From ccaeced4bfeaa25ea115252417beff622c0e08be Mon Sep 17 00:00:00 2001
From: Chris Young <chris@unsatisfactorysoftware.co.uk>
Date: Sun, 3 Feb 2013 18:50:16 +0000
Subject: [PATCH] Make fast scroll code easier to read

---
 amiga/gui.c | 66 ++++++++++++++++++++++++++++++-----------------------
 1 file changed, 38 insertions(+), 28 deletions(-)

diff --git a/amiga/gui.c b/amiga/gui.c
index ba5055a0f..9876a8a77 100755
--- a/amiga/gui.c
+++ b/amiga/gui.c
@@ -1050,6 +1050,28 @@ void ami_update_quals(struct gui_window_2 *gwin)
 	}
 }
 
+bool ami_spacebox_to_ns_coords(struct gui_window_2 *gwin, int *x, int *y,
+	int space_x, int space_y)
+{
+	int xs, ys;
+	int ns_x = space_x;
+	int ns_y = space_y;
+
+	ns_x /= gwin->bw->scale;
+	ns_y /= gwin->bw->scale;
+
+	ami_get_hscroll_pos(gwin, (ULONG *)&xs);
+	ami_get_vscroll_pos(gwin, (ULONG *)&ys);
+
+	ns_x += xs;
+	ns_y += ys;
+
+	*x = ns_x;
+	*y = ns_y;
+
+	return true;	
+}
+
 bool ami_mouse_to_ns_coords(struct gui_window_2 *gwin, int *x, int *y,
 	int mouse_x, int mouse_y)
 {
@@ -1069,19 +1091,7 @@ bool ami_mouse_to_ns_coords(struct gui_window_2 *gwin, int *x, int *y,
 	if((ns_x < 0) || (ns_x > bbox->Width) || (ns_y < 0) || (ns_y > bbox->Height))
 		return false;
 
-	ns_x /= gwin->bw->scale;
-	ns_y /= gwin->bw->scale;
-
-	ami_get_hscroll_pos(gwin, (ULONG *)&xs);
-	ami_get_vscroll_pos(gwin, (ULONG *)&ys);
-
-	ns_x += xs;
-	ns_y += ys;
-
-	*x = ns_x;
-	*y = ns_y;
-
-	return true;	
+	return ami_spacebox_to_ns_coords(gwin, x, y, ns_x, ns_y);
 }
 
 void ami_gui_scroll_internal(struct gui_window_2 *gwin, int xs, int ys)
@@ -3832,10 +3842,13 @@ void ami_do_redraw(struct gui_window_2 *gwin)
 			gwin->redraw_scroll = false;
 
  		if(gwin->new_content) gwin->redraw_scroll = false;
+//		if(gwin->bw->scale != 1.0) gwin->redraw_scroll = false;
 	}
 
 	if(gwin->redraw_scroll)
 	{
+		int x0, y0, x1, y1;
+		
 		gwin->bw->window->c_h_temp = gwin->bw->window->c_h;
 		gui_window_remove_caret(gwin->bw->window);
 
@@ -3846,31 +3859,28 @@ void ami_do_redraw(struct gui_window_2 *gwin)
 
 		if(vcurrent>oldv) /* Going down */
 		{
-			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true,
-					hcurrent, (oldv + height) / gwin->bw->scale - 1,
-					(hcurrent + width) / gwin->bw->scale,
-					(vcurrent + height) / gwin->bw->scale + 1);
+			ami_spacebox_to_ns_coords(gwin, &x0, &y0, 0, height - (vcurrent - oldv));
+			ami_spacebox_to_ns_coords(gwin, &x1, &y1, width, height);
+			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true, x0, y0, x1, y1);
 		}
 		else if(vcurrent<oldv) /* Going up */
 		{
-			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true,
-					hcurrent, vcurrent,
-					hcurrent + (width / gwin->bw->scale),
-					oldv);
+			ami_spacebox_to_ns_coords(gwin, &x0, &y0, 0, 0);
+			ami_spacebox_to_ns_coords(gwin, &x1, &y1, width, oldv - vcurrent);
+			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true, x0, y0, x1, y1);
 		}
 
 		if(hcurrent>oldh) /* Going right */
 		{
-			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true,
-					(width / gwin->bw->scale) + oldh , vcurrent,
-					hcurrent + (width / gwin->bw->scale),
-					vcurrent + (height / gwin->bw->scale));
+			ami_spacebox_to_ns_coords(gwin, &x0, &y0, width - (hcurrent - oldh), 0);
+			ami_spacebox_to_ns_coords(gwin, &x1, &y1, width, height);
+			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true, x0, y0, x1, y1);
 		}
 		else if(hcurrent<oldh) /* Going left */
 		{
-			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true,
-					hcurrent, vcurrent,
-					oldh, vcurrent + (height / gwin->bw->scale));
+			ami_spacebox_to_ns_coords(gwin, &x0, &y0, 0, 0);
+			ami_spacebox_to_ns_coords(gwin, &x1, &y1, oldh - hcurrent, height);
+			ami_do_redraw_limits(gwin->bw->window, gwin->bw, true, x0, y0, x1, y1);
 		}
 	}
 	else