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      1 /*
      2  * Copyright (C) 2006, 2007 Apple Inc.  All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "PlatformWheelEvent.h"
     28 
     29 #include "FloatPoint.h"
     30 #include "FloatSize.h"
     31 #include <windows.h>
     32 #include <windowsx.h>
     33 
     34 namespace WebCore {
     35 
     36 #define HIGH_BIT_MASK_SHORT 0x8000
     37 #define SPI_GETWHEELSCROLLCHARS 0x006C
     38 
     39 static IntPoint positionForEvent(HWND hWnd, LPARAM lParam)
     40 {
     41     POINT point = {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
     42     ScreenToClient(hWnd, &point);
     43     return point;
     44 }
     45 
     46 static IntPoint globalPositionForEvent(HWND hWnd, LPARAM lParam)
     47 {
     48     POINT point = {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
     49     return point;
     50 }
     51 
     52 static int horizontalScrollChars()
     53 {
     54     static ULONG scrollChars;
     55     if (!scrollChars && !SystemParametersInfo(SPI_GETWHEELSCROLLCHARS, 0, &scrollChars, 0))
     56         scrollChars = 1;
     57     return scrollChars;
     58 }
     59 
     60 static int verticalScrollLines()
     61 {
     62     static ULONG scrollLines;
     63     if (!scrollLines && !SystemParametersInfo(SPI_GETWHEELSCROLLLINES, 0, &scrollLines, 0))
     64         scrollLines = 3;
     65     return scrollLines;
     66 }
     67 
     68 PlatformWheelEvent::PlatformWheelEvent(HWND hWnd, const FloatSize& delta, const FloatPoint& location)
     69     : m_isAccepted(false)
     70     , m_shiftKey(false)
     71     , m_ctrlKey(false)
     72     , m_altKey(false)
     73     , m_metaKey(false)
     74 {
     75     m_deltaX = delta.width();
     76     m_deltaY = delta.height();
     77 
     78     m_wheelTicksX = m_deltaX;
     79     m_wheelTicksY = m_deltaY;
     80 
     81     // Global Position is just x, y location of event
     82     POINT point = {location.x(), location.y()};
     83     m_globalPosition = point;
     84 
     85     // Position needs to be translated to our client
     86     ScreenToClient(hWnd, &point);
     87     m_position = point;
     88 }
     89 
     90 PlatformWheelEvent::PlatformWheelEvent(HWND hWnd, WPARAM wParam, LPARAM lParam, bool isMouseHWheel)
     91     : m_position(positionForEvent(hWnd, lParam))
     92     , m_globalPosition(globalPositionForEvent(hWnd, lParam))
     93     , m_isAccepted(false)
     94     , m_shiftKey(wParam & MK_SHIFT)
     95     , m_ctrlKey(wParam & MK_CONTROL)
     96     , m_altKey(GetKeyState(VK_MENU) & HIGH_BIT_MASK_SHORT)
     97     , m_metaKey(m_altKey) // FIXME: We'll have to test other browsers
     98 {
     99     // How many pixels should we scroll per line?  Gecko uses the height of the
    100     // current line, which means scroll distance changes as you go through the
    101     // page or go to different pages.  IE 7 is ~50 px/line, although the value
    102     // seems to vary slightly by page and zoom level.  Since IE 7 has a
    103     // smoothing algorithm on scrolling, it can get away with slightly larger
    104     // scroll values without feeling jerky.  Here we use 100 px per three lines
    105     // (the default scroll amount on Windows is three lines per wheel tick).
    106     static const float cScrollbarPixelsPerLine = 100.0f / 3.0f;
    107     float delta = GET_WHEEL_DELTA_WPARAM(wParam) / static_cast<float>(WHEEL_DELTA);
    108     if (isMouseHWheel) {
    109         // Windows is <-- -/+ -->, WebKit wants <-- +/- -->, so we negate
    110         // |delta| after saving the original value on the wheel tick member.
    111         m_wheelTicksX = delta;
    112         m_wheelTicksY = 0;
    113         delta = -delta;
    114     } else {
    115         // Even though we use shift + vertical wheel to scroll horizontally in
    116         // WebKit, we still note it as a vertical scroll on the wheel tick
    117         // member, so that the DOM event we later construct will match the real
    118         // hardware event better.
    119         m_wheelTicksX = 0;
    120         m_wheelTicksY = delta;
    121     }
    122     if (isMouseHWheel || m_shiftKey) {
    123         m_deltaX = delta * static_cast<float>(horizontalScrollChars()) * cScrollbarPixelsPerLine;
    124         m_deltaY = 0;
    125         m_granularity = ScrollByPixelWheelEvent;
    126     } else {
    127         m_deltaX = 0;
    128         m_deltaY = delta;
    129         int verticalMultiplier = verticalScrollLines();
    130         m_granularity = (verticalMultiplier == WHEEL_PAGESCROLL) ? ScrollByPageWheelEvent : ScrollByPixelWheelEvent;
    131         if (m_granularity == ScrollByPixelWheelEvent)
    132             m_deltaY *= static_cast<float>(verticalMultiplier) * cScrollbarPixelsPerLine;
    133     }
    134 }
    135 
    136 }
    137