[41_7] gs: embedded eps to png and pdf (#1730)

<!-- Thank you for your contribution! -->
## What
+ Fix embedded eps->png
+ Fix embedded eps->pdf

## Why
We need to `url-sys-concretize` the ramdisc url first and then convert
it.

## How to test your changes?
Test it via view 41_eps.tm and export 41_eps.tm to PDF.

TeXmacs/plugins/binary/progs/binary/gs.scm

@@ -44,7 +44,7 @@
            " -dBATCH "
            " -dSAFER "
            " -sDEVICE=bbox "
-           (url->system u))))
+           (url-sys-concretize u))))
          (l (filter (lambda (x) (string-starts? x "%%BoundingBox: "))
                 (string-split out #\newline)))
          (box (and (> (length l) 0)
@@ -80,7 +80,7 @@
              " -dCompatibilityLevel=1.4 "
              (string-append " -sOutputFile=" (url->system to) " ")
              (string-append " -c " (string-quote gs-inline))
-             (string-append " -f " (url->system from) " ")
+             (string-append " -f " (url-sys-concretize from) " ")
              (string-append " -c " (string-quote " grestore ")))))
     (debug-message "io" (string-append "call: " cmd "\n"))
     (system cmd)))
@@ -95,12 +95,12 @@
          (width (if (and opt_w (!= opt_w 0)) opt_w box_w))
          (height (if (and opt_h (!= opt_h 0)) opt_h box_w))
          (page_size_in_px (string-append " -g" (number->string width) "x" (number->string height)))
-         (resolution_in_px (string-append " -r" (number->string (/ (* width 72.0) box_w)) "x"
-                                                (number->string (/ (* height 72.0) box_h)) " "))
+         (resolution_in_px (string-append " -r" (number->string (round (/ (* width 72.0) box_w))) "x"
+                                                (number->string (round (/ (* height 72.0) box_h))) " "))
          (offset-x (number->string (- (first box))))
          (offset-y (number->string (- (second box))))
          (gs-inline
-           (string-append offset-x " " offset-y " translate gsave "))
+           (string-append " " offset-x " " offset-y " translate gsave "))
          (cmd (string-append
                 (string-append
                   (url->system (find-binary-gs))
@@ -111,11 +111,11 @@
                   " -sDEVICE=pngalpha "
                   " -dGraphicsAlphaBits=4 "
                   " -dTextAlphaBits=4 ";
-                  (string-append " -sOutputFile=" (url->system to) " ")
                   page_size_in_px
+                  (string-append " -sOutputFile=" (url->system to) " ")
                   resolution_in_px
                   (string-append " -c " (string-quote gs-inline))
-                  (string-append " -f " (url->system from) " ")
+                  (string-append " -f " (url-sys-concretize from) " ")
                   (string-append " -c " (string-quote " grestore "))))))
     (debug-message "io" (string-append cmd "\n"))
     (system cmd)))

src/Plugins/Ghostscript/gs_utilities.cpp

@@ -90,8 +90,8 @@ gs_image_size (url image, int& w_pt, int& h_pt) {
   else {
     if (DEBUG_CONVERT) debug_convert << "gs eps image size :" << LF;
     int    x1, y1, x2, y2;
-    string buf;
-    ok= !load_string (image, buf, false);
+    string buf= ps_load (image, false);
+    ok        = (N (buf) > 0);
     if (ok) {
       // try finding Bounding box in file:
       ok= ps_read_bbox (buf, x1, y1, x2, y2);

src/System/Files/image_files.cpp

@@ -182,7 +182,7 @@ string
 ps_load (url image, bool conv) {
   if (DEBUG_CONVERT) debug_convert << "ps_load " << image << LF;
 
-  url name= resolve (image);
+  url name= sys_concretize (image);
   if (is_none (name)) name= "$TEXMACS_PATH/misc/pixmaps/unknown.png";
 
   if (is_ramdisc (name)) name= get_from_ramdisc (name);