From d0279cbd913fb9dcada3f7dc6a3435b862a82c47 Mon Sep 17 00:00:00 2001
From: Robin Watts <Robin.Watts@artifex.com>
Date: Fri, 14 Oct 2022 08:51:02 +0100
Subject: [PATCH 154/155] Bug 705955: Restrict the vertical size of clipping
 accums for speed.

Where possible, limit the vertical size of clipping accumulators.
---
 base/gxacpath.c | 18 ++++++++++++++----
 base/gxstroke.c |  4 ++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/base/gxacpath.c b/base/gxacpath.c
index 23c70a0da..df51b6c00 100644
--- a/base/gxacpath.c
+++ b/base/gxacpath.c
@@ -92,16 +92,26 @@ void
 gx_cpath_accum_set_cbox(gx_device_cpath_accum * padev,
                         const gs_fixed_rect * pbox)
 {
+    /* fixed2int_var_ceiling(x) overflows for anything larger
+     * than max_fixed - fixed_scale - 1. So to protect against
+     * us doing bad things when passed a min_fixed/max_fixed box,
+     * clip appropriately. */
+    fixed upperx = pbox->q.x;
+    fixed uppery = pbox->q.y;
+    if (upperx > max_fixed - fixed_scale - 1)
+        upperx = max_fixed - fixed_scale - 1;
+    if (uppery > max_fixed - fixed_scale - 1)
+        uppery = max_fixed - fixed_scale - 1;
     if (padev->list.transpose) {
         padev->clip_box.p.x = fixed2int_var(pbox->p.y);
         padev->clip_box.p.y = fixed2int_var(pbox->p.x);
-        padev->clip_box.q.x = fixed2int_var_ceiling(pbox->q.y);
-        padev->clip_box.q.y = fixed2int_var_ceiling(pbox->q.x);
+        padev->clip_box.q.x = fixed2int_var_ceiling(uppery);
+        padev->clip_box.q.y = fixed2int_var_ceiling(upperx);
     } else {
         padev->clip_box.p.x = fixed2int_var(pbox->p.x);
         padev->clip_box.p.y = fixed2int_var(pbox->p.y);
-        padev->clip_box.q.x = fixed2int_var_ceiling(pbox->q.x);
-        padev->clip_box.q.y = fixed2int_var_ceiling(pbox->q.y);
+        padev->clip_box.q.x = fixed2int_var_ceiling(upperx);
+        padev->clip_box.q.y = fixed2int_var_ceiling(uppery);
     }
 }
 
diff --git a/base/gxstroke.c b/base/gxstroke.c
index 345378437..d069cb6ee 100644
--- a/base/gxstroke.c
+++ b/base/gxstroke.c
@@ -345,6 +345,7 @@ gx_default_stroke_path_shading_or_pattern(gx_device        * pdev,
     gx_device_color devc;
     gx_clip_path stroke_as_clip_path;
     int code;
+    gs_fixed_rect dev_clip_rect = { {min_fixed, min_fixed}, {max_fixed, max_fixed}};
 
     /* We want to make a image of the stroke as a clip path, so
      * create an empty structure on the stack. */
@@ -353,6 +354,9 @@ gx_default_stroke_path_shading_or_pattern(gx_device        * pdev,
         return code;
     /* Now we make an accumulator device that will fill that out. */
     gx_cpath_accum_begin(&adev, stroke_as_clip_path.path.memory, false);
+    if (pdev != 0)
+        (*dev_proc(pdev, get_clipping_box))(pdev, &dev_clip_rect);
+    gx_cpath_accum_set_cbox(&adev, &dev_clip_rect);
     set_nonclient_dev_color(&devc, 0);	/* arbitrary, but not transparent */
     gs_set_logical_op_inline(pgs, lop_default);
     /* Stroke the path to the accumulator. */
-- 
2.30.4