Move nanosvg to a separate file, don't use 'roundf()' (#937)

Replacement of roundf() with nsvg__roundf() fixes one aspect of
issue #937.

Having the nanosvg implementation in its own module was planned anyway.

src/CMakeLists.txt

@@ -507,6 +507,7 @@ set(IMGCPPFILES
   Fl_PNM_Image.cxx
   Fl_Image_Reader.cxx
   Fl_SVG_Image.cxx
+  nanosvg.cxx
   drivers/SVG/Fl_SVG_File_Surface.cxx
 )
 

src/Fl_SVG_Image.cxx

@@ -1,7 +1,7 @@
 //
 // SVG image code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2017-2022 by Bill Spitzak and others.
+// Copyright 2017-2024 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -28,28 +28,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#if !defined(HAVE_LONG_LONG)
-static double strtoll(const char *str, char **endptr, int base) {
-  return (double)strtol(str, endptr, base);
-}
-#endif
-
-#ifdef _MSC_VER
-#pragma warning (push)                  // Save #pragma warning status
-#pragma warning (disable: 4244)         // Switch off conversion warnings
-#endif
-
-#define NANOSVG_ALL_COLOR_KEYWORDS      // Include full list of color keywords.
-#define NANOSVG_IMPLEMENTATION          // Expands implementation
 #include "../nanosvg/nanosvg.h"
-
-#define NANOSVGRAST_IMPLEMENTATION      // Expands implementation
 #include "../nanosvg/nanosvgrast.h"
 
-#ifdef _MSC_VER
-#pragma warning (pop)                  // Restore #pragma warning status
-#endif
-
 #if defined(HAVE_LIBZ)
 #include <zlib.h>
 #endif

src/Makefile

@@ -241,6 +241,7 @@ IMGCPPFILES = \
 	Fl_PNM_Image.cxx \
 	Fl_Image_Reader.cxx \
 	Fl_SVG_Image.cxx \
+	nanosvg.cxx \
 	drivers/SVG/Fl_SVG_File_Surface.cxx
 
 CFILES = flstring.c numericsort.c vsnprintf.c

src/nanosvg.cxx

@@ -0,0 +1,60 @@
+//
+// Implementation of the nanosvg library for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 2017-2024 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+// This code includes the header-only nanosvg library and builds a
+// separate object file comprised of the nanosvg library and nothing
+// else. Moved here from Fl_SVG_Image.cxx for better code separation.
+
+#include <config.h>
+
+#if defined(FLTK_USE_SVG) || defined(FL_DOXYGEN)
+
+// GitHub Issue #937: "Support for HP-UX" (version 11.11, Dec. 2000)
+//
+// C90 does not provide roundf() but nanosvg.h uses it although
+// nanosvgrast.h has a replacement function: nsvg__roundf()
+//
+// Solution: use nsvg_roundf() instead.
+// Advantage: we don't need to check system macros.
+//
+// Note: using nsvg__roundf() in nanosvg.h should be applied upstream.
+//       Once this is available we can remove this comment block and
+//       the following 3-line "fix":
+
+#include <math.h>                       // must be before #define below !
+static float nsvg__roundf(float x);     // prototype (see nanosvgrast.h)
+#define roundf nsvg__roundf             // redefinition (#937)
+
+// End of GitHub Issue #937. Remove this entire block when upstream is patched.
+
+#if !defined(HAVE_LONG_LONG)
+static double strtoll(const char *str, char **endptr, int base) {
+  return (double)strtol(str, endptr, base);
+}
+#endif
+
+#ifdef _MSC_VER
+#pragma warning (disable: 4244)         // Switch off conversion warnings
+#endif
+
+#define NANOSVG_ALL_COLOR_KEYWORDS      // include full list of color keywords
+#define NANOSVG_IMPLEMENTATION          // use nanosvg.h implementation
+#define NANOSVGRAST_IMPLEMENTATION      // use nanosvgrast.h implementation
+
+#include "../nanosvg/nanosvg.h"
+#include "../nanosvg/nanosvgrast.h"
+
+#endif // FLTK_USE_SVG