Added an ImageUtil with some basic utility functions.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4099 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/media/image/ImageUtil.as

@@ -0,0 +1,46 @@
+package com.threerings.media.image {
+
+import flash.display.BitmapData;
+import flash.display.DisplayObject;
+import flash.display.Shape;
+import flash.display.TextField;
+
+import flash.text.TextLineMetrics;
+
+/**
+ * Image and Bitmap related utility functions.
+ */
+public class ImageUtil
+{
+    /**
+     * Create a Shape that will display an error message of the specified
+     * dimensions.
+     */
+    public static function createErrorImage (width :int, height :int) :Shape
+    {
+        var shape :Shape = new Shape();
+        shape.graphics.beginBitmapFill(createErrorBitmap(), null, true);
+        shape.graphics.drawRect(0, 0, width, height);
+        shape.graphics.endFill();
+        return shape;
+    }
+
+    /**
+     * Create a minimally-sized "error" BitmapData.
+     */
+    public static function createErrorBitmap () :BitmapData
+    {
+        var txt :TextField = new TextField();
+        txt.text = "Error";
+        var metrics :TextLineMetrics = txt.getLineMetrics(0);
+        var data :BitmapData = new BitmapData(
+                metrics.width + ERROR_PADDING, metrics.height + ERROR_PADDING,
+                false, 0xFF4040);
+        data.draw(txt);
+        return data;
+    }
+
+    /** The amount to pad error messages by. */
+    private static const ERROR_PADDING :int = 5;
+}
+}