1 #[
2 https://gist.github.com/treeform/782149b5fc938753feacfca43637aa90
3 License: BSD 3-Clause
4 ]#
5 import winim, pixie
6 import winim/inc/windef
7
8 proc takeScreenshot*: Image=
9 # get size of the main screen
10 var screenRect: windef.Rect
11 GetClientRect GetDesktopWindow(), addr screenRect
12 let
13 x = screenRect.left
14 y = screenRect.top
15 w = (screenRect.right - screenRect.left)
16 h = (screenRect.bottom - screenRect.top)
17
18 # create an image
19 var image = newImage(w, h)
20
21 # copy screen data to bitmap
22 var
23 hScreen = GetDC(cast[HWND](nil))
24 hDC = CreateCompatibleDC(hScreen)
25 hBitmap = CreateCompatibleBitmap(hScreen, int32 w, int32 h)
26
27
28 discard SelectObject(hDC, hBitmap)
29 discard BitBlt(hDC, 0, 0, int32 w, int32 h, hScreen, int32 x, int32 y, SRCCOPY)
30
31 # setup bmi structure
32 var mybmi: BITMAPINFO
33 mybmi.bmiHeader.biSize = int32 sizeof(mybmi)
34 mybmi.bmiHeader.biWidth = w
35 mybmi.bmiHeader.biHeight = h
36 mybmi.bmiHeader.biPlanes = 1
37 mybmi.bmiHeader.biBitCount = 32
38 mybmi.bmiHeader.biCompression = BI_RGB
39 mybmi.bmiHeader.biSizeImage = w * h * 4
40
41 # copy data from bmi structure to the flippy image
42 discard CreateDIBSection(hdc, addr mybmi, DIB_RGB_COLORS, cast[ptr pointer](unsafeAddr image.data[0]), 0, 0)
43 discard GetDIBits(hdc, hBitmap, 0, h, cast[ptr pointer](unsafeAddr image.data[0]), addr mybmi, DIB_RGB_COLORS)
44
45 # for some reason windows bitmaps are flipped? flip it back
46 image.flipVertical()
47
48 # for some reason windows uses BGR, convert it to RGB
49 for i in 0 ..< image.height * image.width:
50 swap image.data[i].r, image.data[i].b
51
52 # delete data [they are not needed anymore]
53 DeleteObject hdc
54 DeleteObject hBitmap
55
56 #image.writeFile "screenshot.png"
57 image
58
59 var image = takeScreenshot()
60 image.writeFile "screenshot2.png"
From: https://www.cnblogs.com/StudyCat/p/16452495.html
