Stopped Images.c using Font SWIs instead of fm functions

c/FontManage

@@ -1461,6 +1461,9 @@ void fm_shutdown(void)
 /*                                               */
 /*             Pointer to an int, into which the */
 /*             calculated width is placed.       */
+/*                                               */
+/* Assume:     The two int pointers may not be   */
+/*             NULL.                             */
 /*************************************************/
 
 _kernel_oserror * fm_get_string_width(fm_face h, const char * s, int maxwid, int maxbytes,
@@ -1545,9 +1548,11 @@ _kernel_oserror * fm_get_string_width(fm_face h, const char * s, int maxwid, int
     /* The system font case. */
 
     int wCurr, wLastSplit, oLastSplit, oCurr;
+
     /* (Macro defined in FontManage.h). Important that we take */
     /* account of rounding correctly - compare with formula in */
     /* fm_puts().                                              */
+
     int wChar = (FM_System_Size_X(h) * 10 / (128 * wimpt_dx())) * wimpt_dx() * 400;
 
     wCurr = wLastSplit = oLastSplit = oCurr = 0;

c/Images

@@ -3027,7 +3027,7 @@ _kernel_oserror * image_redraw(browser_data * b, WimpRedrawWindowBlock * r, HStr
         /* Have got some ALT text. First find out the bounding box */
         /* needed to contain that text.                            */
 
-        int    h, ymin, xpos, vcent, stringwidth, stringheight, size;
+        int    h, xpos, vcent, stringwidth, stringheight, size, dummy;
         BBox   fbox;
         BBox * ibox = NULL;
 
@@ -3046,32 +3046,22 @@ _kernel_oserror * image_redraw(browser_data * b, WimpRedrawWindowBlock * r, HStr
 
         /* Find the string width of the ALT text */
 
-        _swix(Font_SetFont, _IN(0), h);
-
-        _swix(Font_StringWidth,
-              _INR(1,5) | _OUT(2),
-
-              tp->text,
-              0x1000000,
-              0x1000000,
-              -1,
-              strlen(tp->text),
-
-              &stringwidth);
+        fm_get_string_width(h,
+                            tp->text,
+                            0x1000000,
+                            strlen(tp->text),
+                            -1,
+                            &dummy,
+                            &stringwidth
+                            );
 
         convert_to_os(stringwidth, &stringwidth);
 
         /* Find the font height */
 
-        _swix(Font_ReadInfo,
-              _IN(0) | _OUT(2) | _OUT(4),
-
-              h,
-
-              &ymin,           /* Font BBox ymin */
-              &stringheight);  /* Font BBox ymax */
+        fm_font_box(h, &fbox);
 
-        stringheight -= ymin;  /* So height = ymax - ymin */
+        stringheight = fbox.ymax - fbox.ymin;
 
         /* Set xpos to the horizontal offset to plot at. */
         /* Remember that 'box' contains the bottom       */
@@ -3080,7 +3070,7 @@ _kernel_oserror * image_redraw(browser_data * b, WimpRedrawWindowBlock * r, HStr
 
         /* Similarly, centre vertically */
 
-        vcent = (box.ymax - stringheight) / 2 - ymin;
+        vcent = (box.ymax - stringheight) / 2 - fbox.ymin;
         if (vcent <= 0) vcent = 10;
         vcent += box.ymin;