有没有办法将一个旋转的 PDF 文档叠加在另一个文档上？

Question

我有 SVG 文档，在工作流程结束时通过 Ghostscript 将其转换为 PDF。现在我必须添加一个新功能。 我需要用 PDF 内容替换 SVG 中的某些元素。它不是 只需叠加，它就可以按比例旋转和缩放，例如下面的图像：

“示例”

我的问题是有什么办法可以用 Ghostscript 做到这一点吗？

目前我只是将其作为 SVG 图像元素的光栅化图像插入，但我需要将其作为矢量进行打印。

注意：我只需要从插入的 PDF 中取出第一页。

我知道有一个 pdftk 可以将一个 PDF 文件覆盖在另一个 PDF 文件上，但我无法用它缩放和旋转覆盖的 PDF 文档。

Answer 1

恐怕，由于 Ghostscript PDF 解释器最近为解决安全漏洞而进行了更改，此代码仅适用于 9.26 及以下版本。将来 PDF 解释器将会发生改变，并且会有更好的方法来实现这一点，但恐怕这是一个长期目标。目前，要使用此代码，您需要坚持使用旧版本。

执行此操作的 PostScript 程序如下：

%!PS

%%
%% This code is copied from pdf_main.ps, pdfshowpage_finish
%% sadly that routine always calls showpage, and we want that
%% to be under our control, so we have to duplicate the code
%% here. Not only that but it uses GS extensions which aren't
%% available outside of startup, so some things it simply can't
%% replicate. As a result some of the error handling is less
%% good.
%%
%% I plan to extend the PDF interpreter with two new
%% routines, pdfnoshowpage_finish and then have both
%% that and pdfshowpage_finish call pdfoptionalshowpage_finish
%% which will take a boolean determining whether to actually
%% call the showpage. At that time we'll alter this code.
%%
/draw_page_content {    % <pagedict> pdfshowpage_finish -
   save /PDFSave exch store
   /PDFdictstackcount countdictstack store
   /PDFexecstackcount count 2 sub store
   (before exec) VMDEBUG

   % set up color space substitution (this must be inside the page save)
   pdfshowpage_setcspacesub

        % Display the actual page contents.
   8 dict begin
   /BXlevel 0 def
   /BMClevel 0 def
   /OFFlevels 0 dict def
   /BGDefault currentblackgeneration def
   /UCRDefault currentundercolorremoval def
        %****** DOESN'T HANDLE COLOR TRANSFER YET ******
   /TRDefault currenttransfer def
  matrix currentmatrix 
  2 dict
  dictbeginpage setmatrix
  /DefaultQstate qstate store

  count 1 sub /pdfemptycount exch store
        % If the page uses any transparency features, show it within
        % a transparency group.
  dup pageusestransparency dup /PDFusingtransparency exch def {
    % Show the page within a PDF 1.4 device filter.
    0 .pushpdf14devicefilter {
      /DefaultQstate qstate store       % device has changed -- reset DefaultQstate
      % If the page has a Group, enclose contents in transparency group.
      % (Adobe Tech Note 5407, sec 9.2)
      dup /Group knownoget {
        1 index /CropBox pget {
          /CropBox exch
        } {
          1 index get_media_box pop /MediaBox exch
        } ifelse
        oforce_elems normrect_elems fix_empty_rect_elems 4 array astore .beginformgroup 
        showpagecontents
        .endtransparencygroup
      } {
        showpagecontents
      } ifelse
    } stopped {
      % abort the transparency device 
      .abortpdf14devicefilter
      /DefaultQstate qstate store   % device has changed -- reset DefaultQstate
      stop
    } if .poppdf14devicefilter
    /DefaultQstate qstate store % device has changed -- reset DefaultQstate
  } {
    showpagecontents
  } ifelse
  .free_page_resources
  % todo: mixing drawing ops outside the device filter could cause
  % problems, for example with the pnga device.

  end           % scratch dict
  % Some PDF files don't have matching q/Q (gsave/grestore) so we need
  % to clean up any left over dicts from the dictstack

  PDFdictstackcount //false
  { countdictstack 2 index le { exit } if
    currentdict /n known not or
    end
  } loop 

  pop
  count PDFexecstackcount sub { pop } repeat
  Repaired      % pass Repaired state around the restore
  PDFSave restore
  currentglobal pdfdict gcheck .setglobal
  .setglobal
  /Repaired exch def
} def

% And now, draw the page from the first PDF file
(d:/temp/SO/target.pdf) (r) file runpdfbegin
save
1 pdfgetpage
dup /Page exch store                                         draw_page_content
restore                                      
runpdfend

% and then the page from the second PDF file
(d:/temp/SO/source.pdf) (r) file runpdfbegin
save
1 pdfgetpage
dup /Page exch store                                        

% Before drawing the second page, adjust the CTM so
% that the bottom left corner of the page is co-incident
% with the bottom left of the area we want to draw the
% page in
75 575 translate

% adjust the size of the output
0.11 0.11 scale

% and rotate it
-46 rotate

draw_page_content
restore                                      
runpdfend

showpage

将其保存在一个文件中，命名为 test.ps，并适当调整 PostScript 程序中的路径。然后使用以下命令运行 Ghostscript：

gs -sDEVICE=pdfwrite -sOutputFile=out.pdf test.ps

，您将获得一个 PDF 文件，类似于我认为您想要的内容。显然，您还需要更改平移/缩放/旋转的数字。

Answer 2

我在这里发布了一个解决方案，支持剪切粘贴的 PDF 文件，以防将来有人需要它。我已向draw_page_content 添加了额外的参数来支持这一点。我发现“dict beginpage setmatrix”命令以某种方式覆盖了剪切路径，并且应该仅在该命令之后设置它。我不是 PostScript 专家，但至少这个解决方案是有效的。再次感谢 KenS 的帮助。

%!PS

%%
%% This code is copied from pdf_main.ps, pdfshowpage_finish
%% sadly that routine always calls showpage, and we want that
%% to be under our control, so we have to duplicate the code
%% here. Not only that but it uses GS extensions which aren't
%% available outside of startup, so some things it simply can't
%% replicate. As a result some of the error handling is less
%% good.
%%
%% I plan to extend the PDF interpreter with two new
%% routines, pdfnoshowpage_finish and then have both
%% that and pdfshowpage_finish call pdfoptionalshowpage_finish
%% which will take a boolean determining whether to actually
%% call the showpage. At that time we'll alter this code.
%%
/draw_page_content {    % <pagedict> pdfshowpage_finish -
   /clipx exch def /clipy exch def /clip_width exch def /clip_height exch def /should_clip exch def
   save /PDFSave exch store
   /PDFdictstackcount countdictstack store
   /PDFexecstackcount count 2 sub store
   (before exec) VMDEBUG

   % set up color space substitution (this must be inside the page save)
   pdfshowpage_setcspacesub

        % Display the actual page contents.
   8 dict begin
   /BXlevel 0 def
   /BMClevel 0 def
   /OFFlevels 0 dict def
   /BGDefault currentblackgeneration def
   /UCRDefault currentundercolorremoval def
        %****** DOESN'T HANDLE COLOR TRANSFER YET ******
   /TRDefault currenttransfer def
  matrix currentmatrix 
  2 dict
  dictbeginpage setmatrix

  % set clipping here
  should_clip 0 gt
  {
    newpath clipx clipy moveto clipx clipy clip_height add lineto clipx clip_width add clipy clip_height add lineto clipx clip_width add clipy lineto closepath clip
  }
  {
  }
  ifelse

  /DefaultQstate qstate store

  count 1 sub /pdfemptycount exch store
        % If the page uses any transparency features, show it within
        % a transparency group.
  dup pageusestransparency dup /PDFusingtransparency exch def {
    % Show the page within a PDF 1.4 device filter.
    0 .pushpdf14devicefilter {
      /DefaultQstate qstate store       % device has changed -- reset DefaultQstate
      % If the page has a Group, enclose contents in transparency group.
      % (Adobe Tech Note 5407, sec 9.2)
      dup /Group knownoget {
        1 index /CropBox pget {
          /CropBox exch
        } {
          1 index get_media_box pop /MediaBox exch
        } ifelse
        oforce_elems normrect_elems fix_empty_rect_elems 4 array astore .beginformgroup 
        showpagecontents
        .endtransparencygroup
      } {
        showpagecontents
      } ifelse
    } stopped {
      % abort the transparency device 
      .abortpdf14devicefilter
      /DefaultQstate qstate store   % device has changed -- reset DefaultQstate
      stop
    } if .poppdf14devicefilter
    /DefaultQstate qstate store % device has changed -- reset DefaultQstate
  } {
    showpagecontents
  } ifelse
  .free_page_resources
  % todo: mixing drawing ops outside the device filter could cause
  % problems, for example with the pnga device.

  end           % scratch dict
  % Some PDF files don't have matching q/Q (gsave/grestore) so we need
  % to clean up any left over dicts from the dictstack

  PDFdictstackcount //false
  { countdictstack 2 index le { exit } if
    currentdict /n known not or
    end
  } loop 

  pop
  count PDFexecstackcount sub { pop } repeat
  Repaired      % pass Repaired state around the restore
  PDFSave restore
  currentglobal pdfdict gcheck .setglobal
  .setglobal
  /Repaired exch def
} bind def

% And now, draw the page from teh first PDF file
(/opt/files/main.pdf) (r) file runpdfbegin
save
1 pdfgetpage
dup /Page exch store 0 1125 1125 0 0 draw_page_content
restore                                      
runpdfend

gsave

% and then the page from the next PDF file
(/opt/files/placement1.pdf) (r) file runpdfbegin
save
1 pdfgetpage
dup /Page exch store                                        

% Before drawing the second page, adjust the CTM so
% that the bottom left corner of the page is co-incident
% with the bottom left of the area we want to draw the
% page in
120 120 translate

% and rotate it
25 rotate

% adjust the size of the output
0.7 0.7 scale

%let's skew file
[1 0 1.3 1 0 0] concat

% draw file and clip it
1 100 100 0 0 draw_page_content

restore                                      
runpdfend
grestore

showpage