I followed this tutorial (there's a bit more than what's listed here because in my code I get a window via mouse click) for grabbing a window as a bitmap and then rendering that bitmap in a different window.
My question:
When that window is minimized or hidden (SW_HIDE) my screen capture doesn't work, so is it possible to capture a window when it is minimized or hidden?
The PrintWindow api works well, I use it for capturing thumbnails for hidden windows. Despite the name, it is different than WM_PRINT and WM_PRINTCLIENT, it works with pretty much every window except for Direct X / WPF windows.
I added some code (C#) but after reviewing how I used the code, I realized that the window isn't actually hidden when I capture its bitmap, its just off screen so this may not work for your case. Could you show the window off screen, do a print and then hide it again?
public static Bitmap PrintWindow(IntPtr hwnd)
{
RECT rc;
WinUserApi.GetWindowRect(hwnd, out rc);
Bitmap bmp = new Bitmap(rc.Width, rc.Height, PixelFormat.Format32bppArgb);
Graphics gfxBmp = Graphics.FromImage(bmp);
IntPtr hdcBitmap = gfxBmp.GetHdc();
bool succeeded = WinUserApi.PrintWindow(hwnd, hdcBitmap, 0);
gfxBmp.ReleaseHdc(hdcBitmap);
if (!succeeded)
{
gfxBmp.FillRectangle(new SolidBrush(Color.Gray), new Rectangle(Point.Empty, bmp.Size));
}
IntPtr hRgn = WinGdiApi.CreateRectRgn(0, 0, 0, 0);
WinUserApi.GetWindowRgn(hwnd, hRgn);
Region region = Region.FromHrgn(hRgn);
if (!region.IsEmpty(gfxBmp))
{
gfxBmp.ExcludeClip(region);
gfxBmp.Clear(Color.Transparent);
}
gfxBmp.Dispose();
return bmp;
}
There are WM_PRINT and WM_PRINTCLIENT messages you can send to the window, which cause its contents to be rendered into the HDC of your choice.
However, these aren't perfect: while the standard Win32 controls handle these correctly, any custom controls in the app might not.
I am trying to get the bitmap of partially hidden controls.
I used code before that did the drawing, but included windows overlapping it. So.. maybe you want to try this.
The WM_PRINTCLIENT should (in my understanding) redraw all inside the control, even if it is not really visible.
const int WM_PRINT = 0x317, WM_PRINTCLIENT = 0x318, PRF_CLIENT = 4,
PRF_CHILDREN = 0x10, PRF_NON_CLIENT = 2,
COMBINED_PRINTFLAGS = PRF_CLIENT | PRF_CHILDREN | PRF_NON_CLIENT;
SendMessage(handle, WM_PRINTCLIENT, (int)hdc, COMBINED_PRINTFLAGS);
//GDIStuff.BitBlt(hdc, 0, 0, width, height, hdcControl, 0, 0, (int)GDIStuff.TernaryRasterOperations.SRCCOPY);
The before code is commented out now. It is based on the code found here: Pocket PC: Draw control to bitmap (accepted answer). It is basically the same as Tim Robinson suggests in this thread.
Also, have a look here
http://www.tcx.be/blog/2004/paint-control-onto-graphics/
Related
I am trying to create a notification Icon based application in which I want to display some numbers ranging from 1-999.
I looked at this video which is similar to what I want to do but here the system tray icon just displays the icon and it shows a pop up rather than the system tray icon showing the number or any text.
Excluding the popup item, all I want to do is to read a number (input from somewhere) and display that number in the notification icon section.
I am open to trying any technology (QT, .net) for doing this. Basically, I am looking for some examples.
While parts of your question are vague, this is very possible, I'd even dare-say quite simple. Since you mentioned you're open to trying any technology, C# would probably simplify things for you.
Generate a new 16 x 16 Bitmap and draw the number to it using the Graphics class.
Convert the Image instance to an Icon instance, after disposing of your Graphics object.
Set the Icon property of your NotifyIcon to the icon you've just created.
These are the basic steps. You'll likely need to do some research if you aren't familiar with the classes used.
Thanks for replying to my question. Here is what I came up with. Not sure if this is what you were talking about.
Bitmap bmp = new Bitmap(WindowsFormsApplication2.Properties.Resources._16by16BitmapIcon);
RectangleF rectf = new RectangleF(2, 2, 16, 16);
Graphics g = Graphics.FromImage(bmp);
g.DrawString("99", new Font("Tahoma", 7), Brushes.Blue, rectf);
pictureBox1.Image = bmp;
pictureBox1.Height = bmp.Height;
pictureBox1.Width = bmp.Width;
g.Dispose();
var thumb = (Bitmap)bmp.GetThumbnailImage(64, 64, null, IntPtr.Zero);
thumb.MakeTransparent();
notifyIcon1.Icon = Icon.FromHandle(thumb.GetHicon());
Now my next question could this be done in a better way? This is my first C Sharp app so any suggestions are welcome!
public void ShowText(string text, Font font, Color col)
{
Brush brush = new SolidBrush(col);
// Create a bitmap and draw text on it
Bitmap bitmap = new Bitmap(16, 16);
Graphics graphics = Graphics.FromImage(bitmap);
graphics.DrawString(text, font, brush, 0, 0);
// Convert the bitmap with text to an Icon
Icon icon = Icon.FromHandle(bitmap.GetHicon());
m_notifyIcon.Icon = icon;
}
My simple Win32 DialogBox contains two static text controls (IDC_STATIC_TITLE and IDC_STATIC_SECONDARY), here's what it looks like in the resource editor:
At run time, the text first string is updated dynamically. Also, the font of the that text string is replaced such that it's bigger than the IDC_STATIC_SECONDARY string below it. The resulting text string might span a single line, two lines, or more.
I want the other static control holding the secondary text to be placed directly underneath the title string at run time. However, my resulting attempt to re-position this control in the WM_INITDIALOG callback isn't working very well. The second string is overlapping the first. I thought I could use DrawText with DT_CALCRECT to compute the height of the primary text string and then move the secondary text string based on the result. My code is coming up a bit short as seen here:
DrawText returns a RECT with coordinates {top=42 bottom=74 left=19 right=461} Subtracting bottom from top is "32". That seems a little short. I suspect I'm not invoking the API correctly and/or an issue with the different mappings between logical and pixel units.
Here's the relevant ATL code. The CMainWindow class just inherits from ATL's CDialogImpl class.
CMainWindow::CMainWindow():
_titleFont(NULL),
_secondaryFont(NULL)
{
LOGFONT logfont = {};
logfont.lfHeight = 30;
_titleFont = CreateFontIndirect(&logfont);
}
LRESULT CMainWindow::OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
CString strTitle;
RECT rectDrawText = {}, rectTitle={}, rectSecondary={};
CWindow wndTitle = GetDlgItem(IDC_STATIC_TITLE);
CWindow wndSecondary = GetDlgItem(IDC_STATIC_SECONDARY);
this->GetDlgItemText(IDC_STATIC_TITLE, strTitle);
wndTitle.SetFont(_titleFont); // font created with Create
wndTitle.GetWindowRect(&rectTitle);
wndSecondary.GetWindowRect(&rectSecondary);
ScreenToClient(&rectTitle);
ScreenToClient(&rectSecondary);
rectDrawText = rectTitle;
DrawText(wndTitle.GetDC(), strTitle, strTitle.GetLength(), &rectDrawText, DT_CALCRECT|DT_WORDBREAK); // compute the actual size of the text
UINT height = rectSecondary.bottom - rectSecondary.top; // get the original height of the secondary text control
rectSecondary.top = rectDrawText.bottom; // position it to be directly below the bottom of the title control
rectSecondary.bottom = rectSecondary.top + height; // add the height back
wndSecondary.MoveWindow(&rectSecondary);
return 0;
}
What am I doing wrong?
Despite what its name may make it sound like, wndTitle.GetDC() doesn't return some pointer/reference that's part of the CWindow and that's the same every call. Instead, it retrieves a brand new device context for the window each time. (It's basically a thin wrapper for the GetDC() Windows API call, right down to returning an HDC instead of the MFC equivalent.)
This device context, despite being associated with the window, is loaded with default parameters, including the default font (which IIRC is that old "System" font from the 16-bit days (most of this screenshot)).
So what you need to do is:
Call wndTitle.GetDC() to get the HDC.
Call SelectObject() to select the correct window font in (you can use WM_GETFONT to get this; not sure if MFC has a wrapper function for it), saving the return value, the previous font, for step 4
Call DrawText()
Call SelectObject() to select the previous font back in
Call wndTitle.ReleaseDC() to state that you are finished using the HDC
More details are on the MSDN page for CWindow::GetDC().
I have a win32 application that runs full screen when started. The application has some button which invoke pop up dialogs.
Is there a way to make the entire desktop (except the pop up) go transparent black unless the pop up is dismissed by the user? what I am talking of is similar to windows 7 UAC pop ups and the background it causes.
Is it possible to do similar stuff for a full screened window app?
It is possible do this…sort of. Perhaps I should say, you can simulate this effect. It won't actually be like the UAC dialog, as the user will still be able to interact with other running applications. There is no such concept as "system modal" available to applications. That's by design, of course. But you can certainly show a "light box" that dims out the rest of the desktop and forces focus on your app's dialog box.
The way I would do it is to create a giant layered window that sits on top of all other windows and covers the entire screen, fill it with black, and set the opacity as desired. Then, before you show a modal dialog (either by calling the MessageBox function or using the DialogBox function to show one of your own custom dialogs), display your light box window. Finally, after the user dismisses the modal dialog, you will destroy the light box window.
Here's some sample code. Error checking is omitted for brevity. So is other good style, like wrapping this mess up in one or more classes.
INT_PTR ShowLightBoxedDialog(HINSTANCE hInstance,
LPCTSTR pDlgTemplate,
HWND hwndParent,
DLGPROC pDlgProc,
BYTE opacityLevel)
{
const TCHAR szLightBoxClass[] = TEXT("LightBoxWndClass");
// Register the light box window class.
static bool lightBoxRegistered = false;
if (!lightBoxRegistered)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(wcex);
wcex.style = CS_NOCLOSE | CS_SAVEBITS;
wcex.lpfnWndProc = LightBoxWndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = NULL;
wcex.hIconSm = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = NULL;
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szLightBoxClass;
RegisterClassEx(&wcex);
lightBoxRegistered = true;
}
// Create and display the light box window.
HWND hwndLightBox = CreateWindowEx(WS_EX_NOACTIVATE | WS_EX_LAYERED,
szLightBoxClass,
NULL,
WS_POPUPWINDOW,
0, 0, 0, 0,
hwndParent,
NULL,
hInstance,
NULL);
SetLayeredWindowAttributes(hwndLightBox, 0, opacityLevel, LWA_ALPHA);
SetWindowPos(hwndLightBox,
HWND_TOP,
GetSystemMetrics(SM_XVIRTUALSCREEN),
GetSystemMetrics(SM_YVIRTUALSCREEN),
GetSystemMetrics(SM_CXVIRTUALSCREEN),
GetSystemMetrics(SM_CYVIRTUALSCREEN),
SWP_SHOWWINDOW);
// Display the modal dialog box (as you normally would).
// NOTE: The dialog box won't appear centered on the screen.
// For that, you will need to write centering code in response
// to the WM_INITDIALOG message in the dialog procedure.
INT_PTR result = DialogBox(hInstance, pDlgTemplate, hwndLightBox, pDlgProc);
//
// For demonstration purposes, I used the following code:
// INT_PTR result = MessageBox(hwndLightBox,
// TEXT("OH NOEZ!\n\nYour system is kaput! Abandon þe all hope."),
// NULL,
// MB_ABORTRETRYIGNORE | MB_ICONERROR);
// Destroy the light box window.
DestroyWindow(hwndLightBox);
// Return the result of the modal dialog box.
return result;
}
You'll notice that basically what I've done is created a wrapper around the DialogBox function, which you use whenever you want a dialog box with a "light box" effect. It takes all of the same parameters (the first 4), and then there's an additional one tacked on the end that allows you to specify the opacity level used for the "light box" effect. Something in the range of 150–200 is probably good. Naturally, you could pick something and hard-code it, but I suffer from severe allergies to hard-coded values. Anyway, it's super easy to call this function from anywhere:
ShowLightBoxedDialog(hInstance, /* your application instance */
MAKEINTRESOURCE(IDD_SAMPLE), /* your dialog template */
hWnd, /* parent window for dialog */
SampleWndProc, /* ptr to dialog procedure */
175); /* light box opacity level */
Because the code takes advantage of how modal dialogs already work in Windows, the user won't be able to interact with any other pieces of your application until they dismiss the dialog box. And because the "light box" window is positioned on top of everything else, it eats all mouse clicks and prevents setting focus to any other application. But it is trivial to work around using something like Alt+Tab.
So this is not a security feature! It is merely a visual effect!
And because it's just a silly visual effect, it's likely to be a frustrating one for your users. I don't actually recommend using it. But now you know how to do it. Wield such power responsibly, etc.
I am relatively new to the Win32/Windows API (non-MFC), and am trying to change the text colour of a static text control. It is already drawn to the screen in black, but I want to change it to another colour using the Windows Colour Chooser dialog, which is opened on clicking a button. Is this possible?
For the button, the WM_COMMAND message is handled on clicking. So far, I have written:
CHOOSECOLOR ccColour;
ccColour.lStructSize = sizeof(ccColour);
ccColour.hwndOwner = hWnd;
ccColour.rgbResult = crLabelTextColour;
ccColour.Flags = CC_FULLOPEN | CC_RGBINIT;
if (ChooseColor(&ccColour) == TRUE)
{
// crLabelTextColour is a COLORREF global variable assigned on loading the program
crLabelTextColour = ccColour.rgbResult;
}
This code, however, fails with an unhandled exception at the if statement, and I'm not sure why! Other examples seem to write code like this.
ChooseColor() crashes because you are not initializing the CHOOSECOLOR structure completely. You are only setting 3 fields, the rest will contain garbage. You'll need to zero-initialize everything, simple to do:
CHOOSECOLOR ccColour = {0};
I was wondering if there is a way to add (programatically, of course) an icon/button/whatever besides plain text to a window (Microsoft Windows window...)'s title bar or next to where the minimize/maximize/close buttons are. I could draw it myself and create an illusion it is a part of the window, but I wonder if in the user32 api there is such a method.
So far, I found a way to disable the minimize/maximize/close buttons but not a way to add a custom one to them. It seems strange to me.
Here is what I am trying to achieve:
I have been wondering how it is done here, since drawing a button for every window using gdi/gdi+ and then detecting if it is overlapped by another window and then displaying only the non-overlapped part seems to me like an unlikely solution. Probably the button has been registered in the window class so that every window has this button. Any pointers what to do?
In addition, how do I create a button at all, assuming I DON'T have Unicode enabled. Then in the following piece of code:
HWND hwndCommandLink = CreateWindow(
L"BUTTON", // Class; Unicode assumed.
L"", // Text will be defined later.
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_COMMANDLINK, // Styles.
10, // x position.
10, // y position.
100, // Button width.
100, // Button height.
hDlg, // Parent window.
NULL, // No menu.
(HINSTANCE)GetWindowLong(hDlg, GWL_HINSTANCE),
NULL); // Pointer not needed.
SendMessage(clHwnd, WM_SETTEXT, 0, (LPARAM)L"Command link");
SendMessage(clHwnd, BCM_SETNOTE, 0, (LPARAM)L"with note");
I have to substitute all the nice Windows constants with their long equivalent....However, when I search for them, all i get is this:
http://msdn.microsoft.com/en-us/library/bb775951(v=VS.85).aspx
Any pointers?