// Creates some content (3 images) and associate them with the image layer
static Obj CreateGroup1(PDFDoc doc, Obj layer)
{
using (ElementWriter writer = new ElementWriter())
using (ElementBuilder builder = new ElementBuilder())
{
writer.Begin(doc);
// Create an Image that can be reused in the document or on the same page.
Image img = Image.Create(doc.GetSDFDoc(), (input_path + "peppers.jpg"));
Element element = builder.CreateImage(img, new Matrix2D(img.GetImageWidth() / 2, -145, 20, img.GetImageHeight() / 2, 200, 150));
writer.WritePlacedElement(element);
GState gstate = element.GetGState(); // use the same image (just change its matrix)
gstate.SetTransform(200, 0, 0, 300, 50, 450);
writer.WritePlacedElement(element);
// use the same image again (just change its matrix).
writer.WritePlacedElement(builder.CreateImage(img, 300, 600, 200, -150));
Obj grp_obj = writer.End();
// Indicate that this form (content group) belongs to the given layer (OCG).
grp_obj.PutName("Subtype", "Form");
grp_obj.Put("OC", layer);
grp_obj.PutRect("BBox", 0, 0, 1000, 1000); // Set the clip box for the content.
// As an example of further configuration, set the image layer to
// be visible on screen, but not visible when printed...
// The AS entry is an auto state array consisting of one or more usage application
// dictionaries that specify how conforming readers shall automatically set the
// state of optional content groups based on external factors.
Obj cfg = doc.GetOCGConfig().GetSDFObj();
Obj auto_state = cfg.FindObj("AS");
if (auto_state == null)
{
auto_state = cfg.PutArray("AS");
}
Obj print_state = auto_state.PushBackDict();
print_state.PutArray("Category").PushBackName("Print");
print_state.PutName("Event", "Print");
print_state.PutArray("OCGs").PushBack(layer);
Obj layer_usage = layer.PutDict("Usage");
Obj view_setting = layer_usage.PutDict("View");
view_setting.PutName("ViewState", "ON");
Obj print_setting = layer_usage.PutDict("Print");
print_setting.PutName("PrintState", "OFF");
return(grp_obj);
}
}
// A utility function used to add new Content Groups (Layers) to the document.
static Group CreateLayer(PDFDoc doc, String layer_name)
{
Group grp = Group.Create(doc, layer_name);
Config cfg = doc.GetOCGConfig();
if (cfg == null)
{
cfg = Config.Create(doc, true);
cfg.SetName("Default");
}
// Add the new OCG to the list of layers that should appear in PDF viewer GUI.
Obj layer_order_array = cfg.GetOrder();
if (layer_order_array == null)
{
layer_order_array = doc.CreateIndirectArray();
cfg.SetOrder(layer_order_array);
}
layer_order_array.PushBack(grp.GetSDFObj());
return(grp);
}
static void Main(string[] args)
{
PDFNet.Initialize();
try
{
using (PDFDoc doc = new PDFDoc())
using (ElementBuilder builder = new ElementBuilder()) // ElementBuilder is used to build new Element objects
using (ElementWriter writer = new ElementWriter()) // ElementWriter is used to write Elements to the page
{
// Create three layers...
Group image_layer = CreateLayer(doc, "Image Layer");
Group text_layer = CreateLayer(doc, "Text Layer");
Group vector_layer = CreateLayer(doc, "Vector Layer");
// Start a new page ------------------------------------
Page page = doc.PageCreate();
writer.Begin(page); // begin writing to this page
// Add new content to the page and associate it with one of the layers.
Element element = builder.CreateForm(CreateGroup1(doc, image_layer.GetSDFObj()));
writer.WriteElement(element);
element = builder.CreateForm(CreateGroup2(doc, vector_layer.GetSDFObj()));
writer.WriteElement(element);
// Add the text layer to the page...
bool enableOCMD = false; // set to 'true' to enable 'ocmd' example.
if (enableOCMD)
{
// A bit more advanced example of how to create an OCMD text layer that
// is visible only if text, image and path layers are all 'ON'.
// An example of how to set 'Visibility Policy' in OCMD.
Obj ocgs = doc.CreateIndirectArray();
ocgs.PushBack(image_layer.GetSDFObj());
ocgs.PushBack(vector_layer.GetSDFObj());
ocgs.PushBack(text_layer.GetSDFObj());
OCMD text_ocmd = OCMD.Create(doc, ocgs, OCMD.VisibilityPolicyType.e_AllOn);
element = builder.CreateForm(CreateGroup3(doc, text_ocmd.GetSDFObj()));
}
else
{
element = builder.CreateForm(CreateGroup3(doc, text_layer.GetSDFObj()));
}
writer.WriteElement(element);
// Add some content to the page that does not belong to any layer...
// In this case this is a rectangle representing the page border.
element = builder.CreateRect(0, 0, page.GetPageWidth(), page.GetPageHeight());
element.SetPathFill(false);
element.SetPathStroke(true);
element.GetGState().SetLineWidth(40);
writer.WriteElement(element);
writer.End(); // save changes to the current page
doc.PagePushBack(page);
// Set the default viewing preference to display 'Layer' tab.
PDFDocViewPrefs prefs = doc.GetViewPrefs();
prefs.SetPageMode(PDFDocViewPrefs.PageMode.e_UseOC);
doc.Save(output_path + "pdf_layers.pdf", SDFDoc.SaveOptions.e_linearized);
Console.WriteLine("Done.");
}
}
catch (PDFNetException e)
{
Console.WriteLine(e.Message);
}
// The following is a code snippet shows how to selectively render
// and export PDF layers.
try
{
using (PDFDoc doc = new PDFDoc(output_path + "pdf_layers.pdf"))
{
doc.InitSecurityHandler();
if (!doc.HasOC())
{
Console.WriteLine("The document does not contain 'Optional Content'");
}
else
{
Config init_cfg = doc.GetOCGConfig();
Context ctx = new Context(init_cfg);
using (PDFDraw pdfdraw = new PDFDraw())
{
pdfdraw.SetImageSize(1000, 1000);
pdfdraw.SetOCGContext(ctx); // Render the page using the given OCG context.
Page page = doc.GetPage(1); // Get the first page in the document.
pdfdraw.Export(page, output_path + "pdf_layers_default.png");
// Disable drawing of content that is not optional (i.e. is not part of any layer).
ctx.SetNonOCDrawing(false);
// Now render each layer in the input document to a separate image.
Obj ocgs = doc.GetOCGs(); // Get the array of all OCGs in the document.
if (ocgs != null)
{
int i, sz = ocgs.Size();
for (i = 0; i < sz; ++i)
{
Group ocg = new Group(ocgs.GetAt(i));
ctx.ResetStates(false);
ctx.SetState(ocg, true);
string fname = "pdf_layers_" + ocg.GetName() + ".png";
Console.WriteLine(fname);
pdfdraw.Export(page, fname);
}
}
// Now draw content that is not part of any layer...
ctx.SetNonOCDrawing(true);
ctx.SetOCDrawMode(Context.OCDrawMode.e_NoOC);
pdfdraw.Export(page, output_path + "pdf_layers_non_oc.png");
Console.WriteLine("Done.");
}
}
}
}
catch (PDFNetException e)
{
Console.WriteLine(e.Message);
}
}