[GTK] Temporary workaround for LineNumberRulerColumn regression #2740

This temporarily reverts the image creation for the
LineNumberRulerColumn on Linux to the state before initializing the
buffer image with an ImageGcDrawer. This does currently not work
properly for all use cases on Linux/GTK because of an issue with the
initialization of Image based on existing ImageData due to the usage of
cairo_image_surface_create.

Linux-specific workaround for
#2740

Author: HeikoKlare

bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/source/LineNumberRulerColumn.java

@@ -42,6 +42,8 @@
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 
+import org.eclipse.core.runtime.Platform.OS;
+
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IRegion;
@@ -687,24 +689,27 @@ private void doubleBufferPaint(GC dest) {
 		}
 
 		if (fBuffer == null) {
-			fBuffer= newFullBufferImage(size);
+			newFullBufferImage(size);
 		} else {
 			doPaint(visibleLines, size);
 		}
 		dest.drawImage(fBuffer, 0, 0);
 	}
 
-	private Image newFullBufferImage(Point size) {
-		ImageGcDrawer imageGcDrawer= (gc, imageWidth, imageHeight) -> {
-			ILineRange lines= JFaceTextUtil.getVisibleModelLines(fCachedTextViewer);
-			if (lines == null) {
-				return;
-			}
-			// We redraw everything; paint directly into the buffer
-			initializeGC(gc, 0, 0, imageWidth, imageHeight);
-			doPaint(gc, lines);
-		};
-		return new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
+	private void newFullBufferImage(Point size) {
+		if (OS.isLinux()) {
+			fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);
+			ILineRange visibleLines= JFaceTextUtil.getVisibleModelLines(fCachedTextViewer);
+			doPaint(visibleLines, size);
+		} else {
+			ImageGcDrawer imageGcDrawer= (gc, imageWidth, imageHeight) -> {
+				ILineRange lines= JFaceTextUtil.getVisibleModelLines(fCachedTextViewer);
+				// We redraw everything; paint directly into the buffer
+				initializeGC(gc, 0, 0, imageWidth, imageHeight);
+				doPaint(gc, lines);
+			};
+			fBuffer= new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
+		}
 	}
 
 	private void doPaint(ILineRange visibleLines, Point size) {