CODEWITHSUNDEEP
c++screendrawinvisible
Kesarion
Kesarion

Reputation: 2848

How to draw to screen in c++?

How would I draw something on the screen ? not the console window but the entire screen, preferably with the console minimised.

Also, would it show up on a printscreen ? What I want to do is create something like a layer on top of the screen that only me and my aplication are aware of yet still be able to use aplications as usual.

Here's an example: Let's say I want 2 yellow squares 5 by 5 pixels in size appearing in the center of the screen on top of all the other applications, unclickable and invisible to a printscreen.

[Edit]

I forgot to mention that I'm using Visual Studio 2010 on Windows XP.

Upvotes: 7

Views: 46003

Answers (4)

johannes
johannes

Reputation: 15969

C++ has no notion of a "screen" and especially none of "graphics". The functionality needed is provided by your operating system. On many systems you will need a "Window" and draw on it. To do this portably, a library like Qt might help. A Windows solution was given by Oops. Maybe you want to use some OpenGL library, or Windows' DirectDraw/Direct3D from DirectX, in case you want to do some 3D stuff with your graphics.

Upvotes: 4

Puppy
Puppy

Reputation: 146930

Windows offers GDI/+, WPF, and DirectX (including Direct2D on Vista+).

Upvotes: 2

Pete Kirkham
Pete Kirkham

Reputation: 49311

The (rather nice but not recently updated) graphics library anti-grain geometry has very simple bindings to display its demos on a variety of windowing systems, you could look at those for examples. But for anything much more involved you're probably talking about operating system specific libraries.

Upvotes: 1

OlimilOops
OlimilOops

Reputation: 6797

in windows you can use the GetDC-function. just a minimalistic example:

#include <Windows.h>
#include <iostream>

void drawRect(){
    HDC screenDC = ::GetDC(0);
    ::Rectangle(screenDC, 200, 200, 300, 300);
::ReleaseDC(0, screenDC);
}
int main(void){
    char c;
    std::cin >> c;
    if (c == 'd') drawRect();
    std::cin >> c;
    return 0;
}

but since Windows Vista it is very slow

Upvotes: 9

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