Recalculate bounding box for the signature description in case no height is set

DEVSIX-7970

Author: AnhelinaM

forms/src/main/java/com/itextpdf/forms/form/renderer/SignatureAppearanceRenderer.java

@@ -178,15 +178,18 @@ protected void adjustFieldLayout(LayoutContext layoutContext) {
                 break;
             case DESCRIPTION:
                 // Default one, it just shows whatever description was defined for the signature.
+                float additionalHeight = calculateAdditionalHeight();
                 if (retrieveHeight() == null) {
                     // Adjust calculated occupied area height to keep the same font size.
                     float calculatedHeight = getOccupiedArea().getBBox().getHeight();
-                    getOccupiedArea().getBBox().moveDown(calculatedHeight * TOP_SECTION)
-                            .setHeight(calculatedHeight * (1 + TOP_SECTION));
-                    bBox.moveDown(calculatedHeight * TOP_SECTION);
+                    // (calcHeight + addHeight + topSect) * (1 - TOP_SECTION) - addHeight = calcHeight, =>
+                    float topSection = (calculatedHeight + additionalHeight) * TOP_SECTION / (1 - TOP_SECTION);
+                    getOccupiedArea().getBBox().moveDown(topSection + additionalHeight)
+                            .setHeight(calculatedHeight + topSection + additionalHeight);
+                    bBox.moveDown(bBox.getBottom() - getOccupiedArea().getBBox().getBottom() - additionalHeight / 2);
                 }
                 descriptionRect = bBox.setHeight(getOccupiedArea().getBBox().getHeight() * (1 - TOP_SECTION)
-                - calculateAdditionalHeight());
+                - additionalHeight);
                 break;
             default:
                 return;

forms/src/test/java/com/itextpdf/forms/form/element/SignatureFieldAppearanceTest.java

@@ -399,7 +399,6 @@ public void fontSizeTest() throws IOException, InterruptedException {
         String cmpPdf = SOURCE_FOLDER + "cmp_fontSizeTest.pdf";
         try (Document document = new Document(new PdfDocument(new PdfWriter(outPdf)))) {
             SignatureFieldAppearance sigField = new SignatureFieldAppearance("SigField");
-            //TODO DEVSIX-7970 Fontsize doesn't get recalculate correctly in SignatureFieldAppearance making the signature look absent
             sigField.setFontSize(20);
             sigField.setContent("test");
             document.add(sigField);

forms/src/test/resources/com/itextpdf/forms/PdfUA2FormTest/cmp_signatureFormTest.pdf

@@ -671,10 +671,10 @@ public void testCopyPagesDoesntEmbedHelveticaFont() throws IOException, Interrup
     }
 
     @Test
-    public void pdfASignatureFieldTestWithAndFontText() throws IOException, InterruptedException {
+    public void pdfASignatureFieldWithTextAndFontTest() throws IOException, InterruptedException {
         String name = "pdfASignatureFieldTestWithText";
         String fileName = DESTINATION_FOLDER + name + ".pdf";
-        String cmp = SOURCE_FOLDER + "cmp/PdfAFormFieldTest/cmp_pdfASignatureFieldTestWithText.pdf";
+        String cmp = SOURCE_FOLDER + "cmp/PdfAFormFieldTest/cmp_" + name + ".pdf";
 
         PdfFont fontFreeSans = PdfFontFactory.createFont(SOURCE_FOLDER + "FreeSans.ttf",
                 "WinAnsi", EmbeddingStrategy.FORCE_EMBEDDED);