_SCREENIMAGE bug?

[LM]

I thought I'd throw this out there to see if anyone has any ideas.

Trying to do a screenshot using image& = _SCREENIMAGE.  My screen is set to 1920x1080, but I only get a partial image of the screen.  This is what I get:
_Width(image&) reports 1536 instead of 1920
_Height(image&) reports 864 instead of 1080

I am wondering if it could have to do with the font/text size zoom in Windows 10?  I have the resolution at 1920x1080 but have the Windows font/text size set at 125%.  1920 /1.25 = 1536 and 1080 / 1.25 = 864.  Not certain yet whether the text size is the issue as I have not had a chance to test my hypothesis.  I need to keep the Windows text size at 125% while still being able to get a full screenshot.

What do people think?  Any other ideas?  If that is the issue, how can I get a full screenshot instead of a partial screenshot?

[191Brian]

Hi

Your calculations seem to indicate you have correctly identified the cause, as far as I can tell the windows 10 is slightly misleading when it describes that setting as the the size of text as it scales the whole screen not just text.  That said I don't know what the solution would be.   

[SpriggsySpriggs]

This is the code block that performs the _SCREENIMAGE function. I'll do some looking online about fixes or workarounds

Code: C++: [Select]

1. int32 func__screenimage(int32 x1,int32 y1,int32 x2,int32 y2,int32 passed){
2.    
3.     #ifdef QB64_WINDOWS
4.        
5.         static int32 init=0;
6.         static int32 x,y,w,h;
7.        
8.         static HWND hwnd;
9.         static RECT rect;
10.         static HDC hdc;
11.        
12.         if (!init){
13.             hwnd=GetDesktopWindow();
14.             GetWindowRect(hwnd,&rect);
15.             x=rect.right-rect.left; y=rect.bottom-rect.top;
16.         }
17.        
18.         hdc=GetDC(NULL);
19.        
20.         static HDC hdc2=NULL;
21.         static HBITMAP bitmap;
22.         static int32 bx,by;
23.        
24.         if (passed){
25.             if (x1<0) x1=0;
26.             if (y1<0) y1=0;
27.             if (x2>x-1) x2=x-1;
28.             if (y2>y-1) y2=y-1;
29.             w=x2-x1+1; h=y2-y1+1;
30.             }else{
31.             x1=0; x2=x-1; y1=0; y2=y-1; w=x; h=y;
32.         }
33.        
34.        
35.        
36.         if (hdc2){
37.             if ((w!=bx)||(h!=by)){
38.                 DeleteObject(bitmap);
39.                 ReleaseDC(NULL,hdc2);
40.                 hdc2=CreateCompatibleDC(hdc);
41.                 bitmap=CreateCompatibleBitmap(hdc,w,h); bx=w; by=h;
42.                 SelectObject(hdc2,bitmap);
43.             }
44.             }else{
45.             hdc2=CreateCompatibleDC(hdc);
46.             bitmap=CreateCompatibleBitmap(hdc,w,h); bx=w; by=h;
47.             SelectObject(hdc2,bitmap);
48.         }
49.        
50.         init=1;
51.        
52.         BitBlt(        hdc2,
53.         0,0,
54.         w,h,
55.         hdc,
56.         x1,y1,
57.         SRCCOPY);
58.        
59.         static BITMAPFILEHEADER   bmfHeader;  
60.         static BITMAPINFOHEADER   bi;
61.         bi.biSize = sizeof(BITMAPINFOHEADER);    
62.         bi.biWidth = w;    
63.         bi.biHeight = -h; //A bottom-up DIB is specified by setting the height to a positive number, while a top-down DIB is specified by setting the height to a negative number. The bitmap color table will be appended to the BITMAPINFO structure.
64.         bi.biPlanes = 1;    
65.         bi.biBitCount = 32;    
66.         bi.biCompression = BI_RGB;    
67.         bi.biSizeImage = 0;  
68.         bi.biXPelsPerMeter = 0;    
69.         bi.biYPelsPerMeter = 0;    
70.         bi.biClrUsed = 0;    
71.         bi.biClrImportant = 0;
72.        
73.         static int32 i,i2;
74.         i2=func__dest();
75.         i=func__newimage(w,h,32,1);
76.         sub__dest(i);
77.        
78.         GetDIBits(hdc2,bitmap,0,h,write_page->offset,(BITMAPINFO*)&bi, DIB_RGB_COLORS);
79.         sub__setalpha(255,NULL,NULL,NULL,0);
80.         sub__dest(i2);
81.        
82.         ReleaseDC(NULL,hdc);
83.         return i;
84.         #else
85.         return func__newimage(func_screenwidth(), func_screenheight(), 32, 1);
86.     #endif
87. }

Try running this below code and let me know your results:

Code: QB64: [Select]

1. Option _Explicit
2.  
3. Type RECT
4.     As Long left, top, right, bottom
5. End Type
6.  
7. Declare Dynamic Library "User32"
8.     Function SetProcessDPIAware%% ()
9. End Declare
10.  
11. Declare CustomType Library
12.     Function GetDesktopWindow%& ()
13.     Function GetWindowRect%% (ByVal hWnd As _Offset, Byval lpRect As _Offset)
14.     Function GetClientRect%% (ByVal hWnd As _Offset, Byval lpRect As _Offset)
15. End Declare
16.  
17. Print SetProcessDPIAware
18. Dim As _Offset desktop
19. Dim As RECT rect, rect2
20. desktop = GetDesktopWindow
21. If desktop Then
22.     If GetWindowRect(desktop, _Offset(rect)) Then
23.         Print rect.left, rect.top, rect.right, rect.bottom
24.         If GetClientRect(desktop, _Offset(rect2)) Then
25.             Print rect2.left, rect2.top, rect2.right, rect2.bottom
26.         End If
27.     End If
28. End If

[Petr]

Just for test: What returns functions _DESKTOPWIDTH and _DESKTOPHEIGHT? If 1920 to 1080, try use image& =  _SCREENIMAGE(0, 0, _DESKTOPWIDTH, _DESKTOPHEIGHT), what it do.

[SpriggsySpriggs]

@Petr Without the program being DPI aware the results will be the scaled resolution, not 1920 x 1080 (I tested your above code and the image is 1536 x 864). I found a fix and I've made a pull request on GitHub.

[Petr]

@SpriggsySpriggs  Oh, thank you for the information :)

[SpriggsySpriggs]

@LM I have found the bug and squashed it, looks like. I am just waiting for the pull request on GitHub to be approved. Once it is, I'll let you know and you can download the Dev build and be A-OK.

[LM]

@LM I have found the bug and squashed it, looks like. I am just waiting for the pull request on GitHub to be approved. Once it is, I'll let you know and you can download the Dev build and be A-OK.

@SpriggsySpriggs
Thanks!  It sounds great that you found the bug.  I appreciate that you are looking in to it!  Please let me know once it is available.

Unfortunately I have not yet had a chance to test the code you asked me to run earlier and probably can't get to it yet for a few hours.  It sounds like you have found the issue/solution so I assume you don't need me to run it anymore, but please let me know if my assumption is incorrect.

[George McGinn]

I will give this code a test on both macOS (Big Sur) and Linux to see if I get the same results.

My guess is that it could be the Windows OS (which is why I don't run it anymore!

I'll do this sometime tonight and post my results here.

[SpriggsySpriggs]

@George McGinn This shouldn't apply to Linux or Mac at all. LM mentioned he is running the code in Windows 10.

[SpriggsySpriggs]

It sounds like you have found the issue/solution so I assume you don't need me to run it anymore, but please let me know if my assumption is incorrect.

@LM I'd be interested to know that it does rectify the issue on your end. If you get a chance to run it, please do. I know it worked for me because I was setting the environment to be aware of the DPI scaling which resulted in correct screenshots. I know it should work on your machine but it would be good to see if it works on yours. Don't feel like you absolutely must, though. Chances are, the bug fix will work and you won't have to worry at all.

[George McGinn]

I tried to run the second program in your post and I get a DYNAMIC LIBRARY not found on line 7 for the statement:
   DECLARE DYNAMIC LIBRARY "User32",6

I think this is a Windows feature, as any program the declares a DYNAMIC LIBRARY will not work on Linux.

I tried. I think this will also be a problem in macOS, so I will not try it there.

George

@LM I'd be interested to know that it does rectify the issue on your end. If you get a chance to run it, please do. I know it worked for me because I was setting the environment to be aware of the DPI scaling which resulted in correct screenshots. I know it should work on your machine but it would be good to see if it works on yours. Don't feel like you absolutely must, though. Chances are, the bug fix will work and you won't have to worry at all.

[SpriggsySpriggs]

@George McGinn This shouldn't apply to Linux or Mac at all. LM mentioned he is running the code in Windows 10.

@George McGinn As LM mentioned in his post, he's using Windows. The code I mentioned you could try running was his code in the original post, not mine. Mine is Windows only since this is a Windows issue. User32 is a Windows DLL.

[LM]

@LM I'd be interested to know that it does rectify the issue on your end. If you get a chance to run it, please do. I know it worked for me because I was setting the environment to be aware of the DPI scaling which resulted in correct screenshots. I know it should work on your machine but it would be good to see if it works on yours. Don't feel like you absolutely must, though. Chances are, the bug fix will work and you won't have to worry at all.

@SpriggsySpriggs
I did not have a chance to run it on the Win 10 machine but I was able to reproduce the issue on a Windows 8.0 machine (resolution 1920x1080, but set to enlarge text).  This is the output from your code:
1
0     0     1536    864
0     0     1536    864

When I do a screenshot with _SCREENIMAGE, I only get part of the screen.  What I get is a 1536 x 864 image that represents the upper left portion of the screen.  The lower right portion that I see on my actual computer screen is not included.

When I change the Windows settings back to not enlarge the text, _SCREENIMAGE grabs the whole screen correctly (1920x1080 image), and the output of your code is: 
1
0     0     1920   1080
0     0     1920   1080

I assume it will work exactly the same on the Windows 10 machine, but I am not able to get to that machine right now.

Does this help?  Thanks!

[SpriggsySpriggs]

Hmmmmm.... That does make me curious..... It should have made the program report back 1920 x 1080. Very curious. Something I haven't asked you yet is if you are on 32 or 64 bit.... Which are you on? It works fine for me in Windows 10 20H2 64 bit with QB64 x64 and with QB64 x32. If you can, try running this code in both your Windows 8 and Windows 10 environments.
@LM

Code: QB64: [Select]

1. Option _Explicit
2.  
3. Type RECT
4.     As Long left, top, right, bottom
5. End Type
6.  
7. Declare Dynamic Library "User32"
8.     Function SetProcessDPIAware%% ()
9. End Declare
10.  
11. Declare Dynamic Library "Shcore"
12.     Function SetProcessDpiAwareness%& (ByVal value As Long)
13. End Declare
14.  
15. Declare CustomType Library
16.     Function GetDesktopWindow%& ()
17.     Function GetWindowRect%% (ByVal hWnd As _Offset, Byval lpRect As _Offset)
18.     Function GetClientRect%% (ByVal hWnd As _Offset, Byval lpRect As _Offset)
19. End Declare
20.  
21. 'Print SetProcessDPIAware
22. Print SetProcessDpiAwareness(1)
23.  
24. Dim As _Offset desktop
25. Dim As RECT rect, rect2
26. desktop = GetDesktopWindow
27. If desktop Then
28.     If GetWindowRect(desktop, _Offset(rect)) Then
29.         Print rect.left, rect.top, rect.right, rect.bottom
30.         If GetClientRect(desktop, _Offset(rect2)) Then
31.             Print rect2.left, rect2.top, rect2.right, rect2.bottom
32.         End If
33.     End If
34. End If