Allow screenshot plugin to optionally return a base64 encoded string …

…to a given function name. Added a README for the screenshot plugin.

iPhone/ScreenShot/README

@@ -0,0 +1,31 @@
+This plugin lets you take a screenshot of the viewable screen in iOS without the top status bar.
+
+You can call this function with
+
+window.navigator.saveScreenshot( bool returnBase64, [string successCallbackString] )
+
+or
+
+PhoneGap.exec("Screenshot.saveScreenshot", returnBase64, [ successCallbackString ] );
+
+Where 
+
+returnBase64 (PNG format for now) is a BOOL to say whether or not we return a base64 encoded string back to Javascript or just let the screenshot get saved to the devices Saved Photos.
+
+and
+
+the optional successCallbackString which is the function that will be called  with the returned base64 encoded string given as the only parameter.
+
+So I used this with something like �
+
+�.
+<button onclick="takeScreenshot();">Take Screenshot</button>
+
+function takeScreenShot() {
+    	PhoneGap.exec("Screenshot.saveScreenshot", true, "returnScreenshotImage");		    	
+}	
+
+function returnScreenshotImage(image) {		
+	base64string = "data:image/png;base64,"+image;
+	$("#image_container").css("background-image", "url("+base64string+")");		 				
+}

iPhone/ScreenShot/ScreenShot.js

@@ -15,8 +15,8 @@ function Screenshot() {
 /**
  * Save the screenshot to the user's Photo Library
  */
-Screenshot.prototype.saveScreenshot = function() {
-    PhoneGap.exec("Screenshot.saveScreenshot");
+Screenshot.prototype.saveScreenshot = function( returnBase64, successCallbackString) {
+    PhoneGap.exec("Screenshot.saveScreenshot", returnBase64, successCallbackString );
 };
 
 PhoneGap.addConstructor(function() 

iPhone/ScreenShot/ScreenShot.m

@@ -11,6 +11,17 @@ @implementation Screenshot
 
 - (void)saveScreenshot:(NSArray*)arguments withDict:(NSDictionary*)options
 {
+	NSUInteger argc = [arguments count];
+	NSString* successCallback = nil, *returnBase64 = false;		
+
+	if (argc > 0) returnBase64 = [arguments objectAtIndex:0];
+	if (argc > 1) successCallback = [arguments objectAtIndex:1];
+
+	if (argc < 1) {
+		NSLog(@"Screenshot.saveScreenshot: Missing 1st parameter.");
+		return;
+	}
+
 	CGRect screenRect = [[UIScreen mainScreen] bounds];
 	CGRect imageRect = CGRectMake(0, 0, CGRectGetWidth(screenRect), CGRectGetHeight(screenRect));
 	UIGraphicsBeginImageContext(imageRect.size);
@@ -23,10 +34,27 @@ - (void)saveScreenshot:(NSArray*)arguments withDict:(NSDictionary*)options
 	[webView.layer renderInContext:ctx];
 
 	UIImage *image1 = UIGraphicsGetImageFromCurrentImageContext();
-	UIImageWriteToSavedPhotosAlbum(image1, nil, nil, nil);
+
+	if (returnBase64) {
+		if (argc < 2) {
+			NSLog(@"Screenshot.saveScreenshot: Missing 2nd parameter.");
+			UIGraphicsEndImageContext();
+			return;
+		} else {
+			NSData *imageData = UIImagePNGRepresentation(image1);
+			NSString *encodedString = [imageData base64Encoding];
+			NSString *jsCallBack;
+			jsCallBack = [ NSString stringWithFormat:@"%@(\"%@\");", successCallback, encodedString ];
+			[webView stringByEvaluatingJavaScriptFromString:jsCallBack];
+		}
+	} else {		
+		UIImageWriteToSavedPhotosAlbum(image1, nil, nil, nil);
+
+		UIAlertView *alert= [[UIAlertView alloc] initWithTitle:nil message:@"Image Saved" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
+		[alert show];
+		[alert release];
+	}
+
 	UIGraphicsEndImageContext();
-	UIAlertView *alert= [[UIAlertView alloc] initWithTitle:nil message:@"Image Saved" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
-	[alert show];
-	[alert release];
 }
 @end