Deprecating Device#getDPI

Having the scale factor being based on the screen DPI leads to
unexpected result e.g. Image too big/small. Having a screen dpi
independent factor leads to consistent results

Author: ShahzaibIbrahim

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Display.java

@@ -2037,6 +2037,12 @@ public int getIconDepth () {
 	};
 }
 
+@Deprecated
+@Override
+public Point getDPI () {
+	return super.getDPI();
+}
+
 ImageList getImageList (int style, int width, int height, int zoom) {
 	if (imageList == null) imageList = new ImageList [4];
 

examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/imageanalyzer/ImageAnalyzer.java

@@ -1172,9 +1172,8 @@ void menuPrint() {
 			if (printerData == null) return;
 
 			Printer printer = new Printer(printerData);
-			Point screenDPI = display.getDPI();
 			Point printerDPI = printer.getDPI();
-			int scaleFactor = printerDPI.x / screenDPI.x;
+			int scaleFactor = printerDPI.x / 100;
 			Rectangle trim = printer.computeTrim(0, 0, 0, 0);
 			if (printer.startJob(currentName)) {
 				if (printer.startPage()) {

examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet361.java

@@ -159,9 +159,8 @@ private static void performPrintAction(final Display display, final Shell shell)
 		data = dialog.open();
 		if (data != null) {
 			Printer printer = new Printer(data);
-			Point screenDPI = display.getDPI();
 			Point printerDPI = printer.getDPI();
-			int scaleFactor = printerDPI.x / screenDPI.x;
+			int scaleFactor = printerDPI.x / 100;
 			Rectangle trim = printer.computeTrim(0, 0, 0, 0);
 			if (printer.startJob("Print Image")) {
 				ImageData imageData = snapshotImage.getImageData();

examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet367.java

@@ -185,7 +185,7 @@ public int getGcStyle() {
 
 		createSeparator(shell);
 
-		new Label (shell, SWT.NONE).setText ("5. 50x50 box\n(Display#getDPI(): " + display.getDPI().x + ")");
+		new Label (shell, SWT.NONE).setText ("5. 50x50 box");
 		Label box= new Label (shell, SWT.NONE);
 		box.setBackground(display.getSystemColor(SWT.COLOR_WIDGET_DARK_SHADOW));
 		box.setLayoutData (new GridData (50, 50));

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_widgets_Display.java

@@ -1573,6 +1573,7 @@ public void test_wake() {
 /* custom */
 boolean disposeExecRan;
 
+@SuppressWarnings("deprecation")
 @Test
 public void test_getDPI() {
 	Display display = new Display();