1 files changed, 115 insertions, 0 deletions
diff --git a/src/Fl_Overlay_Window.cxx b/src/Fl_Overlay_Window.cxx
new file mode 100644
index 000000000..7bbd85904
--- /dev/null
+++ b/src/Fl_Overlay_Window.cxx
@@ -0,0 +1,115 @@
+// Fl_Overlay_Window.C
+
+// A window using double-buffering and able to draw an overlay
+// on top of that.  Uses the hardware to draw the overlay if
+// possible, otherwise it just draws in the front buffer.
+
+#include <config.h>
+#include <FL/Fl.H>
+#include <FL/Fl_Overlay_Window.H>
+#include <FL/fl_draw.H>
+#include <FL/x.H>
+
+void Fl_Overlay_Window::show() {
+  Fl_Double_Window::show();
+  if (overlay_ && overlay_ != this) overlay_->show();
+}
+
+void Fl_Overlay_Window::hide() {
+  Fl_Double_Window::hide();
+}
+
+void Fl_Overlay_Window::flush() {
+  // a non-zero argument copies entire back buffer to window, erasing
+  // the overlay.  We should only do this if fake overlay needs redraw:
+  uchar overlay_damage = damage()&8; clear_damage(damage()&~8);
+  _flush(overlay_damage);
+  if (overlay_ == this) draw_overlay();
+}
+
+void Fl_Overlay_Window::resize(int X, int Y, int W, int H) {
+  Fl_Double_Window::resize(X,Y,W,H);
+  if (overlay_ && overlay_!=this) overlay_->resize(0,0,w(),h());
+}
+
+Fl_Overlay_Window::~Fl_Overlay_Window() {
+  hide();
+//  delete overlay; this is done by ~Fl_Group
+}
+
+#if !HAVE_OVERLAY
+
+int Fl_Overlay_Window::can_do_overlay() {return 0;}
+
+void Fl_Overlay_Window::redraw_overlay() {overlay_ = this; damage(8);}
+
+#else
+
+extern XVisualInfo *fl_find_overlay_visual();
+extern XVisualInfo *fl_overlay_visual;
+extern Colormap fl_overlay_colormap;
+extern unsigned long fl_transparent_pixel;
+static GC gc;	// the GC used by all X windows
+extern uchar fl_overlay; // changes how fl_color(x) works
+
+class _Fl_Overlay : public Fl_Window {
+  friend class Fl_Overlay_Window;
+  void flush();
+  void show();
+public:
+  _Fl_Overlay(int x, int y, int w, int h) :
+    Fl_Window(x,y,w,h) {deactivate();}
+};
+
+int Fl_Overlay_Window::can_do_overlay() {
+  return fl_find_overlay_visual() != 0;
+}
+
+void _Fl_Overlay::show() {
+  if (shown()) {Fl_Window::show(); return;}
+  fl_background_pixel = int(fl_transparent_pixel);
+  Fl_X::make_xid(this, fl_overlay_visual, fl_overlay_colormap);
+  fl_background_pixel = -1;
+  // find the outermost window to tell wm about the colormap:
+  Fl_Window *w = window();
+  for (;;) {Fl_Window *w1 = w->window(); if (!w1) break; w = w1;}
+  XSetWMColormapWindows(fl_display, fl_xid(w), &(Fl_X::i(this)->xid), 1);
+}
+
+void _Fl_Overlay::flush() {
+  fl_window = fl_xid(this);
+  if (!gc) gc = XCreateGC(fl_display, fl_xid(this), 0, 0);
+  fl_gc = gc;
+  fl_overlay = 1;
+  Fl_Overlay_Window *w = (Fl_Overlay_Window *)parent();
+  Fl_X *i = Fl_X::i(this);
+  if (damage() != 2) XClearWindow(fl_display, fl_xid(this));
+  fl_clip_region(i->region); i->region = 0;
+  w->draw_overlay();
+  fl_overlay = 0;
+}
+
+void Fl_Overlay_Window::redraw_overlay() {
+  if (!fl_display) return; // this prevents fluid -c from opening display
+  if (!overlay_) {
+    if (can_do_overlay()) {
+      Fl_Group::current(this);
+      overlay_ = new _Fl_Overlay(0,0,w(),h());
+      Fl_Group::current(0);
+    } else {
+      overlay_ = this;	// fake the overlay
+    }
+  }
+  if (shown()) {
+    if (overlay_ == this)
+      damage(8);
+    else if (!overlay_->shown())
+      overlay_->show();
+    else
+      overlay_->redraw();
+  }
+}
+
+#endif
+
+// End of Fl_Overlay_Window.C