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Merge pull request #7 from plumbojumbo/fix-scan-line-padding
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Scan line padding (take 2)
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@ameingast
ameingast committed Dec 3, 2016
2 parents 579f64b + 487b4a0 commit e6240a0
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Showing 3 changed files with 39 additions and 17 deletions.
4 changes: 2 additions & 2 deletions CocoaImageHashing/OSCategories.h
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Original file line number Diff line number Diff line change
Expand Up @@ -63,8 +63,8 @@ NS_ASSUME_NONNULL_END
NS_ASSUME_NONNULL_BEGIN

+ (NSBitmapImageRep *)imageRepFrom:(NSBitmapImageRep *)sourceImageRep
scaledToWidth:(NSInteger)width
scaledToHeight:(NSInteger)height
scaledToWidth:(NSUInteger)width
scaledToHeight:(NSUInteger)height
usingInterpolation:(NSImageInterpolation)imageInterpolation;

NS_ASSUME_NONNULL_END
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26 changes: 15 additions & 11 deletions CocoaImageHashing/OSCategories.m
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,11 @@ - (void)arrayWithPairCombinations:(BOOL (^)(id leftHand, id rightHand))matcher

#pragma mark - NSData Category

OS_INLINE OS_ALWAYS_INLINE NSUInteger OSBytesPerRowForWidth(NSUInteger width)
{
return (width == 8) ? 32 : OS_ALIGN(4 * width, 64);
}

#if (TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR)

@implementation NSData (CocoaImageHashing)
Expand All @@ -68,10 +73,9 @@ - (NSData *)RGBABitmapDataForResizedImageWithWidth:(NSUInteger)width
return nil;
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
NSMutableData *data = [NSMutableData dataWithLength:height * width * 4];
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bytesPerRow = OSBytesPerRowForWidth(width);
NSUInteger bitsPerComponent = 8;
NSMutableData *data = [NSMutableData dataWithLength:height * bytesPerRow];
CGContextRef context = CGBitmapContextCreate([data mutableBytes], width, height, bitsPerComponent, bytesPerRow, colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
Expand All @@ -95,15 +99,15 @@ - (NSData *)RGBABitmapDataForResizedImageWithWidth:(NSUInteger)width
return nil;
}
NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepFrom:sourceImageRep
scaledToWidth:(NSInteger)width
scaledToHeight:(NSInteger)height
scaledToWidth:width
scaledToHeight:height
usingInterpolation:NSImageInterpolationHigh];
if (!imageRep) {
return nil;
}
unsigned char *pixels = [imageRep bitmapData];
NSData *result = [NSData dataWithBytes:pixels
length:OS_ALIGN(4 * width, 64) * height];
length:OSBytesPerRowForWidth(width) * height];
return result;
}

Expand All @@ -118,19 +122,19 @@ - (NSData *)RGBABitmapDataForResizedImageWithWidth:(NSUInteger)width
@implementation NSBitmapImageRep (CocoaImageHashing)

+ (NSBitmapImageRep *)imageRepFrom:(NSBitmapImageRep *)sourceImageRep
scaledToWidth:(NSInteger)width
scaledToHeight:(NSInteger)height
scaledToWidth:(NSUInteger)width
scaledToHeight:(NSUInteger)height
usingInterpolation:(NSImageInterpolation)imageInterpolation
{
NSBitmapImageRep *imageRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL
pixelsWide:width
pixelsHigh:height
pixelsWide:(NSInteger)width
pixelsHigh:(NSInteger)height
bitsPerSample:8
samplesPerPixel:4
hasAlpha:YES
isPlanar:NO
colorSpaceName:NSCalibratedRGBColorSpace
bytesPerRow:OS_ALIGN(4 * width, 64) // multiple of 64 bytes to improve CG performance
bytesPerRow:(NSInteger)OSBytesPerRowForWidth(width)
bitsPerPixel:0];
[NSGraphicsContext saveGraphicsState];
NSGraphicsContext *context = [NSGraphicsContext graphicsContextWithBitmapImageRep:imageRep];
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26 changes: 22 additions & 4 deletions CocoaImageHashingTests/OSFastGraphicsTests.m
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Original file line number Diff line number Diff line change
Expand Up @@ -124,8 +124,8 @@ - (void)testRotateRGBAMatrixPerformance
- (void)testDCT
{
NSData *imageData = [self loadImageAsData:@"blurred/architecture1.bmp"];
NSData *pixels = [imageData RGBABitmapDataForResizedImageWithWidth:32
andHeight:32];
NSData *pixels = [imageData RGBABitmapDataForResizedImageWithWidth:8
andHeight:8];
double greyscalePixels[32][32] = {{0.0}};
double fastDctPixels[32][32] = {{0.0}};
double dctPixels[32][32] = {{0.0}};
Expand All @@ -143,8 +143,8 @@ - (void)testFastDCTMultithreadedPerformance
{
const NSUInteger iterations = 1024 * 2;
NSData *imageData = [self loadImageAsData:@"blurred/architecture1.bmp"];
NSData *pixels = [imageData RGBABitmapDataForResizedImageWithWidth:32
andHeight:32];
NSData *pixels = [imageData RGBABitmapDataForResizedImageWithWidth:8
andHeight:8];
double fastDctPixels[32][32] = {{0.0}};
double greyscalePixels[32][32] = {{0.0}};
greyscale_pixels_rgba_32_32([pixels bytes], greyscalePixels);
Expand All @@ -158,4 +158,22 @@ - (void)testFastDCTMultithreadedPerformance
NSLog(@"DCT processing %@ MB/s", @(MBs / executionTime));
}

- (void)testResizedRGBABitmapDataScanline
{
NSData *imageData = [self loadImageAsData:@"misc/latrobe.bmp"];
for (NSUInteger dim = 8; dim <= 9; dim++) {
NSData *pixels = [imageData RGBABitmapDataForResizedImageWithWidth:dim
andHeight:dim];
uint64_t *lines = (uint64_t *)[pixels bytes];
NSUInteger length = [pixels length] / sizeof(lines);
for (NSUInteger i = 0; i < length; i += 8) {
XCTAssertNotEqual(lines[i], (uint64_t)0);
XCTAssertNotEqual(lines[i + 1], (uint64_t)0);
XCTAssertNotEqual(lines[i + 2], (uint64_t)0);
XCTAssertNotEqual(lines[i + 3], (uint64_t)0);
XCTAssertNotEqual(lines[i + 4], (uint64_t)0);
}
}
}

@end

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