cfFilterPDFToPDF(): Initialize output page dimensions

Initialize output page dimensions to easily identify if no dimensions
were supplied, to fall back to default size Letter.  Otherwise we get
invalid PDF output if we do not specify the output page dimensions (no
printer IPP attributes) but need them (for print-scaling=fit/fill,
numper-up, booklet).

Author: tillkamppeter

CHANGES.md

@@ -2,6 +2,12 @@
 
 ## CHANGES IN V2.0b2 (TBA)
 
+- cfFilterPDFToPDF(): Initialize output page dimensions to easily
+  identify if no dimensions were supplied, to fall back to default
+  size Letter.  Otherwise we get invalid PDF output if we do not
+  specify the output page dimensions (no printer IPP attributes) but
+  need them (for print-scaling=fit/fill, numper-up, booklet).
+
 - cfFilterGhostscript(): Never supply "-dDEVICEWIDTHPOINTS=0
   -dDEVICEHEIGHTPOINTS=0", if no page size got requested with the job
   (page dimensions are zero in raster header) skip these arguments so

cupsfilters/pdftopdf/pdftopdf.cxx

@@ -888,6 +888,9 @@ cfFilterPDFToPDF(int inputfd,            // I - File descriptor input stream
     param.title = data->job_title;
     param.num_copies = data->copies;
     param.copies_to_be_logged = data->copies;
+    param.page.width = param.page.height = 0;
+    param.page.left = param.page.bottom = -1;
+    param.page.right = param.page.top = -1;
 
     // TODO?! sanity checks