From 61f0a4ec717f33e0121f1212703fed11d1e440f9 Mon Sep 17 00:00:00 2001
From: Yves Rizoud <yrizoud@gmail.com>
Date: Tue, 29 Sep 2009 17:57:43 +0000
Subject: [PATCH] [layers] Sped up the scrolling/adjusting of single layers.
 Speed is no longer relative to the number of visible layers. Pulkomandy, your
 idea of depth buffer was genius.

git-svn-id: svn://pulkomandy.tk/GrafX2/branches/layers@1047 416bcca6-2ee7-4201-b75f-2eb2f807beb1
---
 operatio.c |  3 ++-
 pages.c    | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/operatio.c b/operatio.c
index 83ed306a..332672c7 100644
--- a/operatio.c
+++ b/operatio.c
@@ -3975,7 +3975,8 @@ void Scroll_12_5(void)
     {
       // One layer at once
       Scroll_picture(Main_backups->Pages->Next->Image[Main_current_layer], Main_backups->Pages->Image[Main_current_layer], x_offset, y_offset);
-      Redraw_layered_image();
+      //Redraw_layered_image();
+      Redraw_current_layer();
     }
 
     Display_all_screen();
diff --git a/pages.c b/pages.c
index 9f2bbf1d..75107cc5 100644
--- a/pages.c
+++ b/pages.c
@@ -191,6 +191,27 @@ void Redraw_layered_image(void)
   Download_infos_backup(Main_backups);
 }
 
+void Redraw_current_layer(void)
+{
+  int i;
+  for (i=0; i<Main_image_width*Main_image_height; i++)
+  {
+    byte depth = *(Visible_image_depth_buffer.Image+i);
+    if (depth<=Main_current_layer)
+    {
+      byte color = *(Main_backups->Pages->Image[Main_current_layer]+i);
+      if (color != 0) /* transp color */
+      {
+        *(Visible_image[0].Image+i) = color;
+      }
+      else
+      {
+        *(Visible_image[0].Image+i) = *(Main_backups->Pages->Image[depth]+i);
+      }
+    }
+  }
+}
+
 void Upload_infos_page_main(T_Page * page)
 // Sauve l'écran courant dans la page
 {