Merge lp:~compiz-team/compiz-core/compiz-core.fix_879253 into lp:compiz-core/0.9.5

[Sam Spilsbury]

Fix bug 879253

The math was also a bit out causing flickering in some cases

[Jason Smith (jassmith)]

review: Approve

=== modified file 'plugins/scale/src/scale.cpp'
--- plugins/scale/src/scale.cpp	2011-10-17 09:57:48 +0000
+++ plugins/scale/src/scale.cpp	2011-10-21 15:23:24 +0000
@@ -267,53 +267,63 @@
     if (window->state () & CompWindowStateHiddenMask)
     {
 	GLfloat factor = 0;
+	GLfloat targetX, targetY, targetScale;
+	GLfloat scaleFactor, xFactor, yFactor, divFactor = 3.0f;
 
 	if (priv->slot)
 	{
-	    GLfloat scaleFactor, xFactor, yFactor;
-
-	    /* Don't FDIV0 */
-	    if (priv->scale - priv->slot->scale == 0.0f)
-		scaleFactor = 1.0f;
-	    else
-		scaleFactor = (1.0f - priv->scale) / (1.0f - priv->slot->scale);
-
-	    if (priv->slot->x () - ((float) window->x () + priv->tx) == 0.0f)
-		xFactor = 1.0f;
-	    else
-		xFactor = priv->slot->x () / ((float) window->x () + priv->tx);
-
-	    if (priv->slot->y () - ((float) window->y () + priv->ty) == 0.0f)
-		yFactor = 1.0f;
-	    else
-		yFactor = priv->slot->y () / ((float) window->y () + priv->ty);
-
-	    factor = (scaleFactor + xFactor + yFactor) / 3.0f;
-	    attrib.opacity *= factor;
-	}
-	else
-	{
-	    GLfloat scaleFactor, xFactor, yFactor;
-
-	    /* Don't FDIV0 */
-	    if (priv->scale - priv->slot->scale == 0.0f)
-		scaleFactor = 1.0f;
-	    else
-		scaleFactor = (1.0f - priv->scale) / (1.0f - priv->slot->scale);
-
-	    if (priv->lastTargetX - ((float) window->x () + priv->tx) == 0.0f)
-		xFactor = 1.0f;
-	    else
-		xFactor = priv->lastTargetX / ((float) window->x () + priv->tx);
-
-	    if (priv->lastTargetY - ((float) window->y () + priv->ty) == 0.0f)
-		yFactor = 1.0f;
-	    else
-		yFactor = priv->lastTargetY / ((float) window->y () + priv->ty);
-
-	    factor = (scaleFactor + xFactor + yFactor) / 3.0f;
-	    attrib.opacity *= factor;
-	}
+	    targetX = priv->slot->x ();
+	    targetY = priv->slot->y ();
+	    targetScale = priv->slot->scale;
+	}
+	else
+	{
+	    targetX = priv->lastTargetX;
+	    targetY = priv->lastTargetY;
+	    targetScale = priv->lastTargetScale;
+	}
+
+	/* Don't FDIV0 */
+	if (targetScale - priv->scale == 0.0f)
+	{
+	    divFactor -= 1.0f;
+	    scaleFactor = 1.0f;
+	}
+	else
+	    scaleFactor = (1.0f - priv->scale) / (1.0f - targetScale);
+
+	if (targetX - ((float) window->x () + priv->tx) == 0.0f)
+	{
+	    divFactor -= 1.0f;
+	    xFactor = 1.0f;
+	}
+	else
+	{
+	    float distActual = fabsf (window->x () - ((float) window->x () + priv->tx));
+	    float distTarget = fabsf (window->x () - targetX);
+
+	    xFactor = distActual / distTarget;
+	}
+
+	if (targetY - ((float) window->y () + priv->ty) == 0.0f)
+	{
+	    divFactor -= 1.0f;
+	    yFactor = 1.0f;
+	}
+	else
+	{
+	    float distActual = fabsf (window->y () - ((float) window->y () + priv->ty));
+	    float distTarget = fabsf (window->y () - targetY);
+
+	    yFactor = distActual / distTarget;
+	}
+
+	if (divFactor)
+	    factor = (scaleFactor + xFactor + yFactor) / divFactor;
+	else
+	    factor = 1.0f;
+
+	attrib.opacity *= factor;
     }
 
     if (priv->adjust || priv->slot)