iOS 图片虚化。裁剪。等比例缩放

一、虚化

方法一：coreImage

- (UIImage *)blurryImageUseCoreImage:(UIImage *)image AndBlurLevel:(CGFloat)blur//coreImage虚化
{
    CIContext *context = [CIContext contextWithOptions:nil];
    
    CIImage *inputImage = [[CIImage alloc] initWithImage:image];
    
    CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
    
    [filter setValue:inputImage forKey:kCIInputImageKey];
    
    [filter setValue:[NSNumber numberWithFloat:blur] forKey:@"inputRadius"];
    
    //        CIImage *result = [filter valueForKey:kCIOutputImageKey];
    
    CIImage *result=[filter outputImage];
    
    CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];
    
    UIImage *image1 = [UIImage imageWithCGImage:cgImage];
    
    CGImageRelease(cgImage);
    
    return image1;
}

方法二：

//加模糊效果，image是图片，blur是模糊度
- (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur
{
    if (image==nil)
    {
        DLog(@"error:为图片添加模糊效果时，未能获取原始图片");
        return nil;
    }
    
    //模糊度,
    if ((blur < 0.1f) || (blur > 2.0f)) {
        blur = 0.5f;
    }
    
    //boxSize必须大于0
    int boxSize = (int)(blur * 100);
    boxSize -= (boxSize % 2) + 1;
    DLog(@"boxSize:%i",boxSize);
    //图像处理
    CGImageRef img = image.CGImage;
    //需要引入#import <Accelerate/Accelerate.h>
    /*
     This document describes the Accelerate Framework, which contains C APIs for vector and matrix math, digital signal processing, large number handling, and image processing.
     Accelerate Framework，其中包含C语言应用程序接口（API）的向量和矩阵数学，数字信号处理，大量处理和图像处理。
     */
    
    //图像缓存,输入缓存，输出缓存
    vImage_Buffer inBuffer, outBuffer;
    vImage_Error error;
    //像素缓存
    void *pixelBuffer;
    
    //数据源提供者，Defines an opaque type that supplies Quartz with data.
    CGDataProviderRef inProvider = CGImageGetDataProvider(img);
    // provider’s data.
    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);
    
    //宽，高，字节/行，data
    inBuffer.width = CGImageGetWidth(img);
    inBuffer.height = CGImageGetHeight(img);
    inBuffer.rowBytes = CGImageGetBytesPerRow(img);
    inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);
    
    //像数缓存，字节行*图片高
    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
    
    outBuffer.data = pixelBuffer;
    outBuffer.width = CGImageGetWidth(img);
    outBuffer.height = CGImageGetHeight(img);
    outBuffer.rowBytes = CGImageGetBytesPerRow(img);
    
    
    // 第三个中间的缓存区,抗锯齿的效果
    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);
    
    //Convolves a region of interest within an ARGB8888 source image by an implicit M x N kernel that has the effect of a box filter.
    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    
    
    if (error) {
        DLog(@"error from convolution %ld", error);
    }
    
    //    DLog(@"字节组成部分：%zu",CGImageGetBitsPerComponent(img));
    //颜色空间DeviceRGB
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    //用图片创建上下文,CGImageGetBitsPerComponent(img),7,8
    CGContextRef ctx = CGBitmapContextCreate(
                                             outBuffer.data,
                                             outBuffer.width,
                                             outBuffer.height,
                                             8,
                                             outBuffer.rowBytes,
                                             colorSpace,
                                             CGImageGetBitmapInfo(image.CGImage));
    
    //根据上下文，处理过的图片，重新组件
    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
    
    //clean up
    CGContextRelease(ctx);
    CGColorSpaceRelease(colorSpace);
    
    free(pixelBuffer);
    free(pixelBuffer2);
    CFRelease(inBitmapData);
    
    CGColorSpaceRelease(colorSpace);   //多余的释放
    CGImageRelease(imageRef);
    
    return returnImage;
}

二、裁剪

UIImage分类

-(UIImage*)getSubImage:(CGRect)rect
{
    CGImageRef subImageRef = CGImageCreateWithImageInRect(self.CGImage, rect);//此处有内存泄露
    CGRect smallBounds = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));
    
    UIGraphicsBeginImageContext(smallBounds.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextDrawImage(context, smallBounds, subImageRef);
    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
    UIGraphicsEndImageContext();
    
    return smallImage;
}

三、等比例缩放

UIImage分类

//等比例缩放
-(UIImage*)scaleToSize:(CGSize)size
{
    CGFloat width = CGImageGetWidth(self.CGImage);
    CGFloat height = CGImageGetHeight(self.CGImage);
    
    float verticalRadio = size.height*1.0/height;
    float horizontalRadio = size.width*1.0/width;
    
    float radio = 1;
    if(verticalRadio>1 && horizontalRadio>1)
    {
        radio = verticalRadio > horizontalRadio ? horizontalRadio : verticalRadio;
    }
    else
    {
        radio = verticalRadio < horizontalRadio ? verticalRadio : horizontalRadio;
    }
    
    width = width*radio;
    height = height*radio;
    
    int xPos = (size.width - width)/2;
    int yPos = (size.height-height)/2;
    
    // 创建一个bitmap的context
    // 并把它设置成为当前正在使用的context
    UIGraphicsBeginImageContext(size);
    
    // 绘制改变大小的图片
    [self drawInRect:CGRectMake(xPos, yPos, width, height)];
    
    // 从当前context中创建一个改变大小后的图片
    UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // 使当前的context出堆栈
    UIGraphicsEndImageContext();
    
    // 返回新的改变大小后的图片
    return scaledImage;
}