iOS开发中常用的分类方法---UIImage+extension

UIImage扩展类压缩图片
1.
@interface UIImage (UIImageExt)
- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize;
@end
@implementation UIImage (UIImageExt)
- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize{
UIImage *sourceImage = self;
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
scaleFactor = widthFactor; // scale to fit height
else
scaleFactor = heightFactor; // scale to fit width
scaledWidth= width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor > heightFactor)
{
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}
else if (widthFactor < heightFactor)
{
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width= scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
NSLog(@”could not scale image”);
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}

/**
* 自由拉伸一张图片
*
* @param name 图片名字
* @param left 左边开始位置比例 值范围0-1
* @param top 上边开始位置比例 值范围0-1
*
* @return 拉伸后的Image
*/
+ (UIImage )resizedImageWithName:(NSString )name left:(CGFloat)left top:(CGFloat)top
{
UIImage *image = [UIImage imageNamed:name];
return [image stretchableImageWithLeftCapWidth:image.size.width * left topCapHeight:image.size.height * top];
}

/**
* 根据颜色和大小获取Image
*
* @param color 颜色
* @param size 大小
*
*/
+ (UIImage )imageWithColor:(UIColor )color size:(CGSize)size
{
UIGraphicsBeginImageContextWithOptions(size, 0, [UIScreen mainScreen].scale);
[color set];
UIRectFill(CGRectMake(0, 0, size.width, size.height));
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
/**
* 根据图片和颜色返回一张加深颜色以后的图片
*/
+ (UIImage )colorizeImage:(UIImage )baseImage withColor:(UIColor *)theColor {

UIGraphicsBeginImageContext(CGSizeMake(baseImage.size.width*2, baseImage.size.height*2));

CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect area = CGRectMake(0, 0, baseImage.size.width * 2, baseImage.size.height * 2);

CGContextScaleCTM(ctx, 1, -1);
CGContextTranslateCTM(ctx, 0, -area.size.height);

CGContextSaveGState(ctx);
CGContextClipToMask(ctx, area, baseImage.CGImage);

[theColor set];
CGContextFillRect(ctx, area);

CGContextRestoreGState(ctx);

CGContextSetBlendMode(ctx, kCGBlendModeMultiply);

CGContextDrawImage(ctx, area, baseImage.CGImage);

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

}
/**
* 根据图片返回一张高斯模糊的图片
*
* @param blur 模糊系数
*
* @return 新的图片
*/
- (UIImage *)boxblurImageWithBlur:(CGFloat)blur {

NSData *imageData = UIImageJPEGRepresentation(self, 1); // convert to jpeg
UIImage* destImage = [UIImage imageWithData:imageData];


if (blur < 0.f || blur > 1.f) {
    blur = 0.5f;
}
int boxSize = (int)(blur * 40);
boxSize = boxSize - (boxSize % 2) + 1;

CGImageRef img = destImage.CGImage;

vImage_Buffer inBuffer, outBuffer;

vImage_Error error;

void *pixelBuffer;


//create vImage_Buffer with data from CGImageRef

CGDataProviderRef inProvider = CGImageGetDataProvider(img);
CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);


inBuffer.width = CGImageGetWidth(img);
inBuffer.height = CGImageGetHeight(img);
inBuffer.rowBytes = CGImageGetBytesPerRow(img);

inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);

//create vImage_Buffer for output

pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

if(pixelBuffer == NULL)
    NSLog(@"No pixelbuffer");

outBuffer.data = pixelBuffer;
outBuffer.width = CGImageGetWidth(img);
outBuffer.height = CGImageGetHeight(img);
outBuffer.rowBytes = CGImageGetBytesPerRow(img);

// Create a third buffer for intermediate processing
void *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
vImage_Buffer outBuffer2;
outBuffer2.data = pixelBuffer2;
outBuffer2.width = CGImageGetWidth(img);
outBuffer2.height = CGImageGetHeight(img);
outBuffer2.rowBytes = CGImageGetBytesPerRow(img);

//perform convolution
error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
if (error) {
    NSLog(@"error from convolution %ld", error);
}
error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
if (error) {
    NSLog(@"error from convolution %ld", error);
}
error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
if (error) {
    NSLog(@"error from convolution %ld", error);
}

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef ctx = CGBitmapContextCreate(outBuffer.data,
                                         outBuffer.width,
                                         outBuffer.height,
                                         8,
                                         outBuffer.rowBytes,
                                         colorSpace,
                                         (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

//clean up
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);

free(pixelBuffer);
free(pixelBuffer2);
CFRelease(inBitmapData);

CGImageRelease(imageRef);

return returnImage;

}
/**
* 自由改变Image的大小
*
* @param size 目的大小
*
* @return 修改后的Image
*/
- (UIImage *)cropImageWithSize:(CGSize)size {

float scale = self.size.width/self.size.height;
CGRect rect = CGRectMake(0, 0, 0, 0);

if (scale > size.width/size.height) {

    rect.origin.x = (self.size.width - self.size.height * size.width/size.height)/2;
    rect.size.width  = self.size.height * size.width/size.height;
    rect.size.height = self.size.height;

}else {

    rect.origin.y = (self.size.height - self.size.width/size.width * size.height)/2;
    rect.size.width  = self.size.width;
    rect.size.height = self.size.width/size.width * size.height;

}

CGImageRef imageRef   = CGImageCreateWithImageInRect(self.CGImage, rect);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

return croppedImage;

}