Draw a signature field's box

core/fpdfdoc/cpdf_appearancegenerator.h

@@ -51,6 +51,12 @@ class CPDF_AppearanceGenerator {
                                               FormType type,
                                               const WideString& value_override);
 
+  // A widget that shows only its box, a signature field's or one in no
+  // field: its background (/MK /BG) and border (/MK /BC, /BS) as a text
+  // field draws them, as a new normal appearance.
+  static void GenerateBoxFormAP(CPDF_Document* doc,
+                                CPDF_Dictionary* annot_dict);
+
   // A check box's Off and on appearances: the box, and when on, the symbol
   // its /MK /CA names (a check by default) in its /DA colour (black by
   // default).

core/fpdfdoc/cpdf_appearancegenerator_forms.cpp

@@ -253,21 +253,18 @@ ByteString GenerateListBoxAP(const CPDF_Dictionary* annot_dict,
   return ByteString(body_stream);
 }
 
-void GenerateTextFieldFormAP(fxcrt::ostringstream& app_stream,
-                             const CPDF_Dictionary* annot_dict,
-                             const CFX_FloatRect& bbox,
-                             const DefaultAppearanceInfo& da_info,
-                             CPDF_AnnotFontMap& map,
-                             const CPDF_RichTextLayout::Options& options,
-                             const WideString* value_override) {
-  const AppearanceCharacteristics mk =
-      GetAppearanceCharacteristics(annot_dict->GetDictFor("MK"));
+// A field's background and border, in isolated graphics state: what a text
+// field draws under its text, and all a signature field's box is. A solid
+// border is a stroked rectangle; the other styles draw as a combo box's and
+// a list box's do.
+void WriteFieldBox(fxcrt::ostringstream& app_stream,
+                   const AppearanceCharacteristics& mk,
+                   const BorderStyleInfo& bs,
+                   const CFX_FloatRect& bbox) {
   const bool has_bg =
       mk.background_color.nColorType != CFX_Color::Type::kTransparent;
   const bool has_bc =
       mk.border_color.nColorType != CFX_Color::Type::kTransparent;
-
-  const BorderStyleInfo bs = GetBorderStyleInfo(annot_dict->GetDictFor("BS"));
   const float bw = bs.width;
   const float half_bw = bw / 2.0f;
 
@@ -276,12 +273,6 @@ void GenerateTextFieldFormAP(fxcrt::ostringstream& app_stream,
     stroke_rect.Deflate(half_bw, half_bw);
   }
 
-  CFX_FloatRect body_rect = bbox;
-  body_rect.Deflate(2.0f * bw, bw);
-
-  // Background + border in isolated graphics state. A solid border is a
-  // stroked rectangle; the other styles draw as a combo box's and a list
-  // box's do.
   app_stream << "q\n";
   if (has_bg) {
     app_stream << GenerateColorAP(mk.background_color, PaintOperation::kFill);
@@ -297,6 +288,24 @@ void GenerateTextFieldFormAP(fxcrt::ostringstream& app_stream,
     app_stream << GenerateBorderAP(bbox, bs, mk.border_color);
   }
   app_stream << "Q\n";
+}
+
+void GenerateTextFieldFormAP(fxcrt::ostringstream& app_stream,
+                             const CPDF_Dictionary* annot_dict,
+                             const CFX_FloatRect& bbox,
+                             const DefaultAppearanceInfo& da_info,
+                             CPDF_AnnotFontMap& map,
+                             const CPDF_RichTextLayout::Options& options,
+                             const WideString* value_override) {
+  const AppearanceCharacteristics mk =
+      GetAppearanceCharacteristics(annot_dict->GetDictFor("MK"));
+  const BorderStyleInfo bs = GetBorderStyleInfo(annot_dict->GetDictFor("BS"));
+  const float bw = bs.width;
+
+  CFX_FloatRect body_rect = bbox;
+  body_rect.Deflate(2.0f * bw, bw);
+
+  WriteFieldBox(app_stream, mk, bs, bbox);
 
   // Text content in isolated graphics state with proper clipping
   app_stream << "/Tx BMC\nq\n";
@@ -988,6 +997,25 @@ CPDF_AppearanceGenerator::GenerateEphemeralFormAP(
                      std::move(target.normal_stream)};
 }
 
+// static
+void CPDF_AppearanceGenerator::GenerateBoxFormAP(CPDF_Document* doc,
+                                                 CPDF_Dictionary* annot_dict) {
+  const AppearanceCharacteristics mk =
+      GetAppearanceCharacteristics(annot_dict->GetDictFor("MK"));
+  const BorderStyleInfo bs = GetBorderStyleInfo(annot_dict->GetDictFor("BS"));
+  const AnnotationDimensionsAndColor dims =
+      GetAnnotationDimensionsAndColor(annot_dict);
+
+  fxcrt::ostringstream content;
+  WriteFieldBox(content, mk, bs, dims.bbox);
+  // A new stream, as a check box's are: the old /N may be another widget's
+  // too, or a drawing someone placed in this one.
+  const uint32_t normal_obj_num =
+      CreateFormXObjectStream(doc, content, dims.bbox, dims.matrix);
+  annot_dict->GetOrCreateDictFor(pdfium::annotation::kAP)
+      ->SetNewFor<CPDF_Reference>("N", doc, normal_obj_num);
+}
+
 // static
 void CPDF_AppearanceGenerator::GenerateCheckboxFormAP(
     CPDF_Document* doc,

fpdfsdk/epdf_annot.cpp

@@ -4605,7 +4605,7 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 EPDFAnnot_GenerateFormFieldAP(FPDF_ANNOTATION annot) {
   ScopedFPDFAnnotationView annot_view(annot);
   CPDF_AnnotContext* pContext = CPDFAnnotContextFromFPDFAnnotation(annot);
-  if (!pContext) {
+  if (!pContext || FPDFAnnot_GetSubtype(annot) != FPDF_ANNOT_WIDGET) {
     return false;
   }
 
@@ -4631,8 +4631,10 @@ EPDFAnnot_GenerateFormFieldAP(FPDF_ANNOTATION annot) {
     pLookup = pLookup->GetDictFor("Parent");
   }
 
-  if (ft.IsEmpty()) {
-    return false;
+  // A signature field's widget and one in no field show only their box.
+  if (ft.IsEmpty() || ft == "Sig") {
+    CPDF_AppearanceGenerator::GenerateBoxFormAP(pDoc, pAnnotDict.Get());
+    return true;
   }
 
   uint32_t ff = 0;

fpdfsdk/epdf_form.cpp

@@ -2450,6 +2450,9 @@ void BakeWidgetAppearance(CPDF_Document* doc,
       CPDF_AppearanceGenerator::GenerateFormAP(
           doc, widget, CPDF_AppearanceGenerator::kListBox);
       break;
+    case 7:  // signature: its box, until a signature is drawn into it
+      CPDF_AppearanceGenerator::GenerateBoxFormAP(doc, widget);
+      break;
     default:
       break;
   }

fpdfsdk/epdf_form_embeddertest.cpp

@@ -1478,6 +1478,88 @@ TEST_F(EPDFFormEmbedderTest, AttachWidgetsFormsARadioGroup) {
   UnloadPage(page);
 }
 
+TEST_F(EPDFFormEmbedderTest, AttachToSignatureFieldDrawsItsBox) {
+  ASSERT_TRUE(OpenDocument("hello_world.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+
+  const uint32_t field = EPDFForm_CreateField(
+      document(), EPDF_FORMFIELD_FAMILY_SIGNATURE,
+      GetFPDFWideString(L"approval").get(), 0);
+  ASSERT_GT(field, 0u);
+  const uint32_t widget = CreateWidgetAnnot(page, 20, 200, 180, 240);
+  ASSERT_GT(widget, 0u);
+  {
+    ScopedFPDFAnnotation annot(EPDFPage_GetAnnotByObjectNumber(page, widget));
+    ASSERT_TRUE(annot);
+    ASSERT_TRUE(EPDFAnnot_SetMKColor(annot.get(), EPDF_MK_COLOR_BG, 255, 0, 0));
+    ASSERT_TRUE(EPDFAnnot_SetMKColor(annot.get(), EPDF_MK_COLOR_BC, 0, 0, 255));
+  }
+  ASSERT_TRUE(EPDFForm_AttachWidget(document(), field, widget, nullptr, 0));
+
+  // The box: the background filled, the border stroked inside it.
+  const std::wstring box = GetEffectiveWidgetAppearance(document(), widget);
+  EXPECT_NE(std::wstring::npos, box.find(L"1 0 0 rg"));
+  EXPECT_NE(std::wstring::npos, box.find(L"re f*"));
+  EXPECT_NE(std::wstring::npos, box.find(L"0 0 1 RG"));
+  EXPECT_NE(std::wstring::npos, box.find(L"re s"));
+  UnloadPage(page);
+}
+
+TEST_F(EPDFFormEmbedderTest, SignatureFieldBoxRedrawsInItsNewStyle) {
+  ASSERT_TRUE(OpenDocument("hello_world.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+
+  const uint32_t field = EPDFForm_CreateField(
+      document(), EPDF_FORMFIELD_FAMILY_SIGNATURE,
+      GetFPDFWideString(L"approval").get(), 0);
+  ASSERT_GT(field, 0u);
+  const uint32_t widget = CreateWidgetAnnot(page, 20, 200, 180, 240);
+  ASSERT_GT(widget, 0u);
+  ASSERT_TRUE(EPDFForm_AttachWidget(document(), field, widget, nullptr, 0));
+  // No colours: an empty box.
+  EXPECT_EQ(std::wstring::npos,
+            GetEffectiveWidgetAppearance(document(), widget).find(L"rg"));
+
+  ScopedFPDFAnnotation annot(EPDFPage_GetAnnotByObjectNumber(page, widget));
+  ASSERT_TRUE(annot);
+  ASSERT_TRUE(EPDFAnnot_SetMKColor(annot.get(), EPDF_MK_COLOR_BG, 0, 255, 0));
+  ASSERT_TRUE(EPDFAnnot_GenerateFormFieldAP(annot.get()));
+  EXPECT_NE(std::wstring::npos,
+            GetEffectiveWidgetAppearance(document(), widget).find(L"0 1 0 rg"));
+  UnloadPage(page);
+}
+
+TEST_F(EPDFFormEmbedderTest, WidgetInNoFieldDrawsItsBox) {
+  ASSERT_TRUE(OpenDocument("hello_world.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+
+  const uint32_t widget = CreateWidgetAnnot(page, 20, 200, 180, 240);
+  ASSERT_GT(widget, 0u);
+  ScopedFPDFAnnotation annot(EPDFPage_GetAnnotByObjectNumber(page, widget));
+  ASSERT_TRUE(annot);
+  ASSERT_TRUE(EPDFAnnot_SetMKColor(annot.get(), EPDF_MK_COLOR_BG, 0, 0, 255));
+  ASSERT_TRUE(EPDFAnnot_GenerateFormFieldAP(annot.get()));
+  EXPECT_NE(std::wstring::npos,
+            GetEffectiveWidgetAppearance(document(), widget).find(L"0 0 1 rg"));
+  UnloadPage(page);
+}
+
+TEST_F(EPDFFormEmbedderTest, GenerateFormFieldAPRefusesAnotherSubtype) {
+  ASSERT_TRUE(OpenDocument("hello_world.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+
+  ScopedFPDFAnnotation square(EPDFPage_CreateAnnot(page, FPDF_ANNOT_SQUARE));
+  ASSERT_TRUE(square);
+  EXPECT_FALSE(EPDFAnnot_GenerateFormFieldAP(square.get()));
+  EXPECT_FALSE(EPDFAnnot_HasAppearanceStream(square.get(),
+                                             FPDF_ANNOT_APPEARANCEMODE_NORMAL));
+  UnloadPage(page);
+}
+
 TEST_F(EPDFFormEmbedderTest, AttachToLegacyMergedFieldKeepsFieldId) {
   ASSERT_TRUE(OpenDocument("toggle_fields.pdf"));
   FPDF_PAGE page = LoadPage(0);

public/epdf_annot.h

@@ -1626,10 +1626,14 @@ FPDF_EXPORT int FPDF_CALLCONV EPDFAnnot_GetMKRotation(FPDF_ANNOTATION annot);
 //             symbol /MK /CA names in the /DA colour. A push button: its
 //             background and border, and its caption (/MK /CA) centred in
 //             the /DA font and colour; an icon (/MK /I) is not drawn.
+//   - /Sig, and a widget in no field -> its box: the background and border
+//             as a text field draws them. It replaces whatever the widget
+//             shows, a signature drawn into it included.
 //
 //   annot - handle to a widget annotation.
 //
-// Returns true on success, false if the annotation is not a form field.
+// Returns true on success, false for another subtype or a field type it
+// doesn't draw.
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 EPDFAnnot_GenerateFormFieldAP(FPDF_ANNOTATION annot);
 

public/epdf_form.h

@@ -641,7 +641,8 @@ EPDFForm_CreateField(FPDF_DOCUMENT document,
 // merged field). For checkbox/radio fields |on_state| names the widget's
 // checked appearance state and must be non-empty; for other families pass
 // NULL. Adoption wires /Parent + /Kids, seeds toggle /AP states and /AS,
-// and bakes the family-correct appearance stream. Adopting into a legacy
+// and bakes the family-correct appearance stream (a signature field's: its
+// box, EPDFAnnot_GenerateFormFieldAP()). Adopting into a legacy
 // MERGED field first splits it (the field keeps its object number; the
 // previously merged widget becomes a new kid annotation, whose /P names its
 // page - widget identity changes, field identity never does). |split_objnum| is

testing/embedpdf_layer_mode_writers.txt

@@ -214,6 +214,7 @@ EPDFFontEmbedderTest.WidgetDrawsEachClusterInAFontThatHasIt 20
 EPDFFontEmbedderTest.WidgetDrawsWhatNoFontHasWithTheLastResort 20
 EPDFFontEmbedderTest.WidgetWritesWithADocumentProgram 52
 EPDFFormEmbedderTest.AttachToLegacyMergedFieldKeepsFieldId 6
+EPDFFormEmbedderTest.AttachToSignatureFieldDrawsItsBox 7
 EPDFFormEmbedderTest.AttachWidgetsFormsARadioGroup 11
 EPDFFormEmbedderTest.CalculationOrderSetReplaceAndRemove 1
 EPDFFormEmbedderTest.ChoiceValueAndIndicesAreWrittenAsGiven 3
@@ -230,6 +231,7 @@ EPDFFormEmbedderTest.FieldEmbedMetadataIsSnapshotted 1
 EPDFFormEmbedderTest.FieldEmbedMetadataReadsAndWrites 2
 EPDFFormEmbedderTest.FieldEmbedMetadataWritesTheFieldNotItsParent 1
 EPDFFormEmbedderTest.FieldSettersValidateAndApply 3
+EPDFFormEmbedderTest.GenerateFormFieldAPRefusesAnotherSubtype 2
 EPDFFormEmbedderTest.ListBoxTopIndexIsRead 1
 EPDFFormEmbedderTest.ListBoxValuesAreAnArray 1
 EPDFFormEmbedderTest.MalformedDefaultReadsAsUnsupported 1
@@ -242,13 +244,15 @@ EPDFFormEmbedderTest.RepairCreatesAcroFormAndLinksKids 4
 EPDFFormEmbedderTest.RepairLinksRecoveredFields 1
 EPDFFormEmbedderTest.RequiredMultiSelectArrayIsNotSkippedOnExport 2
 EPDFFormEmbedderTest.SetFieldOptionsWritesOnlyTheOptions 1
+EPDFFormEmbedderTest.SignatureFieldBoxRedrawsInItsNewStyle 8
 EPDFFormEmbedderTest.SplitKeepsEachPlanesActions 5
 EPDFFormEmbedderTest.TextValueAndItsPicture 2
 EPDFFormEmbedderTest.ToggleDefaultIsTheNameItIsGiven 1
 EPDFFormEmbedderTest.ToggleValueIsTheNameItIsGiven 1
 EPDFFormEmbedderTest.ToggleWidgetsTurnOnTheirOwnState 3
 EPDFFormEmbedderTest.TwoPlaneTwinWidgetsFillTogether 9
 EPDFFormEmbedderTest.TypedValueSnapshotPreservesPdfShapes 3
+EPDFFormEmbedderTest.WidgetInNoFieldDrawsItsBox 3
 EPDFFormEmbedderTest.WidgetRotationTurnsItsAppearance 2
 EPDFInkAppearanceEmbedderTest.AZigzagIsOneCubicPerPair 4
 EPDFInkAppearanceEmbedderTest.DrawsAcrobatsCurves 10