Единственный способ сделать это - отсканировать MASK курсоров и найти расстояние между последним установленным пикселем в маске курсора и горячей точкой курсоров Y, мне пришлось сделать это сегодня, так что вот код:
#define useUnsafe
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System;
using System.Windows.Forms;
namespace Utils
{
/// <summary>
/// Provides extension methods for the Cursor class
/// </summary>
/// <remarks>By Aaron Murgatroyd</remarks>
public static class CursorExtensionMethods
{
#region API Functions
/// <summary>
/// Contains the icon information for a Windows API icon
/// </summary>
private struct IconInfo
{
public bool fIcon;
public int xHotspot;
public int yHotspot;
public IntPtr hbmMask;
public IntPtr hbmColor;
}
/// <summary>
/// Gets the icon information for a Windows API icon
/// </summary>
/// <param name="hIcon">The icon to get the info for</param>
/// <param name="pIconInfo">The object to receive the info</param>
/// <returns>True on success, false on failure</returns>
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetIconInfo(IntPtr hIcon, ref IconInfo pIconInfo);
[DllImport("gdi32.dll")]
static extern bool DeleteObject(IntPtr hObject);
#endregion
#region Private Static Methods
/// <summary>
/// Scans bits in bitmap data for a set or unset bit
/// </summary>
/// <param name="byteData">The pointer to the first byte of the first scanline</param>
/// <param name="start">The vertical position to start the scan</param>
/// <param name="lineInc">The number of bytes to move per line</param>
/// <param name="maxLines">The number of lines to scan</param>
/// <param name="set">True to scan for set bits, false to scan for unset bits</param>
/// <param name="fromBottom">True to scan from the bottom of the bitmap, false to scan from the top</param>
/// <returns>The number of lines scanned before a bit was found, or -1 if none found before reaching max lines</returns>
#if useUnsafe
private static unsafe int ScanBits(IntPtr byteData, int start, int lineInc, int maxLines, bool set, bool fromBottom)
#else
private static int ScanBits(IntPtr byteData, int start, int lineInc, int maxLines, bool set, bool fromBottom)
#endif
{
// Calculate the starting byte of the first scanline
#if useUnsafe
byte* lbLine = ((byte*)byteData) + (start * lineInc);
#else
int lbLine = ((int)(byteData) + (start * lineInc));
#endif
int liLine = 0;
// Use lineInc to determines bytes per line
int liBytesPerLine = (lineInc < 0 ? -lineInc : lineInc);
// If we want to search in reverse order
if (fromBottom)
{
// Move to the START of the line
lbLine += lineInc * (maxLines - 1);
// Negate the line increment
lineInc = -lineInc;
}
while (maxLines > 0)
{
// Setup the line scan
#if useUnsafe
byte* lbData = lbLine;
#else
int lbData = lbLine;
#endif
int liByte = liBytesPerLine;
// For each byte in the line
while (liByte > 0)
{
#if !useUnsafe
byte lbByte = Marshal.ReadByte((IntPtr)lbData);
#endif
// If we want set bits, and a bit is set
#if useUnsafe
if (set && *lbData != 0)
#else
if (set && lbByte != 0)
#endif
// Return the line number
return liLine;
else
// If we want unset bits and any bits arent set
#if useUnsafe
if (!set && *lbData != byte.MaxValue)
#else
if (!set && lbByte != byte.MaxValue)
#endif
// Return the line number
return liLine;
// Next byte for scan line
liByte--;
lbData++;
}
// Next scan line
liLine++;
maxLines--;
lbLine += lineInc;
}
// If all lines were scanned, return -1
if (maxLines == 0)
return -1;
else
// Return number of lines scanned
return liLine;
}
#endregion
#region Public Static Methods
/// <summary>
/// Gets the number of pixels between the Y hotspot
/// and the last physical line of a cursor
/// </summary>
/// <param name="cursor">The cursor to scan</param>
/// <returns>
/// The number of lines between the Y hotspot
/// and the last physical line of the cursor
/// </returns>
public static int GetBaseLineHeight(this Cursor cursor)
{
return GetBaseLine(cursor) - cursor.HotSpot.Y;
}
/// <summary>
/// Gets the physical base line of the cursor, that is,
/// the distance between the top of the virtual cursor
/// and the physical base line of the cursor
/// </summary>
/// <param name="cursor">The cursor to scan</param>
/// <returns>The number of lines between the top of the virtual cursor
/// and the physical base line of the curosr</returns>
public static int GetBaseLine(this Cursor cursor)
{
IconInfo liiInfo = new IconInfo();
if (!GetIconInfo(cursor.Handle, ref liiInfo))
return cursor.Size.Height;
Bitmap lbmpBitmap = Bitmap.FromHbitmap(liiInfo.hbmMask);
try
{
BitmapData lbdData = lbmpBitmap.LockBits(
new Rectangle(0, 0, lbmpBitmap.Width, lbmpBitmap.Height),
ImageLockMode.ReadOnly, PixelFormat.Format1bppIndexed);
try
{
// Calculate number of lines in AND scan before any found
int liLine = ScanBits(lbdData.Scan0, 0, lbdData.Stride, cursor.Size.Height, false, true);
// If no AND scan bits found then scan for XOR bits
if (liLine == -1 && lbdData.Height == cursor.Size.Height * 2)
liLine = ScanBits(lbdData.Scan0, cursor.Size.Height, lbdData.Stride, cursor.Size.Height, true, true);
return cursor.Size.Height-liLine;
}
finally
{
lbmpBitmap.UnlockBits(lbdData);
}
}
finally
{
DeleteObject(liiInfo.hbmMask);
DeleteObject(liiInfo.hbmColor);
lbmpBitmap.Dispose();
}
}
#endregion
}
}
Вы можете отменить условное определение "useUnsafe" вверху, поэтому вам не нужно включать небезопасный код, если хотите, но имейте в виду, что в этом режиме он будет работать медленнее.
Так что для этого используются методы расширения, поэтому все, что вам нужно сделать, это добавить Cursor.Current.GetBaseLineHeight () к вашему Cursor.Position.Y, и это будет первая пустая строка под курсором.
т.
Point lptBlankLineUnderCursor = new Point(Cursor.Position.X, Cursor.Position.Y + Cursor.Current.GetBaseLineHeight())