封装CIImage实现实时渲染
CIImage属于CoreImage里面的东东,用来渲染图片的,为什么要封装它呢?其实很简单,封装好之后使用更加方便.
如果直接使用CIImage渲染图片,使用的流程如下:
只要你仔细研究一下CIImage,你会发现,filter部分与context部分是彼此分离的,context只接受一个CIImage,其他的都不管,所以,这个地方,我们就把它拆分成两部分,一部分是filter,一部分是context.
注:context部分执行了CIImage的渲染工作,CIImage的outputImage方法只是封装了要被渲染的步骤而已.
@property(readonly, nonatomic) CIImage *outputImage
Description
Returns a CIImage object that encapsulates the operations configured in the filter. (read-only)
ImageFilter.h + ImageFilter.m
//
// ImageFilter.h
// CoreImageWapper
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import <Foundation/Foundation.h>
#import <CoreImage/CoreImage.h>
#pragma mark - 辅助内联函数
NS_INLINE CIImage* CIImageFromImage(UIImage *image)
{
return [[CIImage alloc] initWithImage:image];
}
#pragma mark - 定义的block
typedef void(^ImageFilterConfigBlock_t)(CIFilter *filter);
@interface ImageFilter : NSObject
#pragma mark - 可读写属性
@property (nonatomic, strong, readwrite) CIImage *inputCIImage; // 输入CIImage
@property (nonatomic, strong, readwrite) NSString *filterName; // 滤镜名字
#pragma mark - 重写了getter方法,注意
@property (nonatomic, strong, readonly) CIImage *outputCIImage; // 输出CIImage
@property (nonatomic, assign, readonly) BOOL filterNameValid; // 滤镜名合法性
#pragma mark - 初始化方法
- (instancetype)init;
- (instancetype)initWithFilterName:(NSString *)filterName;
- (instancetype)initWithFilterName:(NSString *)filterName inputCIImage:(CIImage *)inputCIImage;
#pragma mark - 配置
- (void)configFilter:(ImageFilterConfigBlock_t)block;
@end//
// ImageFilter.m
// CoreImageWapper
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import "ImageFilter.h"
NSArray *filterNameArray = nil;
@interface ImageFilter ()
@property (nonatomic, strong) CIFilter *filter;
@end
@implementation ImageFilter
@synthesize outputCIImage = _outputCIImage;
@synthesize filterNameValid = _filterNameValid;
+ (void)initialize
{
if (self == [ImageFilter class])
{
filterNameArray = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];;
}
}
- (instancetype)init
{
return [self initWithFilterName:nil inputCIImage:nil];
}
- (instancetype)initWithFilterName:(NSString *)filterName
{
return [self initWithFilterName:filterName inputCIImage:nil];
}
- (instancetype)initWithFilterName:(NSString *)filterName inputCIImage:(CIImage *)inputCIImage
{
self = [super init];
if (self)
{
self.filterName = filterName;
self.inputCIImage = inputCIImage;
}
return self;
}
-(CIImage *)outputCIImage
{
if (_filter)
{
return [_filter outputImage];
}
else
{
return nil;
}
}
- (void)configFilter:(ImageFilterConfigBlock_t)block
{
if (_filterName && _inputCIImage)
{
// 创建滤镜
_filter = [CIFilter filterWithName:_filterName
keysAndValues:kCIInputImageKey, _inputCIImage, nil];
// 设置滤镜
block(_filter);
}
block(nil);
}
- (BOOL)filterNameValid
{
BOOL flag = NO;
if (_filterName)
{
for (NSString *name in filterNameArray)
{
if ([_filterName isEqualToString:name] == YES)
{
flag = YES;
break;
}
}
}
return flag;
}
@endImageRender.h + ImageRender.m
//
// ImageRender.h
// CoreImageWapper
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "ImageFilter.h"
@interface ImageRender : NSObject
@property (nonatomic, strong) ImageFilter *imageFilter;
@property (nonatomic, strong) UIImage *outputImage;
- (instancetype)init;
- (instancetype)initWithImageFilter:(ImageFilter *)imageFilter;
- (UIImage *)render;
@end//
// ImageRender.m
// CoreImageWapper
//
// Copyright (c) 2014年 Y.X. All rights reserved.
//
#import "ImageRender.h"
@interface ImageRender ()
@property (nonatomic, strong) CIContext *context;
@end
@implementation ImageRender
- (instancetype)init
{
return [self initWithImageFilter:nil];
}
- (instancetype)initWithImageFilter:(ImageFilter *)imageFilter
{
self = [super init];
if (self)
{
// 基于GPU渲染
self.context = [CIContext contextWithOptions:nil];
self.imageFilter = imageFilter;
}
return self;
}
- (UIImage *)render
{
if (_imageFilter)
{
CIImage *outputCIImage = [_imageFilter outputCIImage];
CGImageRef cgImage = [_context createCGImage:outputCIImage
fromRect:[outputCIImage extent]];
self.outputImage = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
}
return self.outputImage;
}
@end现在,你可以这么使用了:)
好吧,来一个复杂的看看,即时渲染:
- (void)viewDidLoad
{
[super viewDidLoad];
ImageFilter *filter = [ImageFilter new];
ImageRender *render = [ImageRender new];
filter.filterName = @"CIPixellate";
filter.inputCIImage = CIImageFromImage([UIImage imageNamed:@"demo"]);
[filter configFilter:^(CIFilter *filter) {
[filter setValue:@1
forKey:@"inputScale"];
}];
render.imageFilter = filter;
UIImageView *imageView = [[UIImageView alloc] initWithImage:[render render]];
[self.view addSubview:imageView];
imageView.center = self.view.center;
_timer = [[GCDTimer alloc] initInQueue:[GCDQueue globalQueue]];
[_timer event:^{
static int i = 1;
[filter configFilter:^(CIFilter *filter) {
[filter setValue:[NSNumber numberWithInt:(i++)%10 + 1]
forKey:@"inputScale"];
}];
render.imageFilter = filter;
[[GCDQueue mainQueue] execute:^{
imageView.image = [render render];
}];
} timeInterval:NSEC_PER_SEC/10.f];
[_timer start];
}
- (void)viewDidLoad
{
[super viewDidLoad];
ImageFilter *filter = [ImageFilter new];
ImageRender *render = [ImageRender new];
filter.filterName = @"CIHueAdjust";
filter.inputCIImage = CIImageFromImage([UIImage imageNamed:@"demo"]);
[filter configFilter:^(CIFilter *filter) {
[filter setValue:@(3.14f)
forKey:@"inputAngle"];
}];
render.imageFilter = filter;
UIImageView *imageView = [[UIImageView alloc] initWithImage:[render render]];
[self.view addSubview:imageView];
imageView.center = self.view.center;
_timer = [[GCDTimer alloc] initInQueue:[GCDQueue globalQueue]];
[_timer event:^{
static int i = 0;
[filter configFilter:^(CIFilter *filter) {
[filter setValue:[NSNumber numberWithFloat:(i+=1)%314/100.f]
forKey:@"inputAngle"];
}];
render.imageFilter = filter;
[[GCDQueue mainQueue] execute:^{
imageView.image = [render render];
}];
} timeInterval:NSEC_PER_SEC/60.f];
[_timer start];
}
附录:
https://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CoreImageFilterReference/Reference/reference.html#//apple_ref/doc/uid/TP40004346
https://developer.apple.com/library/mac/documentation/graphicsimaging/reference/CoreImageFilterReference/Reference/reference.html
https://developer.apple.com/library/ios/documentation/GraphicsImaging/Conceptual/CoreImaging/CoreImage.pdf
http://www.rapidsnail.com/Tutorial/t/2012/112/30/22766/the-coreimage-ios.aspx
http://www.raywenderlich.com/zh-hans/24773/%E5%88%9D%E5%AD%A6ios6-%E4%B8%AD%E7%9A%84core-image%E6%8A%80%E6%9C%AF
http://my.safaribooksonline.com/book/video/9780321637031/chapter-15dot-secret-patches-core-image-filters-and-glsl-pushing-the-boundaries/ch15sec1lev5
http://stackoverflow.com/questions/17041669/creating-a-blurring-overlay-view/17041983#17041983
