in_memory cairo_ctx for better font rendering when no X available

src/actions.c

@@ -3371,21 +3371,31 @@ void new_polygon(int what, double mousex_snap, double mousey_snap)
    }
 }
 
-#if HAS_CAIRO==1
-static int temporary_x_connection = 0;
-#endif
-void close_temporary_x_connection(void)
+/* try to create a cairo context so we get better font metric calculation (text bbox)
+ * what = 1: create
+ * what = 0 : clear */
+void create_memory_cairo_ctx(int what)
 {
-   #if HAS_CAIRO==1
-   if(temporary_x_connection) {
-     cairo_destroy(xctx->cairo_ctx);
-     cairo_surface_destroy(xctx->cairo_sfc);
-     XDestroyWindow(display, xctx->window);
-     XCloseDisplay(display);
-     display = NULL;
-     temporary_x_connection = 0;
-   }
-   #endif
+#if HAS_CAIRO==1
+  static int created = 0;
+  enum { w = 100, h = 64, bpp = 4 };
+  static unsigned char data[w * h * bpp];
+
+  if(!created && what && !xctx->cairo_ctx) {
+    xctx->cairo_sfc = cairo_image_surface_create_for_data(data,
+                      CAIRO_FORMAT_RGB24, w, h, bpp * w);
+    xctx->cairo_ctx = cairo_create(xctx->cairo_sfc);
+    if(xctx->cairo_ctx) created = 1;
+  }
+
+  if(created && !what && xctx->cairo_ctx ) {
+    cairo_destroy(xctx->cairo_ctx);
+    cairo_surface_destroy(xctx->cairo_sfc);
+    xctx->cairo_ctx = NULL;
+    xctx->cairo_sfc = NULL;
+    created = 0;
+  }
+#endif
 }
 
 #if HAS_CAIRO==1
@@ -3400,28 +3410,9 @@ int text_bbox(const char *str, double xscale, double yscale,
   cairo_font_extents_t fext;
   double ww, hh, maxw;
   
-
-  /* try to create a cairo context so we get better font metric calculation (text bbox) */
-  if(!display) {
-    int screen;  
-    unsigned long white;
-    Visual *visual;
-    if((display = XOpenDisplay(NULL))) {
-      screen = DefaultScreen(display);
-      visual = DefaultVisual(display, screen);
-      white = WhitePixel(display, screen);
-      xctx->window = XCreateSimpleWindow(display, 
-                     DefaultRootWindow(display), 0, 0, 1, 1, CopyFromParent, white, white);
-      xctx->cairo_sfc = cairo_xlib_surface_create(display, xctx->window, visual, 1, 1);
-      xctx->cairo_ctx = cairo_create(xctx->cairo_sfc);
-      temporary_x_connection = 1;
-    }
-  }
-  /* if XOpenDisplay() failed display will be still NULL so we will go with
-   * text_bbox_nocairo() */
-
-  /*                will not match exactly font metrics when doing ps/svg output , but better than nothing */
-  if(!has_x && !display) return text_bbox_nocairo(str, xscale, yscale, rot, flip, hcenter, vcenter, x1, y1,
+  /* if no cairo_ctx is available use text_bbox_nocairo().
+  * will not match exactly font metrics when doing ps/svg output, but better than nothing */
+  if(!has_x && !xctx->cairo_ctx) return text_bbox_nocairo(str, xscale, yscale, rot, flip, hcenter, vcenter, x1, y1,
                                       rx1, ry1, rx2, ry2, cairo_lines, cairo_longest_line);
   size = xscale*52.*cairo_font_scale;
 

src/svgdraw.c

@@ -958,11 +958,6 @@ void svg_draw(void)
   tclsetboolvar("draw_grid", old_grid);
   my_free(_ALLOC_ID_, &svg_colors);
   my_free(_ALLOC_ID_, &unused_layer);
-  /* if xschem started with no X connection, text_bbox() will
-   * try to open an X connection and create a cairo surface 
-   * that will be used to return more precise font metrics for
-   * text bbox calculation. so we close the temporary connection here. */
-  close_temporary_x_connection();
   Tcl_SetResult(interp,"",TCL_STATIC);
 }
 

src/xinit.c

@@ -925,6 +925,8 @@ static void xwin_exit(void)
    for(i = 0; i < cadlayers; ++i) Tk_FreePixmap(display, pixmap[i]);
    #endif
    my_free(_ALLOC_ID_, &pixmap);
+ } else { /* no X */
+   create_memory_cairo_ctx(0); /* clear in-memory created cairo_ctx if any */
  }
  dbg(1, "xwin_exit(): clearing drawing data structures\n");
 
@@ -2047,6 +2049,10 @@ static void resetcairo(int create, int clear, int force_or_resize)
     cairo_surface_destroy(xctx->cairo_save_sfc);
     cairo_destroy(xctx->cairo_ctx);
     cairo_surface_destroy(xctx->cairo_sfc);
+    xctx->cairo_save_ctx = NULL;
+    xctx->cairo_ctx = NULL;
+    xctx->cairo_save_sfc = NULL;
+    xctx->cairo_sfc = NULL;
   }
   if(create && force_or_resize) {
     cairo_font_options_t *options;
@@ -2719,6 +2725,9 @@ int Tcl_AppInit(Tcl_Interp *inter)
     set_snap(0); /* set default value specified in xschemrc as 'snap' else CADSNAP */
     set_grid(0); /* set default value specified in xschemrc as 'grid' else CADGRID */
  } /* if(has_x) */
+ else { /* no X */
+   if(!xctx->cairo_ctx) create_memory_cairo_ctx(1); /* in-memory cairo_ctx for text_bbox when no X is used */
+ }
  dbg(1, "Tcl_AppInit(): done X init\n");
 
 /* pass to tcl values of Alt, Shift, COntrol key masks so bind Alt-KeyPress events will work for windows */

src/xschem.h

@@ -1330,7 +1330,7 @@ extern int text_bbox(const char * str,double xscale, double yscale,
             short rot, short flip, int hcenter, int vcenter, 
             double x1,double y1, double *rx1, double *ry1,
             double *rx2, double *ry2, int *cairo_lines, double *longest_line);
-extern void close_temporary_x_connection(void);
+extern void create_memory_cairo_ctx(int what);
 extern int get_color(int value);
 extern void incr_hilight_color(void);
 extern void get_inst_pin_coord(int i, int j, double *x, double *y);