/// <summary>
/// Attempts to update the current stylus and tablet devices for the latest WM_POINTER message.
/// Will attempt retries if the tablet collection is invalid or does not contain the proper ids.
/// </summary>
/// <param name="deviceId">The id of the TabletDevice</param>
/// <param name="cursorId">The id of the StylusDevice</param>
/// <returns>True if successfully updated, false otherwise.</returns>
private bool UpdateCurrentTabletAndStylus(IntPtr deviceId, uint cursorId)
{
PointerTabletDeviceCollection tablets = Tablet.TabletDevices?.As <PointerTabletDeviceCollection>();
// We have an invalid tablet collection, we should refresh to make sure
// we have the latest.
if (!tablets.IsValid)
{
tablets.Refresh();
// If the refresh fails, we need to skip input here, nothing we can do.
// We'll try to pick up the proper state on the next WM_POINTER message.
if (!tablets.IsValid)
{
return(false);
}
}
_currentTabletDevice = tablets?.GetByDeviceId(deviceId);
_currentStylusDevice = _currentTabletDevice?.GetStylusByCursorId(cursorId);
// Something went wrong when querying the tablet or stylus, attempt a refresh
if (_currentTabletDevice == null || _currentStylusDevice == null)
{
tablets.Refresh();
_currentTabletDevice = tablets?.GetByDeviceId(deviceId);
_currentStylusDevice = _currentTabletDevice?.GetStylusByCursorId(cursorId);
// Still can't get the proper devices, just wait for the next message
if (_currentTabletDevice == null || _currentStylusDevice == null)
{
return(false);
}
}
return(true);
}
/// <summary>
/// Creates raw stylus data from the raw WM_POINTER properties
/// </summary>
/// <param name="pointerData">The current pointer info</param>
/// <param name="tabletDevice">The current TabletDevice</param>
/// <returns>An array of raw pointer data</returns>
private int[] GenerateRawStylusData(PointerData pointerData, PointerTabletDevice tabletDevice)
{
// Since we are copying raw pointer data, we want to use every property supported by this pointer.
// We may never access some of the unknown (unsupported by WPF) properties, but they should be there
// for consumption by the developer.
int pointerPropertyCount = tabletDevice.DeviceInfo.SupportedPointerProperties.Length;
// The data is as wide as the pointer properties and is per history point
int[] rawPointerData = new int[pointerPropertyCount * pointerData.Info.historyCount];
int[] data = new int[0];
// Get the raw data formatted to our supported properties
if (UnsafeNativeMethods.GetRawPointerDeviceData(
pointerData.Info.pointerId,
pointerData.Info.historyCount,
(uint)pointerPropertyCount,
tabletDevice.DeviceInfo.SupportedPointerProperties,
rawPointerData))
{
// Get the X and Y offsets to translate device coords to the origin of the hwnd
int originOffsetX, originOffsetY;
GetOriginOffsetsLogical(out originOffsetX, out originOffsetY);
int numButtons = tabletDevice.DeviceInfo.SupportedPointerProperties.Length - tabletDevice.DeviceInfo.SupportedButtonPropertyIndex;
int rawDataPointSize = (numButtons > 0) ? pointerPropertyCount - numButtons + 1 : pointerPropertyCount;
// Instead of a single entry for each button we use one entry for all buttons so reflect that in the raw data size
data = new int[rawDataPointSize * pointerData.Info.historyCount];
// Skip to the beginning of each stylus point in both the target WPF array and the pointer data array.
// The pointer data is arranged from last point to first point in the history while WPF data is arranged
// the reverse of this (in whole stylus points). Therefore we need to fill backward from pointer data
// via stylus point strides.
for (int i = 0, j = rawPointerData.Length - pointerPropertyCount; i < data.Length; i += rawDataPointSize, j -= pointerPropertyCount)
{
Array.Copy(rawPointerData, j, data, i, rawDataPointSize);
// Apply offsets from the origin to raw pointer data here
data[i + StylusPointDescription.RequiredXIndex] -= originOffsetX;
data[i + StylusPointDescription.RequiredYIndex] -= originOffsetY;
if (numButtons > 0)
{
int buttonIndex = i + rawDataPointSize - 1;
// The last data point probably has garbage in it, so clear it to store button info
data[buttonIndex] = 0;
// Condense any leftover button properties into a single entry
for (int k = tabletDevice.DeviceInfo.SupportedButtonPropertyIndex; k < pointerPropertyCount; k++)
{
int mask = rawPointerData[j + k] << (k - tabletDevice.DeviceInfo.SupportedButtonPropertyIndex);
data[buttonIndex] |= mask;
}
}
}
}
return(data);
}
