Screen capture for multiple-window application - winapi

On either Win32 or wxWidgets, is there an easy way to get a screen capture of an application which has several windows open - e.g. floating toolbars and similar - without getting their desktop, etc, as well?

The easiest would be capturing entire desktop, then enumerating windows and their positions so that you create a region/mask which leaves the windows of the process/application in question. Then applying the mask onto captured image would get you the requested snapshot.

Related

Matching Delphi monitor indexes to Windows Desktop numbering [duplicate]

When you press Identify button in Screen Resolution dialog then Windows shows you big white monitor numbers on each monitor. It was easy to find them programmatically together with monitor coordinates in Windows XP (with EnumDisplayDevices) but on Windows 7 it's broken. How can I do that?
EnumDisplayDevices and GetMonitorInfo are not reliable anymore for that purpose in Windows 7.
I tried GetMonitorInfo and then extracting monitor number from MONITORINFOEX.szDevice (I.E. \.\Display2) with no success. Another guy did that too two years ago and claimed that getMonitorInfo has a bug. This bug was marked as fixed by Microsoft without any comments but it still can be reproduced on a win7 machine having latest updates. (Btw, can anybody tell me - maybe this bug is absent on win8 ?)
I tried QueryDisplayConfig from new CCD API but didn't find needed info.
Does anybody know the way?
Windows does not provide a function that allows applications to obtain the numbers used by the display settings app. The numbers themselves are specific only to the display settings app and have no meaning in the system or in the CCD APIs used to query/set the display topology.
The best option is for applications to define their own criteria for assigning an index when prompting the user to select a display.
I have never wanted to know in my Windows applications the number of monitors, but you can call GetSystemMetrics function with parameter value SM_CMONITORS to get the number of display monitors on a desktop.
I call in my Windows applications function GetSystemMetrics mainly with the parameter values SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN and SM_YVIRTUALSCREEN to avoid opening application windows completely or partly outside the display area. An application window could be nevertheless not visible if the user has extended the display area over multiple monitors, but not all of them are turned on.
The SystemParametersInfo function function with value SPI_GETWORKAREA for uiAction parameter is also very useful to know where an application window can be positioned and how large it can be in width and height on primary screen without being partly hidden by other windows (bars) being always on top.
See also GetMonitorInfo function if more informations from the monitors are required in your Windows application.
For Windows versions supporting WDDM, which Windows 7 does, you can simply use DXGI which is part of DirectX. DXGI allows you to very easily enumerate the existing display adapters, the available display outputs per adapter and the supported display modes per display output. While enumerating there's a lot of additional data you can read out, like handles, identifiers and device names. All of this can easily be used to retrieve the working areas as well. The order in which adapters and outputs are enumerated is defined by the system and matches the order of your configuration screen.
See here for more information: MSDN DXGI Overview

Grab certain windows in Windows 10

I try to grab specific windows on Windows 10. I read some articles from MSDN to get familiar with APIs. My goal is to grab some certain windows, even if there are some windows on top of them (equivalent to OS X CGWindowList API). So if there are 2 windows: A and B, and windows B partially overlaps window A, I would like to be able to capture window A content, without capturing window B that partially covers window it.
According to this link, there are 5 different ways to capture the screen, if I understood them correct, most of them can capture only some regions on the screen, i.e. they don't distinguish between windows. The only API which allows to grab specific windows is "old standby, GDI".
I tried to acquire windows' device contexts using GetWindowDC() function, create a compatible bitmap and then use bit block transfer (BitBlt()). However, it seems that it does not always work as expected.
I've noticed several problems on Windows 10 (did not test on other operating systems):
Window's title bar usually is not captured. I tried to open Notepad and capture the window, but it was not fully captured, part of the scroll bar was not captured as well as a title bar. I tried to capture child windows of Notepad, but it did not work as expected, moreover some child windows are seem to have coordinates which seem to be wrong (the msctls_statusbar32msctls_statusbar32 child window of Notepad had the width which was 3 times bigger than the actual width of the window).
Some apps are not captured at all. For instance applications like "Photos", "Calc", "Settings" are not captured with that approach, when I try to capture them I get a black bitmap. There should be an API which allows capturing such windows, for instance TeamViewer is able to capture those Windows. It seems that all such windows are rendered by ApplicationFrameHost.exe process.
Does anyone know how to solve those issues?

how to access the large "Identify" digit of a Monitor Display in Windows? [duplicate]

When you press Identify button in Screen Resolution dialog then Windows shows you big white monitor numbers on each monitor. It was easy to find them programmatically together with monitor coordinates in Windows XP (with EnumDisplayDevices) but on Windows 7 it's broken. How can I do that?
EnumDisplayDevices and GetMonitorInfo are not reliable anymore for that purpose in Windows 7.
I tried GetMonitorInfo and then extracting monitor number from MONITORINFOEX.szDevice (I.E. \.\Display2) with no success. Another guy did that too two years ago and claimed that getMonitorInfo has a bug. This bug was marked as fixed by Microsoft without any comments but it still can be reproduced on a win7 machine having latest updates. (Btw, can anybody tell me - maybe this bug is absent on win8 ?)
I tried QueryDisplayConfig from new CCD API but didn't find needed info.
Does anybody know the way?
Windows does not provide a function that allows applications to obtain the numbers used by the display settings app. The numbers themselves are specific only to the display settings app and have no meaning in the system or in the CCD APIs used to query/set the display topology.
The best option is for applications to define their own criteria for assigning an index when prompting the user to select a display.
I have never wanted to know in my Windows applications the number of monitors, but you can call GetSystemMetrics function with parameter value SM_CMONITORS to get the number of display monitors on a desktop.
I call in my Windows applications function GetSystemMetrics mainly with the parameter values SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN and SM_YVIRTUALSCREEN to avoid opening application windows completely or partly outside the display area. An application window could be nevertheless not visible if the user has extended the display area over multiple monitors, but not all of them are turned on.
The SystemParametersInfo function function with value SPI_GETWORKAREA for uiAction parameter is also very useful to know where an application window can be positioned and how large it can be in width and height on primary screen without being partly hidden by other windows (bars) being always on top.
See also GetMonitorInfo function if more informations from the monitors are required in your Windows application.
For Windows versions supporting WDDM, which Windows 7 does, you can simply use DXGI which is part of DirectX. DXGI allows you to very easily enumerate the existing display adapters, the available display outputs per adapter and the supported display modes per display output. While enumerating there's a lot of additional data you can read out, like handles, identifiers and device names. All of this can easily be used to retrieve the working areas as well. The order in which adapters and outputs are enumerated is defined by the system and matches the order of your configuration screen.
See here for more information: MSDN DXGI Overview

How can I get monitors numbers from Screen Resolution dialog in win7 programmatically?

When you press Identify button in Screen Resolution dialog then Windows shows you big white monitor numbers on each monitor. It was easy to find them programmatically together with monitor coordinates in Windows XP (with EnumDisplayDevices) but on Windows 7 it's broken. How can I do that?
EnumDisplayDevices and GetMonitorInfo are not reliable anymore for that purpose in Windows 7.
I tried GetMonitorInfo and then extracting monitor number from MONITORINFOEX.szDevice (I.E. \.\Display2) with no success. Another guy did that too two years ago and claimed that getMonitorInfo has a bug. This bug was marked as fixed by Microsoft without any comments but it still can be reproduced on a win7 machine having latest updates. (Btw, can anybody tell me - maybe this bug is absent on win8 ?)
I tried QueryDisplayConfig from new CCD API but didn't find needed info.
Does anybody know the way?
Windows does not provide a function that allows applications to obtain the numbers used by the display settings app. The numbers themselves are specific only to the display settings app and have no meaning in the system or in the CCD APIs used to query/set the display topology.
The best option is for applications to define their own criteria for assigning an index when prompting the user to select a display.
I have never wanted to know in my Windows applications the number of monitors, but you can call GetSystemMetrics function with parameter value SM_CMONITORS to get the number of display monitors on a desktop.
I call in my Windows applications function GetSystemMetrics mainly with the parameter values SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN and SM_YVIRTUALSCREEN to avoid opening application windows completely or partly outside the display area. An application window could be nevertheless not visible if the user has extended the display area over multiple monitors, but not all of them are turned on.
The SystemParametersInfo function function with value SPI_GETWORKAREA for uiAction parameter is also very useful to know where an application window can be positioned and how large it can be in width and height on primary screen without being partly hidden by other windows (bars) being always on top.
See also GetMonitorInfo function if more informations from the monitors are required in your Windows application.
For Windows versions supporting WDDM, which Windows 7 does, you can simply use DXGI which is part of DirectX. DXGI allows you to very easily enumerate the existing display adapters, the available display outputs per adapter and the supported display modes per display output. While enumerating there's a lot of additional data you can read out, like handles, identifiers and device names. All of this can easily be used to retrieve the working areas as well. The order in which adapters and outputs are enumerated is defined by the system and matches the order of your configuration screen.
See here for more information: MSDN DXGI Overview

OSX List of all Valid Open Windows in All Spaces?

I'm wondering if there's a way to reliably retrieve all open VALID windows in all spaces?
The problem I'm encountering now is that on programs like Microsoft Word for Mac there are lots of child windows, resulting in my list being muddied by blank windows with no title, or windows that just don't lead anywhere. For example, for Word I'm getting these 3 windows when I only have 1 document open:
Document 1
Microsoft Word
Desktop
All are from Microsoft Word, and same goes for Excel and Powerpoint, the problem seems to be pretty exclusive to the Microsoft Office suite. Any ideas on how to deal with windows that don't actually have anything?
You can try to correlate with Accessibility (you don't mention how you're getting the window list right now), or just use some heuristics (ignore windows with no title, no workspace number, look at the window tag bits, etc.). Pull up the window list in Quartz Debug, browse around and you'll see some differences. If the window is visible, you can also hold down Control-Option with Quartz Debug in the background to get a pop up HUD with some more detailed information about the window underneath the cursor.
If you're really desperate you could grab the window contents and see if they're all transparent or white.

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