add image border color process method

README.md

@@ -103,14 +103,14 @@ Installation
 1. Download all the files in the YYWebImage subdirectory.
 2. Add the source files to your Xcode project.
 3. Link with required frameworks:
-	* UIKit.framework
-	* CoreFoundation.framework
-	* QuartzCore.framework
-	* AssetsLibrary.framework
-	* ImageIO.framework
-	* Accelerate.framework
-	* MobileCoreServices.framework
-	* libsqlite3
+	* UIKit
+	* CoreFoundation
+	* QuartzCore
+	* AssetsLibrary
+	* ImageIO
+	* Accelerate
+	* MobileCoreServices
+	* sqlite3
 	* libz
 4. Add `Vendor/WebP.framework`(static library) to your Xcode project if you want to support webp.
 5. Import `YYWebImage.h`.
@@ -232,14 +232,14 @@ YYWebImage 是一个异步图片加载框架 ([YYKit](https://github.com/ibireme
 1. 下载 YYWebImage 文件夹内的所有内容。
 2. 将 YYWebModel 内的源文件添加(拖放)到你的工程。
 3. 链接以下 frameworks:
-	* UIKit.framework
-	* CoreFoundation.framework
-	* QuartzCore.framework
-	* AssetsLibrary.framework
-	* ImageIO.framework
-	* Accelerate.framework
-	* MobileCoreServices.framework
-	* libsqlite3
+	* UIKit
+	* CoreFoundation
+	* QuartzCore
+	* AssetsLibrary
+	* ImageIO
+	* Accelerate
+	* MobileCoreServices
+	* sqlite3
 	* libz
 4. 如果你需要支持 webp，可以将 `Vendor/WebP.framework`(静态库) 加入你的工程。
 5. 导入 `YYWebImage.h`。

YYWebImage/Categories/UIImage+YYWebImage.h

@@ -150,6 +150,23 @@
  */
 - (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius;
 
+/**
+ Rounds a new image with a given corner size.
+ 
+ @param radius       The radius of each corner oval. Values larger than half the
+                     rectangle's width or height are clamped appropriately to
+                     half the width or height.
+
+ @param borderWidth  The inset border line width. Values larger than half the rectangle's
+                     width or height are clamped appropriately to half the width 
+                     or height.
+ 
+ @param borderColor  The border stroke color. nil means clear color.
+ */
+- (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius
+                             borderWidth:(CGFloat)borderWidth
+                             borderColor:(UIColor *)borderColor;
+
 /**
  Rounds a new image with a given corner size.
  
@@ -161,13 +178,19 @@
                      rounded. You can use this parameter to round only a subset
                      of the corners of the rectangle.
  
- @param borderWidth  The inset border with clear color. Values larger than half
-                     the rectangle's width or height are clamped appropriately
-                     to half the width or height.
+ @param borderWidth  The inset border line width. Values larger than half the rectangle's
+                     width or height are clamped appropriately to half the width 
+                     or height.
+ 
+ @param borderColor  The border stroke color. nil means clear color.
+ 
+ @param borderLineJoin The border line join.
  */
 - (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius
                                  corners:(UIRectCorner)corners
-                             borderWidth:(CGFloat)borderWidth;
+                             borderWidth:(CGFloat)borderWidth
+                             borderColor:(UIColor *)borderColor
+                          borderLineJoin:(CGLineJoin)borderLineJoin;
 
 /**
  Returns a new rotated image (relative to the center).

YYWebImage/Categories/UIImage+YYWebImage.m

@@ -337,10 +337,21 @@ static NSTimeInterval _yy_CGImageSourceGetGIFFrameDelayAtIndex(CGImageSourceRef
 }
 
 - (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius {
-    return [self yy_imageByRoundCornerRadius:radius corners:UIRectCornerAllCorners borderWidth:0];
+    return [self yy_imageByRoundCornerRadius:radius borderWidth:0 borderColor:nil];
 }
 
-- (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius corners:(UIRectCorner)corners borderWidth:(CGFloat)borderWidth {
+- (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius
+                             borderWidth:(CGFloat)borderWidth
+                             borderColor:(UIColor *)borderColor {
+    return [self yy_imageByRoundCornerRadius:radius corners:UIRectCornerAllCorners borderWidth:borderWidth borderColor:borderColor borderLineJoin:kCGLineJoinMiter];
+}
+
+- (UIImage *)yy_imageByRoundCornerRadius:(CGFloat)radius
+                                 corners:(UIRectCorner)corners
+                             borderWidth:(CGFloat)borderWidth
+                             borderColor:(UIColor *)borderColor
+                          borderLineJoin:(CGLineJoin)borderLineJoin {
+    
     UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
     CGContextRef context = UIGraphicsGetCurrentContext();
     CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
@@ -349,9 +360,28 @@ static NSTimeInterval _yy_CGImageSourceGetGIFFrameDelayAtIndex(CGImageSourceRef
     
     CGFloat minSize = MIN(self.size.width, self.size.height);
     if (borderWidth < minSize / 2) {
-        [[UIBezierPath bezierPathWithRoundedRect:CGRectInset(rect, borderWidth, borderWidth) byRoundingCorners:corners cornerRadii:CGSizeMake(radius, borderWidth)] addClip];
+        UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectInset(rect, borderWidth, borderWidth) byRoundingCorners:corners cornerRadii:CGSizeMake(radius, borderWidth)];
+        [path closePath];
+        
+        CGContextSaveGState(context);
+        [path addClip];
         CGContextDrawImage(context, rect, self.CGImage);
+        CGContextRestoreGState(context);
     }
+    
+    if (borderColor && borderWidth < minSize / 2 && borderWidth > 0) {
+        CGFloat strokeInset = (floor(borderWidth * self.scale) + 0.5) / self.scale;
+        CGRect strokeRect = CGRectInset(rect, strokeInset, strokeInset);
+        CGFloat strokeRadius = radius > self.scale / 2 ? radius - self.scale / 2 : 0;
+        UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:strokeRect byRoundingCorners:corners cornerRadii:CGSizeMake(strokeRadius, borderWidth)];
+        [path closePath];
+        
+        path.lineWidth = borderWidth;
+        path.lineJoinStyle = borderLineJoin;
+        [borderColor setStroke];
+        [path stroke];
+    }
+    
     UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
     UIGraphicsEndImageContext();
     return image;