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Improved visibility checker to fix google#532 and added corresponding…
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… tests.
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Eric Mitchell committed Jun 29, 2017
1 parent 89e67f6 commit 812e500
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Showing 6 changed files with 512 additions and 47 deletions.
122 changes: 101 additions & 21 deletions EarlGrey/Common/GREYVisibilityChecker.m
View file
Original file line number Diff line number Diff line change
Expand Up @@ -689,6 +689,73 @@ + (UIImage *)grey_imageAfterAddingSubview:(UIView *)shiftedView toView:(UIView *
return screenshot;
}

/**
* Given a list of values representing a histogram (values are the heights of the bars), this
* method returns the largest contiguous rectangle in that histogram.
*
* @param histogram The array of values representing the histogram.
* @param length The number of values in the histogram.
*
* @return A CGRect of the largest rectangle in the given histogram.
*/
+ (CGRect)grey_largestRectInHistogram:(uint16_t *)histogram
length:(uint16_t)length {
uint16_t *leftNeighbors = malloc(sizeof(uint16_t) * length);
uint16_t *rightNeighbors = malloc(sizeof(uint16_t) * length);
uint16_t *leftStack = malloc(sizeof(uint16_t) * length);
uint16_t *rightStack = malloc(sizeof(uint16_t) * length);
// Index of the last element on the stack.
NSInteger leftStackIdx = -1;
NSInteger rightStackIdx = -1;
CGRect largestRect = CGRectZero;
CGFloat largestArea = 0;
// We make two passes at once, one from left to right and one from right to left.
for (uint16_t idx = 0; idx < length; idx++) {
uint16_t tailIdx = (length - 1) - idx;
// Find nearest column shorter than this one on either side.
while (leftStackIdx >= 0 && histogram[leftStack[leftStackIdx]] >= histogram[idx]) {
leftStackIdx--;
}
while (rightStackIdx >= 0 && histogram[rightStack[rightStackIdx]] >= histogram[tailIdx]) {
rightStackIdx--;
}
// Set the number of columns at least as tall as this one on either side.
if (leftStackIdx < 0) {
leftNeighbors[idx] = idx;
} else {
leftNeighbors[idx] = idx - leftStack[leftStackIdx] - 1;
}
if (rightStackIdx < 0) {
rightNeighbors[tailIdx] = length - tailIdx - 1;
} else {
rightNeighbors[tailIdx] = rightStack[rightStackIdx] - tailIdx - 1;
}
// Add the current index to the stack
leftStack[++leftStackIdx] = idx;
rightStack[++rightStackIdx] = tailIdx;
}
// Now we have the number of histogram bars immediately left and right of each bar that are at
// least as tall as the given bar. Now we can compute areas easily.
for (NSUInteger idx = 0; idx < length; idx++) {
CGFloat area = (leftNeighbors[idx] + rightNeighbors[idx] + 1) * histogram[idx];
if (area > largestArea) {
largestArea = area;
largestRect.origin.x = idx - leftNeighbors[idx];
largestRect.size.width = leftNeighbors[idx] + rightNeighbors[idx] + 1;
largestRect.size.height = histogram[idx];
}
}
free(leftStack);
leftStack = NULL;
free(rightStack);
rightStack = NULL;
free(leftNeighbors);
leftNeighbors = NULL;
free(rightNeighbors);
rightNeighbors = NULL;
return largestRect;
}

/**
* Calculates the number of pixel in @c afterImage that have different pixel intensity in
* @c beforeImage.
Expand All @@ -699,8 +766,8 @@ + (UIImage *)grey_imageAfterAddingSubview:(UIView *)shiftedView toView:(UIView *
*
* @param afterImage The image containing view with shifted colors.
* @param beforeImage The original image of the view.
* @param[out] outVisiblePixelRect A reference for getting the smallest rectangle enclosing all
* shifted pixels.
* @param[out] outVisiblePixelRect A reference for getting the largest
* rectangle enclosing only visible points in the view.
* @param[out] outDiffBufferOrNULL A reference for getting the GREYVisibilityDiffBuffer that was
* created to detect image diff.
*
Expand All @@ -717,53 +784,66 @@ + (GREYVisiblePixelData)grey_countPixelsInImage:(CGImageRef)afterImage
@"width must be the same");
GREYFatalAssertWithMessage(CGImageGetHeight(beforeImage) == CGImageGetHeight(afterImage),
@"height must be the same");

unsigned char *pixelBuffer = grey_createImagePixelDataFromCGImageRef(beforeImage, NULL);
GREYFatalAssertWithMessage(pixelBuffer, @"pixelBuffer must not be null");
unsigned char *shiftedPixelBuffer = grey_createImagePixelDataFromCGImageRef(afterImage, NULL);
GREYFatalAssertWithMessage(shiftedPixelBuffer, @"shiftedPixelBuffer must not be null");

NSUInteger width = CGImageGetWidth(beforeImage);
NSUInteger height = CGImageGetHeight(beforeImage);
CGFloat minX = FLT_MAX;
CGFloat maxX = -FLT_MAX;
CGFloat minY = FLT_MAX;
CGFloat maxY = -FLT_MAX;
uint16_t *histograms = NULL;
// We only want to perform the relatively expensive rect computation if we've actually
// been asked for it.
if (outVisiblePixelRect) {
histograms = calloc((size_t)(width * height), sizeof(uint16_t));
}
GREYVisiblePixelData visiblePixelData = {0, GREYCGPointNull};
for (NSUInteger x = 0; x < width; x++) {
for (NSUInteger y = 0; y < height; y++) {
// Make sure we go row-order to take advantage of data locality (cuts runtime in half).
for (NSUInteger y = 0; y < height; y++) {
for (NSUInteger x = 0; x < width; x++) {
NSUInteger currentPixelIndex = (y * width + x) * kColorChannelsPerPixel;
// We don't care about the first byte because we are dealing with XRGB format.
BOOL pixelHasDiff = grey_isPixelDifferent(&pixelBuffer[currentPixelIndex + 1],
&shiftedPixelBuffer[currentPixelIndex + 1]);
if (pixelHasDiff) {
minX = MIN(minX, x);
maxX = MAX(maxX, x);
minY = MIN(minY, y);
maxY = MAX(maxY, y);

visiblePixelData.visiblePixelCount++;
// Always pick the bottom and right-most pixel. We may want to consider using tax-cab
// formula to find a pixel that's closest to the center if we encounter problems with this
// approach.
visiblePixelData.visiblePixel.x = x;
visiblePixelData.visiblePixel.y = y;
}

if (outVisiblePixelRect) {
if (y == 0) {
histograms[x] = pixelHasDiff ? 1 : 0;
} else {
histograms[y * width + x] = pixelHasDiff ? (histograms[(y - 1) * width + x] + 1) : 0;
}
}
if (outDiffBufferOrNULL) {
GREYVisibilityDiffBufferSetVisibility(*outDiffBufferOrNULL, x, y, pixelHasDiff);
}
}
}
if (outVisiblePixelRect) {
// Width and height require a +1 to accomodate single pixel images.
*outVisiblePixelRect = visiblePixelData.visiblePixelCount > 0
? CGRectMake(minX, minY, maxX - minX + 1, maxY - minY + 1)
: CGRectZero;
CGRect largestRect = CGRectZero;
for (NSUInteger idx = 0; idx < height; idx++) {
CGRect thisLargest =
[GREYVisibilityChecker grey_largestRectInHistogram:&histograms[idx * width]
length:(uint16_t)width];
if (CGRectArea(thisLargest) > CGRectArea(largestRect)) {
// Because our histograms point up, not down.
thisLargest.origin.y = idx - thisLargest.size.height + 1;
largestRect = thisLargest;
}
}
*outVisiblePixelRect = largestRect;
free(histograms);
histograms = NULL;
}

free(pixelBuffer);
pixelBuffer = NULL;
free(shiftedPixelBuffer);
shiftedPixelBuffer = NULL;
return visiblePixelData;
}

Expand Down
70 changes: 56 additions & 14 deletions Tests/FunctionalTests/Sources/FTRVisibilityTest.m
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,32 @@ - (void)tearDown {
[super tearDown];
}

- (void)testOverlappingViews {
[[EarlGrey selectElementWithMatcher:grey_accessibilityID(@"bottomScrollView")]
performAction:grey_scrollToContentEdge(kGREYContentEdgeTop)];

id<GREYAssertion> assertion = [GREYAssertionBlock assertionWithName:@"coverContentOffsetUnchanged"
assertionBlockWithError:
^BOOL(id element, NSError *__strong *errorOrNil) {
CGPoint offset = ((UIScrollView*) element).contentOffset;
CGPoint expectedOffset = CGPointMake(100, 100);
if (CGPointEqualToPoint(offset, expectedOffset)) {
return YES;
} else {
NSError* error = [[NSError alloc]
initWithDomain:kGREYInteractionErrorDomain
code:
kGREYInteractionAssertionFailedErrorCode
userInfo:@{
NSLocalizedDescriptionKey:
@"Cover view moved."}];
*errorOrNil = error;
return NO;
}
}];
[[EarlGrey selectElementWithMatcher:grey_accessibilityID(@"coverScrollView")] assert:assertion];
}

- (void)testTranslucentViews {
[[EarlGrey selectElementWithMatcher:grey_accessibilityID(@"translucentLabel")]
assertWithMatcher:grey_sufficientlyVisible()];
Expand Down Expand Up @@ -219,20 +245,36 @@ - (void)testVisibilityOfViewsWithSameAccessibilityLabelAndAtIndex {

- (void)testElementsInHierarchyDump {
NSString *hierarchyDump = [GREYElementHierarchy hierarchyStringForAllUIWindows];
NSArray *stringTargetHierarchy =
@[ @"========== Window 1 ==========",
@"========== Window 2 ==========",
@"<UITextEffectsWindow",
@" |--<UIInputSetContainerView:",
@" | |--<UIInputSetHostView:",
@"<UIWindow:",
@" |--<UILayoutContainerView:",
@" | |--<UINavigationTransitionView:",
@" | | |--<UIViewControllerWrapperView:",
@" | | | |--<UIView",
@" | | | | |--<UIView:"];
for (NSString *targetString in stringTargetHierarchy) {
XCTAssertNotEqual([hierarchyDump rangeOfString:targetString].location, (NSUInteger)NSNotFound);
NSArray *stringTargetHierarchy_iOS10Later =
@[ @"========== Window 1 ==========",
@"<UIWindow:",
@" |--<UILayoutContainerView:",
@" | |--<UINavigationTransitionView:",
@" | | |--<UIViewControllerWrapperView:",
@" | | | |--<UIView",
@" | | | | |--<UIView:"];
NSArray *stringTargetHierarchy_iOS9Earlier =
@[ @"========== Window 1 ==========",
@"========== Window 2 ==========",
@"<UITextEffectsWindow",
@" |--<UIInputSetContainerView:",
@" | |--<UIInputSetHostView:",
@"<UIWindow:",
@" |--<UILayoutContainerView:",
@" | |--<UINavigationTransitionView:",
@" | | |--<UIViewControllerWrapperView:",
@" | | | |--<UIView",
@" | | | | |--<UIView:"];
if (iOS10_OR_ABOVE()) {
for (NSString *targetString in stringTargetHierarchy_iOS10Later) {
XCTAssertNotEqual([hierarchyDump rangeOfString:targetString].location,
(NSUInteger)NSNotFound);
}
} else {
for (NSString *targetString in stringTargetHierarchy_iOS9Earlier) {
XCTAssertNotEqual([hierarchyDump rangeOfString:targetString].location,
(NSUInteger)NSNotFound);
}
}
}

Expand Down
2 changes: 2 additions & 0 deletions Tests/FunctionalTests/TestRig/Sources/FTRVisibilityTestViewController.h
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@
// View controller used for visibility checker tests.
@interface FTRVisibilityTestViewController : UIViewController

@property(retain, nonatomic) IBOutlet UIScrollView *bottomScrollView;
@property(retain, nonatomic) IBOutlet UIScrollView *coverScrollView;
@property(retain, nonatomic) IBOutlet UIView *translucentOverlappingView;
@property(retain, nonatomic) IBOutlet UILabel *translucentLabel;
@property(retain, nonatomic) IBOutlet UIButton *button;
Expand Down
12 changes: 12 additions & 0 deletions Tests/FunctionalTests/TestRig/Sources/FTRVisibilityTestViewController.m
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,18 @@ - (void)viewDidLoad {
self.leftView.accessibilityIdentifier = @"AView1";
self.centerView.accessibilityIdentifier = @"AView2";
self.rightView.accessibilityIdentifier = @"AView3";
self.bottomScrollView.accessibilityIdentifier = @"bottomScrollView";
self.coverScrollView.accessibilityIdentifier = @"coverScrollView";
}

- (void)viewDidLayoutSubviews {
[super viewDidLayoutSubviews];

self.bottomScrollView.contentSize = CGSizeMake(1000, 1000);
self.coverScrollView.contentSize = CGSizeMake(1000, 1000);

self.bottomScrollView.contentOffset = CGPointMake(100, 100);
self.coverScrollView.contentOffset = CGPointMake(100, 100);
}

#pragma mark - Private
Expand Down
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