user32: Increased area for scrolling via mouse drag outside scrollbar.

When dragging the scrollbar thumb with the mouse, the mouse is able to move away from the scrollbar and keep scrolling so long as it isn't too far away from the scrollbar. This makes it easier to quickly scroll with the mouse. All that this patch changes is the distance that the mouse can be moved away from the scrollbar before it is consider outside of the scrollbar and returns to its original position. The distances are proportional to the size of the scrollbar.

user32: Increased area for scrolling via mouse drag outside scrollbar.
2f1c7b16 · Dylan Smith · Alexandre Julliard · fcaa5991 · 2f1c7b16
Commit 2f1c7b16 authored Jul 03, 2008 by Dylan Smith Committed by Alexandre Julliard Jul 04, 2008
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Showing with 13 additions and 4 deletions

scroll.c dlls/user32/scroll.c +13 -4

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--- a/dlls/user32/scroll.c
+++ b/dlls/user32/scroll.c
@@ -328,16 +328,25 @@ static UINT SCROLL_GetThumbVal( SCROLLBAR_INFO *infoPtr, RECT *rect,
 static BOOL SCROLL_PtInRectEx( LPRECT lpRect, POINT pt, BOOL vertical )
 {
    RECT rect = *lpRect;
+    int scrollbarWidth;
+    /* Pad hit rect to allow mouse to be dragged outside of scrollbar and
+     * still be considered in the scrollbar. */
    if (vertical)
    {
-	rect.left -= lpRect->right - lpRect->left;
+        scrollbarWidth = lpRect->right - lpRect->left;
-	rect.right += lpRect->right - lpRect->left;
+        rect.left -= scrollbarWidth*8;
+        rect.right += scrollbarWidth*8;
+        rect.top -= scrollbarWidth*2;
+        rect.bottom += scrollbarWidth*2;
    }
    else
    {
-	rect.top -= lpRect->bottom - lpRect->top;
+        scrollbarWidth = lpRect->bottom - lpRect->top;
-	rect.bottom += lpRect->bottom - lpRect->top;
+        rect.left -= scrollbarWidth*2;
+        rect.right += scrollbarWidth*2;
+        rect.top -= scrollbarWidth*8;
+        rect.bottom += scrollbarWidth*8;
    }
    return PtInRect( &rect, pt );
 }