Bug 535123 - [HiDPI][GTK3] Black bands visible in Eclipse UI on x2

display

Fixes black band issues in snippet 365 and tool bars and CTabFolder.

Revert "Revert "Bug 534817 - screenshots do not change""

This reverts commit 742c1cbd39bb33d4c9827db948582faef531b1ba.

This revert fixes SWTBot problem in capturing screenshots

Change-Id: Ibd8dc7ae70befe6db98d89e9d76f7ce68e7ffc8f
Signed-off-by: Sravan Kumar Lakkimsetti <sravankumarl@in.ibm.com>

3 files changed, 17 insertions, 9 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/GC.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/GC.java
index 61894e9490..8eebf8d42a 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/GC.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/GC.java
@@ -1562,6 +1562,11 @@ void fillGradientRectangleInPixels(int x, int y, int width, int height, boolean
 		fromRGB = backgroundRGB;
 		toRGB   = foregroundRGB;
 	}
+	if (vertical) {
+		width = width * (DPIUtil.getDeviceZoom() / 100);
+	} else {
+		height = height * (DPIUtil.getDeviceZoom() / 100);
+	}
 	if (fromRGB.equals(toRGB)) {
 		fillRectangleInPixels(x, y, width, height);
 		return;
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/Image.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/Image.java
index 8301156deb..1c31c6dc61 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/Image.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/Image.java
@@ -1390,18 +1390,15 @@ void init(int width, int height) {
 	this.type = SWT.BITMAP;
 
 	/* Create the pixmap */
-	if (GTK.GTK3) {
-		surface = Cairo.cairo_image_surface_create(Cairo.CAIRO_FORMAT_ARGB32, width, height);
-	} else {
-		surface = GDK.gdk_window_create_similar_surface(GDK.gdk_get_default_root_window(), Cairo.CAIRO_CONTENT_COLOR, width, height);
-	}
+	surface = GDK.gdk_window_create_similar_surface(GDK.gdk_get_default_root_window(), Cairo.CAIRO_CONTENT_COLOR, width, height);
 	if (surface == 0) SWT.error(SWT.ERROR_NO_HANDLES);
-	// When we create a blank image we need to set it to 100 in GTK3 as we don't scale here.
-	// Cairo will scale for us
+	// When we create a blank image we need to set it to 100 in GTK3 as we draw using 100% scale.
+	// Cairo will take care of scaling for us when image needs to be scaled.
 	if (!GTK.GTK3) {
 		currentDeviceZoom = DPIUtil.getDeviceZoom();
 	} else {
 		currentDeviceZoom = 100;
+		Cairo.cairo_surface_set_device_scale(surface, 1f, 1f);
 	}
 	long /*int*/ cairo = Cairo.cairo_create(surface);
 	if (cairo == 0) SWT.error(SWT.ERROR_NO_HANDLES);
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/ImageList.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/ImageList.java
index a611073ea1..0f38b3fec0 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/ImageList.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/ImageList.java
@@ -34,9 +34,15 @@ public static long /*int*/ convertSurface(Image image) {
 		int format = Cairo.cairo_surface_get_content(newSurface) == Cairo.CAIRO_CONTENT_COLOR ? Cairo.CAIRO_FORMAT_RGB24 : Cairo.CAIRO_FORMAT_ARGB32;
 		newSurface = Cairo.cairo_image_surface_create(format, bounds.width, bounds.height);
 		if (newSurface == 0) SWT.error(SWT.ERROR_NO_HANDLES);
+		//retain device scale set in the original surface
 		if (GTK.GTK3) {
-			double scaleFactor = DPIUtil.getDeviceZoom() / 100f;
-			Cairo.cairo_surface_set_device_scale(newSurface, scaleFactor, scaleFactor);
+			double sx[] = new double[1];
+			double sy[] = new double[1];
+			Cairo.cairo_surface_get_device_scale(image.surface, sx, sy);
+			if (sx[0] == 0 || sy[0] == 0){
+				sx[0] = sy[0] = DPIUtil.getDeviceZoom() / 100f;
+			}
+			Cairo.cairo_surface_set_device_scale(newSurface, sx[0], sy[0]);
 		}
 		long /*int*/ cairo = Cairo.cairo_create(newSurface);
 		if (cairo == 0) SWT.error(SWT.ERROR_NO_HANDLES);