Develop Reference

c# Windows form - Reference 32bpp BGRA BackgroundImage with layered window style WS_EX_LAYERED for alpha transparency support? [duplicate]

When I tried from with transparent background, it's not completely transparent.
I tried two code blocks for this issue. First i tried like this code:
public Form1()
{
InitializeComponent();
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
this.FormBorderStyle = FormBorderStyle.None;
//this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}
it look like this picture;
Then i found some different codes and tried ike this;
public Form1()
{
InitializeComponent();
this.TransparencyKey = Color.White;
this.BackColor = Color.White;
this.FormBorderStyle = FormBorderStyle.None;
this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}
And this looks like this picture;
You can see logo with a white border. I want to show only .png Logo completely transparent. What should i do? How can do this?
Here is my Logo image as .png;

You can use Layered Windows:
Using a layered window can significantly improve performance and
visual effects for a window that has a complex shape, animates its
shape, or wishes to use alpha blending effects. The system
automatically composes and repaints layered windows and the windows of
underlying applications. As a result, layered windows are rendered
smoothly, without the flickering typical of complex window regions. In
addition, layered windows can be partially translucent, that is,
alpha-blended.
Create layered window in Windows Forms
Here is some code from msdn code gallery which demonstrates creating Layered Windows in Windows Forms. It allows you to create a shaped splash screen and let you to move it by mouse.
Add PerPixelAlphaForm to the project and then it's enough to inherit from this form and call its SelectBitmap and pass your png to the method to create a layered window.
PerPixelAlphaForm.cs
#region Using directives
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
#endregion
namespace CSWinFormLayeredWindow
{
public partial class PerPixelAlphaForm : Form
{
public PerPixelAlphaForm()
{
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.ShowInTaskbar = false;
this.StartPosition = FormStartPosition.CenterScreen;
this.Load += PerPixelAlphaForm_Load;
}
void PerPixelAlphaForm_Load(object sender, EventArgs e)
{
this.TopMost = true;
}
protected override CreateParams CreateParams
{
get
{
// Add the layered extended style (WS_EX_LAYERED) to this window.
CreateParams createParams = base.CreateParams;
if(!DesignMode)
createParams.ExStyle |= WS_EX_LAYERED;
return createParams;
}
}
/// <summary>
/// Let Windows drag this window for us (thinks its hitting the title
/// bar of the window)
/// </summary>
/// <param name="message"></param>
protected override void WndProc(ref Message message)
{
if (message.Msg == WM_NCHITTEST)
{
// Tell Windows that the user is on the title bar (caption)
message.Result = (IntPtr)HTCAPTION;
}
else
{
base.WndProc(ref message);
}
}
/// <summary>
///
/// </summary>
/// <param name="bitmap"></param>
public void SelectBitmap(Bitmap bitmap)
{
SelectBitmap(bitmap, 255);
}
/// <summary>
///
/// </summary>
/// <param name="bitmap">
///
/// </param>
/// <param name="opacity">
/// Specifies an alpha transparency value to be used on the entire source
/// bitmap. The SourceConstantAlpha value is combined with any per-pixel
/// alpha values in the source bitmap. The value ranges from 0 to 255. If
/// you set SourceConstantAlpha to 0, it is assumed that your image is
/// transparent. When you only want to use per-pixel alpha values, set
/// the SourceConstantAlpha value to 255 (opaque).
/// </param>
public void SelectBitmap(Bitmap bitmap, int opacity)
{
// Does this bitmap contain an alpha channel?
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
{
throw new ApplicationException("The bitmap must be 32bpp with alpha-channel.");
}
// Get device contexts
IntPtr screenDc = GetDC(IntPtr.Zero);
IntPtr memDc = CreateCompatibleDC(screenDc);
IntPtr hBitmap = IntPtr.Zero;
IntPtr hOldBitmap = IntPtr.Zero;
try
{
// Get handle to the new bitmap and select it into the current
// device context.
hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
hOldBitmap = SelectObject(memDc, hBitmap);
// Set parameters for layered window update.
Size newSize = new Size(bitmap.Width, bitmap.Height);
Point sourceLocation = new Point(0, 0);
Point newLocation = new Point(this.Left, this.Top);
BLENDFUNCTION blend = new BLENDFUNCTION();
blend.BlendOp = AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = (byte)opacity;
blend.AlphaFormat = AC_SRC_ALPHA;
// Update the window.
UpdateLayeredWindow(
this.Handle, // Handle to the layered window
screenDc, // Handle to the screen DC
ref newLocation, // New screen position of the layered window
ref newSize, // New size of the layered window
memDc, // Handle to the layered window surface DC
ref sourceLocation, // Location of the layer in the DC
0, // Color key of the layered window
ref blend, // Transparency of the layered window
ULW_ALPHA // Use blend as the blend function
);
}
finally
{
// Release device context.
ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
SelectObject(memDc, hOldBitmap);
DeleteObject(hBitmap);
}
DeleteDC(memDc);
}
}
#region Native Methods and Structures
const Int32 WS_EX_LAYERED = 0x80000;
const Int32 HTCAPTION = 0x02;
const Int32 WM_NCHITTEST = 0x84;
const Int32 ULW_ALPHA = 0x02;
const byte AC_SRC_OVER = 0x00;
const byte AC_SRC_ALPHA = 0x01;
[StructLayout(LayoutKind.Sequential)]
struct Point
{
public Int32 x;
public Int32 y;
public Point(Int32 x, Int32 y)
{ this.x = x; this.y = y; }
}
[StructLayout(LayoutKind.Sequential)]
struct Size
{
public Int32 cx;
public Int32 cy;
public Size(Int32 cx, Int32 cy)
{ this.cx = cx; this.cy = cy; }
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct ARGB
{
public byte Blue;
public byte Green;
public byte Red;
public byte Alpha;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct BLENDFUNCTION
{
public byte BlendOp;
public byte BlendFlags;
public byte SourceConstantAlpha;
public byte AlphaFormat;
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst,
ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc,
Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool DeleteObject(IntPtr hObject);
#endregion
}
}
SplashScreen.cs
public partial class Form4 : CSWinFormLayeredWindow.PerPixelAlphaForm
{
public Form4()
{
InitializeComponent();
this.SelectBitmap(Properties.Resources.splash);
}
}
Note
The original answer was based on turning double buffer off and overriding OnPaintBackground and drawing the image without calling base method. The answer had a known issue; while the form was moveless it was working well but if form was moving or the window behind the form was changed the window was not updating. You can see previous code in revisions. The current edit which is completely based on an MSDN code doesn't have any known issue.

You can choose the level of transparency for an image via changing the alpha coefficient which is between 0 and 255. An image can be a backgrounf image too,no prob
private static Image ToGrayscale(Image s,int alpha)
{
Bitmap tImage = new Bitmap(s);
for (int x = 0; x < tImage.Width; x++)
{
for (int y = 0; y < tImage.Height; y++)
{
Color tCol = tImage.GetPixel(x, y);
Color newColor = Color.FromArgb(alpha, tCol.R, tCol.G, tCol.B);
tImage.SetPixel(x, y, newColor);
}
}
return tImage;
}

Screenshot with BitBlt results in black image on Windows 10

I am using the code below to capture a screenshot of the currently active window. This code comes from Capture screenshot Including Semitransparent windows in .NET, with a few small additions, i.e. it uses GetForegroundWindow and also a timer so that I can select the desired window.
On Windows 10 (x64) this works fine for Firefox browser, but it does not work with Chrome or Edge.
I find it strange that Screenshot captured using BitBlt in C# results a black image on Windows 10 [duplicate] is marked as a duplicate, because the answer from above (first link) does not solve this problem.
Any ideas why it does not work for Chrome or Edge?
Code:
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace App1
{
/// <summary>
/// Description of MainForm.
/// </summary>
public partial class MainForm : Form
{
public MainForm()
{
//
// The InitializeComponent() call is required for Windows Forms designer support.
//
InitializeComponent();
//
// TODO: Add constructor code after the InitializeComponent() call.
//
}
void DoCapture()
{
label1.Text = "Capturing...";
try
{
IntPtr hDesk = GetForegroundWindow();
//IntPtr hDesk = GetDesktopWindow();
var windowRect = new RECT();
GetWindowRect(hDesk, out windowRect);
int width = (int)(windowRect.Right - windowRect.Left);
int height = (int)(windowRect.Bottom - windowRect.Top);
Size sz = new Size(width, height);
sz.Width = (int)(sz.Width * 1.25); // this is just an adjustment for the Windows zoom factor of 125%
sz.Height = (int)(sz.Height * 1.25);
IntPtr hSrce = GetWindowDC(hDesk);
IntPtr hDest = CreateCompatibleDC(hSrce);
IntPtr hBmp = CreateCompatibleBitmap(hSrce, sz.Width, sz.Height);
IntPtr hOldBmp = SelectObject(hDest, hBmp);
bool b = BitBlt(hDest, 0,0, sz.Width, sz.Height, hSrce,
0, 0, CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt);
Bitmap bmp = Bitmap.FromHbitmap(hBmp);
SelectObject(hDest, hOldBmp);
DeleteObject(hBmp);
DeleteDC(hDest);
ReleaseDC(hDesk, hSrce);
bmp.Save(#"c:\temp\test.png");
bmp.Dispose();
label1.Text = "Done";
}
catch (Exception e){
label1.Text = "Exception Occurred";
textBox1.Text = e.ToString();
}
}
void Button1Click(object sender, EventArgs e)
{
timer1.Enabled = true;
}
// P/Invoke declarations
[DllImport("gdi32.dll")]
static extern bool BitBlt(IntPtr hdcDest, int xDest, int yDest, int
wDest, int hDest, IntPtr hdcSource, int xSrc, int ySrc, CopyPixelOperation rop);
[DllImport("user32.dll")]
static extern bool ReleaseDC(IntPtr hWnd, IntPtr hDc);
[DllImport("gdi32.dll")]
static extern IntPtr DeleteDC(IntPtr hDc);
[DllImport("gdi32.dll")]
static extern IntPtr DeleteObject(IntPtr hDc);
[DllImport("gdi32.dll")]
static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight);
[DllImport("gdi32.dll")]
static extern IntPtr CreateCompatibleDC(IntPtr hdc);
[DllImport("gdi32.dll")]
static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp);
[DllImport("user32.dll")]
public static extern IntPtr GetDesktopWindow();
[DllImport("user32.dll")]
public static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
public static extern IntPtr GetWindowDC(IntPtr ptr);
[DllImport("user32.dll")]
static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);
[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
}
void Timer1Tick(object sender, EventArgs e)
{
timer1.Enabled = false;
DoCapture();
}
}
}
Running this in SharpDevelop 5.1

Likely it doesn't work for these 2 browsers because they use a hardware-accelerated graphics context (OpenGL- or DirectX-based) to render their content, and this is incompatible with GDI-based calls.

I can suggest a simple workaround:
First use GetForegroundWindow to get the active window rect. Then call GetDesktopWindow and use that handle with the call to BitBlt:
Just add a single line to above code:
IntPtr hDesk = GetForegroundWindow();
... // get dimensions of active window
hDesk = GetDesktopWindow(); // add this line
IntPtr hSrce = GetWindowDC(hDesk);
IntPtr hDest = CreateCompatibleDC(hSrce);
Works fine.

How to fix memory leak in Word Add-In

I have a MS Word Application Add-in written with VSTO. It contains a button used to create new Letter documents. When pressed a document is instantiated, a WPF dialog is displayed to capture information and then the information is inserted into the document.
On one of my test machines I get the following exception when approximately 40 letters are created in a single Word session:
The disk is full. Free some space on this drive, or save the document
on another disk.
Try one or more of the following:
Close any unneeded documents, programs or windows.
Save the document to another disk.
So I monitored the Winword.exe process using Task Manager:
Memory starts at 97,000k
Memory steadily increases with each letter document until the error is seen at approximately 1,000,000k
If I then close all the documents the memory only drops down to 500,000k
Any tips on how I can troubleshoot the memory leak?
I've gone through my code and ensured that event handlers are unregistered and that i'm disposing objects that need disposing.
Any reference articles that I should be reading?
-- Edit --
Malick, I use unmanaged code to make the WPF window look like an Office dialog. Is there a better way of doing this? I'll try removing it. (edit, there wasn't a change. I'll try the memory monitoring tools)
public class OfficeDialog : Window
{
[DllImport("user32.dll")]
static extern int GetWindowLong(IntPtr hwnd, int index);
[DllImport("user32.dll")]
static extern int SetWindowLong(IntPtr hwnd, int index, int newStyle);
[DllImport("user32.dll")]
static extern bool SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter, int x, int y, int width, int height, uint flags);
[DllImport("user32.dll")]
static extern IntPtr SendMessage(IntPtr hwnd, uint msg, IntPtr wParam, IntPtr lParam);
const int GWL_EXSTYLE = -20;
const int WS_EX_DLGMODALFRAME = 0x0001;
const int SWP_NOSIZE = 0x0001;
const int SWP_NOMOVE = 0x0002;
const int SWP_NOZORDER = 0x0004;
const int SWP_FRAMECHANGED = 0x0020;
const uint WM_SETICON = 0x0080;
const int ICON_SMALL = 0;
const int ICON_BIG = 1;
public OfficeDialog()
{
this.ShowInTaskbar = false;
//this.Topmost = true;
}
public new void ShowDialog()
{
try
{
var helper = new WindowInteropHelper(this);
using (Process currentProcess = Process.GetCurrentProcess())
helper.Owner = currentProcess.MainWindowHandle;
base.ShowDialog();
}
catch (System.ComponentModel.Win32Exception ex)
{
Message.LogWarning(ex);
//this.Topmost = true;
var helper = new WindowInteropHelper(this);
using (Process currentProcess = Process.GetCurrentProcess())
helper.Owner = currentProcess.MainWindowHandle;
base.ShowDialog();
}
}
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
RemoveIcon(this);
HideMinimizeAndMaximizeButtons(this);
//using (Process currentProcess = Process.GetCurrentProcess())
// SetCentering(this, currentProcess.MainWindowHandle);
}
public static void HideMinimizeAndMaximizeButtons(Window window)
{
const int GWL_STYLE = -16;
IntPtr hwnd = new WindowInteropHelper(window).Handle;
long value = GetWindowLong(hwnd, GWL_STYLE);
SetWindowLong(hwnd, GWL_STYLE, (int)(value & -131073 & -65537));
}
public static void RemoveIcon(Window w)
{
// Get this window's handle
IntPtr hwnd = new WindowInteropHelper(w).Handle;
// Change the extended window style to not show a window icon
int extendedStyle = OfficeDialog.GetWindowLong(hwnd, GWL_EXSTYLE);
OfficeDialog.SetWindowLong(hwnd, GWL_EXSTYLE, extendedStyle | WS_EX_DLGMODALFRAME);
// reset the icon, both calls important
OfficeDialog.SendMessage(hwnd, WM_SETICON, (IntPtr)ICON_SMALL, IntPtr.Zero);
OfficeDialog.SendMessage(hwnd, WM_SETICON, (IntPtr)ICON_BIG, IntPtr.Zero);
// Update the window's non-client area to reflect the changes
OfficeDialog.SetWindowPos(hwnd, IntPtr.Zero, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
}
static void SetCentering(Window win, IntPtr ownerHandle)
{
bool isWindow = IsWindow(ownerHandle);
if (!isWindow) //Don't try and centre the window if the ownerHandle is invalid. To resolve issue with invalid window handle error
{
//Message.LogInfo(string.Format("ownerHandle IsWindow: {0}", isWindow));
return;
}
//Show in center of owner if win form.
if (ownerHandle.ToInt32() != 0)
{
var helper = new WindowInteropHelper(win);
helper.Owner = ownerHandle;
win.WindowStartupLocation = WindowStartupLocation.CenterOwner;
}
else
win.WindowStartupLocation = WindowStartupLocation.CenterOwner;
}
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsWindow(IntPtr hWnd);
}

Transparent background image for Form - Smooth edge shape for the Form

When I tried from with transparent background, it's not completely transparent.
I tried two code blocks for this issue. First i tried like this code:
public Form1()
{
InitializeComponent();
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BackColor = Color.Transparent;
this.FormBorderStyle = FormBorderStyle.None;
//this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}
it look like this picture;
Then i found some different codes and tried ike this;
public Form1()
{
InitializeComponent();
this.TransparencyKey = Color.White;
this.BackColor = Color.White;
this.FormBorderStyle = FormBorderStyle.None;
this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
}
And this looks like this picture;
You can see logo with a white border. I want to show only .png Logo completely transparent. What should i do? How can do this?
Here is my Logo image as .png;

You can use Layered Windows:
Using a layered window can significantly improve performance and
visual effects for a window that has a complex shape, animates its
shape, or wishes to use alpha blending effects. The system
automatically composes and repaints layered windows and the windows of
underlying applications. As a result, layered windows are rendered
smoothly, without the flickering typical of complex window regions. In
addition, layered windows can be partially translucent, that is,
alpha-blended.
Create layered window in Windows Forms
Here is some code from msdn code gallery which demonstrates creating Layered Windows in Windows Forms. It allows you to create a shaped splash screen and let you to move it by mouse.
Add PerPixelAlphaForm to the project and then it's enough to inherit from this form and call its SelectBitmap and pass your png to the method to create a layered window.
PerPixelAlphaForm.cs
#region Using directives
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
#endregion
namespace CSWinFormLayeredWindow
{
public partial class PerPixelAlphaForm : Form
{
public PerPixelAlphaForm()
{
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.ShowInTaskbar = false;
this.StartPosition = FormStartPosition.CenterScreen;
this.Load += PerPixelAlphaForm_Load;
}
void PerPixelAlphaForm_Load(object sender, EventArgs e)
{
this.TopMost = true;
}
protected override CreateParams CreateParams
{
get
{
// Add the layered extended style (WS_EX_LAYERED) to this window.
CreateParams createParams = base.CreateParams;
if(!DesignMode)
createParams.ExStyle |= WS_EX_LAYERED;
return createParams;
}
}
/// <summary>
/// Let Windows drag this window for us (thinks its hitting the title
/// bar of the window)
/// </summary>
/// <param name="message"></param>
protected override void WndProc(ref Message message)
{
if (message.Msg == WM_NCHITTEST)
{
// Tell Windows that the user is on the title bar (caption)
message.Result = (IntPtr)HTCAPTION;
}
else
{
base.WndProc(ref message);
}
}
/// <summary>
///
/// </summary>
/// <param name="bitmap"></param>
public void SelectBitmap(Bitmap bitmap)
{
SelectBitmap(bitmap, 255);
}
/// <summary>
///
/// </summary>
/// <param name="bitmap">
///
/// </param>
/// <param name="opacity">
/// Specifies an alpha transparency value to be used on the entire source
/// bitmap. The SourceConstantAlpha value is combined with any per-pixel
/// alpha values in the source bitmap. The value ranges from 0 to 255. If
/// you set SourceConstantAlpha to 0, it is assumed that your image is
/// transparent. When you only want to use per-pixel alpha values, set
/// the SourceConstantAlpha value to 255 (opaque).
/// </param>
public void SelectBitmap(Bitmap bitmap, int opacity)
{
// Does this bitmap contain an alpha channel?
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
{
throw new ApplicationException("The bitmap must be 32bpp with alpha-channel.");
}
// Get device contexts
IntPtr screenDc = GetDC(IntPtr.Zero);
IntPtr memDc = CreateCompatibleDC(screenDc);
IntPtr hBitmap = IntPtr.Zero;
IntPtr hOldBitmap = IntPtr.Zero;
try
{
// Get handle to the new bitmap and select it into the current
// device context.
hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
hOldBitmap = SelectObject(memDc, hBitmap);
// Set parameters for layered window update.
Size newSize = new Size(bitmap.Width, bitmap.Height);
Point sourceLocation = new Point(0, 0);
Point newLocation = new Point(this.Left, this.Top);
BLENDFUNCTION blend = new BLENDFUNCTION();
blend.BlendOp = AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = (byte)opacity;
blend.AlphaFormat = AC_SRC_ALPHA;
// Update the window.
UpdateLayeredWindow(
this.Handle, // Handle to the layered window
screenDc, // Handle to the screen DC
ref newLocation, // New screen position of the layered window
ref newSize, // New size of the layered window
memDc, // Handle to the layered window surface DC
ref sourceLocation, // Location of the layer in the DC
0, // Color key of the layered window
ref blend, // Transparency of the layered window
ULW_ALPHA // Use blend as the blend function
);
}
finally
{
// Release device context.
ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
SelectObject(memDc, hOldBitmap);
DeleteObject(hBitmap);
}
DeleteDC(memDc);
}
}
#region Native Methods and Structures
const Int32 WS_EX_LAYERED = 0x80000;
const Int32 HTCAPTION = 0x02;
const Int32 WM_NCHITTEST = 0x84;
const Int32 ULW_ALPHA = 0x02;
const byte AC_SRC_OVER = 0x00;
const byte AC_SRC_ALPHA = 0x01;
[StructLayout(LayoutKind.Sequential)]
struct Point
{
public Int32 x;
public Int32 y;
public Point(Int32 x, Int32 y)
{ this.x = x; this.y = y; }
}
[StructLayout(LayoutKind.Sequential)]
struct Size
{
public Int32 cx;
public Int32 cy;
public Size(Int32 cx, Int32 cy)
{ this.cx = cx; this.cy = cy; }
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct ARGB
{
public byte Blue;
public byte Green;
public byte Red;
public byte Alpha;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct BLENDFUNCTION
{
public byte BlendOp;
public byte BlendFlags;
public byte SourceConstantAlpha;
public byte AlphaFormat;
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst,
ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc,
Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool DeleteObject(IntPtr hObject);
#endregion
}
}
SplashScreen.cs
public partial class Form4 : CSWinFormLayeredWindow.PerPixelAlphaForm
{
public Form4()
{
InitializeComponent();
this.SelectBitmap(Properties.Resources.splash);
}
}
Note
The original answer was based on turning double buffer off and overriding OnPaintBackground and drawing the image without calling base method. The answer had a known issue; while the form was moveless it was working well but if form was moving or the window behind the form was changed the window was not updating. You can see previous code in revisions. The current edit which is completely based on an MSDN code doesn't have any known issue.

You can choose the level of transparency for an image via changing the alpha coefficient which is between 0 and 255. An image can be a backgrounf image too,no prob
private static Image ToGrayscale(Image s,int alpha)
{
Bitmap tImage = new Bitmap(s);
for (int x = 0; x < tImage.Width; x++)
{
for (int y = 0; y < tImage.Height; y++)
{
Color tCol = tImage.GetPixel(x, y);
Color newColor = Color.FromArgb(alpha, tCol.R, tCol.G, tCol.B);
tImage.SetPixel(x, y, newColor);
}
}
return tImage;
}

How to set the height of a window using c#?

Is it possible to set the height of a window using the window handle or process handle?
I have the following so far, assume the application in question is notepad.
Process[] processes = Process.GetProcessesByName("notepad");
foreach (Process p in processes)
{
if (p.MainWindowTitle == title)
{
handle = p.MainWindowHandle;
while ((handle = p.MainWindowHandle) == IntPtr.Zero)
{
Thread.Sleep(1000);
p.Refresh();
}
break;
}
}
Can I make use of handle or p to set the height of the window?

This is how I would do it:
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace ConsoleApplication1
{
class Program
{
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
[DllImport("user32.dll", SetLastError = true)]
static extern bool GetWindowRect(IntPtr hWnd, ref RECT Rect);
[DllImport("user32.dll", SetLastError = true)]
static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int Width, int Height, bool Repaint);
static void Main(string[] args)
{
Process[] processes = Process.GetProcessesByName("notepad");
foreach (Process p in processes)
{
IntPtr handle = p.MainWindowHandle;
RECT Rect = new RECT();
if (GetWindowRect(handle, ref Rect))
MoveWindow(handle, Rect.left, Rect.right, Rect.right-Rect.left, Rect.bottom-Rect.top + 50, true);
}
}
}
}
While you can do it with SetWindowPos, and SetWindowPos is the newer and more capable API, MoveWindow is just easier to call.

You should be able to use the Win32 SetWindowPos function (use for both position and size). Here's a link for how to do it in C#.
Here's a quick sample. This will move notepad to (10,10) on the screen, and resize it to (450,450):
class Program
{
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);
static void Main(string[] args)
{
Console.WriteLine("Start notepad and hit any key...");
Console.ReadKey(true);
Process[] processes = Process.GetProcessesByName("notepad");
foreach (Process p in processes)
{
var handle = p.MainWindowHandle;
SetWindowPos(handle, new IntPtr(SpecialWindowHandles.HWND_TOP), 10,10,450,450,SetWindowPosFlags.SWP_SHOWWINDOW);
break;
}
}
}
public enum SpecialWindowHandles
{
HWND_TOP = 0,
HWND_BOTTOM = 1,
HWND_TOPMOST = -1,
HWND_NOTOPMOST = -2
}
[Flags]
public enum SetWindowPosFlags : uint
{
SWP_ASYNCWINDOWPOS = 0x4000,
SWP_DEFERERASE = 0x2000,
SWP_DRAWFRAME = 0x0020,
SWP_FRAMECHANGED = 0x0020,
SWP_HIDEWINDOW = 0x0080,
SWP_NOACTIVATE = 0x0010,
SWP_NOCOPYBITS = 0x0100,
SWP_NOMOVE = 0x0002,
SWP_NOOWNERZORDER = 0x0200,
SWP_NOREDRAW = 0x0008,
SWP_NOREPOSITION = 0x0200,
SWP_NOSENDCHANGING = 0x0400,
SWP_NOSIZE = 0x0001,
SWP_NOZORDER = 0x0004,
SWP_SHOWWINDOW = 0x0040,
}