Changeset 287345 in webkit

Timestamp:

Dec 21, 2021, 9:15:33 PM (5 years ago)

Author:

Simon Fraser

Message:

Fuzzy pixel data need to be computed in terms of CSS pixels
​https://bugs.webkit.org/show_bug.cgi?id=232525

Reviewed by Tim Horton.

Tools:

Pixel tolerance is computed in CSS pixels, so have ImageDiff divide the total number of
differing pixels by the square of the scale factor (a single different pixel at 1x becomes 4
different pixels at 2x).

• ImageDiff/ImageDiff.cpp:

(processImages):

• ImageDiff/PlatformImage.cpp:

(ImageDiff::PlatformImage::isCompatible const):
(ImageDiff::PlatformImage::difference):

LayoutTests:

Add a hidpi pixel tolerance test.

• fast/harness/image-diff/hidpi-pixel-tolerance-expected.html: Added.
• fast/harness/image-diff/hidpi-pixel-tolerance.html: Added.
• platform/ios-wk2/TestExpectations: Remove fast/harness/image-diff/fuzz-2-25.html.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/harness/image-diff/hidpi-pixel-tolerance-expected.html (added)
• LayoutTests/fast/harness/image-diff/hidpi-pixel-tolerance.html (added)
• LayoutTests/platform/ios-wk2/TestExpectations (modified) (1 diff)
• Tools/ChangeLog (modified) (1 diff)
• Tools/ImageDiff/ImageDiff.cpp (modified) (1 diff)
• Tools/ImageDiff/PlatformImage.cpp (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2021-12-21  Simon Fraser  <simon.fraser@apple.com>
+
+        Fuzzy pixel data need to be computed in terms of CSS pixels
+        https://bugs.webkit.org/show_bug.cgi?id=232525
+
+        Reviewed by Tim Horton.
+
+        Add a hidpi pixel tolerance test.
+
+        * fast/harness/image-diff/hidpi-pixel-tolerance-expected.html: Added.
+        * fast/harness/image-diff/hidpi-pixel-tolerance.html: Added.
+        * platform/ios-wk2/TestExpectations: Remove fast/harness/image-diff/fuzz-2-25.html.
+
 2021-12-21  Alan Bujtas  <zalan@apple.com>
 

trunk/LayoutTests/platform/ios-wk2/TestExpectations

@@ -1112 +1112 @@
 
 webkit.org/b/157589 fast/text-autosizing/ios/text-autosizing-after-back.html [ Pass Timeout ]
-
-webkit.org/b/232525 fast/harness/image-diff/fuzz-2-25.html [ ImageOnlyFailure ]
 
 # started to fail after new snapshotting in r202532

trunk/Tools/ChangeLog

@@ +1 @@
+2021-12-21  Simon Fraser  <simon.fraser@apple.com>
+
+        Fuzzy pixel data need to be computed in terms of CSS pixels
+        https://bugs.webkit.org/show_bug.cgi?id=232525
+
+        Reviewed by Tim Horton.
+
+        Pixel tolerance is computed in CSS pixels, so have ImageDiff divide the total number of
+        differing pixels by the square of the scale factor (a single different pixel at 1x becomes 4
+        different pixels at 2x).
+
+        * ImageDiff/ImageDiff.cpp:
+        (processImages):
+        * ImageDiff/PlatformImage.cpp:
+        (ImageDiff::PlatformImage::isCompatible const):
+        (ImageDiff::PlatformImage::difference):
+
 2021-12-21  Alex Christensen  <achristensen@webkit.org>
 

trunk/Tools/ImageDiff/ImageDiff.cpp

@@ -59 +59 @@
             fprintf(stderr, "Error: test and reference images differ in alpha. Test image %s alpha, reference image %s alpha.\n",
                 actualImage->hasAlpha() ? "has" : "does not have", baselineImage->hasAlpha() ? "has" : "does not have");
+        } else if (actualImage->scaleFactor() != baselineImage->scaleFactor()) {
+            fprintf(stderr, "Error: test and reference images differ in scale factor. Test image scale factor %.1f, reference image scale factor %.1f.\n",
+                actualImage->scaleFactor(), baselineImage->scaleFactor());
         }
 

trunk/Tools/ImageDiff/PlatformImage.cpp

@@ -37 +37 @@
     return width() == other.width()
         && height() == other.height()
+        && scaleFactor() == other.scaleFactor()
         && rowBytes() == other.rowBytes()
         && hasAlpha() == other.hasAlpha();
@@ -106 +107 @@
         }
 
+        // totalPixels is "CSS pixels" or "points".
+        difference.totalPixels /= (scaleFactor() * scaleFactor());
+
         return PlatformImage::createFromDiffData(diffBuffer, width, height);
     }