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[HELP-CODE]Scanning Screen for pixel color

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Join Date: Sep 2009

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evilguyme

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[HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

so far i have this code..

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#include "stdafx.h"
#include <iostream>
#include <windows.h>
#include <string>
 
 
using namespace std;
 
int main ()
{
	const int r1 = 175;
	const int g1 = 163;
	const int b1 = 134;
 
	HWND hwnd = FindWindow(NULL,"Test - Microsoft Visual Studio");
	SetForegroundWindow(hwnd);
	HDC hdc = GetDC(hwnd);
 
	POINT lame;
	lame.x = 0;
	lame.y = 0;
 
	int x = lame.x;
	int y = lame.y;
 
 
	for (int i = 0; i < 1280; i++)
	{
		x = i;
		y = 0;
 
		COLORREF col = GetPixel(hdc,lame.x,lame.y);
 
		int red1 = GetRValue(col);
		int green1 = GetGValue(col);
		int blue1 = GetBValue(col);
 
 
 
		if (x == 1280)
		{
			y = lame.y++;
			i = 0;
		}
 
		if (y == 801)
		{
			system("pause");
		}
 
		if (red1 == r1 && green1 == g1 && blue1 == b1)
		{
			cout << "Pixel found at: \t" << "X: "<< x << "\t\t" << "Y: " << y << "\n";
			system("pause");
		}
	}
	system("pause");
	return 0;
 
 
 
}
#include "stdafx.h"
#include <iostream>
#include <windows.h>
#include <string>


using namespace std;

int main ()
{
	const int r1 = 175;
	const int g1 = 163;
	const int b1 = 134;

	HWND hwnd = FindWindow(NULL,"Test - Microsoft Visual Studio");
	SetForegroundWindow(hwnd);
	HDC hdc = GetDC(hwnd);
		
	POINT lame;
	lame.x = 0;
	lame.y = 0;

	int x = lame.x;
	int y = lame.y;


	for (int i = 0; i < 1280; i++)
	{
		x = i;
		y = 0;

		COLORREF col = GetPixel(hdc,lame.x,lame.y);

		int red1 = GetRValue(col);
		int green1 = GetGValue(col);
		int blue1 = GetBValue(col);



		if (x == 1280)
		{
			y = lame.y++;
			i = 0;
		}

		if (y == 801)
		{
			system("pause");
		}

		if (red1 == r1 && green1 == g1 && blue1 == b1)
		{
			cout << "Pixel found at: \t" << "X: "<< x << "\t\t" << "Y: " << y << "\n";
			system("pause");
		}
	}
	system("pause");
	return 0;


	
}

i use it for scanning for a certain pixel on the screen but it doesn't seem to be working... no compiler or runtime errors but it just skips straight to press any key to continue...

i also can't find any resources to teach me some bitmap way..
if someone would care to explain how to capture screen to bmp and then analyze it for pixels..

or just tell me where i've gone wrong in my code.

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William Hemsworth William Hemsworth is offline

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

This code is confusing, that's your main problem. I don't understand the need for POINT lame; Also, line 40 is useless as i will never be equal to 1280 (only ever < than 1280).

If you want to loop through every pixel from point (0,0) and (1280,801) to find a pixel, do this:

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/* Untested code */
COLORREF tofind = RGB(175, 163, 134);
COLORREF col;
 
for (int y = 0; y < 801; ++y) {
  for (int x = 0; x < 1280; ++x) {
    col = GetPixel( hdc, x, y );
    if ( col == tofind ) {
      cout << "Pixel found at: \t" << "X: "<< x << "\t\t" << "Y: " << y << "\n";
      cin.ignore();
    }
  }
}
 
cin.ignore();
/* Untested code */
COLORREF tofind = RGB(175, 163, 134);
COLORREF col;

for (int y = 0; y < 801; ++y) {
  for (int x = 0; x < 1280; ++x) {
    col = GetPixel( hdc, x, y );
    if ( col == tofind ) {
      cout << "Pixel found at: \t" << "X: "<< x << "\t\t" << "Y: " << y << "\n";
      cin.ignore();
    }
  }
}

cin.ignore();

Hope this helps.

Last edited by William Hemsworth; Sep 27th, 2009 at 10:38 am.

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evilguyme

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

lemme try that. thnx for the code

that still doesn't work...

still exits program at the end.

so i added

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system("pause");
system("pause");

and now it goes straight to press any key to continue...

i tried setting the color to white (all 0's) and still takes me to the end .. no pixel found.
even at all set at 255 = black it couldn't find anything D:

Last edited by evilguyme; Sep 27th, 2009 at 11:36 am.

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

One thing you may want to bear in mind, the GetPixel function is very slow, so you could literally be waiting 10 minutes before it finds the pixel. To demonstrate just how slow... try executing this code.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int main() {
  COLORREF tofind = RGB(255, 0, 0);
  COLORREF col;
 
  HDC hdc = GetDC(NULL);
 
  for (int y = 0; y < 801; ++y) {
    for (int x = 0; x < 1280; ++x) {
      col = GetPixel( hdc, x, y );
      SetPixel( hdc, x, y, RGB(255,0,0) );
    }
  }
}
int main() {
  COLORREF tofind = RGB(255, 0, 0);
  COLORREF col;

  HDC hdc = GetDC(NULL);

  for (int y = 0; y < 801; ++y) {
    for (int x = 0; x < 1280; ++x) {
      col = GetPixel( hdc, x, y );
      SetPixel( hdc, x, y, RGB(255,0,0) );
    }
  }
}

Last edited by William Hemsworth; Sep 27th, 2009 at 11:26 am.

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

hmm ... then what's a good alternative to GetPixel()?

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 27th, 2009

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Originally Posted by evilguyme

hmm ... then what's a good alternative to GetPixel()?

Learn how to use bitmaps, take a screenshot, and lock the bitmap pixels to gain fast access to them.

Last edited by William Hemsworth; Sep 27th, 2009 at 4:36 pm.

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 28th, 2009

oooh that way...

hmm there doesn't seem to be a perfect tut out there..

i understand how to create an object of the bitmap and use btblts or whatever that API is.

but then how do i scan it for pixels?

google dint help...

[IMG]http://i621.photobucket.com/albums/tt298/evilguyme/StickMovie.gif[/IMG]

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Re: [HELP-CODE]Scanning Screen for pixel color

-2

Sep 28th, 2009

> google dint help

???
It's a win32 FAQ for about 15 years (!)
See on Win32 grp for classic code
to scan very quickly pixels with GDI or GDI+

Last edited by marco93; Sep 28th, 2009 at 10:59 am.

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evilguyme

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Re: [HELP-CODE]Scanning Screen for pixel color

Sep 28th, 2009

it gives me a page not found error..

maybe u can tell me what strings to search for in google?

cuz i searched for like 30 mins and dint find anything good... :O

edit : oh wait nvm i got the site to work.. but its hard navigating in that site... lemme try the search

edit 2: zomg!! i searched pixel there and got no results..

then i searched bitmap and got some 5 lame results...

Last edited by evilguyme; Sep 28th, 2009 at 11:54 am.

[IMG]http://i621.photobucket.com/albums/tt298/evilguyme/StickMovie.gif[/IMG]