tree cd0e34686433786ab2a759ddf619f86faa718931
parent 4ba051cbcfbd379714250b1fe463c1610e7df04c
author jvanverth <jvanverth@google.com> 1457637043 -0800
committer Commit bot <commit-bot@chromium.org> 1457637043 -0800

Use correct gradient calculation for rotated distance fields.

For all uniform scaled matrices, we were using the y coordinate of the
y-direction gradient of the v texel space coordinate to scale the
distance values. The problem is, if you rotate by 90 degrees this value
becomes 0. The correct answer is to take the length of the y-direction
gradient.

BUG=skia:4864
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1776383002

Review URL: https://codereview.chromium.org/1776383002