Changed repainting policy.

First, repainting is done as soon as we get an update, with a maximum
of a certain number of updates per second. We have two modes: a
normal, where there are five  updates every secondes, and a fast mode,
enabled when drawing when updates are propagated immediately.

src/app/screen.cpp

@@ -12,6 +12,9 @@
 
 namespace chrono = std::chrono;
 
+namespace app
+{
+
 /**
  * Time to wait after the last update from VNC before updating the screen
  * (in microseconds).
@@ -19,14 +22,13 @@ namespace chrono = std::chrono;
  * VNC servers tend to send a lot of small updates in a short period of time.
  * This delay allows grouping those small updates into a larger screen update.
  */
-constexpr chrono::milliseconds update_delay{150};
-
-namespace app
-{
-
+constexpr chrono::milliseconds update_delay_normal{200};
+constexpr chrono::milliseconds update_delay_fast{0};
+  
 screen::screen(rmioc::screen& device, rfbClient* vnc_client)
 : device(device)
 , vnc_client(vnc_client)
+, update_delay(update_delay_normal)
 {
     rfbClientSetClientData(
         this->vnc_client,
@@ -40,6 +42,12 @@ screen::screen(rmioc::screen& device, rfbClient* vnc_client)
     this->vnc_client->GotFrameBufferUpdate = screen::update_framebuf;
 }
 
+void screen::set_update_fast() {
+  this->update_delay = update_delay_fast;
+}
+void screen::set_update_normal() {
+  this->update_delay = update_delay_normal;
+}
 void screen::flush_update()
 {
      this->device.update(
@@ -53,12 +61,13 @@ auto screen::event_loop() -> event_loop_status
     {
         int remaining_wait_time =
             chrono::duration_cast<chrono::milliseconds>(
-                this->update_info.last_update_time + update_delay
+                this->update_info.last_update_time + this->update_delay
                 - chrono::steady_clock::now()
             ).count();
 
         if (remaining_wait_time <= 0)
         {
+          this->update_info.last_update_time = chrono::steady_clock::now();
             this->update_info.has_update = false;
 
             log::print("Screen update")
@@ -159,7 +168,7 @@ void screen::update_framebuf(rfbClient* vnc_client, int x, int y, int w, int h)
         that->update_info.has_update = true;
     }
 
-    that->update_info.last_update_time = chrono::steady_clock::now();
+    /*    that->update_info.last_update_time = chrono::steady_clock::now();*/
 }
 
 } // namespace app

src/app/screen.hpp

@@ -29,12 +29,16 @@ public:
 
     /** reMarkable screen device. */
     rmioc::screen& device;
-private:
 
+
+    void set_update_fast();
+    void set_update_normal();
+private:
     /** VNC connection. */
     rfbClient* vnc_client;
 
-    
+  std::chrono::milliseconds update_delay;
+  
     /**
      * Called by the VNC client library to initialize our local framebuffer.
      *