Legacy ImageMagick Discussions Archive

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- (void)posterizeImageWithoutCompression {
	// WITHOUT JPEG COMPRESSION, work done by Karl: karl@xk72.com
	NSLog(@"we're not using JPEG compression");
	
	MagickWandGenesis();
	magick_wand = NewMagickWand();
    
	UIImage * src = [UIImage imageNamed:"ololo.tif"];
	CGImageRef srcCGImage = [src CGImage];
	NSData * srcData = (NSData *) CGDataProviderCopyData(CGImageGetDataProvider(srcCGImage));
	unsigned long width = src.size.width;
	unsigned long height = src.size.height;
	const void *bytes = [srcData bytes];
	const char *map;
	CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(srcCGImage);
	CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(srcCGImage);
	if ((bitmapInfo & kCGBitmapByteOrder32Little) != 0)
		switch (alphaInfo) {
			case kCGImageAlphaLast:
			case kCGImageAlphaPremultipliedLast:
				map = "ABGR";
				break;
			case kCGImageAlphaFirst:
			case kCGImageAlphaPremultipliedFirst:
				map = "BGRA";
				break;
			case kCGImageAlphaNoneSkipLast:
				map = "PBGR";
				break;
			case kCGImageAlphaNoneSkipFirst:
				map = "BGRP";
				break;
			case kCGImageAlphaNone:
				map = "BGR";
				break;
		}
	else {
		switch (alphaInfo) {
			case kCGImageAlphaLast:
			case kCGImageAlphaPremultipliedLast:
				map = "RGBA";
				break;
			case kCGImageAlphaFirst:
			case kCGImageAlphaPremultipliedFirst:
				map = "ARGB";
				break;
			case kCGImageAlphaNoneSkipLast:
				map = "RGBP";
				break;
			case kCGImageAlphaNoneSkipFirst:
				map = "PRGB";
				break;
			case kCGImageAlphaNone:
				map = "RGB";
				break;
		}
	}

       // ==================
       // Here code fail in EXC_BAD_ACCESS when using something differente from UndefinedPixel

	MagickBooleanType status = MagickConstituteImage(magick_wand, width, height, map, UndefinedPixel, bytes);

       // ===================

	if (status == MagickFalse) {
		ThrowWandException(magick_wand);
	}
	
	MagickSetFormat(magick_wand, "pdf");
	MagickSetImageDepth(magick_wand, 8);

        NSString *root = 
        [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask , YES)
        objectAtIndex:0];
  
	const char * filename= [[root stringByAppendingFormat:@"text.pdf"] cStringUsingEncoding:NSUTF8StringEncoding];
	status = MagickWriteImage(magick_wand, filename);
	if (status == MagickFalse) {
		ThrowWandException(magick_wand);
	}