Kill the Invisible Pink Unicorn.

Clearing the colour from fully transparent areas in tilesheets allows
compressing them 2% better.

Thanks Bloaxor for suggesting this.

1 files changed, 4 insertions, 0 deletions

diff --git a/crawl-ref/source/rltiles/tool/tile_page.cc b/crawl-ref/source/rltiles/tool/tile_page.cc
index c8e90bf6af..ea92fedc08 100644
--- a/crawl-ref/source/rltiles/tool/tile_page.cc
+++ b/crawl-ref/source/rltiles/tool/tile_page.cc
@@ -154,6 +154,10 @@ bool tile_page::write_image(const char *filename)
                 tile_colour &dest = pixels[(sx+x) + (sy+y)*m_width];
                 tile_colour &src = m_tiles[i]->get_pixel(ofs_x+x, ofs_y+y);
                 dest = src;
+
+                // Clear colour from transparent areas.
+                if (!dest.a)
+                    dest = tile_colour::transparent;
             }
     }