Partial implementation of FilterUtil.

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@197 ed5b42cb-e716-0410-a449-f6a68f950b19

src/as/com/threerings/flash/FilterUtil.as

@@ -0,0 +1,132 @@
+package com.threerings.flash {
+
+import flash.display.DisplayObject;
+
+import flash.filters.BevelFilter;
+import flash.filters.BitmapFilter;
+import flash.filters.BlurFilter;
+import flash.filters.ColorMatrixFilter;
+import flash.filters.ConvolutionFilter;
+import flash.filters.DisplacementMapFilter;
+import flash.filters.DropShadowFilter;
+import flash.filters.GlowFilter;
+import flash.filters.GradientBevelFilter;
+import flash.filters.GradientGlowFilter;
+
+import com.threerings.util.ClassUtil;
+
+/**
+ * Useful utility methods that wouldn't be needed if the flash API were not so retarded.
+ */
+public class FilterUtil
+{
+    /**
+     * Add the specified filter to the DisplayObject.
+     */
+    public static function addFilter (disp :DisplayObject, filter :BitmapFilter) :void
+    {
+        checkArgs(disp, filter);
+        var filts :Array = disp.filters;
+        if (filts == null) {
+            filts = [];
+        }
+        filts.push(filter);
+        disp.filters = filts;
+    }
+
+    /**
+     * Remove the specified filter from the DisplayObject.
+     * Note that the filter set in the DisplayObject is a clone, so the values
+     * of the specified filter are used to find a match.
+     */
+    public static function removeFilter (disp :DisplayObject, filter :BitmapFilter) :void
+    {
+        checkArgs(disp, filter);
+        var filts :Array = disp.filters;
+        if (filts != null) {
+            for (var ii :int = filts.length - 1; ii >= 0; ii--) {
+                var oldFilter :BitmapFilter = (filts[ii] as BitmapFilter);
+                if (equals(oldFilter, filter)) {
+                    filts.splice(ii, 1);
+                    if (filts.length == 0) {
+                        filts = null;
+                    }
+                    disp.filters = filts;
+                    return; // SUCCESS
+                }
+            }
+        }
+    }
+
+    /**
+     * Are the two filters equals?
+     */
+    public static function equals (f1 :BitmapFilter, f2 :BitmapFilter) :Boolean
+    {
+        if (f1 === f2) { // catch same instance, or both null
+            return true;
+
+        } else if (f1 == null || f2 == null) { // otherwise nulls are no good
+            return false;
+        }
+
+        var c1 :Class = ClassUtil.getClass(f1);
+        if (c1 !== ClassUtil.getClass(f2)) {
+            return false;
+        }
+
+        // when we have two filters of the same class, figure it out by hand...
+        switch (c1) {
+        case BevelFilter:
+            // TODO
+            return false;
+
+        case BlurFilter:
+            // TODO
+            return false;
+
+        case ColorMatrixFilter:
+            // TODO
+            return false;
+
+        case ConvolutionFilter:
+            // TODO
+            return false;
+
+        case DisplacementMapFilter:
+            // TODO
+            return false;
+
+        case DropShadowFilter:
+            // TODO
+            return false;
+
+        case GlowFilter:
+            var gf1 :GlowFilter = (f1 as GlowFilter);
+            var gf2 :GlowFilter = (f2 as GlowFilter);
+            return (gf1.alpha == gf2.alpha) && (gf1.blurX == gf2.blurX) &&
+                (gf1.blurY == gf2.blurY) && (gf1.color == gf2.color) && (gf1.inner == gf2.inner) &&
+                (gf1.knockout == gf2.knockout) && (gf1.quality == gf2.quality) &&
+                (gf1.strength == gf2.strength);
+
+        case GradientBevelFilter:
+            // TODO
+            return false;
+
+        case GradientGlowFilter:
+            // TODO
+            return false;
+
+        default:
+            throw new ArgumentError("OMG! Unknown filter type: " + c1);
+        }
+    }
+
+    protected static function checkArgs (disp :DisplayObject, filter :BitmapFilter) :void
+    {
+        if (disp == null || filter == null) {
+            throw new ArgumentError("args may not be null");
+        }
+    }
+}
+}