tree f911454d2def14530ebb85a3e6c08e8fde5de937
parent 2fc79bcadc2317a06cdd8102dbd75fbc02d9a9bc
author Tom Sepez <tsepez@chromium.org> 1624566139 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> 1624566139 +0000

CStretchEngine: ensure sum of pixel weights is kFixedPointOne.

When calculating pixel weights using floating point arithmetic and
rounding, there is no guarantee that the sum of the rounding errors
will be zero. Instead, accumulate the error and distribute as we
compute weights. Finally, include those few fractional bits into
the last weight.

Bug: pdfium:1688
Change-Id: I7585731ad6aca1557b46e3a26eb3ddcb0aab59ca
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/82012
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>