WebWheelEvent WebEventFactory::createWebWheelEvent(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) { // Taken from WebCore static const float cScrollbarPixelsPerLine = 100.0f / 3.0f; POINT globalPosition = point(lParam); POINT position = globalPosition; ::ScreenToClient(hWnd, &position); WebWheelEvent::Granularity granularity = WebWheelEvent::ScrollByPixelWheelEvent; WebEvent::Modifiers modifiers = modifiersForEvent(wParam); double timestamp = ::GetTickCount() * 0.001; // ::GetTickCount returns milliseconds (Chrome uses GetMessageTime() / 1000.0) int deltaX = 0; int deltaY = 0; int wheelTicksX = 0; int wheelTicksY = 0; float delta = GET_WHEEL_DELTA_WPARAM(wParam) / static_cast<float>(WHEEL_DELTA); bool isMouseHWheel = (message == WM_VISTA_MOUSEHWHEEL); if (isMouseHWheel) { wheelTicksX = delta; wheelTicksY = 0; delta = -delta; } else { wheelTicksX = 0; wheelTicksY = delta; } if (isMouseHWheel || (modifiers & WebEvent::ShiftKey)) { deltaX = delta * static_cast<float>(horizontalScrollChars()) * cScrollbarPixelsPerLine; deltaY = 0; granularity = WebWheelEvent::ScrollByPixelWheelEvent; } else { deltaX = 0; deltaY = delta; int verticalMultiplier = verticalScrollLines(); if (verticalMultiplier == WHEEL_PAGESCROLL) granularity = WebWheelEvent::ScrollByPageWheelEvent; else { granularity = WebWheelEvent::ScrollByPixelWheelEvent; deltaY *= static_cast<float>(verticalMultiplier) * cScrollbarPixelsPerLine; } } return WebWheelEvent(WebEvent::Wheel, position, globalPosition, FloatSize(deltaX, deltaY), FloatSize(wheelTicksX, wheelTicksY), granularity, modifiers, timestamp); }
PlatformWheelEvent::PlatformWheelEvent(HWND hWnd, WPARAM wParam, LPARAM lParam, bool isMouseHWheel) : PlatformEvent(PlatformEvent::Wheel, wParam & MK_SHIFT, wParam & MK_CONTROL, GetKeyState(VK_MENU) & HIGH_BIT_MASK_SHORT, GetKeyState(VK_MENU) & HIGH_BIT_MASK_SHORT, ::GetTickCount() * 0.001) , m_position(positionForEvent(hWnd, lParam)) , m_globalPosition(globalPositionForEvent(hWnd, lParam)) , m_directionInvertedFromDevice(false) { float scaleFactor = deviceScaleFactorForWindow(hWnd); // How many pixels should we scroll per line? Gecko uses the height of the // current line, which means scroll distance changes as you go through the // page or go to different pages. IE 7 is ~50 px/line, although the value // seems to vary slightly by page and zoom level. Since IE 7 has a // smoothing algorithm on scrolling, it can get away with slightly larger // scroll values without feeling jerky. Here we use 100 px per three lines // (the default scroll amount on Windows is three lines per wheel tick). static const float cScrollbarPixelsPerLine = scaleFactor * 100.0f / 3.0f; float delta = GET_WHEEL_DELTA_WPARAM(wParam) / (scaleFactor * static_cast<float>(WHEEL_DELTA)); if (isMouseHWheel) { // Windows is <-- -/+ -->, WebKit wants <-- +/- -->, so we negate // |delta| after saving the original value on the wheel tick member. m_wheelTicksX = delta; m_wheelTicksY = 0; delta = -delta; } else { // Even though we use shift + vertical wheel to scroll horizontally in // WebKit, we still note it as a vertical scroll on the wheel tick // member, so that the DOM event we later construct will match the real // hardware event better. m_wheelTicksX = 0; m_wheelTicksY = delta; } if (isMouseHWheel || shiftKey()) { m_deltaX = delta * static_cast<float>(horizontalScrollChars()) * cScrollbarPixelsPerLine; m_deltaY = 0; m_granularity = ScrollByPixelWheelEvent; } else { m_deltaX = 0; m_deltaY = delta; int verticalMultiplier = verticalScrollLines(); m_granularity = (verticalMultiplier == WHEEL_PAGESCROLL) ? ScrollByPageWheelEvent : ScrollByPixelWheelEvent; if (m_granularity == ScrollByPixelWheelEvent) m_deltaY *= static_cast<float>(verticalMultiplier) * cScrollbarPixelsPerLine; } }