issue trying to screen capture a UIView in iOS - ios

Question

my app has a ViewController which contains inside a UIView (CanvasView) where you can draw your signature (I added a label "Hi Little John" to differentiate it), and I also added a UIImage below it for making a capture by touching a camera button
Now when I touch the camera button it only captures the UIView and UILabel but not the signature as it shows
I have a two classes: my UIView class (CanvasView) and my UIViewController, in my CanvasView I have this code for the screenshot:
#implementation CanvasView
-(UIImage *)getCanvasScreenshot{
//first it makes an UIImage from the view
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *sourceImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//now it will position the image, X/Y away from top left corner to get the portion required
UIGraphicsBeginImageContext(self.frame.size);
[sourceImage drawAtPoint:CGPointMake(0, 0)];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
//some other code goes here...
#end
in my ViewController's class I have a my IBAction which triggers the event
- (IBAction)captureSignature:(id)sender {
self.imageFirma.image = [canvasView getCanvasScreenshot];
}
I want to capture the signature on my picture
any help I'll appreciate
thanks in advance
***** EDIT** the code for rendering the signature is in CanvasView as well, it's three methods
(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
depending of the event if the touch is:
at the begining (touchesBegan)
if is it moving (touchesMoved)
or if is finished (touchesEnded)
for rendering the stroke all of them call to a method named:
(void) addLineToAndRenderStroke:(SmoothStroke*)currentStroke toPoint:(CGPoint)end toWidth:(CGFloat)width toColor:(UIColor*)color
I can go deeper if you want but it's kinda long because it is a framework for making strokes on the canvas, and the code of all these methods are:
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
if(![JotStylusManager sharedInstance].enabled){
for (UITouch *touch in touches) {
[self addLineToAndRenderStroke:[self getStrokeForTouchHash:touch.hash]
toPoint:[touch locationInView:self]
toWidth:[self widthForPressure:JOT_MIN_PRESSURE]
toColor:[self colorForPressure:JOT_MIN_PRESSURE]];
}
}
}
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
if(![JotStylusManager sharedInstance].enabled){
for (UITouch *touch in touches) {
// check for other brands of stylus,
// or process non-Jot touches
//
// for this example, we'll simply draw every touch if
// the jot sdk is not enabled
[self addLineToAndRenderStroke:[self getStrokeForTouchHash:touch.hash]
toPoint:[touch locationInView:self]
toWidth:[self widthForPressure:JOT_MIN_PRESSURE]
toColor:[self colorForPressure:JOT_MIN_PRESSURE]];
}
}
}
-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
if(![JotStylusManager sharedInstance].enabled){
for(UITouch* touch in touches){
SmoothStroke* currentStroke = [self getStrokeForTouchHash:touch.hash];
// now line to the end of the stroke
[self addLineToAndRenderStroke:currentStroke
toPoint:[touch locationInView:self]
toWidth:[self widthForPressure:JOT_MIN_PRESSURE]
toColor:[self colorForPressure:JOT_MIN_PRESSURE]];
// this stroke is now finished, so add it to our completed strokes stack
// and remove it from the current strokes, and reset our undo state if any
[_stackOfStrokes addObject:currentStroke];
[currentStrokes removeObjectForKey:#([touch hash])];
[stackOfUndoneStrokes removeAllObjects];
}
}
}
- (void) addLineToAndRenderStroke:(SmoothStroke*)currentStroke toPoint:(CGPoint)end toWidth:(CGFloat)width toColor:(UIColor*)color{
// fetch the current and previous elements
// of the stroke. these will help us
// step over their length for drawing
AbstractBezierPathElement* previousElement = [currentStroke.segments lastObject];
// Convert touch point from UIView referential to OpenGL one (upside-down flip)
end.y = self.bounds.size.height - end.y;
if(![currentStroke addPoint:end withWidth:width andColor:color]) return;
//
// ok, now we have the current + previous stroke segment
// so let's set to drawing it!
[self renderElement:[currentStroke.segments lastObject] fromPreviousElement:previousElement includeOpenGLPrep:YES];
}