macro "Replace each ROI with a single centroid black pixel on white background)" {
/*	This macro draws a single pixel at the centroid of each particle.
	The foreground is white and the background is black.
*/
	if (roiManager("count")>0) {
		saveSettings();
		setBatchMode(true); 
		setForegroundColor(0, 0, 0);
		setBackgroundColor(255, 255, 255);
		run("Select All");
		run("Clear", "slice");
		for (i=0; i<roiManager("Count"); i++) {
			showProgress(-i, roiManager("count"));
			roiManager("select", i);
			Roi.getBounds(Rx, Ry, Rwidth, Rheight);
			rCtrX = round(Rx+Rwidth/2);
			rCtrY = round(Ry+Rheight/2);
			setResult("ROIctr_X\(px\)", i, rCtrX);
			setResult("ROIctr_Y\(px\)", i, rCtrY);
			run("Clear");
			setPixel(rCtrX, rCtrY, 0);
		}
		run("Select None");
		run("Hide Overlay");
		restoreSettings();
		run("Collect Garbage"); 
		setBatchMode("exit & display"); 
	}
	else {
		closeNonImageByTitle("ROI Manager");
		exit("This macro requires ROIs");
	}
}
function closeNonImageByTitle(windowTitle) { /* obviously */
	if (isOpen(windowTitle)) {
		selectWindow(windowTitle);
		run("Close");
	}
}