Develop Reference

Fliped cursor icon on desktop recording using directshow

Using Directshow.NET I have developed an application which will record the desktop screen, to get mouse pointer we need to paint mouse pointer by our own. So I added SampleGrabber adn in BufferCB I have written below code:
public const Int32 CURSOR_SHOWING = 0x00000001;
[StructLayout(LayoutKind.Sequential)]
public struct ICONINFO
{
public bool fIcon;
public Int32 xHotspot;
public Int32 yHotspot;
public IntPtr hbmMask;
public IntPtr hbmColor;
}
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public Int32 x;
public Int32 y;
}
[StructLayout(LayoutKind.Sequential)]
public struct CURSORINFO
{
public Int32 cbSize;
public Int32 flags;
public IntPtr hCursor;
public POINT ptScreenPos;
}
[DllImport("user32.dll")]
public static extern bool GetCursorInfo(out CURSORINFO pci);
[DllImport("user32.dll")]
public static extern IntPtr CopyIcon(IntPtr hIcon);
[DllImport("user32.dll")]
public static extern bool DrawIcon(IntPtr hdc, int x, int y, IntPtr hIcon);
[DllImport("user32.dll")]
public static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);
public int BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)
{
Graphics g;
Bitmap v;
v = new Bitmap(m_videoWidth, m_videoHeight, m_stride, System.Drawing.Imaging.PixelFormat.Format24bppRgb, pBuffer);
g = Graphics.FromImage(v);
CURSORINFO cursorInfo;
cursorInfo.cbSize = Marshal.SizeOf(typeof(CURSORINFO));
if (GetCursorInfo(out cursorInfo))
{
if (cursorInfo.flags == CURSOR_SHOWING)
{
var iconPointer = CopyIcon(cursorInfo.hCursor);
ICONINFO iconInfo;
int iconX, iconY;
if (GetIconInfo(iconPointer, out iconInfo))
{
iconX = cursorInfo.ptScreenPos.x - ((int)iconInfo.xHotspot);
iconY = cursorInfo.ptScreenPos.y - ((int)iconInfo.yHotspot);
DrawIcon(g.GetHdc(), iconX, iconY, cursorInfo.hCursor);
g.ReleaseHdc();
g.Dispose();
v.Dispose();
}
}
}
return 0;
}
This code is painting the mouse cursor but cursor is flipped on Y axis.
It's may be because in BufferCB if we convert pBuffer in Bitmap then that frame is flipped on Y axis. To solve this I flipped current frame on Y axis by adding v.RotateFlip(RotateFlipType.RotateNoneFlipY); inside BufferCB after this change mouse pointer is not visible in desktop recording video.
How I can flip mouse pointer?
Update #1
I converted icon pointer to Icon then into Bitmap using Icon.ToBitmap() and then flipped on Y axis, here is code (Thanks to #Roman R.):
...
iconX = cursorInfo.ptScreenPos.x - ((int)iconInfo.xHotspot);
iconY = cursorInfo.ptScreenPos.y - ((int)iconInfo.yHotspot);
Icon ic = Icon.FromHandle(iconPointer);
Bitmap icon = ic.ToBitmap();
icon.RotateFlip(RotateFlipType.RotateNoneFlipY);
g.DrawImage(icon, iconX, iconY);
g.Dispose();
v.Dispose();
icon.Dispose();
ic.Dispose();
...
Only one issue I am facing in above modification sometimes I get ArgumentException at line Bitmap icon = ic.ToBitmap();
System.ArgumentException occurred
HResult=-2147024809
Message=Parameter is not valid.
Source=System.Drawing
StackTrace:
at System.Drawing.Bitmap.FromHicon(IntPtr hicon)
InnerException:
I disposed all the bitmaps used, still i get this exception.

The problem you have here is your BufferCB implementation. You create a temporary Graphics/Bitmap object, so that it could be updated with the cursor overlay. You have this bitmap upside down and normal draw of the icon applies it flipped.
You need to take into account that normal order of lines of 24-bit RGB buffer you get with BufferCB callback is bottom-to-top; order of lines Bitmap constructor expects is the opposite. You need to transfer lines into Bitmap in reversed order, then get them back respectively. I am not sure if negative stride works out there well, presumably it will not. Or simply overlay the cursor pre-flipped, to compensate for flipped background and overlay coordinates too.

You have another option of painting correct mouse pointer. Just take a mouse pointer's PNG image and in BufferCB:
public int BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)
{
Graphics g;
Bitmap v;
v = new Bitmap(m_videoWidth, m_videoHeight, m_stride, System.Drawing.Imaging.PixelFormat.Format24bppRgb, pBuffer);
g = Graphics.FromImage(v);
CURSORINFO cursorInfo;
cursorInfo.cbSize = Marshal.SizeOf(typeof(CURSORINFO));
if (GetCursorInfo(out cursorInfo))
{
if (cursorInfo.flags == CURSOR_SHOWING)
{
var iconPointer = CopyIcon(cursorInfo.hCursor);
ICONINFO iconInfo;
int iconX, iconY;
if (GetIconInfo(iconPointer, out iconInfo))
{
iconX = cursorInfo.ptScreenPos.x - ((int)iconInfo.xHotspot);
iconY = cursorInfo.ptScreenPos.y - ((int)iconInfo.yHotspot);
//DRAW STATIC POINTER IMAGE
Bitmap pointerImage = new Bitmap('pointer.png');
g.DrawImage(pointerImage,iconX,iconY);
g.Dispose();
v.Dispose();
}
}
}
return 0;
}

GetWindowRect returning 0

I am trying to find the window size of a new process that I am opening, but it is returning 0 for the height and width. Here is my code:
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GetWindowRect(IntPtr hWnd, ref RECT rect);
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left; // x position of upper-left corner
public int Top; // y position of upper-left corner
public int Right; // x position of lower-right corner
public int Bottom; // y position of lower-right corner
}
static void Main(string[] args)
{
Process process = new Process();
process.StartInfo.FileName = #"C:\Program Files (x86)\FirstClass\fcc32.exe";
//C:\Program Files (x86)\FirstClass\fcc32.exe
process.Start();
Console.WriteLine(process.HandleCount);
IntPtr hWnd = process.MainWindowHandle;
RECT rect = new RECT();
process.WaitForInputIdle();
GetWindowRect(hWnd, ref rect);
int width = rect.Right - rect.Left;
int height = rect.Bottom - rect.Top;
Console.WriteLine("Height: " + height + ", Width: " + width);
Console.ReadLine();
}

Thanks for the answers everybody, but the actual problem was that I was doing
IntPtr hWnd = process.MainWindowHandle;
before the process window had actually had a chance to open.

The signature is wrong it should be:
[DllImport("user32.dll", SetLastError=true)]
static extern bool GetWindowRect(IntPtr hwnd, out RECT lpRect);
change calling code accordingly:
RECT rect;
process.WaitForInputIdle();
GetWindowRect(hWnd, out rect);

c# Mouse click simulation to hwnd at x/y position

at the last 3 Days I found a lot of code for simulating mouse clicks to other windows. but none of them has worked.
I have the window handle hwnd and the X/Y position (pixel) where the click has to be.
The X/Y position is the position inside the window.
The best code I've found is this:
public void click(IntPtr hWnd, int x, int y)
{
RECT rec = new RECT();
GetWindowRect(hWnd, ref rec);
int newx = x - rec.Left;
int newy = y - rec.Top;
SendMessage(hWnd, WM_LBUTTONDOWN, 1, ((newy << 0x10) | newx));
SendMessage(hWnd, WM_LBUTTONUP, 0, ((newy << 0x10) | newx));
}
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern int SendMessage(IntPtr A_0, int A_1, int A_2, int A_3);
[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);
But it does not work 100% correctly.
It simulates a mouseclick at the correct window, but at the position of my real cursor.
And after this click my mouse jumps to a random position on the screen.
I hope someone has a working code and a small description how it works.
Thanks

Use this code to simulate the left mouse click in a certain position
//This is a replacement for Cursor.Position in WinForms
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern bool SetCursorPos(int x, int y);
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern void mouse_event(int dwFlags, int dx, int dy, int cButtons, int dwExtraInfo);
public const int MOUSEEVENTF_LEFTDOWN = 0x02;
public const int MOUSEEVENTF_LEFTUP = 0x04;
//This simulates a left mouse click
public static void LeftMouseClick(int xpos, int ypos)
{
SetCursorPos(xpos, ypos);
mouse_event(MOUSEEVENTF_LEFTDOWN, xpos, ypos, 0, 0);
mouse_event(MOUSEEVENTF_LEFTUP, xpos, ypos, 0, 0);
}

After replacing the cursor pointer with an image, how to center the image on the mouse pointer location instead of the top left corner of the image?

I have a cursor image .cur with maximum Width and Height of 250 pixels which i fully need.
I already managed to the replace the mouse pointer image with this cur image instead when holding right click.
The problem is that when using I'm doing that the pointer is associated with the top left corner of the image so when I go beyond for example the bounds of the canvas the cur image disappear and I go back to the normal pointer image.
I want this cur image to be centered on the mouse pointer location, not on it's top left corner. How can I do that?
private void canvas_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
Cursor cPro = new Cursor(#"C:\Users\Faris\Desktop\C# Testing Projects\cPro.cur");
globalValues.cursorSave = canvas.Cursor;
canvas.Cursor = cPro;
}
private void canvas_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
{
canvas.Cursor = globalValues.cursorSave;
}

You have two options:
In Visual Studio, open the cursor file or resource in the image editor and select the Hotspot Tool from the toolbar. Then click on the new hotspot and save the file.
Create a cursor pragmatically using a bitmap and specify the hot spot yourself.
The code below is from here:
namespace CursorTest
{
public struct IconInfo
{
public bool fIcon;
public int xHotspot;
public int yHotspot;
public IntPtr hbmMask;
public IntPtr hbmColor;
}
public class CursorTest : Form
{
public CursorTest()
{
this.Text = "Cursor Test";
Bitmap bitmap = new Bitmap(140, 25);
Graphics g = Graphics.FromImage(bitmap);
using (Font f = new Font(FontFamily.GenericSansSerif, 10))
g.DrawString("{ } Switch On The Code", f, Brushes.Green, 0, 0);
this.Cursor = CreateCursor(bitmap, 3, 3);
bitmap.Dispose();
}
[DllImport("user32.dll")]
public static extern IntPtr CreateIconIndirect(ref IconInfo icon);
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetIconInfo(IntPtr hIcon, ref IconInfo pIconInfo);
public static Cursor CreateCursor(Bitmap bmp, int xHotSpot, int yHotSpot)
{
IconInfo tmp = new IconInfo();
GetIconInfo(bmp.GetHicon(), ref tmp);
tmp.xHotspot = xHotSpot;
tmp.yHotspot = yHotSpot;
tmp.fIcon = false;
return new Cursor(CreateIconIndirect(ref tmp));
}
}
}

Why do I get a height and Width of 0?

Why do I get a heigh and Width of 0 with the below:
static void Main(string[] args)
{
Process notePad = new Process();
notePad.StartInfo.FileName = "notepad.exe";
notePad.Start();
IntPtr handle = notePad.Handle;
RECT windowRect = new RECT();
GetWindowRect(handle, ref windowRect);
int width = windowRect.Right - windowRect.Left;
int height = windowRect.Bottom - windowRect.Top;
Console.WriteLine("Height: " + height + ", Width: " + width);
Console.ReadLine();
}
Here is my definition of GetWindowRect:
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);
This is my definition for RECT:
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left; // x position of upper-left corner
public int Top; // y position of upper-left corner
public int Right; // x position of lower-right corner
public int Bottom; // y position of lower-right corner
}
Thanks all for any help.

You are passing a process handle to a function, GetWindowRect, that expects a window handle. Naturally, this fails. You should send Notepad.MainWindowHandle instead.

You may be querying the size before notepad has fully started up. Try this:
notePad.Start();
notePad.WaitForInputIdle(); // Waits for notepad to finish startup
IntPtr handle = notePad.Handle;

I like using pinvoke.net to sanity check all my PInvokes. GetWindowRect is described well at: http://pinvoke.net/default.aspx/user32/GetWindowRect.html