s", repr(exc))
+            cast(DictionaryObject, self._root_object[CatalogDictionary.ACRO_FORM])[
+                need_appearances
+            ] = BooleanObject(state)
+        except Exception as exc:  # pragma: no cover
+            logger_warning(
+                f"set_need_appearances_writer({state}) catch : {exc}", __name__
+            )
 
     def add_page(
         self,
@@ -801,11 +816,96 @@ def _get_qualified_field_name(self, parent: DictionaryObject) -> Optional[str]:
                 return qualified_parent + "." + cast(str, parent["/T"])
         return cast(str, parent["/T"])
 
+    def _update_text_field(self, field: DictionaryObject) -> None:
+        # Calculate rectangle dimensions
+        _rct = cast(RectangleObject, field[AA.Rect])
+        rct = RectangleObject((0, 0, _rct[2] - _rct[0], _rct[3] - _rct[1]))
+
+        # Extract font information
+        font_properties: Any = (
+            cast(str, field[AA.DA]).replace("\n", " ").replace("\r", " ").split(" ")
+        )
+        font_name = font_properties[font_properties.index("Tf") - 2]
+        font_height = float(font_properties[font_properties.index("Tf") - 1])
+        y_offset = rct.height - 1 - font_height
+
+        # Retrieve field text and selected values
+        field_flags = field.get(FA.Ff, 0)
+        if field.get(FA.FT, "/Tx") == "/Ch" and field_flags & FA.FfBits.Combo == 0:
+            txt = "\n".join(field.get(FA.Opt, {}))
+            sel = field.get("/V", [])
+            if not isinstance(sel, list):
+                sel = [sel]
+        else:  # /Tx
+            txt = field.get("/V", "")
+            sel = []
+
+        # Generate appearance stream
+        ap_stream = f"q\n/Tx BMC \nq\n1 1 {rct.width - 1} {rct.height - 1} re\nW\nBT\n{field[AA.DA]}\n".encode()
+        for line_number, line in enumerate(txt.replace("\n", "\r").split("\r")):
+            if line in sel:
+                # may be improved but can not find how get fill working => replaced with lined box
+                ap_stream += (
+                    f"1 {y_offset - (line_number * font_height * 1.4) - 1} {rct.width - 2} {font_height + 2} re\n"
+                    f"0.5 0.5 0.5 rg s\n{field[AA.DA]}\n"
+                ).encode()
+            if line_number == 0:
+                ap_stream += f"2 {y_offset} Td\n".encode()
+            else:
+                # Td is a relative translation
+                ap_stream += f"0 {- font_height * 1.4} Td\n".encode()
+            ap_stream += b"(" + str(line).encode("UTF-8") + b") Tj\n"
+        ap_stream += b"ET\nQ\nEMC\nQ\n"
+
+        # Create appearance dictionary
+        dct = DecodedStreamObject.initialize_from_dictionary(
+            {
+                NameObject("/Type"): NameObject("/XObject"),
+                NameObject("/Subtype"): NameObject("/Form"),
+                NameObject("/BBox"): rct,
+                "__streamdata__": ByteStringObject(ap_stream),
+                "/Length": 0,
+            }
+        )
+
+        # Retrieve font information from AcroForm dictionary
+        dr: Any = cast(
+            dict, cast(DictionaryObject, self._root_object["/AcroForm"]).get("/DR", {})
+        )
+        if isinstance(dr, IndirectObject):
+            dr = dr.get_object()
+        dr = dr.get("/Font", {})
+        if isinstance(dr, IndirectObject):
+            dr = dr.get_object()
+
+        # Update Resources with font information if necessary
+        if font_name in dr:
+            dct[NameObject("/Resources")] = DictionaryObject(
+                {
+                    NameObject("/Font"): DictionaryObject(
+                        {NameObject(font_name): dr[font_name].indirect_reference}
+                    )
+                }
+            )
+        if AA.AP not in field:
+            field[NameObject(AA.AP)] = DictionaryObject(
+                {NameObject("/N"): self._add_object(dct)}
+            )
+        elif "/N" not in cast(DictionaryObject, field[AA.AP]):
+            cast(DictionaryObject, field[NameObject(AA.AP)])[
+                NameObject("/N")
+            ] = self._add_object(dct)
+        else:  # [/AP][/N] exists
+            n = field[AA.AP]["/N"].indirect_reference.idnum  # type: ignore
+            self._objects[n - 1] = dct
+            dct.indirect_reference = IndirectObject(n, 0, self)
+
     def update_page_form_field_values(
         self,
         page: PageObject,
         fields: Dict[str, Any],
         flags: FieldFlag = OPTIONAL_READ_WRITE_FIELD,
+        auto_regen: Optional[bool] = True,
     ) -> None:
         """
         Update the form field values for a given page from a fields dictionary.
@@ -821,57 +921,57 @@ def update_page_form_field_values(
             flags: An integer (0 to 7). The first bit sets ReadOnly, the
                 second bit sets Required, the third bit sets NoExport. See
                 PDF Reference Table 8.70 for details.
+            auto_regen: set/unset the need_appearances flag ;
+                the flag is unchanged if auto_regen is None
         """
-        self.set_need_appearances_writer()
+        if isinstance(auto_regen, bool):
+            self.set_need_appearances_writer(auto_regen)
         # Iterate through pages, update field values
         if PG.ANNOTS not in page:
             logger_warning("No fields to update on this page", __name__)
             return
-        for j in range(len(page[PG.ANNOTS])):  # type: ignore
-            writer_annot = page[PG.ANNOTS][j].get_object()  # type: ignore
+        for writer_annot in page[PG.ANNOTS]:  # type: ignore
+            writer_annot = cast(DictionaryObject, writer_annot.get_object())
             # retrieve parent field values, if present
-            writer_parent_annot = DictionaryObject()  # fallback if it's not there
-            if PG.PARENT in writer_annot:
-                writer_parent_annot = writer_annot[PG.PARENT]
-            for field in fields:
+            writer_parent_annot = writer_annot.get(
+                PG.PARENT, DictionaryObject()
+            ).get_object()
+            for field, value in fields.items():
                 if (
-                    writer_annot.get(FieldDictionaryAttributes.T) == field
+                    writer_annot.get(FA.T) == field
                     or self._get_qualified_field_name(writer_annot) == field
                 ):
-                    if writer_annot.get(FieldDictionaryAttributes.FT) == "/Btn":
-                        writer_annot.update(
-                            {
-                                NameObject(
-                                    AnnotationDictionaryAttributes.AS
-                                ): NameObject(fields[field])
-                            }
-                        )
-                    writer_annot.update(
-                        {
-                            NameObject(FieldDictionaryAttributes.V): TextStringObject(
-                                fields[field]
-                            )
-                        }
-                    )
+                    if isinstance(value, list):
+                        lst = ArrayObject()
+                        for v in value:
+                            lst.append(TextStringObject(v))
+                        writer_annot[NameObject(FA.V)] = lst
+                    else:
+                        writer_annot[NameObject(FA.V)] = TextStringObject(value)
+                    if writer_annot.get(FA.FT) in ("/Btn"):
+                        # case of Checkbox button (no /FT found in Radio widgets
+                        writer_annot[NameObject(AA.AS)] = NameObject(value)
+                    elif (
+                        writer_annot.get(FA.FT) == "/Tx"
+                        or writer_annot.get(FA.FT) == "/Ch"
+                    ):
+                        # textbox
+                        self._update_text_field(writer_annot)
+                    elif writer_annot.get(FA.FT) == "/Sig":
+                        # signature
+                        logger_warning("Signature forms not implemented yet", __name__)
                     if flags:
-                        writer_annot.update(
-                            {
-                                NameObject(FieldDictionaryAttributes.Ff): NumberObject(
-                                    flags
-                                )
-                            }
-                        )
+                        writer_annot[NameObject(FA.Ff)] = NumberObject(flags)
                 elif (
-                    writer_parent_annot.get(FieldDictionaryAttributes.T) == field
+                    writer_parent_annot.get(FA.T) == field
                     or self._get_qualified_field_name(writer_parent_annot) == field
                 ):
-                    writer_parent_annot.update(
-                        {
-                            NameObject(FieldDictionaryAttributes.V): TextStringObject(
-                                fields[field]
-                            )
-                        }
-                    )
+                    writer_parent_annot[NameObject(FA.V)] = TextStringObject(value)
+                    for k in writer_parent_annot[NameObject(FA.Kids)]:
+                        k = k.get_object()
+                        k[NameObject(AA.AS)] = NameObject(
+                            value if value in k[AA.AP]["/N"] else "/Off"
+                        )
 
     def updatePageFormFieldValues(
         self,
@@ -2166,14 +2266,12 @@ def add_uri(
         lnk = DictionaryObject()
         lnk.update(
             {
-                NameObject(AnnotationDictionaryAttributes.Type): NameObject(PG.ANNOTS),
-                NameObject(AnnotationDictionaryAttributes.Subtype): NameObject("/Link"),
-                NameObject(AnnotationDictionaryAttributes.P): page_link,
-                NameObject(AnnotationDictionaryAttributes.Rect): rect,
+                NameObject(AA.Type): NameObject(PG.ANNOTS),
+                NameObject(AA.Subtype): NameObject("/Link"),
+                NameObject(AA.P): page_link,
+                NameObject(AA.Rect): rect,
                 NameObject("/H"): NameObject("/I"),
-                NameObject(AnnotationDictionaryAttributes.Border): ArrayObject(
-                    border_arr
-                ),
+                NameObject(AA.Border): ArrayObject(border_arr),
                 NameObject("/A"): lnk2,
             }
         )