From f9039b2ae21988783feae9b362818e7923e82d14 Mon Sep 17 00:00:00 2001
From: Michael R Sweet <michael.r.sweet@gmail.com>
Date: Tue, 6 Oct 1998 18:21:25 +0000
Subject: Initial revision

git-svn-id: file:///fltk/svn/fltk/trunk@2 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 test/doublebuffer.cxx | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 test/doublebuffer.cxx

(limited to 'test/doublebuffer.cxx')

diff --git a/test/doublebuffer.cxx b/test/doublebuffer.cxx
new file mode 100644
index 000000000..b15bc02c3
--- /dev/null
+++ b/test/doublebuffer.cxx
@@ -0,0 +1,99 @@
+// Double-buffering test.
+
+// This demo shows how double buffering helps, by drawing the
+// window in a particularily bad way.
+
+// The single-buffered window will blink as it updates.  The
+// double buffered one will not.  It will take just as long
+// (or longer) to update, but often it will appear to be faster.
+
+// This demo should work for both the GL and X versions of Fl,
+// even though the double buffering mechanism is totally different.
+
+#include <FL/Fl.H>
+#include <FL/Fl_Single_Window.H>
+#include <FL/Fl_Double_Window.H>
+#include <FL/Fl_Box.H>
+#include <FL/fl_draw.H>
+#include <FL/Fl_Hor_Slider.H>
+#include <stdlib.h>
+#include <FL/math.h>
+#include <stdio.h>
+
+// this purposely draws each line 10 times to be slow:
+void star(int w, int h, int n) {
+  fl_push_matrix();
+  fl_translate(w/2, h/2);
+  fl_scale(w/2, h/2);
+  for (int i = 0; i < n; i++) {
+    for (int j = i+1; j < n; j++)/* for (int k=0; k<10; k++)*/ {
+      fl_begin_line();
+      fl_vertex(cos(2*M_PI*i/n+.1), sin(2*M_PI*i/n+.1));
+      fl_vertex(cos(2*M_PI*j/n+.1), sin(2*M_PI*j/n+.1));
+      fl_end_line();
+    }
+  }
+  fl_pop_matrix();
+}
+
+int sides[2] = {20,20};
+
+void slider_cb(Fl_Widget* o, long v) {
+  sides[v] = int(((Fl_Slider*)o)->value());
+  o->parent()->redraw();
+}
+
+void bad_draw(int w,int h,int which) {
+//   for (int i=0; i<10; i++) {
+//     fl_color(7); fl_rectf(0,0,w,h); fl_color(0); star(w,h);
+//     fl_color(0); fl_rectf(0,0,w,h); fl_color(7); star(w,h);
+//   }
+  fl_color(FL_BLACK); fl_rectf(0,0,w,h);
+  fl_color(FL_WHITE); star(w,h,sides[which]);
+  //  for (int x=0; x<sides[which]; x++) for (int y=0; y<sides[which]; y++)
+  //fl_draw_box(FL_UP_BOX, 10*x, 10*y, 25,25, FL_GRAY);
+}
+
+class single_blink_window : public Fl_Single_Window {
+  void draw() {bad_draw(w(),h(),0); draw_child(*child(0));}
+public:
+  single_blink_window(int x, int y,int w,int h,const char *l)
+    : Fl_Single_Window(x,y,w,h,l) {resizable(this);}
+};
+
+class double_blink_window : public Fl_Double_Window {
+  void draw() {bad_draw(w(),h(),1); draw_child(*child(0));}
+public:
+  double_blink_window(int x, int y, int w,int h,const char *l)
+    : Fl_Double_Window(x,y,w,h,l) {resizable(this);}
+};
+
+int main() {
+  if (!Fl::visual(FL_DOUBLE))
+    printf("Xdbe not supported, faking double buffer with pixmaps.\n");
+  Fl_Window w01(420,420,"Fl_Single_Window"); w01.box(FL_FLAT_BOX);
+  single_blink_window w1(10,10,400,400,"Fl_Single_Window");
+  w1.box(FL_FLAT_BOX); w1.color(FL_BLACK); //w1.position(100,200);
+  Fl_Hor_Slider slider0(20,370,360,25);
+  slider0.range(2,30);
+  slider0.step(1);
+  slider0.value(sides[0]);
+  slider0.callback(slider_cb, 0);
+  w1.end();
+  w01.end();
+  Fl_Window w02(420,420,"Fl_Double_Window"); w02.box(FL_FLAT_BOX);
+  double_blink_window w2(10,10,400,400,"Fl_Double_Window");
+  w2.box(FL_FLAT_BOX); w2.color(FL_BLACK); //w2.position(600,200);
+  Fl_Hor_Slider slider1(20,370,360,25);
+  slider1.range(2,30);
+  slider1.step(1);
+  slider1.value(sides[0]);
+  slider1.callback(slider_cb, 1);
+  w2.end();
+  w02.end();
+  w01.show();
+  w1.show();
+  w02.show();
+  w2.show();
+  return Fl::run();
+}
-- 
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