Add Ian's offscreen test program.

Same commit as branch-1.3, svn r11287.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11288 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

.gitignore

@@ -197,6 +197,7 @@
 /test/minimum
 /test/native-filechooser
 /test/navigation
+/test/offscreen
 /test/output
 /test/overlay
 /test/pack

test/CMakeLists.txt

@@ -65,6 +65,7 @@ CREATE_EXAMPLE(pack pack.cxx fltk)
 CREATE_EXAMPLE(pixmap pixmap.cxx fltk)
 CREATE_EXAMPLE(pixmap_browser pixmap_browser.cxx "fltk;fltk_images")
 CREATE_EXAMPLE(preferences preferences.fl fltk)
+CREATE_EXAMPLE(offscreen offscreen.cxx fltk)
 CREATE_EXAMPLE(radio radio.fl fltk)
 CREATE_EXAMPLE(resize resize.fl fltk)
 CREATE_EXAMPLE(resizebox resizebox.cxx fltk)

test/Makefile

@@ -70,6 +70,7 @@ CPPFILES =\
 	minimum.cxx \
 	native-filechooser.cxx \
 	navigation.cxx \
+	offscreen.cxx \
 	output.cxx \
 	overlay.cxx \
 	pack.cxx \
@@ -142,6 +143,7 @@ ALL =	\
 	minimum$(EXEEXT) \
 	native-filechooser$(EXEEXT) \
 	navigation$(EXEEXT) \
+	offscreen$(EXEEXT) \
 	output$(EXEEXT) \
 	overlay$(EXEEXT) \
 	pack$(EXEEXT) \
@@ -415,6 +417,8 @@ native-filechooser$(EXEEXT): native-filechooser.o $(IMGLIBNAME)
 
 navigation$(EXEEXT): navigation.o
 
+offscreen$(EXEEXT): offscreen.o
+
 output$(EXEEXT): output.o $(FLLIBNAME)
 	echo Linking $@...
 	$(CXX) $(ARCHFLAGS) $(CXXFLAGS) $(LDFLAGS) -o $@ output.o $(LINKFLTKFORMS) $(LDLIBS)

test/demo.menu

@@ -45,6 +45,7 @@
 		@di:transparency:animated
 	@d:cursor:cursor
 	@d:labels:label
+	@d:offscreen:offscreen
 	@d:rotated text:rotated_text
 	@d:fl_arc:arc
 	@d:fl_curve:curve

test/offscreen.cxx

@@ -0,0 +1,260 @@
+//
+// "$Id$"
+//
+// Offscreen drawing test program for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2016 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
+//
+
+/* Standard headers */
+#include <stdlib.h>
+#include <time.h> // time() - used to seed rand()
+
+/* Fltk headers */
+#include <FL/Fl.H>
+#include <FL/Fl_Double_Window.H>
+#include <FL/x.H>
+#include <FL/Fl_Box.H>
+#include <FL/fl_draw.H>
+
+static Fl_Double_Window *main_window = 0;
+
+// constants to define the view etc.
+static const int offscreen_size = 1000;
+static const int win_size = 512;
+static const int first_useful_color = 56;
+static const int last_useful_color = 255;
+static const int num_iterations = 300;
+static const double max_line_width = 9.0;
+static const double delta_time = 0.1;
+
+/*****************************************************************************/
+class oscr_box : public Fl_Box
+{
+public:
+  oscr_box(int x, int y, int w, int h);
+  void oscr_drawing(void);
+  bool has_oscr() const
+  {
+    if (oscr) return true;
+    return false;
+  }
+private:
+  void draw();
+  int handle(int event);
+  // Generate "random" values for the line display
+  double random_val(int v) const
+  {
+    double dr = (double)(rand()) / (double)(RAND_MAX); // 0.0 to 1.0
+    dr = dr * (double)(v); // 0 to v
+    return dr;
+  }
+  // The offscreen surface
+  Fl_Offscreen oscr;
+  // variables used to handle "dragging" of the view within the box
+  int x1, y1;   // drag start positions
+  int xoff, yoff; // drag offsets
+  int drag_state; // non-zero if drag is in progress
+  int page_x, page_y; // top left of view area
+  // Width and height of the offscreen surface
+  int offsc_w, offsc_h;
+};
+
+/*****************************************************************************/
+oscr_box::oscr_box(int x, int y, int w, int h) :
+  Fl_Box(x, y, w, h), // base box
+  oscr(0), // offscreen is not set at start
+  x1(0), y1(0), drag_state(0), // not dragging view
+  page_x((offscreen_size - win_size) / 2), // roughly centred in view
+  page_y((offscreen_size - win_size) / 2),
+  offsc_w(0), offsc_h(0) // offscreen size - initially none
+{ } // Constructor
+
+/*****************************************************************************/
+void oscr_box::draw()
+{
+  int wd = w();
+  int ht = h();
+  int xo = x();
+  int yo = y();
+
+  fl_color(fl_gray_ramp(19)); // a light grey background shade
+  fl_rectf(xo, yo, wd, ht); // fill the box with this colour
+
+  // then add the offscreen on top of the grey background
+  if (has_oscr()) // offscreen exists
+  {
+    fl_copy_offscreen(xo, yo, wd, ht, oscr, page_x, page_y);
+  }
+  else  // create offscreen
+  {
+    // some hosts may need a valid window context to base the offscreen on...
+    main_window->make_current();
+    offsc_w = offscreen_size;
+    offsc_h = offscreen_size;
+    oscr = fl_create_offscreen(offsc_w, offsc_h);
+  }
+} // draw method
+
+/*****************************************************************************/
+int oscr_box::handle(int ev)
+{
+  int ret = Fl_Box::handle(ev);
+  // handle dragging of visible page area - if a valid context exists
+  if (has_oscr())
+  {
+    switch (ev)
+    {
+    case FL_ENTER:
+      main_window->cursor(FL_CURSOR_MOVE);
+      ret = 1;
+      break;
+
+    case FL_LEAVE:
+      main_window->cursor(FL_CURSOR_DEFAULT);
+      ret = 1;
+      break;
+
+    case FL_PUSH:
+      x1 = Fl::event_x_root();
+      y1 = Fl::event_y_root();
+      drag_state = 1; // drag
+      ret = 1;
+      break;
+
+    case FL_DRAG:
+      if (drag_state == 1) // dragging page
+      {
+	int x2 = Fl::event_x_root();
+	int y2 = Fl::event_y_root();
+	xoff = x1 - x2;
+	yoff = y1 - y2;
+	x1 = x2;
+	y1 = y2;
+	page_x += xoff;
+	page_y += yoff;
+	// check the page bounds
+	if (page_x < -w())
+	{
+	  page_x = -w();
+	}
+	else if (page_x > offsc_w)
+	{
+	  page_x = offsc_w;
+	}
+	if (page_y < -h())
+	{
+	  page_y = -h();
+	}
+	else if (page_y > offsc_h)
+	{
+	  page_y = offsc_h;
+	}
+	redraw();
+      }
+      ret = 1;
+      break;
+
+    case FL_RELEASE:
+      drag_state = 0;
+      ret = 1;
+      break;
+
+    default:
+      break;
+    }
+  }
+  return ret;
+} // handle
+
+/*****************************************************************************/
+void oscr_box::oscr_drawing(void)
+{
+  Fl_Color col;
+  static int icol = first_useful_color;
+  static int ox = (offscreen_size / 2);
+  static int oy = (offscreen_size / 2);
+  static int iters = num_iterations + 1; // Must be set on first pass!
+
+  if (!has_oscr())
+  {
+    return; // no valid offscreen, nothing to do here
+  }
+
+  fl_begin_offscreen(oscr); /* Open the offscreen context for drawing */
+  {
+    if (iters > num_iterations) // clear the offscreen and start afresh
+    {
+      fl_color(FL_WHITE);
+      fl_rectf(0, 0, offsc_w, offsc_h);
+      iters = 0;
+    }
+    iters++;
+
+    icol++;
+    if (icol > last_useful_color)
+    {
+      icol = first_useful_color;
+    }
+    col = static_cast<Fl_Color>(icol);
+    fl_color(col); // set the colour
+
+    double drx = random_val(offsc_w);
+    double dry = random_val(offsc_h);
+    double drt = random_val(max_line_width);
+
+    int ex = static_cast<int>(drx);
+    int ey = static_cast<int>(dry);
+    fl_line_style(FL_SOLID, static_cast<int>(drt));
+    fl_line(ox, oy, ex, ey);
+    ox = ex;
+    oy = ey;
+  }
+  fl_end_offscreen(); // close the offscreen context
+  redraw();
+} // oscr_drawing
+
+/*****************************************************************************/
+static oscr_box *os_box = 0; // a widget to view the offscreen with
+
+/*****************************************************************************/
+static void oscr_anim(void *)
+{
+  os_box->oscr_drawing(); // if the offscreen exists, draw something
+  Fl::repeat_timeout(delta_time, oscr_anim);
+} // oscr_anim
+
+/*****************************************************************************/
+int main(int argc, char **argv)
+{
+  int dim1 = win_size;
+  main_window = new Fl_Double_Window(dim1, dim1, "Offscreen demo");
+  main_window->begin();
+
+  dim1 -= 10;
+  os_box = new oscr_box(5, 5, dim1, dim1);
+  main_window->end();
+  main_window->resizable(os_box);
+
+  main_window->show(argc, argv);
+
+  srand(time(NULL)); // seed the random sequence generator
+
+  Fl::add_timeout(delta_time, oscr_anim);
+
+  return Fl::run();
+} // main
+
+//
+// End of "$Id$".
+//