diff options
| -rw-r--r-- | libdimension/png.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/libdimension/png.c b/libdimension/png.c index bc547a1..20190d8 100644 --- a/libdimension/png.c +++ b/libdimension/png.c @@ -306,8 +306,9 @@ dmnsn_png_write_canvas_impl(dmnsn_progress *progress, dmnsn_array_get(canvas->optimizers, i, &optimizer); if (optimizer.optimizer_fn == &dmnsn_png_optimizer_fn) { for (y = 0; y < height; ++y) { - png_write_row(png_ptr, - (png_bytep)((uint16_t *)optimizer.ptr + 4*y*width)); + /* Invert the rows. PNG coordinates are fourth quadrant. */ + uint16_t *row = (uint16_t *)optimizer.ptr + 4*(height - y - 1)*width; + png_write_row(png_ptr, (png_bytep)row); dmnsn_increment_progress(progress); } |