From 13a09526d2120c244471e03b6ae979016ef88e83 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 23 Aug 2014 14:16:55 +0100 Subject: [PATCH] traps,xcb: Prefilter zero-area boxes when converting traps The rectangular tesselation routines rely on the presuming that all the boxes it has to handle are already filtered to remove empty boxes. << /width 800 /height 600 >> surface context 0.0848671 0 0 0.0848671 39.907812 5.608896 matrix transform 8 0 m 12.417969 0 16 3.582031 16 8 c 16 12.417969 12.417969 16 8 16 c 3.582031 16 0 12.417969 0 8 c 0 3.582031 3.582031 0 8 0 c h clip 16 0 m 8 8 l 16 16 l h clip 0 0 16 16 rectangle fill Triggers the error given a traps tesselator like cairo-xlib. Reported-by: Henrique Lengler Analyzed-by: Massimo Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81699 Signed-off-by: Chris Wilson --- src/cairo-traps-compositor.c | 28 +++++++++++++++++----------- src/cairo-xcb-surface-render.c | 29 ++++++++++++++++++----------- 2 files changed, 35 insertions(+), 22 deletions(-) diff --git a/src/cairo-traps-compositor.c b/src/cairo-traps-compositor.c index 8d679656d..88c7597a2 100644 --- a/src/cairo-traps-compositor.c +++ b/src/cairo-traps-compositor.c @@ -1393,7 +1393,7 @@ boxes_for_traps (cairo_boxes_t *boxes, cairo_traps_t *traps, cairo_antialias_t antialias) { - int i; + int i, j; /* first check that the traps are rectilinear */ if (antialias == CAIRO_ANTIALIAS_NONE) { @@ -1423,17 +1423,21 @@ boxes_for_traps (cairo_boxes_t *boxes, boxes->chunks.size = traps->num_traps; if (antialias != CAIRO_ANTIALIAS_NONE) { - for (i = 0; i < traps->num_traps; i++) { + for (i = j = 0; i < traps->num_traps; i++) { /* Note the traps and boxes alias so we need to take the local copies first. */ cairo_fixed_t x1 = traps->traps[i].left.p1.x; cairo_fixed_t x2 = traps->traps[i].right.p1.x; cairo_fixed_t y1 = traps->traps[i].top; cairo_fixed_t y2 = traps->traps[i].bottom; - boxes->chunks.base[i].p1.x = x1; - boxes->chunks.base[i].p1.y = y1; - boxes->chunks.base[i].p2.x = x2; - boxes->chunks.base[i].p2.y = y2; + if (x1 == x2 || y1 == y2) + continue; + + boxes->chunks.base[j].p1.x = x1; + boxes->chunks.base[j].p1.y = y1; + boxes->chunks.base[j].p2.x = x2; + boxes->chunks.base[j].p2.y = y2; + j++; if (boxes->is_pixel_aligned) { boxes->is_pixel_aligned = @@ -1444,7 +1448,7 @@ boxes_for_traps (cairo_boxes_t *boxes, } else { boxes->is_pixel_aligned = TRUE; - for (i = 0; i < traps->num_traps; i++) { + for (i = j = 0; i < traps->num_traps; i++) { /* Note the traps and boxes alias so we need to take the local copies first. */ cairo_fixed_t x1 = traps->traps[i].left.p1.x; cairo_fixed_t x2 = traps->traps[i].right.p1.x; @@ -1452,10 +1456,12 @@ boxes_for_traps (cairo_boxes_t *boxes, cairo_fixed_t y2 = traps->traps[i].bottom; /* round down here to match Pixman's behavior when using traps. */ - boxes->chunks.base[i].p1.x = _cairo_fixed_round_down (x1); - boxes->chunks.base[i].p1.y = _cairo_fixed_round_down (y1); - boxes->chunks.base[i].p2.x = _cairo_fixed_round_down (x2); - boxes->chunks.base[i].p2.y = _cairo_fixed_round_down (y2); + boxes->chunks.base[j].p1.x = _cairo_fixed_round_down (x1); + boxes->chunks.base[j].p1.y = _cairo_fixed_round_down (y1); + boxes->chunks.base[j].p2.x = _cairo_fixed_round_down (x2); + boxes->chunks.base[j].p2.y = _cairo_fixed_round_down (y2); + j += (boxes->chunks.base[j].p1.x != boxes->chunks.base[j].p2.x && + boxes->chunks.base[j].p1.y != boxes->chunks.base[j].p2.y); } } diff --git a/src/cairo-xcb-surface-render.c b/src/cairo-xcb-surface-render.c index 163bc4111..3361f9cbc 100644 --- a/src/cairo-xcb-surface-render.c +++ b/src/cairo-xcb-surface-render.c @@ -2902,7 +2902,7 @@ _boxes_for_traps (cairo_boxes_t *boxes, cairo_traps_t *traps, cairo_antialias_t antialias) { - int i; + int i, j; _cairo_boxes_init (boxes); @@ -2912,17 +2912,21 @@ _boxes_for_traps (cairo_boxes_t *boxes, boxes->chunks.size = traps->num_traps; if (antialias != CAIRO_ANTIALIAS_NONE) { - for (i = 0; i < traps->num_traps; i++) { + for (i = j = 0; i < traps->num_traps; i++) { /* Note the traps and boxes alias so we need to take the local copies first. */ cairo_fixed_t x1 = traps->traps[i].left.p1.x; cairo_fixed_t x2 = traps->traps[i].right.p1.x; cairo_fixed_t y1 = traps->traps[i].top; cairo_fixed_t y2 = traps->traps[i].bottom; - boxes->chunks.base[i].p1.x = x1; - boxes->chunks.base[i].p1.y = y1; - boxes->chunks.base[i].p2.x = x2; - boxes->chunks.base[i].p2.y = y2; + if (x1 == x2 || y1 == y2) + continue; + + boxes->chunks.base[j].p1.x = x1; + boxes->chunks.base[j].p1.y = y1; + boxes->chunks.base[j].p2.x = x2; + boxes->chunks.base[j].p2.y = y2; + j++; if (boxes->is_pixel_aligned) { boxes->is_pixel_aligned = @@ -2933,7 +2937,7 @@ _boxes_for_traps (cairo_boxes_t *boxes, } else { boxes->is_pixel_aligned = TRUE; - for (i = 0; i < traps->num_traps; i++) { + for (i = j = 0; i < traps->num_traps; i++) { /* Note the traps and boxes alias so we need to take the local copies first. */ cairo_fixed_t x1 = traps->traps[i].left.p1.x; cairo_fixed_t x2 = traps->traps[i].right.p1.x; @@ -2941,10 +2945,13 @@ _boxes_for_traps (cairo_boxes_t *boxes, cairo_fixed_t y2 = traps->traps[i].bottom; /* round down here to match Pixman's behavior when using traps. */ - boxes->chunks.base[i].p1.x = _cairo_fixed_round_down (x1); - boxes->chunks.base[i].p1.y = _cairo_fixed_round_down (y1); - boxes->chunks.base[i].p2.x = _cairo_fixed_round_down (x2); - boxes->chunks.base[i].p2.y = _cairo_fixed_round_down (y2); + boxes->chunks.base[j].p1.x = _cairo_fixed_round_down (x1); + boxes->chunks.base[j].p1.y = _cairo_fixed_round_down (y1); + boxes->chunks.base[j].p2.x = _cairo_fixed_round_down (x2); + boxes->chunks.base[j].p2.y = _cairo_fixed_round_down (y2); + + j += (boxes->chunks.base[j].p1.x != boxes->chunks.base[j].p2.x && + boxes->chunks.base[j].p1.y != boxes->chunks.base[j].p2.y); } } }