Enable zooming on macOS WebKit control with Command +/- keys

If keydown events for Command +/= or Command - are not consumed by any
event handler, invoke the native methods `makeTextLarger` or
`makeTextSmaller` on the WebKit control to provide zooming functionality
on macOS.

Author: tobias-melcher

bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/cocoa/OS.java

@@ -991,6 +991,8 @@ public static Selector getSelector (long value) {
 public static final long sel_canBecomeKeyWindow = Selector.sel_canBecomeKeyWindow.value;
 public static final long sel_canDragRowsWithIndexes_atPoint_ = Selector.sel_canDragRowsWithIndexes_atPoint_.value;
 public static final long sel_canGoBack = Selector.sel_canGoBack.value;
+public static final long sel_makeTextLarger = Selector.sel_makeTextLarger.value;
+public static final long sel_makeTextSmaller = Selector.sel_makeTextSmaller.value;
 public static final long sel_canGoForward = Selector.sel_canGoForward.value;
 public static final long sel_canRedo = Selector.sel_canRedo.value;
 public static final long sel_canShowMIMEType_ = Selector.sel_canShowMIMEType_.value;

bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/cocoa/Selector.java

@@ -234,6 +234,8 @@ public enum Selector {
 	, sel_canBecomeKeyWindow("canBecomeKeyWindow")
 	, sel_canDragRowsWithIndexes_atPoint_("canDragRowsWithIndexes:atPoint:")
 	, sel_canGoBack("canGoBack")
+	, sel_makeTextLarger("makeTextLarger:")
+	, sel_makeTextSmaller("makeTextSmaller:")
 	, sel_canGoForward("canGoForward")
 	, sel_canRedo("canRedo")
 	, sel_canShowMIMEType_("canShowMIMEType:")

bundles/org.eclipse.swt/Eclipse SWT PI/cocoa/org/eclipse/swt/internal/cocoa/WebView.java

@@ -31,6 +31,14 @@ public boolean canGoBack() {
 	return OS.objc_msgSend_bool(this.id, OS.sel_canGoBack);
 }
 
+public void makeTextLarger() {
+	OS.objc_msgSend(this.id, OS.sel_makeTextLarger);
+}
+
+public void makeTextSmaller() {
+	OS.objc_msgSend(this.id, OS.sel_makeTextSmaller);
+}
+
 public boolean canGoForward() {
 	return OS.objc_msgSend_bool(this.id, OS.sel_canGoForward);
 }

bundles/org.eclipse.swt/Eclipse SWT WebKit/cocoa/org/eclipse/swt/browser/WebKit.java

@@ -1586,6 +1586,10 @@ void handleEvent(long evtId) {
 				} else if (translatedKey == 'x') {
 					webView.cut (webView);
 					event.preventDefault();
+				} else if (translatedKey == '=' || translatedKey == '+') {
+					webView.makeTextLarger();
+				} else if (translatedKey == '-') {
+					webView.makeTextSmaller();
 				}
 			}
 		}