Render Devices and Overprint Proofing

THPDFRenderDevice provides one loaded-page rendering entry point for bitmap, device-context, and enhanced-metafile targets

Device classes

THPDFBitmapRenderDevice owns a TBitmap until TakeBitmap transfers it, THPDFDeviceContextRenderDevice draws into an external HDC such as a printer canvas, and THPDFMetafileRenderDevice owns a vector TMetafile until TakeMetafile transfers it

THPDFRenderDeviceKind identifies each target without relying on runtime class checks

Process and spot proof preview

Set RenderOverprintPreview to True to simulate overprint for vector and text paints governed by /OP, /op, and /OPM

A named process plate replaces its previous value, while process plates absent from DeviceGray, Separation, or DeviceN paints remain unchanged

For DeviceCMYK under /OPM 1, zero-valued components leave the corresponding destination plates unchanged and nonzero components replace them

DeviceGray names the black process plate, /None paints no plates, and /All paints every process plate

Unknown Separation and DeviceN colourants are treated as spot inks and combined through their tint transform and alternate color space; process colourants named inside DeviceN retain direct plate semantics

Images and shadings continue through their complete raster color pipelines rather than the constant-color vector proof path

Transparency-group knockout remains active and is composited in the same bounded paint snapshot path