Does anyone know how to get a the bitmap of a Mac and Windwos browser window? I want to capture images from Chrome or FireFox as they are rendered and pass them into a C++ based plug-in.
I've looked into using a Chrome extension, but it's not practical.
Willing to do a Mac and Windows native app.
With the windows API you can grab screenshots fairly easy.
// get the device context of the screen
HDC hScreenDC = CreateDC("DISPLAY", NULL, NULL, NULL);
// and a device context to put it in
HDC hMemoryDC = CreateCompatibleDC(hScreenDC);
int width = GetDeviceCaps(hScreenDC, HORZRES);
int height = GetDeviceCaps(hScreenDC, VERTRES);
// maybe worth checking these are positive values
HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, width, height);
// get a new bitmap
HBITMAP hOldBitmap = SelectObject(hMemoryDC, hBitmap);
BitBlt(hMemoryDC, 0, 0, width, height, hScreenDC, 0, 0, SRCCOPY);
hBitmap = SelectObject(hMemoryDC, hOldBitmap);
// clean up
DeleteDC(hMemoryDC);
DeleteDC(hScreenDC);
// now your image is held in hBitmap. You can save it or do whatever with it
Im not sure about the exact area of the browser tho, or how to solve it for Mac. If nothing else, its a start.
Related
I have created a second desktop using CreateDesktop and im not switching to it. Also i have created some processes in it like Explorer.exe and Winrar.exe. Next i have a code which takes Screenshot of current desktop to clipboard. Both CreateDesktop and Screenshot works, But Screenshot of that new desktop or window returns a black bitmap:
This is the screenshot for a window in a desktop which returns current desktop:
// hwnd is handle to winrar or ... created in a new desktop retrieved by EnumDesktopWindow
RECT rc;
GetClientRect(hwnd, &rc);
const HDC hScreenDC = GetDC(nullptr);
const HDC hMemoryDC = CreateCompatibleDC(hScreenDC);
const int width = GetDeviceCaps(hScreenDC, HORZRES);
const int height = GetDeviceCaps(hScreenDC, VERTRES);
const HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, width, height);
HBITMAP(SelectObject(hMemoryDC, hBitmap));
BitBlt(hMemoryDC, 0, 0, width, height, hScreenDC, 0, 0, SRCCOPY);
OpenClipboard(nullptr);
EmptyClipboard();
SetClipboardData(CF_BITMAP, hBitmap);
CloseClipboard();
DeleteDC(hMemoryDC);
DeleteDC(hScreenDC);
I have implemented both this methods in c# but same thing happens there.
There are great resources like:
Capture screenshot of hidden desktop
take a screenshot of a desktop created using createdesktop api
C# – SCREEN CAPTURE WITH VISTA DWM (SHARED DIRECT3D SURFACE)
Window Contents Capturing using WM_PRINT Message
how to capture screen from another desktop?(CreateDesktop)
Also this is like a dead topic, No new article, Explanation or solution to it.
I have read most of them but no luck, This was my closest try i think. Also language doesnt matter for me: C#, C++, Python or ... .
I found the solution, It is interesting but no perfect, Just resolves my needs.
After CreateDesktop by calling OpenDesktop then SetThreadDesktop then using the screenshot code you get the screenshot of the window which is created inside CreateDesktop, Also no need for Creating Explorer.exe inside it if you just want the window:
CreateDesktopW(L"NewDesktop"); // CreateDesktop code here. This is my function
const HDESK Handle = OpenDesktopW(L"NewDesktop", 0, 0, GENERIC_ALL);
SetThreadDesktop(Handle);
// Above ScreenShot code here ...
The screenshot code needs a PrintWindow:
RECT rc;
GetClientRect(hwnd, &rc);
const HDC hScreenDC = GetDC(nullptr);
const HDC hMemoryDC = CreateCompatibleDC(hScreenDC);
const int width = GetDeviceCaps(hScreenDC, HORZRES);
const int height = GetDeviceCaps(hScreenDC, VERTRES);
const HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, width, height);
HBITMAP(SelectObject(hMemoryDC, hBitmap));
BitBlt(hMemoryDC, 0, 0, width, height, hScreenDC, 0, 0, SRCCOPY);
/// ADDED CODE
PrintWindow(hWnd, hMemoryDC, PW_CLIENTONLY);
///
OpenClipboard(nullptr);
EmptyClipboard();
SetClipboardData(CF_BITMAP, hBitmap);
CloseClipboard();
DeleteDC(hMemoryDC);
DeleteDC(hScreenDC);
Mine worked with a winrar.exe window inside a inactive desktop. You can try this then paste it to paint to see the result.
There is just one thing, The whole area of the screenshot bitmap is black except the window handle that i want which is fine by me. I think i should get handle of every window from bottom to top in order then mix them up.
All additions to this are appreciated.
I would like to do something which I believe is fairly simple but since I am new to the winapi I am finding a lot of problems. Basically I have an HDC (which I am BitBlitting from a loaded Bitmap) and I am drawing a rectangle on it. Then I would like to BitBlt that HDC onto a new HBITMAP Object, but alas for now to no avail.
Here is my code which I have been trying to get to work for a couple of hours now
BITMAPINFO info;
Bitmap *tempbmp = Bitmap::FromFile(L"C:\\Users\\abelajc\\Pictures\\BackgroundImage.png", false);
HBITMAP loadedbackground;
tempbmp->GetHBITMAP(NULL, &loadedbackground);
HBRUSH hRed = CreateSolidBrush(RGB(255, 0, 0));
HDC pDC = GetDC(0);
HDC TmpDC = CreateCompatibleDC(pDC); //main DC on which we will paint on
HDC dcBmp = CreateCompatibleDC(TmpDC); //DC for the loadedbackground HBitmap
HGDIOBJ TmpObj2 = SelectObject(dcBmp , tempbmp); //Selecting Bitmap in DC
BitBlt(TmpDC, 0, 0, 512, 512, dcBmp, 0, 0, SRCCOPY);
SelectObject(dcBmp, TmpObj2); //Deselecting Bitmap from DC
DeleteDC(dcBmp);
RECT rectangle;
SetRect(&rectangle, 5, 5, 20, 20);
FillRect(TmpDC, &rectangle, hRed);
HDC hCompDC = CreateCompatibleDC(TmpDC);
HBITMAP hBmp = CreateCompatibleBitmap(TmpDC, 512, 512);
HBITMAP hOld = (HBITMAP)SelectObject(hCompDC, hBmp);
BitBlt(hCompDC, 0, 0, 512, 512, TmpDC, 0, 0, SRCCOPY);
SelectObject(hCompDC, hOld);
DeleteDC(hCompDC);
Bitmap *image = new Bitmap(hBmp, NULL);
I think you just need some clarification about GDI.
A DC is exactly what its name imply : a device context. It's just a context, nothing concrete. Some DCs are context to a real graphic device, some others (memory DCs) are context to a virtual graphic surface in memory. The DCs you create with CreateCompatibleDC are memory DC, but creating the DC only create the context, not the memory surface. As the MSDN documentation says :
Before an application can use a memory DC for drawing operations, it must select a bitmap of the correct width and height into the DC.
You need to associate a HBITMAP with the DC. After doing that, you can consider that drawing to the DC is essentially drawing to the bitmap. The memory DC is the 'window' to the bitmap.
Once you understand that, you will see that your program can be greatly shortened. Feel free to comment if you still have problems.
How to convert HICON to HBITMAP in VC++?
I know this is an FAQ but all the solutions I've found on Google don't work. What I need is a function which takes a parameter HICON and returns HBITMAP.
Greatest if possible to make conversion to 32-bit bitmap even the icon is 24-bit, 16-bit or 8-bit.
This is the code, I don't know where it goes wrong:
HBITMAP icon_to_bitmap(HICON Icon_Handle) {
HDC Screen_Handle = GetDC(NULL);
HDC Device_Handle = CreateCompatibleDC(Screen_Handle);
HBITMAP Bitmap_Handle =
CreateCompatibleBitmap(Device_Handle,GetSystemMetrics(SM_CXICON),
GetSystemMetrics(SM_CYICON));
HBITMAP Old_Bitmap = (HBITMAP)SelectObject(Device_Handle,Bitmap_Handle);
DrawIcon(Device_Handle, 0,0, Icon_Handle);
SelectObject(Device_Handle,Old_Bitmap);
DeleteDC(Device_Handle);
ReleaseDC(NULL,Screen_Handle);
return Bitmap_Handle;
}
this code do it:
HICON hIcon = (HICON)LoadImage(instance, MAKEINTRESOURCEW(IDI_ICON), IMAGE_ICON, width, height, 0);
ICONINFO iconinfo;
GetIconInfo(hIcon, &iconinfo);
HBITMAP hBitmap = iconinfo.hbmColor;
and this is the code in the *.rc file:
IDI_ICON ICON "example.ico"
and this is the code in the *.h file:
#define IDI_ICON 4000
HDC hDC = GetDC(NULL);
HDC hMemDC = CreateCompatibleDC(hDC);
HBITMAP hMemBmp = CreateCompatibleBitmap(hDC, x, y);
HBITMAP hResultBmp = NULL;
HGDIOBJ hOrgBMP = SelectObject(hMemDC, hMemBmp);
DrawIconEx(hMemDC, 0, 0, hIcon, x, y, 0, NULL, DI_NORMAL);
hResultBmp = hMemBmp;
hMemBmp = NULL;
SelectObject(hMemDC, hOrgBMP);
DeleteDC(hMemDC);
ReleaseDC(NULL, hDC);
DestroyIcon(hIcon);
return hResultBmp;
I don't have code readily available to share, but I think this is pretty easy. You have to create the HBITMAP, create a device context, select the bitmap into the DC (this will make the bitmap the drawing area for this DC). Finally call the DrawIcon() function to draw your icon on this DC. After that detach the bitmap from the DC and destroy the DC. Your bitmap now should be ready to go.
Update after looking at your code:
I believe the problem is in the createCompatibleBitmap call. You are asking for a bitmap compatible with the memory DC, but memory DCs start with a 1 bit/pixel bitmap selected into them. Try asking for a bitmap compatible with the screen DC instead.
Update 2: you may want to look at this question as it seems related to your problem.
I found this(similar code works for me - 32x32 icons with or without alpha data):
used CopyImage (msdn link)
HICON hICON = /*your code here*/
HBITMAP hBITMAPcopy;
ICONINFOEX IconInfo;
BITMAP BM_32_bit_color;
BITMAP BM_1_bit_mask;
// 1. From HICON to HBITMAP for color and mask separately
//.cbSize required
//memset((void*)&IconInfo, 0, sizeof(ICONINFOEX));
IconInfo.cbSize = sizeof(ICONINFOEX);
GetIconInfoEx( hICON , &IconInfo);
//HBITMAP IconInfo.hbmColor is 32bit per pxl, however alpha bytes can be zeroed or can be not.
//HBITMAP IconInfo.hbmMask is 1bit per pxl
// 2. From HBITMAP to BITMAP for color
// (HBITMAP without raw data -> HBITMAP with raw data)
// LR_CREATEDIBSECTION - DIB section will be created,
// so .bmBits pointer will not be null
hBITMAPcopy = (HBITMAP)CopyImage(IconInfo.hbmColor, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);
// (HBITMAP to BITMAP)
GetObject(hBITMAPcopy, sizeof(BITMAP), &BM_32_bit_color);
//Now: BM_32_bit_color.bmBits pointing to BGRA data.(.bmWidth * .bmHeight * (.bmBitsPixel/8))
// 3. From HBITMAP to BITMAP for mask
hBITMAPcopy = (HBITMAP)CopyImage(IconInfo.hbmMask, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);
GetObject(hBITMAPcopy, sizeof(BITMAP), &BM_1_bit_mask);
//Now: BM_1_bit_mask.bmBits pointing to mask data (.bmWidth * .bmHeight Bits!)
BM_32_bit_color bitmap may be have Alpha *channel*(each 4th byte) already set! So - check for it before u add mask bit to color data.
was using XP without issue for a long time. switched to 7 and trying to capture screenshots with my previously functioning code no longer works. simple concept and relatively generic code...just find the window that i call and save it as a .png. any ideas what might make this bad boy run again? can't debug with my current setup, but it makes it all the way and spits out the error message after bmp->save(...) ...couldn't save image file. edit: also a file does get created/saved, but it is blank and not written to. perhaps the bitmap encoding or GDI is screwed up?
bool CScreenShot::Snap(CString wintitle, CString file, CString& ermsg)
{
ermsg = ""; // no error message
// create screen shot bitmap
EnumWinProcStruct prm = {0, (LPSTR)(LPCTSTR)wintitle, 0};
// Find the descriptor of the window with the caption wintitle
EnumDesktopWindows(0, EnumWindowsProc, (LPARAM)&prm);
if(!prm.hwnd)
{
ermsg.Format("couldn't find window \"%s\"", wintitle);
return false;
}
// Make the window the topmost window
SetWindowPos(prm.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE);
Sleep(300);
// Get device context for the top-level window and client rect
HDC hDC = GetDC(prm.hwnd);
RECT rc;
GetClientRect(prm.hwnd, &rc);
HDC memDC = CreateCompatibleDC(hDC);
// Set the size and color depth for the screen shot image
BITMAPINFO bmpInfo;
memset(&bmpInfo, 0, sizeof(bmpInfo));
bmpInfo.bmiHeader.biSize = sizeof(bmpInfo.bmiHeader);
bmpInfo.bmiHeader.biWidth = rc.right - rc.left;
bmpInfo.bmiHeader.biHeight = rc.bottom - rc.top;
bmpInfo.bmiHeader.biPlanes = 1;
bmpInfo.bmiHeader.biBitCount = 24;
bmpInfo.bmiHeader.biCompression = BI_RGB;
bmpInfo.bmiHeader.biSizeImage = bmpInfo.bmiHeader.biWidth * bmpInfo.bmiHeader.biHeight * 3;
// Create memory buffer and perform a bit-block transfer of the color data from the window to the memory
LPVOID addr;
HBITMAP memBM = CreateDIBSection(memDC, &bmpInfo, DIB_RGB_COLORS, &addr, 0, 0);
HGDIOBJ stdBM = SelectObject(memDC, memBM);
BOOL OK = BitBlt(memDC, 0, 0, bmpInfo.bmiHeader.biWidth, bmpInfo.bmiHeader.biHeight, hDC, 0, 0, SRCCOPY);
ReleaseDC(prm.hwnd, hDC);
SetWindowPos(prm.hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE);
// Initialize GDI+.
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
if(GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL) != Ok)
{
ermsg.Format("couldn't start GDI+");
return false;
}
// Create a Bitmap object for work with images defined by pixel data from the GDI HBitmap and the GDI HPalette.
Bitmap* bmp = ::new Bitmap(memBM, DIB_RGB_COLORS);
SelectObject(memDC, stdBM);
DeleteObject(memBM);
DeleteDC(memDC);
// Find the encoder for "image/png" mime type
CLSID encoderClsid;
EncoderParameters encoderParameters;
GetEncoderClsid(L"image/png", &encoderClsid);
encoderParameters.Count = 0;
// Convert file name to Unicode (wide-char) string.
WCHAR fn[_MAX_PATH];
MultiByteToWideChar(CP_THREAD_ACP, MB_PRECOMPOSED, file, file.GetLength() + 1, fn, _MAX_PATH);
// Save the screen shot into the specified file using image encoder with the mime style "image/png"
if(bmp->Save(fn, &encoderClsid, &encoderParameters) != Ok)
{
ermsg.Format("couldn't save image file \"%s\"", file);
return false;
}
::delete bmp;
GdiplusShutdown(gdiplusToken);
return true;
}
The error message implies that you're trying to save the file to a folder that you don't have permission to write to. Many folders such as Program Files are now protected. Since you didn't include the path in your sample code I'm unable to determine if this is the actual problem.
Edit: Another possibility is that the Bitmap is improperly constructed which causes the Save to fail. The second parameter to the constructor is supposed to be a handle to a palette, I think DIB_RGB_COLORS would be invalid here and you should use NULL. Also there are a couple of caveats noted in the Microsoft documentation and perhaps the different OS versions react differently when you break the rules:
You are responsible for deleting the GDI bitmap and the GDI palette. However, you should not delete the GDI bitmap or the GDI palette until after the GDI+ Bitmap::Bitmap object is deleted or goes out of scope.
Do not pass to the GDI+ Bitmap::Bitmap constructor a GDI bitmap or a GDI palette that is currently (or was previously) selected into a device context.
win7 won't accept encoderParameters.Count == 0 for some reason. Set that == 1 and you should be all set.
you probably could also just remove that parameter from Save() (overloaded)
I have a Window (win32 API) Application in visual c++. I am not using MFC. I have to add a picutre box to my application and Change the image of this picture box periodically. Can any one help me out in achieving the above task? Thanks in advance.
This is quite a complex task to post full code here, but I will try to give a few guidelines on how to do it:
First method is to load the image and paint it
Load your image (unfortunately the plain Win32 API has support for quite a few image formats BMP, ICO ...).
HBITMAP hImage = (HBITMAP)LoadImage(NULL, (LPCSTR)file, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE | LR_LOADTRANSPARENT);
Store the handle above somewhere in your application where you can access it from your WindowProcedure
In the WinProc on the WM_PAINT message you will need to paint the image. The code is something like:
HDC hdcMem = CreateCompatibleDC(hDC); // hDC is a DC structure supplied by Win32API
SelectObject(hdcMem, hImage);
StretchBlt(
hDC, // destination DC
left, // x upper left
top, // y upper left
width, // destination width
height, // destination height
hdcMem, // you just created this above
0,
0, // x and y upper left
w, // source bitmap width
h, // source bitmap height
SRCCOPY); // raster operation
Should work.
Now, the second way of doing it is to create a static control, with type being SS_BITMAP and set its image as:
hImage = LoadImage(NULL, file, IMAGE_BITMAP, w, h, LR_LOADFROMFILE);
SendMessage(hwnd, STM_SETIMAGE, IMAGE_BITMAP, (LPARAM)hImage);
where hwnd is the handle of your static control.