Unicode C
Unicode C
PDF Signature Appearance Width and Height
See more PDF Signatures Examples
This example explains how the width and height of the signature appearance rectangle box is determined.Chilkat Unicode C Downloads
#include <C_CkPdfW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkCertW.h>
void ChilkatSample(void)
{
BOOL success;
HCkPdfW pdf;
HCkJsonObjectW json;
HCkJsonObjectW jAppearance;
HCkCertW cert;
success = FALSE;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
pdf = CkPdfW_Create();
// Load a PDF to be signed.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
success = CkPdfW_LoadFile(pdf,L"qa_data/pdf/hello.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
CkPdfW_Dispose(pdf);
return;
}
// Options for signing are specified in JSON.
json = CkJsonObjectW_Create();
// In most cases, the signingCertificateV2 and signingTime attributes are required.
CkJsonObjectW_UpdateInt(json,L"signingCertificateV2",1);
CkJsonObjectW_UpdateInt(json,L"signingTime",1);
// Put the signature on page 1, top left
CkJsonObjectW_UpdateInt(json,L"page",1);
CkJsonObjectW_UpdateString(json,L"appearance.y",L"top");
CkJsonObjectW_UpdateString(json,L"appearance.x",L"left");
// Add some text.
CkJsonObjectW_UpdateString(json,L"appearance.text[0]",L"Digitally signed by: cert_cn");
CkJsonObjectW_UpdateString(json,L"appearance.text[1]",L"current_dt");
// Add a built-in SVG graphic to the right.
CkJsonObjectW_UpdateString(json,L"appearance.image",L"blue-check-mark");
CkJsonObjectW_UpdateString(json,L"appearance.imagePlacement",L"right");
CkJsonObjectW_UpdateString(json,L"appearance.imageOpacity",L"100");
// There are 4 ways the width and height of the signature rectangle can be specified.
// 1) The width and height (in points) are both explicitly specified.
// User space coordinates use "points" where 72 points equals 1 inch.
// For example (3 inches wide and 1 inch high)
// The fontScale is automatically chose to fit. In addition, if a graphic (JPG or built-in SVG) is included,
// it is automatically scaled such that the text + graphic fit together in the specified rectangle.
// Note: When both height and width are explicitly specified, the resultant signature appearance rectangle
// will match one of the dimensions, but the other dimension will be equal or smaller. This is because the text
// must be proportionally scaled.
CkJsonObjectW_UpdateInt(json,L"appearance.width",72 * 3);
CkJsonObjectW_UpdateInt(json,L"appearance.height",72);
// The signature would have this appearance. In this case, the height is actually less than 1 inch because
// if Chilkat chose a fontScale to fill the height, the resulting text's width would be too long for the desired width.
// (image:https://example-code.com/images/explicit_width_height.jpg/endImage)
// 2) The width is explicitly specified, but we use the keyword "auto" for height.
// In this case, the fontScale is chosen to achieve the desired width,
// and the height will be whatever the result of the chosen font scale.
// In this example, the width is 4 inches, and the height is "auto".
CkJsonObjectW_UpdateInt(json,L"appearance.width",72 * 4);
CkJsonObjectW_UpdateString(json,L"appearance.height",L"auto");
// The signature would have this appearance:
// (image:https://example-code.com/images/explicit_width_auto_height.jpg/endImage)
// 3) The height is explicitly specified, but we use the keyword "auto" for width.
// In this case, the fontScale is chosen to achieve the desired height,
// and the width will be whatever the result of the chosen font scale.
// In this example, the height is 1 inch (72 points) and the width is "auto".
CkJsonObjectW_UpdateString(json,L"appearance.width",L"auto");
CkJsonObjectW_UpdateInt(json,L"appearance.height",72);
// The signature would have this appearance.
// (image:https://example-code.com/images/explicit_height_auto_width.jpg/endImage)
// 4) Finally, we don't need to specify width/height at all. Instead, we can choose a fontScale
// and the dimensions of the PDF signature appearance's rectangle will be the result of using the
// specified fontScale.
jAppearance = CkJsonObjectW_Create();
CkJsonObjectW_ObjectOf2(json,L"appearance",jAppearance);
CkJsonObjectW_Delete(jAppearance,L"width");
CkJsonObjectW_Delete(jAppearance,L"height");
CkJsonObjectW_UpdateString(json,L"appearance.fontScale",L"10.0");
// With fontScale = "10.0"
// (image:https://example-code.com/images/font_scale_10.jpg/endImage)
// Load the signing certificate. (Use your own certificate.)
cert = CkCertW_Create();
success = CkCertW_LoadPfxFile(cert,L"qa_data/pfx/myPdfSigningCert.pfx",L"pfx_password");
if (success == FALSE) {
wprintf(L"%s\n",CkCertW_lastErrorText(cert));
CkPdfW_Dispose(pdf);
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jAppearance);
CkCertW_Dispose(cert);
return;
}
// Tell the pdf object to use the certificate for signing.
success = CkPdfW_SetSigningCert(pdf,cert);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
CkPdfW_Dispose(pdf);
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jAppearance);
CkCertW_Dispose(cert);
return;
}
success = CkPdfW_SignPdf(pdf,json,L"qa_output/hello_signed.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
CkPdfW_Dispose(pdf);
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jAppearance);
CkCertW_Dispose(cert);
return;
}
wprintf(L"The PDF has been successfully cryptographically signed.\n");
CkPdfW_Dispose(pdf);
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jAppearance);
CkCertW_Dispose(cert);
}