Tryanks/pdfsign
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Refactor object handling

Browse Source
This commit is contained in:
Paul van Brouwershaven
2024-12-11 16:24:26 +01:00
parent 21dd78d75e
commit e5cdb61bea
11 changed files with 311 additions and 327 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
sign/pdfvisualsignature.go
View File

@@ -1,6 +1,7 @@
package sign
import (
"bytes"
"fmt"
"strconv"
@@ -26,20 +27,20 @@ const (
// pageNumber: the page number where the signature should be placed.
// rect: the rectangle defining the position and size of the signature field.
// Returns the visual signature string and an error if any.
func (context *SignContext) createVisualSignature(visible bool, pageNumber int, rect [4]float64) (visual_signature string, err error) {
// Initialize the visual signature object with its ID.
visual_signature = strconv.Itoa(int(context.VisualSignData.ObjectId)) + " 0 obj\n"
func (context *SignContext) createVisualSignature(visible bool, pageNumber int, rect [4]float64) ([]byte, error) {
var visual_signature bytes.Buffer
// Define the object as an annotation.
visual_signature += "<< /Type /Annot"
visual_signature.WriteString("<< /Type /Annot")
// Specify the annotation subtype as a widget.
visual_signature += " /Subtype /Widget"
visual_signature.WriteString(" /Subtype /Widget")
if visible {
// Set the position and size of the signature field if visible.
visual_signature += fmt.Sprintf(" /Rect [%f %f %f %f]", rect[0], rect[1], rect[2], rect[3])
visual_signature.WriteString(fmt.Sprintf(" /Rect [%f %f %f %f]", rect[0], rect[1], rect[2], rect[3]))
} else {
// Set the rectangle to zero if the signature is invisible.
visual_signature += " /Rect [0 0 0 0]"
visual_signature.WriteString(" /Rect [0 0 0 0]")
}
// Retrieve the root object from the PDF trailer.
@@ -64,7 +65,7 @@ func (context *SignContext) createVisualSignature(visible bool, pageNumber int,
// Find the page object by its number.
page, err := findPageByNumber(root.Key("Pages"), pageNumber)
if err != nil {
return "", err
return nil, err
}
// Get the pointer to the page object.
@@ -74,16 +75,16 @@ func (context *SignContext) createVisualSignature(visible bool, pageNumber int,
context.VisualSignData.PageId = page_ptr.GetID()
// Add the page reference to the visual signature.
visual_signature += " /P " + strconv.Itoa(int(page_ptr.GetID())) + " " + strconv.Itoa(int(page_ptr.GetGen())) + " R"
visual_signature.WriteString(" /P " + strconv.Itoa(int(page_ptr.GetID())) + " " + strconv.Itoa(int(page_ptr.GetGen())) + " R")
}
// Define the annotation flags for the signature field (132)
// annotationFlags := AnnotationFlagPrint | AnnotationFlagNoZoom | AnnotationFlagNoRotate | AnnotationFlagReadOnly | AnnotationFlagLockedContents
visual_signature += fmt.Sprintf(" /F %d", 132)
visual_signature.WriteString(fmt.Sprintf(" /F %d", 132))
// Define the field type as a signature.
visual_signature += " /FT /Sig"
visual_signature.WriteString(" /FT /Sig")
// Set a unique title for the signature field.
visual_signature += " /T " + pdfString("Signature "+strconv.Itoa(len(context.SignData.ExistingSignatures)+1))
visual_signature.WriteString(" /T " + pdfString("Signature "+strconv.Itoa(len(context.SignData.ExistingSignatures)+1)))
// (Optional) A set of bit flags specifying the interpretation of specific entries
// in this dictionary. A value of 1 for the flag indicates that the associated entry
@@ -92,16 +93,15 @@ func (context *SignContext) createVisualSignature(visible bool, pageNumber int,
// (Reasons); 5 (LegalAttestation); 6 (AddRevInfo); and 7 (DigestMethod).
// For PDF 2.0 the following bit flags are added: 8 (Lockdocument); and 9
// (AppearanceFilter). Default value: 0.
visual_signature += " /Ff 0"
visual_signature.WriteString(" /Ff 0")
// Reference the signature dictionary.
visual_signature += " /V " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R"
visual_signature.WriteString(" /V " + strconv.Itoa(int(context.SignData.ObjectId)) + " 0 R")
// Close the dictionary and end the object.
visual_signature += " >>"
visual_signature += "\nendobj\n"
visual_signature.WriteString(" >>\n")
return visual_signature, nil
return visual_signature.Bytes(), nil
}
// Helper function to find a page by its number.