Add new Fl_SVG_Image class to support scalable vector graphics images using the (modified) nanosvg software.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12413 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 82 insertions, 0 deletions

diff --git a/FL/Fl_SVG_Image.H b/FL/Fl_SVG_Image.H
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+//
+// "$Id: Fl_SVG_Image.H 12239 2017-05-17 11:54:18Z manolo $"
+//
+// SVG Image header file for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 2017 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:
+//
+//     http://www.fltk.org/COPYING.php
+//
+// Please report all bugs and problems on the following page:
+//
+//     http://www.fltk.org/str.php
+//
+
+#ifndef FL_SVG_IMAGE_H
+#define FL_SVG_IMAGE_H
+
+#include <FL/Fl_Image.H>
+
+struct NSVGimage;
+
+/** The Fl_SVG_Image class supports loading, caching and drawing of scalable vector graphics (SVG) images.
+ The FLTK library performs parsing and rasterization of SVG data using a modified version 
+ of the \c nanosvg software (https://github.com/memononen/nanosvg) © 2013-14 Mikko Mononen 
+ (memon@inside.org). The software modification allows the option to change the image ratio 
+ while performing rasterization.
+ 
+ Use Fl_Image::fail() to check if the Fl_SVG_Image failed to load. fail() returns ERR_FILE_ACCESS 
+ if the file could not be opened or read, and ERR_FORMAT if the SVG format could not be decoded. 
+ If the image has loaded correctly, w(), h(), and d() should return values greater than zero.
+ 
+ Rasterization is not done until the image is first drawn or resize() is called. Therefore, 
+ array() is NULL until then. The delayed rasterization ensures an Fl_Shared_Image based on 
+ an SVG image and scaled to its display size by calling Fl_Shared_Image::scale() will be 
+ always rasterized to the exact screen resolution.
+ 
+ The Fl_SVG_Image class draws images computed by \c nanosvg: one known limitation is that text
+ within \c <text\></text\> blocks is not rendered.
+ 
+ The FLTK library can optionally be built without SVG support; in that case, 
+ class Fl_SVG_Image is unavailable.
+ */
+class FL_EXPORT Fl_SVG_Image : public Fl_RGB_Image {
+private:
+  typedef struct {
+    NSVGimage* svg_image;
+    int ref_count;
+  } counted_NSVGimage;
+  counted_NSVGimage* counted_svg_image_;
+  bool rasterized_;
+  int raster_w_, raster_h_;
+  bool to_desaturate_;
+  Fl_Color average_color_;
+  float average_weight_;
+  float svg_scaling_(int W, int H);
+  void rasterize_(int W, int H);
+  void init_(const char *filename, char *filedata, Fl_SVG_Image *copy_source);
+  virtual int draw_scaled_(int X, int Y, int W, int H);
+  Fl_SVG_Image(Fl_SVG_Image *source);
+public:
+  /** Set this to \c false to allow image re-scaling that alters the image aspect ratio.
+   Upon object creation, \c proportional is set to \c true, and the aspect ratio is kept constant.*/
+  bool proportional;
+  Fl_SVG_Image(const char *filename, char *filedata = NULL);
+  virtual ~Fl_SVG_Image();
+  virtual Fl_Image *copy(int W, int H);
+  void resize(int width, int height);
+  virtual void desaturate();
+  virtual void color_average(Fl_Color c, float i);
+  virtual void draw(int X, int Y, int W, int H, int cx = 0, int cy = 0);
+  void draw(int X, int Y) { draw(X, Y, w(), h(), 0, 0); }
+};
+
+#endif // FL_SVG_IMAGE_H
+
+//
+// End of "$Id: Fl_SVG_Image.H 12239 2017-05-17 11:54:18Z manolo $".
+//