ImageExporterPlugIn.m

/*
        File: ImageExporterPlugIn.m
    Abstract: ImageExporterPlugin class.
     Version: 1.0
    
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*/
 
/* It's highly recommended to use CGL macros instead of changing the current context for plug-ins that perform OpenGL rendering */
#import <OpenGL/CGLMacro.h>
 
#import "ImageExporterPlugIn.h"
 
#define kQCPlugIn_Name              @"Image Exporter"
#define kQCPlugIn_Description       @"Writes the input image as a series of .png files to disk."
 
@implementation ImageExporterPlugIn
 
/* We need to declare the input / output properties as dynamic as Quartz Composer will handle their implementation */
@dynamic inputImage, inputPath;
 
+ (NSDictionary*) attributes
{
    /* Return the attributes of this plug-in */
    return [NSDictionary dictionaryWithObjectsAndKeys:kQCPlugIn_Name, QCPlugInAttributeNameKey, kQCPlugIn_Description, QCPlugInAttributeDescriptionKey, nil];
}
 
+ (NSDictionary*) attributesForPropertyPortWithKey:(NSString*)key
{
    /* Return the attributes for the plug-in property ports */
    if([key isEqualToString:@"inputImage"])
    return [NSDictionary dictionaryWithObjectsAndKeys:@"Image", QCPortAttributeNameKey, nil];
    if([key isEqualToString:@"inputPath"])
    return [NSDictionary dictionaryWithObjectsAndKeys:@"Destination Path", QCPortAttributeNameKey, @"~/Desktop", QCPortAttributeDefaultValueKey, nil];
    
    return nil;
}
 
+ (QCPlugInExecutionMode) executionMode
{
    /* This plug-in is a consumer (it renders to image files) */
    return kQCPlugInExecutionModeConsumer;
}
 
+ (QCPlugInTimeMode) timeMode
{
    /* This plug-in does not depend on the time (time parameter is completely ignored in the -execute:atTime:withArguments: method) */
    return kQCPlugInTimeModeNone;
}
 
@end
 
@implementation ImageExporterPlugIn (Execution)
 
- (BOOL) startExecution:(id<QCPlugInContext>)context
{
    /* Reset image file index */
    _index = 0;
    
    return YES;
}
 
- (BOOL) execute:(id<QCPlugInContext>)context atTime:(NSTimeInterval)time withArguments:(NSDictionary*)arguments
{
    id<QCPlugInInputImageSource>    qcImage = self.inputImage;
    NSString*                       pixelFormat;
    CGColorSpaceRef                 colorSpace;
    CGDataProviderRef               dataProvider;
    CGImageRef                      cgImage;
    CGImageDestinationRef           imageDestination;
    NSURL*                          fileURL;
    BOOL                            success;
    
    /* Make sure we have a new image */
    if(![self didValueForInputKeyChange:@"inputImage"] || !qcImage || ![self.inputPath length])
    return YES;
    
    /* Figure out pixel format and colorspace to use */
    colorSpace = [qcImage imageColorSpace];
    if(CGColorSpaceGetModel(colorSpace) == kCGColorSpaceModelMonochrome)
    pixelFormat = QCPlugInPixelFormatI8;
    else if(CGColorSpaceGetModel(colorSpace) == kCGColorSpaceModelRGB)
#if __BIG_ENDIAN__
    pixelFormat = QCPlugInPixelFormatARGB8;
#else
    pixelFormat = QCPlugInPixelFormatBGRA8;
#endif
    else
    return NO;
    
    /* Get a buffer representation from the image in its native colorspace */
    if(![qcImage lockBufferRepresentationWithPixelFormat:pixelFormat colorSpace:colorSpace forBounds:[qcImage imageBounds]])
    return NO;
    
    /* Create CGImage from buffer */
    dataProvider = CGDataProviderCreateWithData(NULL, [qcImage bufferBaseAddress], [qcImage bufferPixelsHigh] * [qcImage bufferBytesPerRow], NULL);
    cgImage = CGImageCreate([qcImage bufferPixelsWide], [qcImage bufferPixelsHigh], 8, (pixelFormat == QCPlugInPixelFormatI8 ? 8 : 32), [qcImage bufferBytesPerRow], colorSpace, (pixelFormat == QCPlugInPixelFormatI8 ? 0 : kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host), dataProvider, NULL, false, kCGRenderingIntentDefault);
    CGDataProviderRelease(dataProvider);
    if(cgImage == NULL) {
        [qcImage unlockBufferRepresentation];
        return NO;
    }
    
    /* Write CGImage to disk as PNG file */
    fileURL = [NSURL fileURLWithPath:[[self.inputPath stringByStandardizingPath] stringByAppendingPathComponent:[NSString stringWithFormat:@"Image-%05i.png", ++_index]]];
    imageDestination = (fileURL ? CGImageDestinationCreateWithURL((CFURLRef)fileURL, kUTTypePNG, 1, NULL) : NULL);
    if(imageDestination == NULL) {
        CGImageRelease(cgImage);
        [qcImage unlockBufferRepresentation];
        return NO;
    }
    CGImageDestinationAddImage(imageDestination, cgImage, NULL);
    success = CGImageDestinationFinalize(imageDestination);
    CFRelease(imageDestination);
    
    /* Destroy CGImage */
    CGImageRelease(cgImage);
    
    /* Release buffer representation */
    [qcImage unlockBufferRepresentation];
    
    return success;
}
 
@end