BitmapData.clear has 4 new optional parameters: x, y, width and height, that define the area to be cleared. If left undefined it works exactly the same as before and clears the entire canvas.

Author: photonstorm

README.md

@@ -379,6 +379,7 @@ Version 2.4 - "Katar" - in dev
 * Debug.currentAlpha wasn't being used to set the alpha of the Debug context at all (was always set to 1) but now updates the alpha of the Debug context before anything is rendered to it (thanks @wayfu #1888)
 * If the device is detected as a Windows Phone the renderer is automatically set to use Canvas, even if WebGL or AUTO was requested (thanks @ramarro123 #1706)
 * RandomDataGenerator.weightedPick has been tweaked slightly to allow for a more even distribution of weights. It still favors the earlier array elements, but will accurately include 'distance' elements as well (thanks @gingerbeardman #1751)
+* BitmapData.clear has 4 new optional parameters: x, y, width and height, that define the area to be cleared. If left undefined it works exactly the same as before and clears the entire canvas.
 
 ### Bug Fixes
 

src/gameobjects/BitmapData.js

@@ -416,12 +416,24 @@ Phaser.BitmapData.prototype = {
     /**
     * Clears the BitmapData context using a clearRect.
     *
+    * You can optionally define the area to clear.
+    * If the arguments are left empty it will clear the entire canvas.
+    *
     * @method Phaser.BitmapData#clear
+    * @param {number} [x=0] - The x coordinate of the top-left of the area to clear.
+    * @param {number} [y=0] - The y coordinate of the top-left of the area to clear.
+    * @param {number} [width] - The width of the area to clear. If undefined it will use BitmapData.width.
+    * @param {number} [height] - The height of the area to clear. If undefined it will use BitmapData.height.
     * @return {Phaser.BitmapData} This BitmapData object for method chaining.
     */
-    clear: function () {
+    clear: function (x, y, width, height) {
+
+        if (typeof x === 'undefined') { x = 0; }
+        if (typeof y === 'undefined') { y = 0; }
+        if (typeof width === 'undefined') { width = this.width; }
+        if (typeof height === 'undefined') { height = this.height; }
 
-        this.context.clearRect(0, 0, this.width, this.height);
+        this.context.clearRect(x, y, width, height);
 
         this.dirty = true;
 

typescript/phaser.d.ts

@@ -1,7 +1,7 @@
 /// <reference path="pixi.d.ts" />
 /// <reference path="p2.d.ts" />
 
-// Type definitions for Phaser 2.4.0 2015-Jul-08
+// Type definitions for Phaser 2.4.0 2015-Jul-09
 // Project: https://github.com/photonstorm/phaser
 
 declare class Phaser {
@@ -244,7 +244,7 @@ declare module Phaser {
         blendSourceOver(): Phaser.BitmapData;
         blendXor(): Phaser.BitmapData;
         circle(x: number, y: number, radius: number, fillStyle?: string): Phaser.BitmapData;
-        clear(): Phaser.BitmapData;
+        clear(x?: number, y?: number, width?: number, height?: number): Phaser.BitmapData;
         cls(): Phaser.BitmapData;
         copy(source?: any, x?: number, y?: number, width?: number, height?: number, tx?: number, ty?: number, newWidth?: number, newHeight?: number, rotate?: number, anchorX?: number, anchorY?: number, scaleX?: number, scaleY?: number, alpha?: number, blendMode?: number, roundPx?: boolean): Phaser.BitmapData;
         copyPixels(source: any, area: Phaser.Rectangle, x: number, y: number, alpha?: number): void;