text: //
  // "$Id: Fl_Tiled_Image.cxx 10602 2015-03-02 10:23:20Z AlbrechtS $"
  //
  // Tiled image code for the Fast Light Tool Kit (FLTK).
  //
  // Copyright 1998-2015 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
  //
  
  
  #include <FL/Fl.H>
  #include <FL/Fl_Tiled_Image.H>
  #include <FL/Fl_Window.H>
  #include <FL/fl_draw.H>
  
  /**
    The constructors create a new tiled image containing the specified image.
    Use a width and height of 0 to tile the whole window/widget.
  
    \note Due to implementation constraints in FLTK 1.3.3 and later width
      and height of 0 may not work as expected when used as background image
      in widgets other than windows. You may need to center and clip the
      image (label) and set the label type to FL_NORMAL_LABEL. Doing so will
      let the tiled image fill the whole widget as its background image.
      Other combinations of label flags may or may not work.
  
    \code
    #include "bg.xpm"
    Fl_Pixmap *bg_xpm = new Fl_Pixmap(bg_xpm);
    Fl_Tiled_Image *bg_tiled = new Fl_Tiled_Image(bg_xpm,0,0);
  
    Fl_Box *box = new Fl_Box(40,40,300,100,"");
    box->box(FL_UP_BOX);
    box->labeltype(FL_NORMAL_LABEL);
    box->align(FL_ALIGN_INSIDE | FL_ALIGN_CENTER | FL_ALIGN_CLIP);
    box->image(bg_tiled);
    \endcode
  
    \note Setting an image (label) for a window may not work as expected due
      to implementation constraints in FLTK 1.3.x and maybe later. The reason
      is the way Fl::scheme() initializes the window's label type and image.
      A possible workaround is to use another Fl_Group as the only child widget
      and to set the background image for this group as described above.
  
    \todo Fix Fl_Tiled_Image as background image for widgets and windows
      and fix the implementation of Fl::scheme(const char *).
  */
  Fl_Tiled_Image::Fl_Tiled_Image(Fl_Image *i,	// I - Image to tile
                                 int      W,	// I - Width of tiled area
  			       int      H) :	// I - Height of tiled area
    Fl_Image(W,H,0) {
    image_       = i;
    alloc_image_ = 0;
  
    // giving to the tiled image the screen size may fail with multiscreen
    // configurations, so we leave it with w = h = 0 (STR #3106)
    // if (W == 0) w(Fl::w());
    // if (H == 0) h(Fl::h());
  }
  /**
    The destructor frees all memory and server resources that are used by
    the tiled image.
  */
    Fl_Tiled_Image::~Fl_Tiled_Image() {
    if (alloc_image_) delete image_;
  }
  
  
  //
  // 'Fl_Tiled_Image::copy()' - Copy and resize a tiled image...
  //
  
  Fl_Image *			// O - New image
  Fl_Tiled_Image::copy(int W,	// I - New width
                       int H) {	// I - New height
    if (W == w() && H == h()) return this;
    else return new Fl_Tiled_Image(image_, W, H);
  }
  
  
  //
  // 'Fl_Tiled_Image::color_average()' - Blend colors...
  //
  
  void
  Fl_Tiled_Image::color_average(Fl_Color c,	// I - Color to blend with
                                float    i) {	// I - Blend fraction
    if (!alloc_image_) {
      image_       = image_->copy();
      alloc_image_ = 1;
    }
  
    image_->color_average(c, i);
  }
  
  
  //
  // 'Fl_Tiled_Image::desaturate()' - Convert the image to grayscale...
  //
  
  void
  Fl_Tiled_Image::desaturate() {
    if (!alloc_image_) {
      image_       = image_->copy();
      alloc_image_ = 1;
    }
  
    image_->desaturate();
  }
  
  
  //
  // 'Fl_Tiled_Image::draw()' - Draw a tiled image.
  //
  /**
    Draws a tiled image.
  
    Tiled images can be used as background images for widgets and windows.
    However, due to implementation constraints, you must take care when
    setting label types and alignment flags. Only certain combinations work as
    expected, others may yield unexpected results and undefined behavior.
  
    This draw method can draw multiple copies of one image in an area given
    by \p X, \p Y, \p W, \p H.
  
    The optional arguments \p cx and \p cy can be used to crop the image
    starting at offsets (cx, cy). \p cx and \p cy must be \>= 0 (negative values
    are ignored). If one of the values is greater than the image width or height
    resp. (\p cx \>= image()->w() or \p cy \>= image()->h()) nothing is drawn,
    because the resulting image would be empty.
  
    After calculating the resulting image size the image is drawn as often
    as necessary to fill the given area, starting at the top left corner.
  
    If both \p W and \p H are 0 the image is repeated as often as necessary
    to fill the entire window, unless there is a valid clip region. If you
    want to fill only one particular widget's background, then you should
    either set a clip region in your draw() method or use the label alignment
    flags \p FL_ALIGN_INSIDE|FL_ALIGN_CLIP to make sure the image is clipped.
  
    This may be improved in a later version of the library.
  */
  void
  Fl_Tiled_Image::draw(int X,	// I - Starting X position
                       int Y,	// I - Starting Y position
  		     int W,	// I - Width of area to be filled
  		     int H,	// I - Height of area to be filled
  		     int cx,	// I - "Source" X position
  		     int cy) {	// I - "Source" Y position
  
    int iw = image_->w();		// effective image width
    int ih = image_->h();		// effective image height
  
    if (!iw || !ih) return;
    if (cx >= iw || cy >= ih) return;
  
    if (cx < 0) cx = 0;		// ignore negative values
    if (cy < 0) cy = 0;
  
    // W and H null means the image is potentially as large as the current window
    // or widget. The latter can not be checked here, hence we use the whole
    // window as well and rely on appropriate clipping. See comments above.
    // This should be fixed! (AlbrechtS, 01 Mar 2015)
  
    if (W == 0 && H == 0 && Fl_Window::current()) {
      W = Fl_Window::current()->w();
      H = Fl_Window::current()->h();
      X = Y = 0;
    }
  
    if (W == 0 || H == 0) return;
  
    fl_push_clip(X, Y, W, H);
  
    if (cx > 0) iw -= cx;		// crop image
    if (cy > 0) ih -= cy;
  
    for (int yy = Y; yy < H; yy += ih) {
      if (fl_not_clipped(X,yy,W,ih)) {
        for (int xx = X; xx < W; xx += iw) {
  	if (fl_not_clipped(xx,yy,iw,ih)) {
  	  image_->draw(xx,yy,iw,ih,cx,cy);
  	}
        }
      }
    }
    fl_pop_clip();
  }
  
  
  //
  // End of "$Id: Fl_Tiled_Image.cxx 10602 2015-03-02 10:23:20Z AlbrechtS $".
  //
  