SetPageTransparencyGroup

Vector graphics, Text, Page layout

Description

Sets the selected page's transparency group dictionary. This is useful when page content uses masks, soft masks, blend modes, or composited captured content and the page needs a defined blending colour space.

PDF version behaviour: page transparency groups use the PDF 1.4 /Group transparency model. If the current document version is lower and the save version is not locked, SetPageTransparencyGroup automatically raises the document to PDF 1.4 and records transparency group in AutoBumpedFeatures. If the caller locks a lower save version, the compatibility gate rejects the save with LastErrorCode 602.

Syntax

Delphi

function TPDFlib.SetPageTransparencyGroup(CS, Isolate, Knockout: Integer): Integer;

ActiveX

Function PDFlib::SetPageTransparencyGroup(CS As Long, Isolate As Long, Knockout As Long) As Long

DLL

int DLSetPageTransparencyGroup(int InstanceID, int CS, int Isolate, int Knockout);

Parameters

CS	The blending colour space: 1 = `DeviceRGB`, 2 = `DeviceCMYK`.
Isolate	Set to 1 to isolate the transparency group from the page backdrop; set to 0 for a non-isolated group.
Knockout	Set to 1 to enable knockout behaviour inside the group; set to 0 for normal compositing.

Return values

0	The colour-space selector is invalid, no page is selected, or the current PDF/A mode forbids the transparency group.
1	The page transparency group was set successfully.