[gs-commits] ghostpdl branch, gs9.28-temp-for-testing, updated. gs9.28-temp-for-testing-tag-2-g5e538ae

The ghostpdl branch, gs9.28-temp-for-testing has been updated
       via  5e538ae744ce9b0089b67b846a52802099ec0f40 (commit)
      from  72e3efc7d0b732060b2507bfa4d859c79ebc420e (commit)

----------------------------------------------------------------------
commit 5e538ae744ce9b0089b67b846a52802099ec0f40
Author: Robin Watts <[email protected]>
Date:   Fri Aug 23 15:06:17 2019 +0100

    Fix deep color transparency issue.
    
    Fix overflow in art_pdf_composite_knockout_16, seen in:
    
       tests_private/comparefiles/Bug690546.pdf.psdcmyk16.72.0

diff --git a/base/gxblend.c b/base/gxblend.c
index f3bf38d..38c27cb 100644
--- a/base/gxblend.c
+++ b/base/gxblend.c
@@ -2542,14 +2542,16 @@ art_pdf_composite_knockout_16(uint16_t *gs_restrict dst,
             tmp = (65535 - dst_alpha) * src_shape + 0x8000;
             result_alpha = dst_alpha + ((tmp + (tmp >> 16)) >> 16);
 
-            if (result_alpha != 0)
+            if (result_alpha != 0) {
+                dst_alpha += dst_alpha>>15;
                 for (i = 0; i < n_chan; i++) {
                     /* todo: optimize this - can strength-reduce so that
                        inner loop is a single interpolation */
-                    tmp = dst[i] * dst_alpha * (65535 - src_shape) +
-                        ((int)src[i]) * 65535 * src_shape + (result_alpha << 15);
-                    dst[i] = tmp / (result_alpha * 65535);
+                    tmp = ((dst[i] * dst_alpha)>>16) * (65535 - src_shape) +
+                        ((int)src[i]) * src_shape + (result_alpha>>1);
+                    dst[i] = tmp / result_alpha;
                 }
+            }
             dst[n_chan] = result_alpha;
         }
     } else {


Summary of changes:
 base/gxblend.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)