RFDrawImage, add imageSize guard, improve draw result with stroke.

Author: BB9z

Diff for: RFDrawImage/RFDrawImage.h

@@ -1,25 +1,23 @@
 /*!
-    RFDrawImage
-    RFUI
-
-    Copyright (c) 2014 BB9z
-    https://github.com/RFUI/Alpha
-
-    The MIT License (MIT)
-    http://www.opensource.org/licenses/mit-license.php
-
-    BETA
+ RFDrawImage
+ RFUI
+ 
+ Copyright (c) 2014, 2018 BB9z
+ https://github.com/RFUI/Alpha
+ 
+ The MIT License (MIT)
+ http://www.opensource.org/licenses/mit-license.php
  */
 #import <RFKit/RFRuntime.h>
 
 @interface RFDrawImage : NSObject
 
-+ (UIImage *)imageWithSizeColor:(CGSize)imageSize fillColor:(UIColor *)color;
++ (nonnull UIImage *)imageWithSizeColor:(CGSize)imageSize fillColor:(nonnull UIColor *)color;
 
-+ (UIImage *)imageWithRoundingCorners:(UIEdgeInsets)cornerRadius
++ (nonnull UIImage *)imageWithRoundingCorners:(UIEdgeInsets)cornerRadius
                                  size:(CGSize)imageSize
-                            fillColor:(UIColor *)fillColor
-                          strokeColor:(UIColor *)strokeColor
+                            fillColor:(nonnull UIColor *)fillColor
+                          strokeColor:(nullable UIColor *)strokeColor
                           strokeWidth:(CGFloat)strokeWidth
                             boxMargin:(UIEdgeInsets)boxMargin
                    resizableCapInsets:(UIEdgeInsets)resizableCapInset

Diff for: RFDrawImage/RFDrawImage.m

@@ -4,6 +4,8 @@
 @implementation RFDrawImage
 
 + (UIImage *)imageWithSizeColor:(CGSize)imageSize fillColor:(UIColor *)color {
+    NSParameterAssert(imageSize.width > 0 && imageSize.height > 0);
+
     UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
     CGContextRef context = UIGraphicsGetCurrentContext();
 
@@ -16,7 +18,8 @@ + (UIImage *)imageWithSizeColor:(CGSize)imageSize fillColor:(UIColor *)color {
 }
 
 + (UIImage *)imageWithRoundingCorners:(UIEdgeInsets)cornerRadius size:(CGSize)imageSize fillColor:(UIColor *)fillColor strokeColor:(UIColor *)strokeColor strokeWidth:(CGFloat)strokeWidth boxMargin:(UIEdgeInsets)margin resizableCapInsets:(UIEdgeInsets)resizableCapInsets scaleFactor:(CGFloat)scaleFactor {
-
+    NSParameterAssert(imageSize.width > 0 && imageSize.height > 0);
+    
     UIGraphicsBeginImageContextWithOptions(imageSize, NO, scaleFactor);
 
     CGFloat r_lt = cornerRadius.top;
@@ -42,12 +45,15 @@ + (UIImage *)imageWithRoundingCorners:(UIEdgeInsets)cornerRadius size:(CGSize)im
     [path addArcWithCenter:c_rt radius:r_rt startAngle:0 endAngle:M_PI_2 *3 clockwise:NO];
 
     [path closePath];
+    [path addClip];                     // Stop stroke draw outside
     [fillColor setFill];
     [path fill];
 
-    [strokeColor setStroke];
-    path.lineWidth = strokeWidth;
-    [path stroke];
+    if (strokeWidth > 0) {
+        [strokeColor setStroke];
+        path.lineWidth = strokeWidth * 2; // Double due to the chip
+        [path stroke];
+    }
 
 	UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
 	UIGraphicsEndImageContext();