[ease] [editor] Greatly improve slide redraw performance.

[Nate Stedman <natesm src gnome org>]

commit eb05dd589ddd75f904e81b6c34225d3add444333
Author: Nate Stedman <natesm gmail com>
Date:   Sat Jul 24 20:28:47 2010 -0400

    [editor] Greatly improve slide redraw performance.

 src/ease-color.vala       |   16 +++++++++++++
 src/ease-gradient.vala    |   56 +++++++++++++++++++++++++++++++++++++++++++-
 src/ease-slide-actor.vala |    3 +-
 src/ease-slide.vala       |   53 ++++++++++++++++++++++++++++++++++++++++--
 4 files changed, 121 insertions(+), 7 deletions(-)
---
diff --git a/src/ease-color.vala b/src/ease-color.vala
index 0ac068f..4355918 100644
--- a/src/ease-color.vala
+++ b/src/ease-color.vala
@@ -65,6 +65,7 @@ public class Ease.Color : GLib.Object
 				red_priv = 1;
 			}
 			else red_priv = value;
+			if (!silence_changed) changed(this);
 		}
 	}
 	private double red_priv;
@@ -88,6 +89,7 @@ public class Ease.Color : GLib.Object
 				green_priv = 1;
 			}
 			else green_priv = value;
+			if (!silence_changed) changed(this);
 		}
 	}
 	private double green_priv;
@@ -111,6 +113,7 @@ public class Ease.Color : GLib.Object
 				blue_priv = 1;
 			}
 			else blue_priv = value;
+			if (!silence_changed) changed(this);
 		}
 	}
 	private double blue_priv;
@@ -134,6 +137,7 @@ public class Ease.Color : GLib.Object
 				alpha_priv = 1;
 			}
 			else alpha_priv = value;
+			if (!silence_changed) changed(this);
 		}
 	}
 	private double alpha_priv;
@@ -153,10 +157,13 @@ public class Ease.Color : GLib.Object
 		}
 		set
 		{
+			silence_changed = true;
 			red = value.red / 255f;
 			green = value.green / 255f;
 			blue = value.blue / 255f;
 			alpha = value.alpha / 255f;
+			silence_changed = false;
+			changed(this);
 		}
 	}
 	
@@ -177,14 +184,23 @@ public class Ease.Color : GLib.Object
 		}
 		set
 		{
+			silence_changed = true;
 			red = value.red / 65535f;
 			green = value.green / 65535f;
 			blue = value.blue / 65535f;
 			alpha = 1;
+			silence_changed = false;
+			changed(this);
 		}
 	}
 	
 	/**
+	 * Emitted when any of the color's properties is changed.
+	 */
+	public signal void changed(Color self);
+	private bool silence_changed;
+	
+	/**
 	 * Creates an opaque color.
 	 */
 	public Color.rgb(double r, double g, double b)
diff --git a/src/ease-gradient.vala b/src/ease-gradient.vala
index 2a0bee0..7655531 100644
--- a/src/ease-gradient.vala
+++ b/src/ease-gradient.vala
@@ -33,12 +33,42 @@ public class Ease.Gradient : GLib.Object
 	/**
 	 * The starting { link Color} of the gradient.
 	 */
-	public Color start { get; set; }
+	public Color start
+	{
+		get { return start_priv; }
+		set
+		{
+			if (start_priv != null)
+			{
+				start_priv.changed.disconnect(color_changed);
+			}
+			
+			start_priv = value;
+			start_priv.changed.connect(color_changed);
+			changed(this);
+		}
+	}
+	private Color start_priv;
 	
 	/**
 	 * The ending { link Color} of the gradient.
 	 */
-	public Color end { get; set; }
+	public Color end
+	{
+		get { return end_priv; }
+		set
+		{
+			if (end_priv != null)
+			{
+				end_priv.changed.disconnect(color_changed);
+			}
+			
+			end_priv = value;
+			end_priv.changed.connect(color_changed);
+			changed(this);
+		}
+	}
+	private Color end_priv;
 	
 	/**
 	 * The { link GradientType} of the gradient.
@@ -51,6 +81,11 @@ public class Ease.Gradient : GLib.Object
 	public double angle { get; set; }
 	
 	/**
+	 * Emitted when the gradient's appearance is changed in any way.
+	 */
+	public signal void changed(Gradient self);
+	
+	/**
 	 * Returns a copy of the default background gradient.
 	 */
 	public static Gradient default_background
@@ -67,6 +102,9 @@ public class Ease.Gradient : GLib.Object
 		end = end_color;
 		mode = GradientType.LINEAR;
 		angle = 0;
+		
+		notify["mode"].connect((a, b) => changed(this));
+		notify["angle"].connect((a, b) => changed(this));
 	}
 	
 	/**
@@ -77,6 +115,9 @@ public class Ease.Gradient : GLib.Object
 		this(start_color, end_color);
 		mode = GradientType.LINEAR_MIRRORED;
 		angle = 0;
+		
+		notify["mode"].connect((a, b) => changed(this));
+		notify["angle"].connect((a, b) => changed(this));
 	}
 	
 	/**
@@ -87,6 +128,9 @@ public class Ease.Gradient : GLib.Object
 		this(start_color, end_color);
 		mode = GradientType.RADIAL;
 		angle = 0;
+		
+		notify["mode"].connect((a, b) => changed(this));
+		notify["angle"].connect((a, b) => changed(this));
 	}
 	
 	/**
@@ -180,6 +224,14 @@ public class Ease.Gradient : GLib.Object
 		
 		cr.restore();
 	}
+	
+	/**
+	 * Signal handler for { link Color.changed} signals.
+	 */
+	private void color_changed(Color change)
+	{
+		changed(this);
+	}
 }
 
 /**
diff --git a/src/ease-slide-actor.vala b/src/ease-slide-actor.vala
index b2c7704..2afe905 100644
--- a/src/ease-slide-actor.vala
+++ b/src/ease-slide-actor.vala
@@ -173,8 +173,7 @@ public class Ease.SlideActor : Clutter.Group
 
 		add_actor(contents);
 		
-		// TODO: this completely _destroys_ performance.
-		slide.changed.connect((s) => set_background());
+		slide.background_changed.connect((s) => set_background());
 	}
 	
 	/**
diff --git a/src/ease-slide.vala b/src/ease-slide.vala
index 79d7f21..8a2d8ad 100644
--- a/src/ease-slide.vala
+++ b/src/ease-slide.vala
@@ -74,7 +74,22 @@ public class Ease.Slide : GLib.Object
 	 * To use this property, { link background_type} must also be set to
 	 * { link BackgroundType.COLOR}.
 	 */
-	public Color? background_color { get; set; }
+	public Color background_color
+	{
+		get { return background_color_priv; }
+		set
+		{
+			if (background_color_priv != null)
+			{
+				background_color_priv.changed.disconnect(bg_changed);
+			}
+			
+			background_color_priv = value;
+			background_color_priv.changed.connect(bg_changed);
+			changed(this);
+		}
+	}
+	private Color background_color_priv;
 	
 	/**
 	 * The background gradient, if this slide uses a gradient for a background.
@@ -82,7 +97,22 @@ public class Ease.Slide : GLib.Object
 	 * To use this property, { link background_type} must also be set to
 	 * { link BackgroundType.GRADIENT}.
 	 */
-	public Gradient? background_gradient { get; set; }
+	public Gradient background_gradient
+	{
+		get { return background_gradient_priv; }
+		set
+		{
+			if (background_gradient_priv != null)
+			{
+				background_gradient_priv.changed.disconnect(bg_changed);
+			}
+			
+			background_gradient_priv = value;
+			background_gradient_priv.changed.connect(bg_changed);
+			changed(this);
+		}
+	}
+	private Gradient background_gradient_priv;
 	
 	/**
 	 * The background image, if this slide uses an image for a background.
@@ -171,9 +201,18 @@ public class Ease.Slide : GLib.Object
 	public signal void changed(Slide self);
 	
 	/**
+	 * Emitted when the background of this Slide is altered in any way.
+	 */
+	public signal void background_changed(Slide self);
+	
+	/**
 	 * Create a new Slide.
 	 */
-	public Slide() {}
+	public Slide()
+	{
+		notify["background-type"].connect((a, b) => background_changed(this));
+		notify["background-image"].connect((a, b) => background_changed(this));
+	}
 	
 	/**
 	 * Create a new Slide assigned to a { link Document}.
@@ -184,6 +223,7 @@ public class Ease.Slide : GLib.Object
 	 */
 	public Slide.with_owner(Document owner)
 	{
+		base();
 		parent = owner;
 	}
 	
@@ -203,6 +243,8 @@ public class Ease.Slide : GLib.Object
 	public Slide.from_master(Slide master, Document? document,
 	                         int width, int height, bool is_new)
 	{
+		base();
+		
 		// set basic properties
 		transition = master.transition;
 		transition_time = master.transition_time;
@@ -367,6 +409,11 @@ public class Ease.Slide : GLib.Object
 		
 		html += "</div>\n";
 	}
+	
+	private void bg_changed(GLib.Object sender)
+	{
+		background_changed(this);
+	}
 }
 
 public enum Ease.BackgroundType