Gmt module: Add interface to ghostscript.

modules/gmt/modgmt.cpp

@@ -1,6 +1,7 @@
 #include "modgmt.h"
 #include "modgmt_func.h"
 #include "modgmt_internals.h"
+#include "modgmt_gsfuncs.h"
 
 // Initialisation function
 int gmt_module_init(void* p)
@@ -42,5 +43,10 @@ int gmt_module_init(void* p)
  RegisterFunction("Font",GMT_Type<struct gmt_font>);
  RegisterFunction("Shift",GMT_LayerShift);
  RegisterFunction("DrawFrame",GMT_DrawFrame);
+
+ CheckGhostscriptAbilities();
+ // Calculating bounding box is critical
+ if(!gs_abilities.havebbox) return 1;
+
  return 0;
 }

modules/gmt/modgmt_gsfuncs.cpp

@@ -0,0 +1,165 @@
+#include <string.h>
+#include <unistd.h>
+#include "common.h"
+#include "modgmt_gsfuncs.h"
+
+struct gs_abilities_struct gs_abilities;
+
+static int gs_callback_out(void *caller_handle, const char *buf, int len)
+{
+ struct gs_runtime* r=static_cast<struct gs_runtime*>(caller_handle);
+ if(0!=r->out) r->out->append(buf,len);
+ return len;
+}
+
+static int gs_callback_err(void *caller_handle, const char *buf, int len)
+{
+ struct gs_runtime* r=static_cast<struct gs_runtime*>(caller_handle);
+ if(0!=r->err) r->err->append(buf,len);
+ return len;
+}
+
+static int gs_callback_in(void *caller_handle, char *buf, int len)
+{
+ struct gs_runtime* r=static_cast<struct gs_runtime*>(caller_handle);
+ if(r->pos>=r->in->length()) return 0;
+ size_t rem=r->in->length()-r->pos;
+ if(rem>static_cast<size_t>(len)) rem=len;
+ memcpy(buf,r->in->c_str()+r->pos,rem);
+ r->pos+=rem;
+ return rem;
+}
+
+struct gsworkthreadpars
+{
+ struct gs_runtime* r;
+ gs_callback input_callback;
+ int fd;
+ const std::string* opts;
+ int ret;
+};
+
+// This function call gs_* in separate thread, because ghostscript write to stdout
+static void* gsworkthread(void* x)
+{
+ struct gsworkthreadpars* p=reinterpret_cast<struct gsworkthreadpars*>(x);
+ WordList wl;
+ if(-1==p->fd) wl=Split("-dSAFER -q -o/dev/null "+*(p->opts)+" -");
+ else wl=Split("-dSAFER -dDOINTERPOLATE -q -o/dev/fd/"+ToString(p->fd)+" "+*(p->opts)+" -");
+ int argc=wl.size()+1;
+ char** argv;
+ int i;
+ void* gs;
+
+ argv=new char*[argc];
+ argv[0]=new char[2]; argv[0][0]='G'; argv[0][1]=0;
+ i=1;
+ for(auto& opt: wl)
+ {
+  argv[i]=new char[opt.length()+1];
+  memcpy(argv[i],opt.c_str(),opt.length()+1);
+  i++;
+ }
+
+ p->ret=gsapi_new_instance(&gs,p->r);
+ if(p->ret<0) goto end;
+ gsapi_set_stdio(gs,p->input_callback?p->input_callback:gs_callback_in,gs_callback_out,gs_callback_err);
+ p->ret=gsapi_init_with_args(gs,argc,argv);
+ if(0==p->ret || e_Quit==p->ret) p->ret=gsapi_exit(gs);
+ else gsapi_exit(gs);
+ if(e_Quit==p->ret) p->ret=0;
+ gsapi_delete_instance(gs);
+
+ end:
+ close(p->fd);
+ for(i=0;i<argc;i++) delete[] argv[i];
+ delete[] argv;
+ return &p->ret;
+}
+
+// Main function for prepare and run ghostscript
+static int GhostRun(const std::string& opts, struct gs_runtime* r, std::string* out, gs_callback input=0)
+{
+ struct gsworkthreadpars wp;
+ int* pret;
+
+ wp.r=r;
+ wp.input_callback=input;
+ wp.opts=&opts;
+ wp.ret=0;
+ wp.fd=-1;
+
+ if(0!=out)
+ {
+  int pipefd[2];
+  pthread_t wthr;
+  ssize_t br;
+  char buffer[4096];
+
+  pipe(pipefd);
+  wp.fd=pipefd[1];
+
+  out->erase();
+  pthread_create(&wthr,0,&gsworkthread,&wp);
+  do
+  {
+   br=read(pipefd[0],buffer,4096);
+   out->append(buffer,br);
+  } while(0!=br);
+  close(pipefd[0]);
+  out->shrink_to_fit();
+  pthread_join(wthr,reinterpret_cast<void**>(&pret));
+ }
+ else pret=reinterpret_cast<int*>(gsworkthread(&wp));
+
+ return *pret;
+}
+
+
+// This function run ghostscript with input data in string
+int GhostRun(const std::string& opts, const std::string& input, std::string* sout, std::string* serr, std::string* out)
+{
+ struct gs_runtime r;
+
+ r.in=&input;
+ r.pos=0;
+ r.out=sout;
+ r.err=serr;
+ return GhostRun(opts,&r,out);
+}
+
+// This function run ghostscript with input data provided by callback function
+int GhostRun(const std::string& opts, gs_callback input, void* inputdata, std::string* sout, std::string* serr, std::string* out)
+{
+ struct gs_runtime r;
+
+ r.indata=inputdata;
+ r.out=sout;
+ r.err=serr;
+ return GhostRun(opts,&r,out,input);
+}
+
+void CheckGhostscriptAbilities()
+{
+ std::string out;
+ gs_abilities.havepdf=gs_abilities.havebbox=gs_abilities.havepngmono=gs_abilities.havepngmonod=gs_abilities.havepng16=gs_abilities.havepng256=gs_abilities.havepnggray=gs_abilities.havepng16m=gs_abilities.havejpeg=gs_abilities.havejpeggray=false;
+
+ if(0!=GhostRun("-sDEVICE=nullpage","devicenames ==",&out,0,0)) return;
+
+ WordList wl=Split(out,"[]/ \t");
+ for(auto& i:wl)
+ {
+  if("pdfwrite"==i) gs_abilities.havepdf=true;
+  if("bbox"==i) gs_abilities.havebbox=true;
+  if("pngmono"==i) gs_abilities.havepngmono=true;
+  if("pngmonod"==i) gs_abilities.havepngmonod=true;
+  if("png16"==i) gs_abilities.havepng16=true;
+  if("png256"==i) gs_abilities.havepng256=true;
+  if("pnggray"==i) gs_abilities.havepnggray=true;
+  if("png16m"==i) gs_abilities.havepng16m=true;
+  if("jpeg"==i) gs_abilities.havejpeg=true;
+  if("jpeggray"==i) gs_abilities.havejpeggray=true;
+ }
+
+// gs_abilities.havepdf=(0==GhostRun("-sDEVICE=pdfwrite -dCompatibilityLevel=1.4","gsave 1 0 0 setrgbcolor 5 setlinewidth 100 100 moveto 200 200 lineto stroke grestore showpage",0,0,0));
+}

modules/gmt/modgmt_gsfuncs.h

@@ -0,0 +1,38 @@
+#ifndef MODGMT_GSFUNCS_H
+#define MODGMT_GSFUNCS_H
+#include <string>
+#include <ghostscript/iapi.h>
+#include <ghostscript/ierrors.h>
+
+struct gs_abilities_struct
+{
+ bool havepngmono,havepngmonod,havepng16,havepng256,havepnggray,havepng16m;
+ bool havejpeg,havejpeggray;
+ bool havepdf,havebbox;
+};
+
+extern struct gs_abilities_struct gs_abilities;
+
+struct gs_runtime
+{
+ union
+ {
+  struct
+  {
+   const std::string* in;
+   uint pos;
+  };
+  void* indata;
+ };
+ std::string* out;
+ std::string* err;
+};
+
+typedef int (*gs_callback)(void *caller_handle, char *buf, int len);
+
+int GhostRun(const std::string& opts, const std::string& input, std::string* sout, std::string* serr, std::string* out);
+int GhostRun(const std::string& opts, gs_callback input, void* inputdata, std::string* sout, std::string* serr, std::string* out);
+
+void CheckGhostscriptAbilities();
+
+#endif