pixie/examples/realtime_win32.nim

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## This example show how to have real time pixie using win32 API.
import pixie, winim/lean
let
w: int32 = 256
h: int32 = 256
var
screen = newImage(w, h)
ctx = newContext(screen)
frameCount = 0
hwnd: HWND
running = true
proc draw() =
# draw shiny sphere on gradient background
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let linerGradient = newPaint(pkGradientLinear)
linerGradient.gradientHandlePositions.add(vec2(0, 0))
linerGradient.gradientHandlePositions.add(vec2(0, 256))
linerGradient.gradientStops.add(
ColorStop(color: rgbx(0, 0, 0, 255), position: 0))
linerGradient.gradientStops.add(
ColorStop(color: rgbx(255, 255, 255, 255), position: 1))
ctx.fillStyle = linerGradient
ctx.fillRect(0, 0, 256, 256)
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let radialGradient = newPaint(pkGradientRadial)
radialGradient.gradientHandlePositions.add(vec2(128, 128))
radialGradient.gradientHandlePositions.add(vec2(256, 128))
radialGradient.gradientHandlePositions.add(vec2(128, 256))
radialGradient.gradientStops.add(
ColorStop(color: rgbx(255, 255, 255, 255), position: 0))
radialGradient.gradientStops.add(
ColorStop(color: rgbx(0, 0, 0, 255), position: 1))
ctx.fillStyle = radialGradient
ctx.fillCircle(vec2(128.0, 128.0 + sin(float(frameCount)/10.0) * 20), 76.8)
inc frameCount
# Draw image pixels onto win32 window.
let
w = screen.width.int32
h = screen.height.int32
dc = GetDC(hwnd)
var info = BITMAPINFO()
info.bmiHeader.biBitCount = 32
info.bmiHeader.biWidth = w
info.bmiHeader.biHeight = h
info.bmiHeader.biPlanes = 1
info.bmiHeader.biSize = DWORD sizeof(BITMAPINFOHEADER)
info.bmiHeader.biSizeImage = w * h * 4
info.bmiHeader.biCompression = BI_RGB
var bgrBuffer = newSeq[uint8](screen.data.len * 4)
# Convert to BGRA.
for i, c in screen.data:
bgrBuffer[i*4+0] = c.b
bgrBuffer[i*4+1] = c.g
bgrBuffer[i*4+2] = c.r
discard StretchDIBits(
dc,
0,
h - 1,
w,
-h,
0,
0,
w,
h,
bgrBuffer[0].addr,
info,
DIB_RGB_COLORS,
SRCCOPY
)
discard ReleaseDC(hwnd, dc)
proc windowProc(hwnd: HWND, message: UINT, wParam: WPARAM,
lParam: LPARAM): LRESULT {.stdcall.} =
case message
of WM_DESTROY:
PostQuitMessage(0)
running = false
return 0
else:
return DefWindowProc(hwnd, message, wParam, lParam)
proc main() =
var
hInstance = GetModuleHandle(nil)
appName = "Win32/Pixie"
msg: MSG
wndclass: WNDCLASS
wndclass.style = CS_HREDRAW or CS_VREDRAW
wndclass.lpfnWndProc = windowProc
wndclass.cbClsExtra = 0
wndclass.cbWndExtra = 0
wndclass.hInstance = hInstance
wndclass.hIcon = LoadIcon(0, IDI_APPLICATION)
wndclass.hCursor = LoadCursor(0, IDC_ARROW)
wndclass.hbrBackground = GetStockObject(WHITE_BRUSH)
wndclass.lpszMenuName = nil
wndclass.lpszClassName = appName
if RegisterClass(wndclass) == 0:
MessageBox(0, "This program requires Windows NT!", appName, MB_ICONERROR)
return
# Figure out the right size of the window we want.
var rect: lean.RECT
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rect.left = 0
rect.top = 0
rect.right = w
rect.bottom = h
AdjustWindowRectEx(cast[LPRECT](rect.addr), WS_OVERLAPPEDWINDOW, 0, 0)
# Open the window.
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hwnd = CreateWindow(
appName,
"Win32/Pixie",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
rect.right - rect.left,
rect.bottom - rect.top,
0,
0,
hInstance,
nil
)
ShowWindow(hwnd, SW_SHOW)
UpdateWindow(hwnd)
while running:
draw()
PeekMessage(msg, 0, 0, 0, PM_REMOVE)
TranslateMessage(msg)
DispatchMessage(msg)
main()