Add classes Fl_SVG_File_Surface and Fl_EPS_File_Surface to draw to SVG and EPS.

Test programs device and pixmap_browser use these new classes.
Class Fl_SVG_File_Surface can be optionally made non functional using the
--disable-svg configure option or turning off OPTION_USE_SVG in CMake.
Class Fl_EPS_File_Surface can be optionally made non functional using the
--disable-print configure option or turning off OPTION_PRINT_SUPPORT in CMake.

2 files changed, 131 insertions, 1 deletions

diff --git a/FL/Fl_PostScript.H b/FL/Fl_PostScript.H
index 6d26490dc..ad6a6cd4a 100644
--- a/FL/Fl_PostScript.H
+++ b/FL/Fl_PostScript.H
@@ -3,7 +3,7 @@
 //
 // Support for graphics output to PostScript file for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2019 by Bill Spitzak and others.
+// Copyright 2010-2020 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
@@ -206,6 +206,11 @@ public:
   // ---
   Fl_Bitmask create_bitmask(int w, int h, const uchar *array) { return 0L; }
   virtual int has_feature(driver_feature feature_mask) { return feature_mask & PRINTER; }
+  
+  int start_eps(int width, int height);
+  void ps_origin(int x, int y);
+  void ps_translate(int, int);
+  void ps_untranslate();
 };
 
 /**
@@ -310,6 +315,58 @@ public:
   static const char *file_chooser_title;
 };
 
+/** Encapsulated PostScript drawing surface.
+ This drawing surface allows to store any FLTK graphics in vectorial form in an "Encapsulated PostScript" file.
+ \n Usage example:
+ \code
+   Fl_Window *win = ...// Window to draw to an .eps file
+   int ww = win->decorated_w();
+   int wh = win->decorated_h();
+   FILE *eps = fl_fopen("/path/to/mywindow.eps", "w");
+   if (eps) {
+     Fl_EPS_File_Surface *surface = new Fl_EPS_File_Surface(ww, wh, eps, win->color());
+     Fl_Surface_Device::push_current(surface);
+     surface->draw_decorated_window(win);
+     Fl_Surface_Device::pop_current();
+     delete surface; // the .eps file is not complete until the destructor was run
+     fclose(eps);
+   }
+ \endcode
+ */
+class FL_EXPORT Fl_EPS_File_Surface : public Fl_Widget_Surface {
+private:
+  void complete_();
+protected:
+  /** Returns the PostScript driver of this drawing surface. */
+  inline Fl_PostScript_Graphics_Driver *driver() { return (Fl_PostScript_Graphics_Driver*)Fl_Surface_Device::driver(); }
+public:
+  /**
+  Constructor.
+  \param width,height Width and height of the EPS drawing area
+  \param eps A writable FILE pointer where the Encapsulated PostScript data will be sent
+  \param background Color expected to cover the background of the EPS drawing area.
+  This parameter affects only the drawing of transparent Fl_RGB_Image objects:
+  transparent areas of RGB images are blended with the \p background color.
+  */
+  Fl_EPS_File_Surface(int width, int height, FILE *eps, Fl_Color background = FL_WHITE);
+  /**
+   Destructor.
+   The underlying FILE pointer remains open after destruction of the Fl_EPS_File_Surface object
+   unless close() was called.
+   */
+  ~Fl_EPS_File_Surface();
+  virtual int printable_rect(int *w, int *h);
+  /** Returns the underlying FILE pointer */
+  FILE *file() { return driver()->output; }
+  virtual void origin(int x, int y);
+  virtual void origin(int *px, int *py);
+  virtual void translate(int x, int y);
+  virtual void untranslate();
+  /** Closes using fclose() the underlying FILE pointer.
+   The only operation possible with the Fl_EPS_File_Surface object after calling close() is its destruction. */
+  int close();
+};
+
 #endif // Fl_PostScript_H
 
 //
diff --git a/FL/Fl_SVG_File_Surface.H b/FL/Fl_SVG_File_Surface.H
new file mode 100644
index 000000000..272f7db1f
--- /dev/null
+++ b/FL/Fl_SVG_File_Surface.H
@@ -0,0 +1,73 @@
+//
+// Declaration of Fl_SVG_File_Surface in the Fast Light Tool Kit (FLTK).
+//
+// Copyright 2020 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 report all bugs and problems on the following page:
+//
+//     https://www.fltk.org/str.php
+//
+
+#ifndef Fl_SVG_File_Surface_H
+#define Fl_SVG_File_Surface_H
+
+#include <FL/Fl_Widget_Surface.H>
+#include <stdio.h>
+
+/** A drawing surface producing a Scalable Vector Graphics (SVG) file.
+ This drawing surface allows to store any FLTK graphics in vectorial form in a "Scalable Vector Graphics" file.
+ \n Usage example:
+ \code
+   Fl_Window *win = ...// Window to draw to a .svg file
+   int ww = win->decorated_w();
+   int wh = win->decorated_h();
+   FILE *svg = fl_fopen("/path/to/mywindow.svg", "w");
+   if (svg) {
+     Fl_SVG_File_Surface *surface = new Fl_SVG_File_Surface(ww, wh, svg);
+     Fl_Surface_Device::push_current(surface);
+     fl_color(FL_WHITE);
+     fl_rectf(0, 0, ww, wh);
+     surface->draw_decorated_window(win);
+     Fl_Surface_Device::pop_current();
+     delete surface; // the .svg file is not complete until the destructor was run
+     fclose(svg);
+   }
+ \endcode
+ \note FLTK uses the PNG and JPEG libraries to encode images to the SVG format. If JPEG is
+ not available at application build time, PNG is enough (but produces a quite larger output).
+ If PNG isn't available either, images don't appear in the SVG output.
+*/
+class FL_EXPORT Fl_SVG_File_Surface : public Fl_Widget_Surface {
+  int width_, height_;
+public:
+  /**
+  Constructor of the SVG drawing surface.
+  \param width,height Width and height of the graphics area in FLTK drawing units
+  \param svg A writable FILE pointer where the SVG data are to be sent. The resulting SVG data are not complete until after destruction of the Fl_SVG_File_Surface object or after calling close().
+  */
+  Fl_SVG_File_Surface(int width, int height, FILE *svg);
+  /**
+   Destructor.
+   The underlying FILE pointer remains open after destruction of the Fl_SVG_File_Surface object
+   unless close() was called.
+   */
+  ~Fl_SVG_File_Surface();
+  /** Returns the underlying FILE pointer */
+  FILE *file();
+  virtual void origin(int x, int y);
+  virtual void translate(int x, int y);
+  virtual void untranslate();
+  virtual int printable_rect(int *w, int *h);
+  /** Closes with function fclose() the FILE pointer where SVG data is output.
+  The only operation possible after this on the Fl_SVG_File_Surface object is its destruction.
+  \return The value returned by fclose(). */
+  int close();
+};
+
+#endif /* Fl_SVG_File_Surface_H */