[Skia] Add a test case for blending mode used for image masks.
There is no existing pixel test that provides test coverage on the
`SkBlendMode` used in SetBitmapPaint() when image masks are not
completely opaque.
This CL adds a new test based on pixel test bug_591137.in in which the
characters are transparent and overlap with each other to prevent future
regression in this function.
Bug: pdfium:1746
Change-Id: I4165040313274644d7302a2e0b85b1046a643107
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/91750
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Nigi <nigi@chromium.org>
diff --git a/testing/SUPPRESSIONS b/testing/SUPPRESSIONS
index 94eaedd..ee548b2 100644
--- a/testing/SUPPRESSIONS
+++ b/testing/SUPPRESSIONS
@@ -356,6 +356,9 @@
# TODO(pdfium:1571): Remove after associated bug is fixed
bug_1571.in * * * *
+# TODO(pdfium:1746): Remove after associated bug is fixed
+bug_1746.in * * * skia
+
# TODO(chromium:237527): Remove after associated bug is fixed
bug_237527_1.in * * * *
diff --git a/testing/resources/pixel/bug_1746.in b/testing/resources/pixel/bug_1746.in
new file mode 100644
index 0000000..ca2a4b2
--- /dev/null
+++ b/testing/resources/pixel/bug_1746.in
@@ -0,0 +1,122 @@
+{{header}}
+{{object 1 0}} <<
+ /Type /Catalog
+ /Pages 2 0 R
+>>
+endobj
+{{object 2 0}} <<
+ /Type /Pages
+ /Count 1
+ /MediaBox [0 0 200 200]
+ /Kids [3 0 R]
+>>
+endobj
+{{object 3 0}} <<
+ /Type /Page
+ /Parent 2 0 R
+ /Contents 4 0 R
+ /Resources <<
+ /ExtGState <<
+ /GS0 8 0 R
+ >>
+ /Font <<
+ /F1 5 0 R
+ >>
+ /XObject <<
+ /Img 9 0 R
+ >>
+ >>
+>>
+endobj
+{{object 4 0}} <<
+ {{streamlen}}
+>>
+stream
+q
+/GS0 gs
+q
+0 1 0 rg
+BT
+/F1 2 Tf
+1 0 0 1 50 50 Tm
+(a)Tj
+ET
+Q
+q
+0 0 1 rg
+BT
+/F1 2 Tf
+1 0 0 1 72 80 Tm
+(a)Tj
+ET
+Q
+Q
+endstream
+endobj
+{{object 5 0}} <<
+ /Type /Font
+ /Subtype /Type3
+ /CharProcs <<
+ /a0 7 0 R
+ >>
+ /Encoding 6 0 R
+ /FirstChar 97
+ /FontBBox [0 0 1000 1000]
+ /FontMatrix [1 0 0 1 0 0]
+ /LastChar 97
+ /Widths [60]
+>>
+endobj
+{{object 6 0}} <<
+ /Type /Encoding
+ /BaseEncoding /WinAnsiEncoding
+ /Differences [97 /a0]
+>>
+endobj
+{{object 7 0}} <<
+ {{streamlen}}
+>>
+stream
+50 0 4 -1 48 45 d1
+q
+4 -1 m
+4 45 l
+48 45 l
+48 -1 l
+h
+W n
+q
+44 0 0 46 4.1 -1.1 cm
+/Img Do
+Q
+Q
+endstream
+endobj
+{{object 8 0}} <<
+ /Type /ExtGState
+ /CA 0.5
+ /ca 0.5
+>>
+endobj
+{{object 9 0}} <<
+ /Type /XObject
+ /Subtype /Image
+ /BitsPerComponent 1
+ /Decode [1 0]
+ /DecodeParms [null <</Columns 44 /K -1>>]
+ /Filter [/ASCIIHexDecode /CCITTFaxDecode]
+ /Height 46
+ /ImageMask true
+ /Width 44
+ {{streamlen}}
+>>
+stream
+26a08680de081e11e187840830f4137a4df0ef4dbedbffff6ffdaf0c2f1f
+fff21b34c82e33044e7c11a09c205e105e97a5e97a5ffa5fe0a3f5ffafff
+b5c9aaa30bed27adb4ad70da4da5b6128f0c426b216818500100100a
+endstream
+endobj
+{{xref}}
+{{trailer}}
+{{startxref}}
+%%EOF
diff --git a/testing/resources/pixel/bug_1746_expected.pdf.0.png b/testing/resources/pixel/bug_1746_expected.pdf.0.png
new file mode 100644
index 0000000..08c41d1
--- /dev/null
+++ b/testing/resources/pixel/bug_1746_expected.pdf.0.png
Binary files differ
