Replacing usages of Device#getDPI

Having the scale factor being based on the screen DPI leads to
unexpected result. Having a screen dpi independent factor leads to
consistent results.

Author: ShahzaibIbrahim

org.eclipse.draw2d.examples/sandbox/swt/bugs/Bug81467.java

@@ -15,14 +15,14 @@
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.printing.Printer;
-import org.eclipse.swt.widgets.Display;
 
 import org.eclipse.draw2d.PrinterGraphics;
 import org.eclipse.draw2d.SWTGraphics;
 
 public class Bug81467 {
 
 	public static void main(String[] args) {
+		final float DOTS_PER_INCH = 96.0f;
 		Font font = new Font(null, "Helvetica", 12, 0); //$NON-NLS-1$
 		Printer printer = new Printer();
 		printer.startJob("bugzilla 81467"); //$NON-NLS-1$
@@ -31,7 +31,7 @@ public static void main(String[] args) {
 		SWTGraphics graphics = new SWTGraphics(gc);
 		PrinterGraphics printGraphics = new PrinterGraphics(graphics, printer);
 
-		printGraphics.scale((double) printer.getDPI().x / Display.getDefault().getDPI().x);
+		printGraphics.scale(printer.getDPI().x / DOTS_PER_INCH);
 		printGraphics.setFont(font);
 		printGraphics.drawString("Hello world", 50, 50); //$NON-NLS-1$
 		printGraphics.dispose();

org.eclipse.gef/src/org/eclipse/gef/internal/ui/rulers/RulerFigure.java

@@ -13,7 +13,6 @@
 package org.eclipse.gef.internal.ui.rulers;
 
 import org.eclipse.swt.SWT;
-import org.eclipse.swt.widgets.Display;
 
 import org.eclipse.draw2d.ColorConstants;
 import org.eclipse.draw2d.Figure;
@@ -52,6 +51,7 @@ public class RulerFigure extends Figure {
 	 * paintFigure(Graphics) method.
 	 */
 	private static final int BORDER_WIDTH = 3;
+	private static final float DOTS_PER_INCH = 96.0f;
 
 	private boolean horizontal;
 	private int unit;
@@ -78,7 +78,7 @@ protected double getDPU() {
 			case RulerProvider.UNIT_PIXELS -> dpu = 1.0;
 			case RulerProvider.UNIT_CUSTOM -> dpu = rulerProvider.getCustomRulerDPU();
 			default -> {
-				dpu = transposer.t(new Dimension(Display.getCurrent().getDPI())).height;
+				dpu = DOTS_PER_INCH;
 				if (getUnit() == RulerProvider.UNIT_CENTIMETERS) {
 					dpu = dpu / 2.54;
 				}