objective-c - 应用程序包中的 ImageMagick

Question

我发现问题（链接）女巫与我的问题非常相似。答案中的代码看起来是我一直在寻找的东西：

-(id)init
{
    if ([super init])
    {
        NSString* bundlePath = [[NSBundle mainBundle] bundlePath];
        NSString* imageMagickPath = [bundlePath stringByAppendingPathComponent:@"/Contents/Resources/ImageMagick"];
        NSString* imageMagickLibraryPath = [imageMagickPath stringByAppendingPathComponent:@"/lib"];

        MAGICK_HOME = imageMagickPath;
        DYLD_LIBRARY_PATH = imageMagickLibraryPath;
    }
    return self;
}

-(void)composite
{
    NSTask *task = [[NSTask alloc] init];

    // the ImageMagick library needs these two environment variables.
    NSMutableDictionary* environment = [[NSMutableDictionary alloc] init];
    [environment setValue:MAGICK_HOME forKey:@"MAGICK_HOME"];
    [environment setValue:DYLD_LIBRARY_PATH forKey:@"DYLD_LIBRARY_PATH"];

    // helper function from
    // http://www.karelia.com/cocoa_legacy/Foundation_Categories/NSFileManager__Get_.m
    NSString* pwd = [Helpers pathFromUserLibraryPath:@"MyApp"];

    // executable binary path
    NSString* exe = [MAGICK_HOME stringByAppendingPathComponent:@"/bin/composite"];

    [task setEnvironment:environment];
    [task setCurrentDirectoryPath:pwd]; // pwd
    [task setLaunchPath:exe]; // the path to composite binary
    // these are just example arguments
    [task setArguments:[NSArray arrayWithObjects: @"-gravity", @"center", @"stupid hat.png", @"IDR663.gif", @"bla.png", nil]];
    [task launch];
    [task waitUntilExit];
}

但是当我尝试使用它时，我遇到了 6 个错误：

Use of undeclared identifier 'MAGICK_HOME'
Use of undeclared identifier 'DYLD_LIBRARY_PATH'
Use of undeclared identifier 'MAGICK_HOME'
Use of undeclared identifier 'DYLD_LIBRARY_PATH'
Use of undeclared identifier 'Helpers'
Use of undeclared identifier 'MAGICK_HOME'

我该如何解决？

Answer 1

要使用您链接的代码，您可能只需要将它们声明为全局变量。

NSString * MAGICK_HOME = nil;
NSString * DYLD_LIBRARY_PATH = nil;

@implementation ...

替换Helpers为[self class]，并添加来自链接源的函数：

/*
    NSFileManager: Get the path within the user's Library directory
    Original Source: <http://cocoa.karelia.com/Foundation_Categories/NSFileManager__Get_.m>
    (See copyright notice at <http://cocoa.karelia.com>)
*/

/*" Return the path in the user library path of the given sub-path.  In other words, if given inSubPath is "foo", the path returned will be /Users/myUser/Library/foo
"*/
-  (NSString *) pathFromUserLibraryPath:(NSString *)inSubPath
{
    NSArray *domains = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask,YES);
    NSString *baseDir= [domains objectAtIndex:0];
    NSString *result = [baseDir stringByAppendingPathComponent:inSubPath];
    return result;
}