Since BitmapEx was unified into a single premultiplied 32-bit BGRA Bitmap, converting such a bitmap runs a per-pixel loop that builds a BitmapColor and dispatches through the `GetPixelFromData` / `SetPixelOnData`, (un)premultiplying one channel at a time. Add a fast scanline path for the common case, a premultiplied 32-bit truecolor bitmap (ABGR/ARGB/BGRA/RGBA). It resolves each channel's byte offset once and then moves the scanline bytes directly, using the premultiply / unpremultiply lookup tables. Signed-off-by: Karthik <karthik.godha@collabora.com> Change-Id: Ie8ee47055bdffca9e06d48955fdc0b61b34e08ac Reviewed-on: https://gerrit.collaboraoffice.com/c/online/+/6752 Reviewed-by: Michael Stahl <michael.stahl@collabora.com> Tested-by: Jenkins CPCI <releng@collaboraoffice.com> (cherry picked from commit 54c68922eaa2d2c4e20e10091ad4911e8d32aed2) Reviewed-on: https://gerrit.libreoffice.org/c/core/+/208641 Tested-by: Jenkins