Add color tolerance parameter

thorthugnasty · Jan 26, 2017 · e8eff24 · e8eff24
1 parent ef24bce
commit e8eff24
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Showing 7 changed files with 160 additions and 19 deletions.
diff --git a/FBSnapshotTestCase/Categories/UIImage+Compare.h b/FBSnapshotTestCase/Categories/UIImage+Compare.h
@@ -32,6 +32,6 @@
 
 @interface UIImage (Compare)
 
-- (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance;
+- (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance colorTolerance:(CGFloat)colorTolerance;
 
 @end
diff --git a/FBSnapshotTestCase/Categories/UIImage+Compare.m b/FBSnapshotTestCase/Categories/UIImage+Compare.m
@@ -44,7 +44,7 @@
 
 @implementation UIImage (Compare)
 
-- (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance
+- (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance colorTolerance:(CGFloat)colorTolerance
 {
   NSAssert(CGSizeEqualToSize(self.size, image.size), @"Images must be same size.");
 
@@ -97,7 +97,7 @@ - (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance
   BOOL imageEqual = YES;
 
   // Do a fast compare if we can
-  if (tolerance == 0) {
+  if (tolerance == 0 && colorTolerance == 0) {
     imageEqual = (memcmp(referenceImagePixels, imagePixels, referenceImageSizeBytes) == 0);
   } else {
     // Go through each pixel in turn and see if it is different
@@ -111,12 +111,30 @@ - (BOOL)fb_compareWithImage:(UIImage *)image tolerance:(CGFloat)tolerance
       // If this pixel is different, increment the pixel diff count and see
       // if we have hit our limit.
       if (p1->raw != p2->raw) {
-        numDiffPixels ++;
-
-        CGFloat percent = (CGFloat)numDiffPixels / pixelCount;
-        if (percent > tolerance) {
-          imageEqual = NO;
-          break;
+        BOOL pixelsEqual = YES;
+        if (colorTolerance == 0) {
+          pixelsEqual = NO;
+        } else {
+          long dr = (long)p1->pixels.red - (long)p2->pixels.red;
+          long dg = (long)p1->pixels.green - (long)p2->pixels.green;
+          long db = (long)p1->pixels.blue - (long)p2->pixels.blue;
+
+          double distanceSquared = (float) (dr * dr + dg * dg + db * db);
+          distanceSquared /= (255.0 * 255.0); // Scale each channel from 0 - 255 to 0 - 1.0
+
+          if (distanceSquared > colorTolerance * colorTolerance) {
+            pixelsEqual = NO;
+          }
+        }
+
+        if (!pixelsEqual) {
+          numDiffPixels++;
+
+          CGFloat percent = (CGFloat)numDiffPixels / pixelCount;
+          if (percent > tolerance) {
+            imageEqual = NO;
+            break;
+          }
         }
       }
 

diff --git a/FBSnapshotTestCase/FBSnapshotTestCase.h b/FBSnapshotTestCase/FBSnapshotTestCase.h
@@ -163,19 +163,54 @@
                      tolerance:(CGFloat)tolerance
                          error:(NSError **)errorPtr;
 
+/**
+ Performs the comparison or records a snapshot of the layer if recordMode is YES.
+ @param layer The Layer to snapshot
+ @param referenceImagesDirectory The directory in which reference images are stored.
+ @param identifier An optional identifier, used if there are multiple snapshot tests in a given -test method.
+ @param tolerance The percentage difference to still count as identical - 0 mean pixel perfect, 1 means I don't care
+ @param colorTolerance The euclidean distance allowable between two colors (with each channel 0-1.0) to consider pixels to be "identical". colorTolerance is applied before calculating percentage of pixels that are different.
+ @param errorPtr An error to log in an XCTAssert() macro if the method fails (missing reference image, images differ, etc).
+ @returns YES if the comparison (or saving of the reference image) succeeded.
+ */
+- (BOOL)compareSnapshotOfLayer:(CALayer *)layer
+      referenceImagesDirectory:(NSString *)referenceImagesDirectory
+                    identifier:(NSString *)identifier
+                     tolerance:(CGFloat)tolerance
+                colorTolerance:(CGFloat)colorTolerance
+                         error:(NSError **)errorPtr;
+
+/**
+ Performs the comparison or records a snapshot of the view if recordMode is YES.
+ @param view The view to snapshot
+ @param referenceImagesDirectory The directory in which reference images are stored.
+ @param identifier An optional identifier, used if there are multiple snapshot tests in a given -test method.
+ @param tolerance The percentage difference to still count as identical - 0 mean pixel perfect, 1 means I don't care
+ @param errorPtr An error to log in an XCTAssert() macro if the method fails (missing reference image, images differ, etc).
+ @returns YES if the comparison (or saving of the reference image) succeeded.
+ */
+- (BOOL)compareSnapshotOfView:(UIView *)view
+     referenceImagesDirectory:(NSString *)referenceImagesDirectory
+                   identifier:(NSString *)identifier
+                    tolerance:(CGFloat)tolerance
+                        error:(NSError **)errorPtr;
+
+
 /**
  Performs the comparison or records a snapshot of the view if recordMode is YES.
  @param view The view to snapshot
  @param referenceImagesDirectory The directory in which reference images are stored.
  @param identifier An optional identifier, used if there are multiple snapshot tests in a given -test method.
  @param tolerance The percentage difference to still count as identical - 0 mean pixel perfect, 1 means I don't care
+ @param colorTolerance The euclidean distance allowable between two colors (with each channel 0-1.0) to consider pixels to be "identical". colorTolerance is applied before calculating percentage of pixels that are different.
  @param errorPtr An error to log in an XCTAssert() macro if the method fails (missing reference image, images differ, etc).
  @returns YES if the comparison (or saving of the reference image) succeeded.
  */
 - (BOOL)compareSnapshotOfView:(UIView *)view
      referenceImagesDirectory:(NSString *)referenceImagesDirectory
                    identifier:(NSString *)identifier
                     tolerance:(CGFloat)tolerance
+               colorTolerance:(CGFloat)colorTolerance
                         error:(NSError **)errorPtr;
 
 /**

diff --git a/FBSnapshotTestCase/FBSnapshotTestCase.m b/FBSnapshotTestCase/FBSnapshotTestCase.m
@@ -75,19 +75,54 @@ - (BOOL)compareSnapshotOfLayer:(CALayer *)layer
                     referenceImagesDirectory:referenceImagesDirectory
                                   identifier:identifier
                                    tolerance:tolerance
+                              colorTolerance:0
                                        error:errorPtr];
 }
 
+
+
+- (BOOL)compareSnapshotOfLayer:(CALayer *)layer
+      referenceImagesDirectory:(NSString *)referenceImagesDirectory
+                    identifier:(NSString *)identifier
+                     tolerance:(CGFloat)tolerance
+                colorTolerance:(CGFloat)colorTolerance
+                         error:(NSError **)errorPtr
+{
+  return [self _compareSnapshotOfViewOrLayer:layer
+                    referenceImagesDirectory:referenceImagesDirectory
+                                  identifier:identifier
+                                   tolerance:tolerance
+                              colorTolerance:colorTolerance
+                                       error:errorPtr];
+}
+
+- (BOOL)compareSnapshotOfView:(UIView *)view
+     referenceImagesDirectory:(NSString *)referenceImagesDirectory
+                   identifier:(NSString *)identifier
+                    tolerance:(CGFloat)tolerance
+                        error:(NSError **)errorPtr
+{
+  return [self _compareSnapshotOfViewOrLayer:view
+                    referenceImagesDirectory:referenceImagesDirectory
+                                  identifier:identifier
+                                   tolerance:tolerance
+                              colorTolerance:0
+                                       error:errorPtr];
+}
+
+
 - (BOOL)compareSnapshotOfView:(UIView *)view
      referenceImagesDirectory:(NSString *)referenceImagesDirectory
                    identifier:(NSString *)identifier
                     tolerance:(CGFloat)tolerance
+               colorTolerance:(CGFloat)colorTolerance
                         error:(NSError **)errorPtr
 {
   return [self _compareSnapshotOfViewOrLayer:view
                     referenceImagesDirectory:referenceImagesDirectory
                                   identifier:identifier
                                    tolerance:tolerance
+                              colorTolerance:colorTolerance
                                        error:errorPtr];
 }
 
@@ -123,13 +158,15 @@ - (BOOL)_compareSnapshotOfViewOrLayer:(id)viewOrLayer
              referenceImagesDirectory:(NSString *)referenceImagesDirectory
                            identifier:(NSString *)identifier
                             tolerance:(CGFloat)tolerance
+                            colorTolerance:(CGFloat)colorTolerance
                                 error:(NSError **)errorPtr
 {
   _snapshotController.referenceImagesDirectory = referenceImagesDirectory;
   return [_snapshotController compareSnapshotOfViewOrLayer:viewOrLayer
                                                   selector:self.invocation.selector
                                                 identifier:identifier
                                                  tolerance:tolerance
+                                                 colorTolerance:colorTolerance
                                                      error:errorPtr];
 }
 

diff --git a/FBSnapshotTestCase/FBSnapshotTestController.h b/FBSnapshotTestCase/FBSnapshotTestController.h
@@ -110,6 +110,23 @@ extern NSString *const FBDiffedImageKey;
                    identifier:(NSString *)identifier
                         error:(NSError **)errorPtr;
 
+/**
+ Performs the comparison of a view or layer.
+ @param view The view or layer to snapshot.
+ @param selector The test method being run.
+ @param identifier An optional identifier, used is there are muliptle snapshot tests in a given -test method.
+ @param tolerance The percentage of pixels that can differ and still be considered 'identical'
+ @param colorTolerance The euclidean distance allowable between two colors (with each channel 0-1.0) to consider pixels to be "identical". colorTolerance is applied before calculating percentage of pixels that are different.
+ @param error An error to log in an XCTAssert() macro if the method fails (missing reference image, images differ, etc).
+ @returns YES if the comparison (or saving of the reference image) succeeded.
+ */
+- (BOOL)compareSnapshotOfViewOrLayer:(id)viewOrLayer
+                            selector:(SEL)selector
+                          identifier:(NSString *)identifier
+                           tolerance:(CGFloat)tolerance
+                      colorTolerance:(CGFloat)colorTolerance
+                               error:(NSError **)errorPtr;
+
 /**
  Performs the comparison of a view or layer.
  @param view The view or layer to snapshot.
@@ -149,6 +166,21 @@ extern NSString *const FBDiffedImageKey;
                     tolerance:(CGFloat)tolerance
                         error:(NSError **)errorPtr;
 
+/**
+ Performs a pixel-by-pixel comparison of the two images with an allowable margin of error.
+ @param referenceImage The reference (correct) image.
+ @param image The image to test against the reference.
+ @param tolerance The percentage of pixels that can differ and still be considered 'identical'
+  @param colorTolerance The euclidean distance allowable between two colors (with each channel 0-1.0) to consider pixels to be "identical". colorTolerance is applied before calculating percentage of pixels that are different.
+ @param errorPtr An error that indicates why the comparison failed if it does.
+ @returns YES if the comparison succeeded and the images are the same(ish).
+ */
+- (BOOL)compareReferenceImage:(UIImage *)referenceImage
+                      toImage:(UIImage *)image
+                    tolerance:(CGFloat)tolerance
+               colorTolerance:(CGFloat)colorTolerance
+                        error:(NSError **)errorPtr;
+
 /**
  Saves the reference image and the test image to `failedOutputDirectory`.
  @param referenceImage The reference (correct) image.

diff --git a/FBSnapshotTestCase/FBSnapshotTestController.m b/FBSnapshotTestCase/FBSnapshotTestController.m
@@ -91,11 +91,21 @@ - (BOOL)compareSnapshotOfViewOrLayer:(id)viewOrLayer
                           identifier:(NSString *)identifier
                            tolerance:(CGFloat)tolerance
                                error:(NSError **)errorPtr
+{
+  return [self compareSnapshotOfViewOrLayer:viewOrLayer selector:selector identifier:identifier tolerance:tolerance colorTolerance:0.0 error:errorPtr];
+}
+
+- (BOOL)compareSnapshotOfViewOrLayer:(id)viewOrLayer
+                            selector:(SEL)selector
+                          identifier:(NSString *)identifier
+                           tolerance:(CGFloat)tolerance
+                           colorTolerance:(CGFloat)colorTolerance
+                               error:(NSError **)errorPtr
 {
   if (self.recordMode) {
     return [self _recordSnapshotOfViewOrLayer:viewOrLayer selector:selector identifier:identifier error:errorPtr];
   } else {
-    return [self _performPixelComparisonWithViewOrLayer:viewOrLayer selector:selector identifier:identifier tolerance:tolerance error:errorPtr];
+    return [self _performPixelComparisonWithViewOrLayer:viewOrLayer selector:selector identifier:identifier tolerance:tolerance colorTolerance:colorTolerance error:errorPtr];
   }
 }
 
@@ -127,10 +137,18 @@ - (UIImage *)referenceImageForSelector:(SEL)selector
 - (BOOL)compareReferenceImage:(UIImage *)referenceImage
                       toImage:(UIImage *)image
                     tolerance:(CGFloat)tolerance
+                        error:(NSError **)errorPtr {
+  return [self compareReferenceImage:image toImage:image tolerance:0 colorTolerance:0 error:errorPtr];
+}
+
+- (BOOL)compareReferenceImage:(UIImage *)referenceImage
+                      toImage:(UIImage *)image
+                    tolerance:(CGFloat)tolerance
+               colorTolerance:(CGFloat)colorTolerance
                         error:(NSError **)errorPtr
 {
   BOOL sameImageDimensions = CGSizeEqualToSize(referenceImage.size, image.size);
-  if (sameImageDimensions && [referenceImage fb_compareWithImage:image tolerance:tolerance]) {
+  if (sameImageDimensions && [referenceImage fb_compareWithImage:image tolerance:tolerance colorTolerance:colorTolerance]) {
     return YES;
   }
 
@@ -275,12 +293,13 @@ - (BOOL)_performPixelComparisonWithViewOrLayer:(id)viewOrLayer
                                       selector:(SEL)selector
                                     identifier:(NSString *)identifier
                                      tolerance:(CGFloat)tolerance
+                                     colorTolerance:(CGFloat)colorTolerance
                                          error:(NSError **)errorPtr
 {
   UIImage *referenceImage = [self referenceImageForSelector:selector identifier:identifier error:errorPtr];
   if (nil != referenceImage) {
     UIImage *snapshot = [self _imageForViewOrLayer:viewOrLayer];
-    BOOL imagesSame = [self compareReferenceImage:referenceImage toImage:snapshot tolerance:tolerance error:errorPtr];
+    BOOL imagesSame = [self compareReferenceImage:referenceImage toImage:snapshot tolerance:tolerance colorTolerance:colorTolerance error:errorPtr];
     if (!imagesSame) {
       NSError *saveError = nil;
       if ([self saveFailedReferenceImage:referenceImage testImage:snapshot selector:selector identifier:identifier error:&saveError] == NO) {

diff --git a/FBSnapshotTestCase/SwiftSupport.swift b/FBSnapshotTestCase/SwiftSupport.swift
@@ -9,15 +9,15 @@
 */
 
 public extension FBSnapshotTestCase {
-  public func FBSnapshotVerifyView(view: UIView, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
-    FBSnapshotVerifyViewOrLayer(view, identifier: identifier, suffixes: suffixes, tolerance: tolerance, file: file, line: line)
+  public func FBSnapshotVerifyView(view: UIView, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, colorTolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
+    FBSnapshotVerifyViewOrLayer(view, identifier: identifier, suffixes: suffixes, tolerance: tolerance, colorTolerance: colorTolerance,file: file, line: line)
   }
 
-  public func FBSnapshotVerifyLayer(layer: CALayer, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
-    FBSnapshotVerifyViewOrLayer(layer, identifier: identifier, suffixes: suffixes, tolerance: tolerance, file: file, line: line)
+  public func FBSnapshotVerifyLayer(layer: CALayer, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, colorTolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
+    FBSnapshotVerifyViewOrLayer(layer, identifier: identifier, suffixes: suffixes, tolerance: tolerance, colorTolerance: colorTolerance, file: file, line: line)
   }
 
-  private func FBSnapshotVerifyViewOrLayer(viewOrLayer: AnyObject, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
+  private func FBSnapshotVerifyViewOrLayer(viewOrLayer: AnyObject, identifier: String = "", suffixes: NSOrderedSet = FBSnapshotTestCaseDefaultSuffixes(), tolerance: CGFloat = 0, colorTolerance: CGFloat = 0, file: StaticString = #file, line: UInt = #line) {
     let envReferenceImageDirectory = self.getReferenceImageDirectoryWithDefault(FB_REFERENCE_IMAGE_DIR)
     var error: NSError?
     var comparisonSuccess = false
@@ -27,15 +27,15 @@ public extension FBSnapshotTestCase {
         let referenceImagesDirectory = "\(envReferenceImageDirectory)\(suffix)"
         if viewOrLayer.isKindOfClass(UIView) {
           do {
-            try compareSnapshotOfView(viewOrLayer as! UIView, referenceImagesDirectory: referenceImagesDirectory, identifier: identifier, tolerance: tolerance)
+            try compareSnapshotOfView(viewOrLayer as! UIView, referenceImagesDirectory: referenceImagesDirectory, identifier: identifier, tolerance: tolerance, colorTolerance: colorTolerance)
             comparisonSuccess = true
           } catch let error1 as NSError {
             error = error1
             comparisonSuccess = false
           }
         } else if viewOrLayer.isKindOfClass(CALayer) {
           do {
-            try compareSnapshotOfLayer(viewOrLayer as! CALayer, referenceImagesDirectory: referenceImagesDirectory, identifier: identifier, tolerance: tolerance)
+            try compareSnapshotOfLayer(viewOrLayer as! CALayer, referenceImagesDirectory: referenceImagesDirectory, identifier: identifier, tolerance: tolerance, colorTolerance: colorTolerance)
             comparisonSuccess = true
           } catch let error1 as NSError {
             error = error1