[Gtk4] Fix blurry images on widgets at HiDPI

bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c

@@ -15270,6 +15270,18 @@ JNIEXPORT void JNICALL OS_NATIVE(swt_1fixed_1restack)
 }
 #endif
 
+#ifndef NO_swt_1scaled_1paintable_1new
+JNIEXPORT jlong JNICALL OS_NATIVE(swt_1scaled_1paintable_1new)
+	(JNIEnv *env, jclass that, jlong arg0, jint arg1, jint arg2)
+{
+	jlong rc = 0;
+	OS_NATIVE_ENTER(env, that, swt_1scaled_1paintable_1new_FUNC);
+	rc = (jlong)swt_scaled_paintable_new((GdkTexture*)arg0, arg1, arg2);
+	OS_NATIVE_EXIT(env, that, swt_1scaled_1paintable_1new_FUNC);
+	return rc;
+}
+#endif
+
 #ifndef NO_swt_1set_1lock_1functions
 JNIEXPORT void JNICALL OS_NATIVE(swt_1set_1lock_1functions)
 	(JNIEnv *env, jclass that)

bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.h

@@ -335,6 +335,9 @@
 #define NO_swt_1fixed_1add
 #define NO_swt_1fixed_1remove
 
+// No GdkPaintable on GTK3
+#define NO_swt_1scaled_1paintable_1new
+
 #endif
 
 #include "os_custom.h"

bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.c

@@ -2263,3 +2263,96 @@ JNIEXPORT jlong JNICALL OS_NATIVE(content_1providers_1create_1gvalue)
 	OS_NATIVE_EXIT(env, that, content_1providers_1create_1gvalue_FUNC)
 	return (jlong)v;
 }
+
+#if defined(GTK4)
+/*
+ * SwtScaledPaintable: a GdkPaintable wrapping a GdkTexture that advertises a
+ * fixed logical (point) intrinsic size. GtkPicture measures a plain GdkTexture
+ * using its device-pixel size, which inflates widgets at HiDPI. By reporting the
+ * logical size here while drawing the full-resolution texture, images keep their
+ * correct logical footprint and render crisply (no down/up-scaling).
+ */
+#define SWT_TYPE_SCALED_PAINTABLE (swt_scaled_paintable_get_type ())
+G_DECLARE_FINAL_TYPE (SwtScaledPaintable, swt_scaled_paintable, SWT, SCALED_PAINTABLE, GObject)
+
+struct _SwtScaledPaintable
+{
+	GObject parent_instance;
+	GdkTexture* texture;
+	int width;
+	int height;
+};
+
+static void swt_scaled_paintable_paintable_init (GdkPaintableInterface* iface);
+
+G_DEFINE_TYPE_WITH_CODE (SwtScaledPaintable, swt_scaled_paintable, G_TYPE_OBJECT,
+	G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE, swt_scaled_paintable_paintable_init))
+
+static void swt_scaled_paintable_snapshot (GdkPaintable* paintable, GdkSnapshot* snapshot, double width, double height)
+{
+	SwtScaledPaintable* self = SWT_SCALED_PAINTABLE (paintable);
+	if (self->texture != NULL) {
+		/* Draw the full device-resolution texture into the (logical) box. */
+		gdk_paintable_snapshot (GDK_PAINTABLE (self->texture), snapshot, width, height);
+	}
+}
+
+static int swt_scaled_paintable_get_intrinsic_width (GdkPaintable* paintable)
+{
+	return SWT_SCALED_PAINTABLE (paintable)->width;
+}
+
+static int swt_scaled_paintable_get_intrinsic_height (GdkPaintable* paintable)
+{
+	return SWT_SCALED_PAINTABLE (paintable)->height;
+}
+
+static double swt_scaled_paintable_get_intrinsic_aspect_ratio (GdkPaintable* paintable)
+{
+	SwtScaledPaintable* self = SWT_SCALED_PAINTABLE (paintable);
+	if (self->height <= 0) return 0.0;
+	return (double) self->width / (double) self->height;
+}
+
+static GdkPaintableFlags swt_scaled_paintable_get_flags (GdkPaintable* paintable)
+{
+	return GDK_PAINTABLE_STATIC_SIZE | GDK_PAINTABLE_STATIC_CONTENTS;
+}
+
+static void swt_scaled_paintable_paintable_init (GdkPaintableInterface* iface)
+{
+	iface->snapshot = swt_scaled_paintable_snapshot;
+	iface->get_intrinsic_width = swt_scaled_paintable_get_intrinsic_width;
+	iface->get_intrinsic_height = swt_scaled_paintable_get_intrinsic_height;
+	iface->get_intrinsic_aspect_ratio = swt_scaled_paintable_get_intrinsic_aspect_ratio;
+	iface->get_flags = swt_scaled_paintable_get_flags;
+}
+
+static void swt_scaled_paintable_dispose (GObject* object)
+{
+	SwtScaledPaintable* self = SWT_SCALED_PAINTABLE (object);
+	g_clear_object (&self->texture);
+	G_OBJECT_CLASS (swt_scaled_paintable_parent_class)->dispose (object);
+}
+
+static void swt_scaled_paintable_class_init (SwtScaledPaintableClass* klass)
+{
+	G_OBJECT_CLASS (klass)->dispose = swt_scaled_paintable_dispose;
+}
+
+static void swt_scaled_paintable_init (SwtScaledPaintable* self)
+{
+	self->texture = NULL;
+	self->width = 0;
+	self->height = 0;
+}
+
+GdkPaintable* swt_scaled_paintable_new (GdkTexture* texture, int width, int height)
+{
+	SwtScaledPaintable* self = g_object_new (SWT_TYPE_SCALED_PAINTABLE, NULL);
+	self->texture = texture != NULL ? g_object_ref (texture) : NULL;
+	self->width = width;
+	self->height = height;
+	return GDK_PAINTABLE (self);
+}
+#endif /* GTK4 */

bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.h

@@ -135,6 +135,15 @@ struct _SwtFixedClass
 
 GType swt_fixed_get_type (void) G_GNUC_CONST;
 
+#if defined(GTK4)
+/*
+ * GdkPaintable that wraps a GdkTexture but advertises a fixed logical (point)
+ * intrinsic size. Used so GtkPicture measures images in logical points (avoiding
+ * HiDPI inflation) while still drawing the full device-resolution texture crisply.
+ */
+GdkPaintable* swt_scaled_paintable_new (GdkTexture* texture, int width, int height);
+#endif
+
 #if defined(GTK4)
 void swt_fixed_add(SwtFixed* fixed, GtkWidget* widget);
 void swt_fixed_remove(SwtFixed* fixed, GtkWidget* widget);

bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h

@@ -1233,6 +1233,7 @@ typedef enum {
 	swt_1fixed_1remove_FUNC,
 	swt_1fixed_1resize_FUNC,
 	swt_1fixed_1restack_FUNC,
+	swt_1scaled_1paintable_1new_FUNC,
 	swt_1set_1lock_1functions_FUNC,
 	ubuntu_1menu_1proxy_1get_FUNC,
 } OS_FUNCS;

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

@@ -579,6 +579,12 @@ public static String getEnvironmentalVariable (String envVarName) {
 	/** @category custom */
 	public static final native long swt_fixed_get_type();
 
+	/**
+	 * @param texture cast=(GdkTexture*)
+	 * @category custom
+	 */
+	public static final native long swt_scaled_paintable_new(long texture, int width, int height);
+
 	/** @category custom */
 	public static final native long swt_fixed_accessible_get_type();
 	/**

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/ImageList.java

@@ -176,13 +176,6 @@ public static long createPixbuf(Image image) {
 		}
 	}
 	Cairo.cairo_surface_destroy(surface);
-	if (GTK.GTK4) {
-		//Scaling needed as the image surface will be different from the image size depending on the display scale
-		long scaledPixbuf = GDK.gdk_pixbuf_scale_simple(pixbuf, image.getBounds().width, image.getBounds().height, GDK.GDK_INTERP_BILINEAR);
-		OS.g_object_unref(pixbuf);
-		pixbuf = scaledPixbuf;
-	}
-
 	return pixbuf;
 }
 

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Button.java

@@ -1158,8 +1158,11 @@ private void _setImage (Image image) {
 			long pixbuf = ImageList.createPixbuf(image);
 			long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 			OS.g_object_unref(pixbuf);
-			GTK4.gtk_picture_set_paintable(imageHandle, texture);
+			Rectangle bounds = image.getBounds();
+			long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
 			OS.g_object_unref(texture);
+			GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+			OS.g_object_unref(paintable);
 		} else {
 			GTK3.gtk_image_set_from_surface(imageHandle, image.surface);
 		}

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ExpandItem.java

@@ -518,7 +518,11 @@ public void setImage (Image image) {
 			long pixbuf = ImageList.createPixbuf(image);
 			long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 			OS.g_object_unref(pixbuf);
-			GTK4.gtk_picture_set_paintable(imageHandle, texture);
+			Rectangle bounds = image.getBounds();
+			long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
+			OS.g_object_unref(texture);
+			GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+			OS.g_object_unref(paintable);
 		} else {
 			GTK3.gtk_image_set_from_surface(imageHandle, image.surface);
 		}

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Label.java

@@ -650,8 +650,11 @@ public void setImage (Image image) {
 			long pixbuf = ImageList.createPixbuf(image);
 			long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 			OS.g_object_unref(pixbuf);
-			GTK4.gtk_picture_set_paintable(imageHandle, texture);
+			Rectangle bounds = image.getBounds();
+			long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
 			OS.g_object_unref(texture);
+			GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+			OS.g_object_unref(paintable);
 		} else {
 			GTK3.gtk_image_set_from_surface(imageHandle, image.surface);
 		}

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/ToolItem.java

@@ -781,8 +781,11 @@ void gtk4_enter_event(long controller, double x, double y, long event) {
 				long pixbuf = ImageList.createPixbuf(hotImage);
 				long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 				OS.g_object_unref(pixbuf);
-				GTK4.gtk_picture_set_paintable(imageHandle, texture);
+				Rectangle bounds = hotImage.getBounds();
+				long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
 				OS.g_object_unref(texture);
+				GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+				OS.g_object_unref(paintable);
 			}
 		}
 	}
@@ -853,8 +856,11 @@ void gtk4_leave_event(long controller, long event) {
 					long pixbuf = ImageList.createPixbuf(image);
 					long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 					OS.g_object_unref(pixbuf);
-					GTK4.gtk_picture_set_paintable(imageHandle, texture);
+					Rectangle bounds = image.getBounds();
+					long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
 					OS.g_object_unref(texture);
+					GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+					OS.g_object_unref(paintable);
 				}
 			}
 		}
@@ -1376,24 +1382,22 @@ void _setImage (Image image) {
 			long pixbuf = ImageList.createPixbuf(image);
 			long texture = GDK.gdk_texture_new_for_pixbuf(pixbuf);
 			OS.g_object_unref(pixbuf);
-			GTK4.gtk_picture_set_paintable(imageHandle, texture);
-			OS.g_object_unref(texture);
 			/*
-			 * Pin the GtkPicture to the image's logical (point) size so it occupies the
-			 * same footprint as the previously used GtkImage. The texture is created
-			 * from a device-scaled pixbuf whose intrinsic size is in pixels; without a
-			 * size request GtkPicture would measure to those pixel dimensions, inflating
-			 * the ToolItem and causing overlaps (e.g. the CTabFolder chevron toolbar).
+			 * Wrap the full-resolution texture in a paintable that reports the image's
+			 * logical (point) size, so the GtkPicture keeps the same footprint as the
+			 * previously used GtkImage and renders crisply at HiDPI.
 			 */
 			Rectangle bounds = image.getBounds();
-			GTK.gtk_widget_set_size_request(imageHandle, bounds.width, bounds.height);
+			long paintable = OS.swt_scaled_paintable_new(texture, bounds.width, bounds.height);
+			OS.g_object_unref(texture);
+			GTK4.gtk_picture_set_paintable(imageHandle, paintable);
+			OS.g_object_unref(paintable);
 		} else {
 			GTK3.gtk_image_set_from_surface(imageHandle, imageList.getSurface(imageIndex));
 		}
 	} else {
 		if(GTK.GTK4) {
 			GTK4.gtk_picture_set_paintable(imageHandle, 0);
-			GTK.gtk_widget_set_size_request(imageHandle, -1, -1);
 			gtk_widget_hide(imageHandle);
 		} else {
 			GTK3.gtk_image_set_from_surface(imageHandle, 0);