getPixel() and dual monitors

[vIndie]

It doesn't appear that getPixel works correctly on the secondary monitor in dual monitor setup, it returns 255,255,255 regardless of the actual color of the pixel.

Here is the code I used to test.

Code: Select all

function main()
	while(1) do
		hwnd = foregroundWindow();
		if (hwnd ~= 0) then
			hdc = openDC(hwnd);
			if (hdc) then
				x,y = mouseGetPos();
				-- printf("mouse_x: %d, mouse_y: %d", x, y);
				r,g,b = getPixel(hdc, x, y);
				printf("(%d, %d) RGB: %d, %d, %d\n", x,y, r, g, b);
				closeDC(hdc);
			end
		end
		stopPE();
	end
end

startMacro(main);

[Administrator]

Well, first problem is that getPixel expects client coordinates, not screen coordinates. That means that 0,0 is the top-left of the window, not the top-left of your screen. So, if you had dual monitors running 1920x1080 resolution and you had your mouse positioned at, say, 2000x20 (near the top-left corner of your second screen), that would be beyond the client area of the window, and hence be an invalid position to read pixel information from.