Logarithmic scroll speed setting: speed doubles every 3 steps.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5288 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 9 insertions, 3 deletions

diff --git a/firmware/drivers/lcd-recorder.c b/firmware/drivers/lcd-recorder.c
index a711a8f..8f8e9f9 100644
--- a/firmware/drivers/lcd-recorder.c
+++ b/firmware/drivers/lcd-recorder.c
@@ -94,7 +94,7 @@ static volatile int scrolling_lines=0; /* Bitpattern of which lines are scrollin
 static void scroll_thread(void);
 static char scroll_stack[DEFAULT_STACK_SIZE];
 static const char scroll_name[] = "scroll";
-static char scroll_speed = 8; /* updates per second */
+static char scroll_ticks = 12; /* # of ticks between updates*/
 static int scroll_delay = HZ/2; /* ticks delay before start */
 static char scroll_step = 6;  /* pixels per scroll step */
 static int bidir_limit = 50;  /* percent */
@@ -856,9 +856,15 @@ void lcd_stop_scroll(void)
     scrolling_lines=0;
 }
 
+static const char scroll_tick_table[16] = {
+ /* Hz values:
+    1, 1.25, 1.55, 2, 2.5, 3.12, 4, 5, 6.25, 8.33, 10, 12.5, 16.7, 20, 25, 33 */
+    100, 80, 64, 50, 40, 32, 25, 20, 16, 12, 10, 8, 6, 5, 4, 3
+};
+
 void lcd_scroll_speed(int speed)
 {
-    scroll_speed = speed;
+    scroll_ticks = scroll_tick_table[speed];
 }
 
 void lcd_scroll_step(int step)
@@ -933,7 +939,7 @@ static void scroll_thread(void)
             lcd_update_rect(xpos, ypos, LCD_WIDTH - xpos, pf->height);
         }
 
-        sleep(HZ/scroll_speed);
+        sleep(scroll_ticks);
     }
 }