How would you draw something to your screen? Not in one specific window that you make but, on top of everything you have currently open? Like for example a dot or circle?
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How would you draw something to your screen? Not in one specific window that you make but, on top of everything you have currently open? Like for example a dot or circle?
Call GetDCEx with hwnd = NULL. You'll get a HDC for the entire screen. You'll be able to draw anywhere on the screen regardless what windows are there.
Sorry I am pretty new to win32 could you please elaborate?
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Viggy
Here's a sample that uses a thread.
Put the following function in any Win32 application:
You start the thread using the following code:Code:DWORD WINAPI MyThread(LPVOID lpParameter)
{
HDC hdc;
SIZE s;
s.cx = ::GetSystemMetrics(SM_CXSCREEN);
s.cy = ::GetSystemMetrics(SM_CYSCREEN);
int x, y, z, r, g, b;
HBRUSH hbr, hbrOld;
while(TRUE)
{
x = s.cx * rand() / RAND_MAX; // position x
y = s.cy * rand() / RAND_MAX; // position y
z = 100 * rand() / RAND_MAX; // radius
r = 255 * rand() / RAND_MAX; // red color componennt
g = 255 * rand() / RAND_MAX;// green color component
b = 255 * rand() / RAND_MAX;// blue color component
hbr = ::CreateSolidBrush(RGB(r,g,b));
hdc = ::GetDCEx(NULL, 0, 0);
hbrOld = (HBRUSH) ::SelectObject(hdc, hbr);
::Ellipse(hdc, x - z, y - z, x + z, y + z);
::SelectObject(hdc, hbrOld);
::DeleteObject(hbr);
::ReleaseDC(NULL, hdc);
::Sleep(20);
}
}
This line can be antwhere in the Win32 application, just make sure it's in a place where it will be excuted exactly once (you can place it in the InitInstance function).Code:::CreateThread(0, 0, MyThread, 0, 0, 0);
It will fill the whole screen with colorfull circles.
That will draw on my desktop not just one specific window?
I repeat: "It will fill the *W.H.O.L.E. S.C.R.E.E.N.* with colorful circles".Quote:
Originally Posted by serpentinez
Instead of asking, why don't you try it ?
Yay, it works! Thank you soo much!!!
BTW I wasn't home so I just wanted to make sure! :D Thanks again!
EDIT: Okay, now I have this code:But every time I minimize then maximize a window the yellow circle disappears even while I have the application running (not that I would want it to stay after I close it but just to tell you that I am running the application). I have tried getting rid of the 'return 0;' at the end of the function but then I get an error saying that the function needs to return a value. Could anyone help please?Code:#include <windows.h>
#include "wtypes.h"
#include <iostream>
const char g_szClassName[] = "testWindowClass";
// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
DWORD WINAPI MyThread(LPVOID lpParameter)
{
HDC hdc;
SIZE s;
s.cx = ::GetSystemMetrics(SM_CXSCREEN);
s.cy = ::GetSystemMetrics(SM_CYSCREEN);
int x, y, z, r, g, b;
int horizontal = 0;
int vertical = 0;
RECT desktop;
// Get a handle to the desktop window
const HWND hDesktop = GetDesktopWindow();
// Get the size of screen to the variable desktop
GetWindowRect(hDesktop, &desktop);
// The top left corner will have coordinates (0,0)
// and the bottom right corner will have coordinates
// (horizontal, vertical)
horizontal = desktop.right;
vertical = desktop.bottom;
HBRUSH hbr, hbrOld;
x = horizontal / 4; //s.cx * rand() / RAND_MAX; // position x
y = vertical / 4; //s.cy * rand() / RAND_MAX; // position y
z = 30; // radius
r = 255; // red color componennt
g = 200;// green color component
b = 0;// blue color component
hbr = ::CreateSolidBrush(RGB(r,g,b));
hdc = ::GetDCEx(NULL, 0, 0);
hbrOld = (HBRUSH) ::SelectObject(hdc, hbr);
::Ellipse(hdc, x - z, y - z, x + z, y + z);
::SelectObject(hdc, hbrOld);
::DeleteObject(hbr);
::ReleaseDC(NULL, hdc);
::Sleep(20);
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
::CreateThread(0, 0, MyThread, 0, 0, 0);
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Cannot Register Window!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"Test Window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Cannot Create Window!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}