title: FLTK - Mac iOS image not displayed
body: <p>I am using FLTK library (version 1.3.5) on iOS Mojave 10.14.6: I wrote this simple program</p>
  
  <pre><code>#include &lt;stdlib.h&gt;
  #include &lt;FL/Fl.H&gt;
  #include &lt;FL/platform.H&gt;
  #include &lt;FL/Fl_Window.H&gt;
  #include &lt;FL/Fl_JPEG_Image.H&gt;
  #include &lt;FL/Fl_PNG_Image.H&gt;
  #include &lt;FL/Fl_Box.H&gt;
  
  int main(int argc, char **argv) {
  
      Fl_Window *G_win = 0;
      G_win = new Fl_Window(650,650,"test");
  
      Fl_Box* BG = new Fl_Box(0,0,650,650);
      Fl_PNG_Image *bg = new Fl_PNG_Image("scheme.png");
      BG-&gt;image(bg);
  
      Fl_Box* text = new Fl_Box(250,20,150,20,"There should be an image down below. Is it so?");
  
      G_win-&gt;end();
      G_win-&gt;show(argc, argv);
      return Fl::run();
  }
  </code></pre>
  
  <p>and I compile it with the following Makefile (found <a href="https://www.fltk.org/articles.php?L599" rel="nofollow noreferrer">here</a>):</p>
  
  <pre><code>CC  = $(shell fltk-config --cc)
  CXX = $(shell fltk-config --cxx)
  
  CFLAGS   = $(shell fltk-config --cflags) -Wall -O3 -I/other/include/paths...
  CXXFLAGS = $(shell fltk-config --cxxflags) -Wall -O3 -I/other/include/paths...
  
  LINKFLTK = $(shell fltk-config --ldstaticflags)
  LINKFLTK_GL = $(shell fltk-config --use-gl --ldstaticflags)
  LINKFLTK_IMG = $(shell fltk-config --use-images --ldstaticflags)
  
  STRIP      = strip
  POSTBUILD  = fltk-config --post # Required on OSX, does nothing on other platforms, so safe to call
  
  all: myApp
  
  main.o: main.cpp 
      $(CC) -c $&lt; $(CCFLAGS)
  
  myApp:  main.o 
      $(CXX) -o $@ main.o  $(LINKFLTK_IMG) $(LINKFLTK_GL)
      $(STRIP) $@
      $(POSTBUILD) $@  # only required on OSX, but call it anyway for portability
  </code></pre>
  
  <p>I get hence the binary <code>myApp</code> and the application <code>myApp</code>: when I type ./myApp in the shell eveything works fine (top image), while by double-clicking on the icon there is no image displayed (bottom image).</p>
  
  <p><a href="https://i.stack.imgur.com/bUCLV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bUCLV.png" alt="Executing the binary"></a> <a href="https://i.stack.imgur.com/mO3Ib.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mO3Ib.png" alt="double clicking on the app"></a></p>
  
  <p>I got no errors during compilation, nor warnings. Are there any problems with the Makefile? Is it Mac iOS related?</p>