Convert from line scrolling to pixel scrolling. Increase pixel scroll amount...

webkit/glue/webinputevent_mac.mm

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006-2009 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 17 matching lines @@
 
 #include "config.h"
 
 #include "wtf/ASCIICType.h"
 #include "webkit/glue/webinputevent.h"
 #include "webkit/glue/event_conversion.h"
 
 #undef LOG
 #include "base/logging.h"
 
-static const unsigned long kDefaultScrollLinesPerWheelDelta = 3;
-
 // WebMouseEvent --------------------------------------------------------------
 
 WebMouseEvent::WebMouseEvent(NSEvent *event, NSView* view) {
   switch ([event type]) {
     case NSMouseExited:
       type = MOUSE_LEAVE;
       button = BUTTON_NONE;
       break;
     case NSLeftMouseDown:
       type = [event clickCount] == 2 ? MOUSE_DOUBLE_CLICK : MOUSE_DOWN;
@@ skipping 79 matching lines @@
 
   // Set coordinates by translating event coordinates from screen to client.
   NSPoint location = [NSEvent mouseLocation];  // global coordinates
   global_x = location.x;
   global_y = location.y;
   NSPoint windowLocal = [event locationInWindow];
   location = [view convertPoint:windowLocal fromView:nil];
   x = location.x;
   y = [view frame].size.height - location.y;  // flip y
 
-  // Convert wheel delta amount to a number of lines to scroll.
+  // Convert wheel delta amount to a number of pixels to scroll.
+  static const float kScrollbarPixelsPerTick = 40.0f;
   float wheel_delta = [event deltaY];
-  const float delta_lines = wheel_delta * kDefaultScrollLinesPerWheelDelta;
+  const float delta_lines = wheel_delta * kScrollbarPixelsPerTick;
 
   // Set scroll amount based on above calculations.
   if ([event modifierFlags] & NSShiftKeyMask) {
-    // Scrolling up should move left, scrolling down should move right.  This is
-    // opposite Safari, but seems more consistent with vertical scrolling.
     delta_x = delta_lines;
     delta_y = 0;
   } else {
     delta_x = 0;
     delta_y = delta_lines;
   }
   scroll_by_page = false;
 }
 
 // WebKeyboardEvent -----------------------------------------------------------
@@ skipping 849 matching lines @@
       [unmodified_str length] < kTextLengthCap) {
     [text_str getCharacters:&text[0]];
     [unmodified_str getCharacters:&unmodified_text[0]];
   } else {
     LOG(ERROR) << "Event had text too long; dropped";
   }
   [identifier_str getCString:&key_identifier[0]
                    maxLength:kIdentifierLengthCap
                     encoding:NSASCIIStringEncoding];
 }