From dec079d312a2dcf73d20446bebd2935e8a6a9e41 Mon Sep 17 00:00:00 2001 From: wm4 Date: Wed, 11 Jan 2017 07:10:13 +0100 Subject: render: clip BorderStyle=4 against screen ASS_Images returned by libass are guaranteed to be clipped. Not doing this will cause invalid memory accesses in applications which try to use this guarantee. Fixes #254. --- libass/ass_render.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) (limited to 'libass') diff --git a/libass/ass_render.c b/libass/ass_render.c index d0f827d..101131e 100644 --- a/libass/ass_render.c +++ b/libass/ass_render.c @@ -2413,15 +2413,23 @@ static void render_and_combine_glyphs(ASS_Renderer *render_priv, static void add_background(ASS_Renderer *render_priv, EventImages *event_images) { - void *nbuffer = ass_aligned_alloc(1, event_images->width * event_images->height, false); + int left = event_images->left; + int top = event_images->top; + int right = event_images->left + event_images->width; + int bottom = event_images->top + event_images->height; + left = FFMINMAX(left, 0, render_priv->width); + top = FFMINMAX(top, 0, render_priv->height); + right = FFMINMAX(right, 0, render_priv->width); + bottom = FFMINMAX(bottom, 0, render_priv->height); + int w = right - left; + int h = bottom - top; + if (w < 1 || h < 1) + return; + void *nbuffer = ass_aligned_alloc(1, w * h, false); if (!nbuffer) return; - memset(nbuffer, 0xFF, event_images->width * event_images->height); - ASS_Image *img = my_draw_bitmap(nbuffer, event_images->width, - event_images->height, - event_images->width, - event_images->left, - event_images->top, + memset(nbuffer, 0xFF, w * h); + ASS_Image *img = my_draw_bitmap(nbuffer, w, h, w, left, top, render_priv->state.c[3], NULL); if (img) { img->next = event_images->imgs; -- cgit v1.2.3