bccu#1845 - Calc tile rendering very slow

For some reason trying to draw exactly the
region of the tile results in black tiles.
That is, when the top rows and left columns
are not drawn, black tiles show.

This patch still reduces the time to render
a given tile by limiting the bottom-most row
and right-most column to the max necessary.
For large tabs rendering the first few 100
rows is very fast (<100ms at most).

More work is necessary to reduce drawing time
for large sheets (when rendering tiles at the
bottom). Still, even those slow bottom-rows
are now faster with this patch.

Currently the slowest function by far is
ScGridWindow::DrawContent.

Change-Id: I6e88c7b3a1c483bf43bfcfb38f4b41ffc08a9744
Reviewed-on: https://gerrit.libreoffice.org/25586
Reviewed-by: Ashod Nakashian <ashnakash@gmail.com>
Tested-by: Ashod Nakashian <ashnakash@gmail.com>

0 files changed, 0 insertions, 0 deletions