GPUImage源码解读(十八)
GPUImageFilterPipeline 继承自NSObject，它的主要作用是管理滤镜链，自身不能参与响应链中。可以用来构建简单的滤镜组合。如果滤镜比较复杂或是涉及到多个纹理的处理，GPUImageFilterGroup则是更好的选择。
属性
// filter数组
@property (strong) NSMutableArray *filters;
// 输入对象
@property (strong) GPUImageOutput *input;
// 输出对象
@property (strong) id <GPUImageInput> output;构造方法。可以通过指定filter数组以及配置字典、文件来构造GPUImageFilterPipeline
- (id) initWithOrderedFilters:(NSArray*) filters input:(GPUImageOutput*)input output:(id <GPUImageInput>)output;
- (id) initWithConfiguration:(NSDictionary*) configuration input:(GPUImageOutput*)input output:(id <GPUImageInput>)output;
- (id) initWithConfigurationFile:(NSURL*) configuration input:(GPUImageOutput*)input output:(id <GPUImageInput>)output;
// 根据输入的filter数组、GPUImageOutput、GPUImageInput构建GPUImageFilterPipeline
- (id)initWithOrderedFilters:(NSArray *)filters input:(GPUImageOutput *)input output:(id <GPUImageInput>)output {
self = [super init];
if (self) {
self.input = input;
self.output = output;
self.filters = [NSMutableArray arrayWithArray:filters];
[self _refreshFilters];
}
return self;
}
// 根据filter配置字典、GPUImageOutput、GPUImageInput构建GPUImageFilterPipeline
- (id)initWithConfiguration:(NSDictionary *)configuration input:(GPUImageOutput *)input output:(id <GPUImageInput>)output {
self = [super init];
if (self) {
self.input = input;
self.output = output;
if (![self _parseConfiguration:configuration]) {
NSLog(@"Sorry, a parsing error occurred.");
abort();
}
[self _refreshFilters];
}
return self;
}
// 根据filter配置文件的URL、GPUImageOutput、GPUImageInput构建GPUImageFilterPipeline
- (id)initWithConfigurationFile:(NSURL *)configuration input:(GPUImageOutput *)input output:(id <GPUImageInput>)output {
return [self initWithConfiguration:[NSDictionary dictionaryWithContentsOfURL:configuration] input:input output:output];
}
// 解析配置文件
- (BOOL)_parseConfiguration:(NSDictionary *)configuration {
NSArray *filters = [configuration objectForKey:@"Filters"];
if (!filters) {
return NO;
}
NSError *regexError = nil;
// 匹配配置文件参数如：float(1.0), CGPoint(1.0, 2.0) 等类型
NSRegularExpression *parsingRegex = [NSRegularExpression regularExpressionWithPattern:@"(float|CGPoint|NSString)\\((.*?)(?:,\\s*(.*?))*\\)"
options:0
error:®exError];
// It's faster to put them into an array and then pass it to the filters property than it is to call [self addFilter:] every time
NSMutableArray *orderedFilters = [NSMutableArray arrayWithCapacity:[filters count]];
for (NSDictionary *filter in filters) {
// 由FilterName生成相应的实例对象
NSString *filterName = [filter objectForKey:@"FilterName"];
Class theClass = NSClassFromString(filterName);
GPUImageOutput<GPUImageInput> *genericFilter = [[theClass alloc] init];
// Set up the properties
NSDictionary *filterAttributes;
// 解析Attributes，并传递参数
if ((filterAttributes = [filter objectForKey:@"Attributes"])) {
for (NSString *propertyKey in filterAttributes) {
// Set up the selector
SEL theSelector = NSSelectorFromString(propertyKey);
NSInvocation *inv = [NSInvocation invocationWithMethodSignature:[theClass instanceMethodSignatureForSelector:theSelector]];
[inv setSelector:theSelector];
[inv setTarget:genericFilter];
// check selector given with parameter
if ([propertyKey hasSuffix:@":"]) {
stringValue = nil;
// Then parse the arguments
NSMutableArray *parsedArray;
if ([[filterAttributes objectForKey:propertyKey] isKindOfClass:[NSArray class]]) {
NSArray *array = [filterAttributes objectForKey:propertyKey];
parsedArray = [NSMutableArray arrayWithCapacity:[array count]];
for (NSString *string in array) {
NSTextCheckingResult *parse = [parsingRegex firstMatchInString:string
options:0
range:NSMakeRange(0, [string length])];
NSString *modifier = [string substringWithRange:[parse rangeAtIndex:1]];
if ([modifier isEqualToString:@"float"]) {
// Float modifier, one argument
CGFloat value = [[string substringWithRange:[parse rangeAtIndex:2]] floatValue];
[parsedArray addObject:[NSNumber numberWithFloat:value]];
[inv setArgument:&value atIndex:2];
} else if ([modifier isEqualToString:@"CGPoint"]) {
// CGPoint modifier, two float arguments
CGFloat x = [[string substringWithRange:[parse rangeAtIndex:2]] floatValue];
CGFloat y = [[string substringWithRange:[parse rangeAtIndex:3]] floatValue];
CGPoint value = CGPointMake(x, y);
[parsedArray addObject:[NSValue valueWithCGPoint:value]];
} else if ([modifier isEqualToString:@"NSString"]) {
// NSString modifier, one string argument
stringValue = [[string substringWithRange:[parse rangeAtIndex:2]] copy];
[inv setArgument:&stringValue atIndex:2];
} else {
return NO;
}
}
[inv setArgument:&parsedArray atIndex:2];
} else {
NSString *string = [filterAttributes objectForKey:propertyKey];
NSTextCheckingResult *parse = [parsingRegex firstMatchInString:string
options:0
range:NSMakeRange(0, [string length])];
NSString *modifier = [string substringWithRange:[parse rangeAtIndex:1]];
if ([modifier isEqualToString:@"float"]) {
// Float modifier, one argument
CGFloat value = [[string substringWithRange:[parse rangeAtIndex:2]] floatValue];
[inv setArgument:&value atIndex:2];
} else if ([modifier isEqualToString:@"CGPoint"]) {
// CGPoint modifier, two float arguments
CGFloat x = [[string substringWithRange:[parse rangeAtIndex:2]] floatValue];
CGFloat y = [[string substringWithRange:[parse rangeAtIndex:3]] floatValue];
CGPoint value = CGPointMake(x, y);
[inv setArgument:&value atIndex:2];
} else if ([modifier isEqualToString:@"NSString"]) {
// NSString modifier, one string argument
stringValue = [[string substringWithRange:[parse rangeAtIndex:2]] copy];
[inv setArgument:&stringValue atIndex:2];
} else {
return NO;
}
}
}
[inv invoke];
}
}
[orderedFilters addObject:genericFilter];
}
self.filters = orderedFilters;
return YES;
}配置文件示例
其它方法
Last updated