[Xquartz-changes] xserver: Branch 'master'

Jeremy Huddleston jeremyhu at freedesktop.org
Thu Apr 19 19:48:41 PDT 2012


Rebased ref, commits from common ancestor:
commit cc89640fbe665e151e3c3fa60f76015ff27bfe50
Author: Jeremy Huddleston <jeremyhu at apple.com>
Date:   Thu Apr 19 18:48:22 2012 -0700

    XQuartz: Add a hack to better handle clicky wheel scroll mice
    
    We loose information from AppKit being in our way.  Before adopting
    smooth scrolling, we always rounded-up the number of scroll button
    clicks per NSEvent.  Now, the scroll value is accumulated in the
    dix, and clicky scroll wheels with legacy X11 clients are seeing
    an accumulation of error due to so many translations (button press
    to smooth scrolling value in AppKit, passed to the dix, and then
    synthesized into a button press).  This attempts to make the
    situation better.
    
    http://xquartz.macosforge.org/trac/ticket/562
    
    Signed-off-by: Jeremy Huddleston <jeremyhu at apple.com>

diff --git a/hw/xquartz/X11Application.m b/hw/xquartz/X11Application.m
index 3e9f108..9ce11d4 100644
--- a/hw/xquartz/X11Application.m
+++ b/hw/xquartz/X11Application.m
@@ -1643,6 +1643,26 @@ handle_mouse:
     {
         float deltaX = [e deltaX];
         float deltaY = [e deltaY];
+        CGEventRef cge = [e CGEvent];
+        BOOL isContinuous =
+            CGEventGetIntegerValueField(cge, kCGScrollWheelEventIsContinuous);
+
+#if 0
+        /* Scale the scroll value by line height */
+        CGEventSourceRef source = CGEventCreateSourceFromEvent(cge);
+        if (source) {
+            double lineHeight = CGEventSourceGetPixelsPerLine(source);
+            CFRelease(source);
+            
+            /* There's no real reason for the 1/5 ratio here other than that
+             * it feels like a good ratio after some testing.
+             */
+            
+            deltaX *= lineHeight / 5.0;
+            deltaY *= lineHeight / 5.0;
+        }
+#endif
+        
 #if !defined(XPLUGIN_VERSION) || XPLUGIN_VERSION == 0
         /* If we're in the background, we need to send a MotionNotify event
          * first, since we aren't getting them on background mouse motion
@@ -1663,6 +1683,93 @@ handle_mouse:
             deltaY *= -1;
         }
 #endif
+        /* This hack is in place to better deal with "clicky" scroll wheels:
+         * http://xquartz.macosforge.org/trac/ticket/562
+         */
+        if (!isContinuous) {
+            static NSTimeInterval lastScrollTime = 0.0;
+
+            /* These store how much extra we have already scrolled.
+             * ie, this is how much we ignore on the next event.
+             */
+            static double deficit_x = 0.0;
+            static double deficit_y = 0.0;
+
+            /* If we have past a second since the last scroll, wipe the slate
+             * clean
+             */
+            if ([e timestamp] - lastScrollTime > 1.0) {
+                deficit_x = deficit_y = 0.0;
+            }
+            lastScrollTime = [e timestamp];
+
+            if (deltaX != 0.0) {
+                /* If we changed directions, wipe the slate clean */
+                if ((deficit_x < 0.0 && deltaX > 0.0) ||
+                    (deficit_x > 0.0 && deltaX < 0.0)) {
+                    deficit_x = 0.0;
+                }
+
+                /* Eat up the deficit, but ensure that something is
+                 * always sent 
+                 */
+                if (fabs(deltaX) > fabs(deficit_x)) {
+                    deltaX -= deficit_x;
+
+                    if (deltaX > 0.0) {
+                        deficit_x = ceil(deltaX) - deltaX;
+                        deltaX = ceil(deltaX);
+                    } else {
+                        deficit_x = floor(deltaX) - deltaX;
+                        deltaX = floor(deltaX);
+                    }
+                } else {
+                    deficit_x -= deltaX;
+
+                    if (deltaX > 0.0) {
+                        deltaX = 1.0;
+                    } else {
+                        deltaX = -1.0;
+                    }
+
+                    deficit_x += deltaX;
+                }
+            }
+
+            if (deltaY != 0.0) {
+                /* If we changed directions, wipe the slate clean */
+                if ((deficit_y < 0.0 && deltaY > 0.0) ||
+                    (deficit_y > 0.0 && deltaY < 0.0)) {
+                    deficit_y = 0.0;
+                }
+
+                /* Eat up the deficit, but ensure that something is
+                 * always sent 
+                 */
+                if (fabs(deltaY) > fabs(deficit_y)) {
+                    deltaY -= deficit_y;
+
+                    if (deltaY > 0.0) {
+                        deficit_y = ceil(deltaY) - deltaY;
+                        deltaY = ceil(deltaY);
+                    } else {
+                        deficit_y = floor(deltaY) - deltaY;
+                        deltaY = floor(deltaY);
+                    }
+                } else {
+                    deficit_y -= deltaY;
+
+                    if (deltaY > 0.0) {
+                        deltaY = 1.0;
+                    } else {
+                        deltaY = -1.0;
+                    }
+
+                    deficit_y += deltaY;
+                }
+            }
+        }
+
         DarwinSendScrollEvents(deltaX, deltaY);
         break;
     }


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