185673 2018-05-15 23:00:27 -0700 Letter spacing in canvas text renders differently based on sub pixel placement 2018-05-15 23:46:03 -0700 1 1 1 Unclassified WebKit Canvas WebKit Nightly Build Unspecified Unspecified NEW InRadar P2 Normal --- 1 jonlee webkit-unassigned dino mmaxfield sabouhallawa simon.fraser webkit-bug-importer zalan oldest_to_newest 1424247 0 340470 jonlee 2018-05-15 23:00:27 -0700 Created attachment 340470 Test See test page. I'm rendering text at various sub-pixel locations. The text appears to jiggle. It's worse 1x than 2x. Compare to Chrome and Firefox, which do not suffer from this. 1424248 1 webkit-bug-importer 2018-05-15 23:01:40 -0700 <rdar://problem/40285072> 1424251 2 mmaxfield 2018-05-15 23:46:03 -0700 Yeah, we have a dupe of this. Every time we disable sub pixel quantization, we get a huge regression because our CoreGraphics glyph cache hit rate plummets. 340470 2018-05-15 23:00:27 -0700 2018-05-15 23:00:27 -0700 Test test.html text/html 1514 jonlee PCFET0NUWVBFIGh0bWw+CjxodG1sPgo8aGVhZD4KCTxtZXRhIGNoYXJzZXQ9InV0Zi04Ij4KPHN0 eWxlPgpkaXYgewoJcG9zaXRpb246IHJlbGF0aXZlOwoJd2lkdGg6IDMwMHB4OwoJaGVpZ2h0OiAy MDBweDsKfQoKY2FudmFzIHsKCXBvc2l0aW9uOiBhYnNvbHV0ZTsKCWxlZnQ6IDA7Cgl0b3A6IDA7 Cgl3aWR0aDogMTAwJTsKCWhlaWdodDogMTAwJTsKfQo8L3N0eWxlPgo8L2hlYWQ+Cjxib2R5Pgo8 aDE+MXg8L2gxPgo8ZGl2IHN0eWxlPSJiYWNrZ3JvdW5kLWNvbG9yOnJlZCI+Cgk8Y2FudmFzIGlk PSJhIj48L2NhbnZhcz4KPC9kaXY+CjxoMT4yeDwvaDE+CjxkaXYgc3R5bGU9ImJhY2tncm91bmQt Y29sb3I6Ymx1ZSI+Cgk8Y2FudmFzIGlkPSJiIj48L2NhbnZhcz4KPC9kaXY+Cgo8c2NyaXB0Pgp3 ID0gMzAwOwpoID0gMjAwOwoKWyJhIiwgImIiXS5mb3JFYWNoKGZ1bmN0aW9uKGlkKSB7Cgl2YXIg Y2FudmFzID0gZG9jdW1lbnQuZ2V0RWxlbWVudEJ5SWQoaWQpOwoJdmFyIGNvbnRleHQgPSB3aW5k b3dbaWRdID0gY2FudmFzLmdldENvbnRleHQoIjJkIik7CgoJaWYgKGlkID09ICJiIikgewoJCWNh bnZhcy53aWR0aCA9IHcgKiB3aW5kb3cuZGV2aWNlUGl4ZWxSYXRpbzsKCQljYW52YXMuaGVpZ2h0 ID0gaCAqIHdpbmRvdy5kZXZpY2VQaXhlbFJhdGlvOwoJCWNvbnRleHQuc2NhbGUod2luZG93LmRl dmljZVBpeGVsUmF0aW8sIHdpbmRvdy5kZXZpY2VQaXhlbFJhdGlvKTsKCX0gZWxzZSB7CgkJY2Fu dmFzLndpZHRoID0gdzsKCQljYW52YXMuaGVpZ2h0ID0gaDsKCX0KCiAgICBjYW52YXMuc3R5bGUu d2lkdGggPSB3ICsgInB4IjsKICAgIGNhbnZhcy5zdHlsZS5oZWlnaHQgPSBoICsgInB4IjsKCglj b250ZXh0LmZvbnQgPSAiNTJweCBIZWx2ZXRpY2EiOwoJY29udGV4dC50ZXh0QWxpZ24gPSAiY2Vu dGVyIjsKCWNvbnRleHQudGV4dEJhc2VsaW5lID0gIm1pZGRsZSI7Cgljb250ZXh0LmZpbGxTdHls ZSA9ICJ3aGl0ZSI7Cn0pOwoKZnVuY3Rpb24gYW5pbWF0ZSgpIHsKCVthLCBiXS5mb3JFYWNoKGZ1 bmN0aW9uKGNvbnRleHQpIHsKICAgICAgICB2YXIgYW5nbGUgPSBEYXRlLm5vdygpIC8gNjEyOwoK ICAgICAgICBjb250ZXh0LmNsZWFyUmVjdCgwLCAwLCB3LCBoKTsKCiAgICAgICAgdmFyIHN0ZXBY ID0gTWF0aC5zaW4oYW5nbGUpICogMS41OwogICAgICAgIHZhciBzdGVwWSA9IE1hdGguY29zKGFu Z2xlKSAqIC41OwogICAgICAgIHZhciB4ID0gLXN0ZXBYICogMzsKICAgICAgICB2YXIgeSA9IC1z dGVwWSAqIDM7CiAgICAgICAgY29udGV4dC5maWxsVGV4dCgi0LTQuNC30LDQudC9Iiwgdy8yICsg eCwgaC8zICsgeSk7CgogICAgICAgIGNvbnRleHQuZmlsbFRleHQoItC00LjQt9Cw0LnQvSIsIE1h dGguZmxvb3Iody8yICsgeCksIE1hdGguZmxvb3IoaCoyLzMgKyB5KSk7Cgl9KTsKCXJlcXVlc3RB bmltYXRpb25GcmFtZShhbmltYXRlKTsKfQoKCnJlcXVlc3RBbmltYXRpb25GcmFtZShhbmltYXRl KTsKCgo8L3NjcmlwdD4KCjwvYm9keT4KCjwvaHRtbD4=