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POHow Can I Iterate an ARGB Bitmap?
 

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  1. POHow Can I Iterate an ARGB Bitmap?
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    <p>I am a bit confused. I have an ARGB bitmap into an <code>unsigned char*</code> array and I just want to iterate the array to check if pixels are black or white. Can anyone post me a sample code for this?</p> <p>To get the array I am using this methods.</p> <pre><code>CGContextRef CreateARGBBitmapContext (CGSize size) { CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); if (colorSpace == NULL) { fprintf(stderr, "Error allocating color space\n"); return NULL; } void *bitmapData = malloc(size.width * size.height * 4); if (bitmapData == NULL) { fprintf (stderr, "Error: Memory not allocated!"); CGColorSpaceRelease(colorSpace); return NULL; } CGContextRef context = CGBitmapContextCreate (bitmapData, size.width, size.height, 8, size.width * 4, colorSpace, kCGImageAlphaPremultipliedFirst); CGColorSpaceRelease(colorSpace ); if (context == NULL) { fprintf (stderr, "Error: Context not created!"); free (bitmapData); return NULL; } return context; } - (unsigned char *)bitmapFromImage:(UIImage *)image { //Create a bitmap for the given image. CGContextRef contex = CreateARGBBitmapContext(image.size); if (contex == NULL) { return NULL; } CGRect rect = CGRectMake(0.0f, 0.0f, image.size.width, image.size.height); CGContextDrawImage(contex, rect, image.CGImage); unsigned char *data = CGBitmapContextGetData(contex); CGContextRelease(contex); return data; } </code></pre> <p>To test all, I am using this.</p> <pre><code>- (void)viewDidLoad { [super viewDidLoad]; NSString *path = [[NSBundle mainBundle] pathForResource:@"verticalLine320x460" ofType:@"png"]; UIImage *image = [[UIImage alloc] initWithContentsOfFile:path]; unsigned char *imageBitmap = (unsigned char *)[self bitmapFromImage:image]; [image release]; } </code></pre> <p>Thanks for read.</p>
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    1. USDaniel García Baena
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