[gs-commits] ghostpdl branch, gs9.28-temp-for-testing, updated. gs9.28-temp-for-testing-tag-17-g92bc858

The ghostpdl branch, gs9.28-temp-for-testing has been updated
       via  92bc858b03f206a0e08ca956cb3e5d2a825dffe8 (commit)
      from  d80a7eacb629029828ccb79b8bee03a0b471b8c1 (commit)

----------------------------------------------------------------------
commit 92bc858b03f206a0e08ca956cb3e5d2a825dffe8
Author: Robin Watts <[email protected]>
Date:   Mon Sep 2 12:59:33 2019 +0100

    Fix deep color mattes.
    
    As seen with the content vanishing when rendering
    tests_private/pdf/sumatra/uninitialized_value_with_JPX_images.pdf
    to psdcmyk16. The Softmask on the image has a Matte of [1,1,1]
    and the calculations in the current code overflow, meaning that
    it comes out as completely white.
    
    We resort to 64bit to avoid the overflow. Mattes are vanishingly
    rare, so speed shouldn't be an issue. We can revisit if we ever
    find a case that matters.

diff --git a/base/gdevp14.c b/base/gdevp14.c
index aecc354..b7d3d57 100644
--- a/base/gdevp14.c
+++ b/base/gdevp14.c
@@ -708,10 +708,12 @@ resolve_matte(pdf14_buf *maskbuf, byte *src_data, int src_planestride, int src_r
                 int      b   = mask_tr_fn[top+1]-a;
                 uint16_t matte_alpha = a + ((0x80 + b*(idx & 0xff))>>8);
 
+                /* matte's happen rarely enough that we allow ourselves to
+                 * resort to 64bit here. */
                 if (matte_alpha != 0 && matte_alpha != 0xffff) {
                     for (i = 0; i < src_profile->num_comps; i++) {
                         int val = src_curr_ptr[i * src_planestride] - maskbuf->matte[i];
-                        int temp = ((unsigned int)(val * 0xffff) / matte_alpha) + maskbuf->matte[i];
+                        int temp = (((int64_t)val) * 0xffff / matte_alpha) + maskbuf->matte[i];
 
                         /* clip */
                         if (temp > 0xffff)


Summary of changes:
 base/gdevp14.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)