From 7a6b60d0ec1abac316917690878011c3228a6fb7 Mon Sep 17 00:00:00 2001 From: Robin Watts Date: Wed, 7 Dec 2011 17:58:00 +0000 Subject: Fix tile coverage calculations. The code attempts to spot cases where a pattern tile is so large that only 1 repeat is visible. Due to rounding errors, this test could sometimes fail, and (on badly formed files) we'd attempt to allocate huge pixmaps. The fix is to allow for rounding errors. --- pdf/pdf_interpret.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'pdf') diff --git a/pdf/pdf_interpret.c b/pdf/pdf_interpret.c index 55e66e61..f598e9fb 100644 --- a/pdf/pdf_interpret.c +++ b/pdf/pdf_interpret.c @@ -1151,10 +1151,15 @@ pdf_show_pattern(pdf_csi *csi, pdf_pattern *pat, fz_rect area, int what) /* patterns are painted using the ctm in effect at the beginning of the content stream */ /* get bbox of shape in pattern space for stamping */ area = fz_transform_rect(invptm, area); - x0 = floorf(area.x0 / pat->xstep); - y0 = floorf(area.y0 / pat->ystep); - x1 = ceilf(area.x1 / pat->xstep); - y1 = ceilf(area.y1 / pat->ystep); + + /* When calculating the number of tiles required, we adjust by a small + * amount to allow for rounding errors. By choosing this amount to be + * smaller than 1/256, we guarantee we won't cause problems that will + * be visible even under our most extreme antialiasing. */ + x0 = floorf(area.x0 / pat->xstep + 0.001); + y0 = floorf(area.y0 / pat->ystep + 0.001); + x1 = ceilf(area.x1 / pat->xstep - 0.001); + y1 = ceilf(area.y1 / pat->ystep - 0.001); oldtopctm = csi->top_ctm; oldtop = csi->gtop; -- cgit v1.2.3