Render shadows using Gtk (#250)

* Render shadows using Gtk

* Do only apply shadow on fullscreen/maximized windows

* Add per-workspace style-class

* update shadow values

* Disconnect signals

data/gala.css

@@ -28,3 +28,19 @@
     color: #333;
 }
 
+.decoration {
+   border-radius: 4px 4px 0 0;
+   box-shadow:
+        0 0 0 1px alpha (#000, 0.3),
+        0 14px 20px rgba(0, 0, 0, 0.35),
+        0 10px 10px rgba(0, 0, 0, 0.22);
+}
+
+.workspace.decoration {
+    border-radius: 4px;
+    box-shadow:
+        0 0 0 1px alpha (#000, 0.2),
+        0 8px 10px 1px alpha (#000, 0.14),
+        0 3px 14px 2px alpha (#000, 0.12),
+        0 5px 5px -3px alpha (#000, 0.4);
+}

src/ShadowEffect.vala

@@ -36,10 +36,25 @@ namespace Gala
 		// the sizes of the textures often repeat, especially for the background actor
 		// so we keep a cache to avoid creating the same texture all over again.
 		static Gee.HashMap<string,Shadow> shadow_cache;
+		static Gtk.StyleContext style_context;
 
-		static construct
+		class construct
 		{
 			shadow_cache = new Gee.HashMap<string,Shadow> ();
+			var default_css = new Gtk.CssProvider ();
+			try {
+				default_css.load_from_path (Config.PKGDATADIR + "/gala.css");
+			} catch (Error e) {
+				warning ("Loading default styles failed: %s", e.message);
+			}
+
+			var style_path = new Gtk.WidgetPath ();
+			var id = style_path.append_type (typeof (Gtk.Window));
+
+			style_context = new Gtk.StyleContext ();
+			style_context.add_provider (default_css, Gtk.STYLE_PROVIDER_PRIORITY_FALLBACK);
+			style_context.add_class ("decoration");
+			style_context.set_path (style_path);
 		}
 
 		public int shadow_size { get; construct; }
@@ -47,6 +62,7 @@ namespace Gala
 
 		public float scale_factor { get; set; default = 1; }
 		public uint8 shadow_opacity { get; set; default = 255; }
+		public string? css_class { get; set; default = null; }
 
 		Cogl.Material material;
 		string? current_key = null;
@@ -70,7 +86,6 @@ namespace Gala
 		Cogl.Texture? get_shadow (int width, int height, int shadow_size, int shadow_spread)
 		{
 			var old_key = current_key;
-
 			current_key = "%ix%i:%i:%i".printf (width, height, shadow_size, shadow_spread);
 			if (old_key == current_key)
 				return null;
@@ -84,19 +99,24 @@ namespace Gala
 				return shadow.texture;
 			}
 
-			// fill a new texture for this size
-			var buffer = new Granite.Drawing.BufferSurface (width, height);
-			buffer.context.rectangle (shadow_size - shadow_spread, shadow_size - shadow_spread,
-				width - shadow_size * 2 + shadow_spread * 2, height - shadow_size * 2 + shadow_spread * 2);
-			buffer.context.set_source_rgba (0, 0, 0, 0.7);
-			buffer.context.fill ();
-
-			buffer.exponential_blur (shadow_size / 2);
-
 			var surface = new Cairo.ImageSurface (Cairo.Format.ARGB32, width, height);
 			var cr = new Cairo.Context (surface);
+			cr.set_source_rgba (0, 0, 0, 0);
+			cr.fill ();
+
+			cr.set_operator (Cairo.Operator.OVER);
+			cr.save ();
+			cr.scale (scale_factor, scale_factor);
+			style_context.save ();
+			if (css_class != null) {
+				style_context.add_class (css_class);
+			}
+
+			style_context.set_scale ((int)scale_factor);
+			style_context.render_background (cr, shadow_size, shadow_size, width - shadow_size * 2, height - shadow_size * 2);
+			style_context.restore ();
+			cr.restore ();
 
-			cr.set_source_surface (buffer.surface, 0, 0);
 			cr.paint ();
 
 			var texture = new Cogl.Texture.from_data (width, height, 0, Cogl.PixelFormat.BGRA_8888_PRE,
@@ -121,9 +141,10 @@ namespace Gala
 		public override void paint (EffectPaintFlags flags)
 		{
 			var bounding_box = get_bounding_box ();
-			var shadow = get_shadow ((int) (bounding_box.x2 - bounding_box.x1), (int) (bounding_box.y2 - bounding_box.y1),
-				shadow_size, shadow_spread);
+			var width = (int) (bounding_box.x2 - bounding_box.x1);
+			var height = (int) (bounding_box.y2 - bounding_box.y1);
 
+			var shadow = get_shadow (width, height, shadow_size, shadow_spread);
 			if (shadow != null)
 				material.set_layer (0, shadow);
 

src/Widgets/WindowClone.vala

@@ -22,7 +22,7 @@ namespace Gala
 {
 	class WindowShadowEffect : ShadowEffect
 	{
-		public Meta.Window window { get; construct; }
+		public unowned Meta.Window window { get; construct; }
 
 		public WindowShadowEffect (Meta.Window window, int shadow_size, int shadow_spread)
 		{
@@ -136,6 +136,9 @@ namespace Gala
 
 			window.unmanaged.connect (unmanaged);
 			window.notify["on-all-workspaces"].connect (on_all_workspaces_changed);
+			window.notify["fullscreen"].connect (check_shadow_requirements);
+			window.notify["maximized-horizontally"].connect (check_shadow_requirements);
+			window.notify["maximized-vertically"].connect (check_shadow_requirements);
 
 			if (overview_mode) {
 				var click_action = new ClickAction ();
@@ -184,6 +187,9 @@ namespace Gala
 		{
 			window.unmanaged.disconnect (unmanaged);
 			window.notify["on-all-workspaces"].disconnect (on_all_workspaces_changed);
+			window.notify["fullscreen"].disconnect (check_shadow_requirements);
+			window.notify["maximized-horizontally"].disconnect (check_shadow_requirements);
+			window.notify["maximized-vertically"].disconnect (check_shadow_requirements);
 
 			if (shadow_update_timeout != 0)
 				Source.remove (shadow_update_timeout);
@@ -224,8 +230,7 @@ namespace Gala
 
 			transition_to_original_state (false);
 
-			shadow_effect = new WindowShadowEffect (window, 40, 5);
-			clone.add_effect_with_name ("shadow", shadow_effect);
+			check_shadow_requirements ();
 
 			if (should_fade ())
 				opacity = 0;
@@ -243,6 +248,21 @@ namespace Gala
 			}
 		}
 
+		void check_shadow_requirements ()
+		{
+			if (window.fullscreen || window.maximized_horizontally && window.maximized_vertically) {
+				if (shadow_effect == null) {
+					shadow_effect = new WindowShadowEffect (window, 40, 5);
+					clone.add_effect_with_name ("shadow", shadow_effect);
+				}
+			} else {
+				if (shadow_effect != null) {
+					clone.remove_effect (shadow_effect);
+					shadow_effect = null;
+				}
+			}
+		}
+
 		/**
 		 * If we are in overview mode, we may display windows from workspaces other than
 		 * the current one. To ease their appearance we have to fade them in.
@@ -423,9 +443,9 @@ namespace Gala
 			shadow_transition.progress_mode = MultitaskingView.ANIMATION_MODE;
 
 			if (show)
-				shadow_transition.interval = new Clutter.Interval (typeof (uint8), shadow_effect.shadow_opacity, 255);
+				shadow_transition.interval = new Clutter.Interval (typeof (uint8), shadow_opacity, 255);
 			else
-				shadow_transition.interval = new Clutter.Interval (typeof (uint8), shadow_effect.shadow_opacity, 0);
+				shadow_transition.interval = new Clutter.Interval (typeof (uint8), shadow_opacity, 0);
 
 			add_transition ("shadow-opacity", shadow_transition);
 		}

src/Widgets/WorkspaceClone.vala

@@ -35,7 +35,9 @@ namespace Gala
 			var primary = screen.get_primary_monitor ();
 			var monitor_geom = screen.get_monitor_geometry (primary);
 
-			add_effect (new ShadowEffect (40, 5));
+			var effect = new ShadowEffect (40, 5);
+			effect.css_class = "workspace";
+			add_effect (effect);
 		}
 
 		public override void paint ()