Move transfer functions to 16 bits.

This means that in 'deep' modes, we sample them in 257 places
(0000,0100,....ff00,ffff) rather than 256 (00,01,...ff), and
in 16 bits rather than 8. We also interpolate them on reading.

This in turn increases the size of the data put into the clist.

1 files changed, 45 insertions, 40 deletions

diff --git a/base/gxblend.c b/base/gxblend.c
index 0dd1a8a26..f95129254 100644
--- a/base/gxblend.c
+++ b/base/gxblend.c
@@ -2661,7 +2661,7 @@ typedef void (*art_pdf_compose_group_fn)(byte *tos_ptr, bool tos_isolated, int t
                                          int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
                                          byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride,
                                          byte *nos_alpha_g_ptr, bool nos_knockout, int nos_shape_offset, int nos_tag_offset,
-                                         byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+                                         byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
                                          byte *backdrop_ptr, bool has_matte, int n_chan, bool additive, int num_spots, bool overprint,
                                          gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
                                          const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev);
@@ -2678,7 +2678,7 @@ template_compose_group(byte *gs_restrict tos_ptr, bool tos_isolated,
                        bool nos_knockout, int nos_shape_offset,
                        int nos_tag_offset, byte *gs_restrict mask_row_ptr,
                        int has_mask, pdf14_buf *gs_restrict maskbuf,
-                       byte mask_bg_alpha, byte *gs_restrict mask_tr_fn,
+                       byte mask_bg_alpha, const byte *gs_restrict mask_tr_fn,
                        byte *gs_restrict backdrop_ptr, bool has_matte,
                        int n_chan, bool additive, int num_spots,
                        bool overprint, gx_color_index drawn_comps,
@@ -2916,7 +2916,7 @@ compose_group_knockout(byte *tos_ptr, bool tos_isolated, int tos_planestride, in
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -2933,7 +2933,7 @@ compose_group_nonknockout_blend(byte *tos_ptr, bool tos_isolated, int tos_planes
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -2950,7 +2950,7 @@ compose_group_nonknockout_nonblend_isolated_allmask_common(byte *tos_ptr, bool t
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3015,7 +3015,7 @@ compose_group_nonknockout_nonblend_isolated_mask_common(byte *tos_ptr, bool tos_
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3105,7 +3105,7 @@ compose_group_nonknockout_nonblend_isolated_nomask_common(byte *tos_ptr, bool to
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3122,7 +3122,7 @@ compose_group_nonknockout_nonblend_nonisolated_mask_common(byte *tos_ptr, bool t
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3139,7 +3139,7 @@ compose_group_nonknockout_nonblend_nonisolated_nomask_common(byte *tos_ptr, bool
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3156,7 +3156,7 @@ compose_group_nonknockout_noblend_general(byte *tos_ptr, bool tos_isolated, int
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3173,7 +3173,7 @@ compose_group_alphaless_knockout(byte *tos_ptr, bool tos_isolated, int tos_plane
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3190,7 +3190,7 @@ compose_group_alphaless_nonknockout(byte *tos_ptr, bool tos_isolated, int tos_pl
               int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               byte *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, byte *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, byte *mask_tr_fn,
+              byte *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, byte mask_bg_alpha, const byte *mask_tr_fn,
               byte *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3379,13 +3379,22 @@ do_compose_group(pdf14_buf *tos, pdf14_buf *nos, pdf14_buf *maskbuf,
 #endif
 }
 
+static inline uint16_t
+interp16(const uint16_t *table, uint16_t idx)
+{
+    byte     top = idx>>8;
+    uint16_t a   = table[top];
+    int      b   = table[top+1]-a;
+
+    return a + ((0x80 + b*(idx & 0xff))>>8);
+}
 
 typedef void (*art_pdf_compose_group16_fn)(uint16_t *tos_ptr, bool tos_isolated, int tos_planestride, int tos_rowstride,
                                          uint16_t alpha, uint16_t shape, gs_blend_mode_t blend_mode, bool tos_has_shape,
                                          int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
                                          uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride,
                                          uint16_t *nos_alpha_g_ptr, bool nos_knockout, int nos_shape_offset, int nos_tag_offset,
-                                         uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+                                         uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
                                          uint16_t *backdrop_ptr, bool has_matte, int n_chan, bool additive, int num_spots, bool overprint,
                                          gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
                                          const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev);
@@ -3402,7 +3411,7 @@ template_compose_group16(uint16_t *gs_restrict tos_ptr, bool tos_isolated,
                          bool nos_knockout, int nos_shape_offset,
                          int nos_tag_offset, uint16_t *gs_restrict mask_row_ptr,
                          int has_mask, pdf14_buf *gs_restrict maskbuf,
-                         uint16_t mask_bg_alpha, byte *gs_restrict mask_tr_fn,
+                         uint16_t mask_bg_alpha, const uint16_t *gs_restrict mask_tr_fn,
                          uint16_t *gs_restrict backdrop_ptr, bool has_matte,
                          int n_chan, bool additive, int num_spots,
                          bool overprint, gx_color_index drawn_comps,
@@ -3463,8 +3472,7 @@ template_compose_group16(uint16_t *gs_restrict tos_ptr, bool tos_isolated,
                     matte_alpha = 0xffff;
                 } else {
                     if (has_matte)
-                        /* FIXME: Not ideal */
-                        matte_alpha = mask_tr_fn[*mask_curr_ptr >> 8] * 0x101;
+                        matte_alpha = interp16(mask_tr_fn, *mask_curr_ptr);
                 }
             }
 
@@ -3521,8 +3529,7 @@ template_compose_group16(uint16_t *gs_restrict tos_ptr, bool tos_isolated,
 
             if (mask_curr_ptr != NULL) {
                 if (in_mask_rect) {
-                    /* FIXME: Not ideal */
-                    uint16_t mask = mask_tr_fn[(*mask_curr_ptr++)>>8] * 0x101;
+                    uint16_t mask = interp16(mask_tr_fn, *mask_curr_ptr++);
                     int tmp = pix_alpha * (mask+(mask>>15)) + 0x8000;
                     pix_alpha = (tmp >> 16);
                 } else {
@@ -3654,7 +3661,7 @@ compose_group16_knockout(uint16_t *tos_ptr, bool tos_isolated, int tos_planestri
               bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3671,7 +3678,7 @@ compose_group16_nonknockout_blend(uint16_t *tos_ptr, bool tos_isolated, int tos_
               gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3688,7 +3695,7 @@ compose_group16_nonknockout_nonblend_isolated_allmask_common(uint16_t *tos_ptr,
               uint16_t shape, gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3700,8 +3707,7 @@ compose_group16_nonknockout_nonblend_isolated_allmask_common(uint16_t *tos_ptr,
     for (y = y1 - y0; y > 0; --y) {
         uint16_t *gs_restrict mask_curr_ptr = mask_row_ptr;
         for (x = 0; x < width; x++) {
-            /* FIXME: Not ideal */
-            int mask = mask_tr_fn[(*mask_curr_ptr++)>>8] * 0x101;
+            int mask = interp16(mask_tr_fn, *mask_curr_ptr++);
             uint16_t src_alpha = tos_ptr[n_chan * tos_planestride];
             if (src_alpha != 0) {
                 uint16_t a_b;
@@ -3759,7 +3765,7 @@ compose_group16_nonknockout_nonblend_isolated_mask_common(uint16_t *tos_ptr, boo
               gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3791,8 +3797,7 @@ compose_group16_nonknockout_nonblend_isolated_mask_common(uint16_t *tos_ptr, boo
 
             if (mask_curr_ptr != NULL) {
                 if (in_mask_rect) {
-                    /* FIXME: Not ideal */
-                    int mask = mask_tr_fn[(*mask_curr_ptr++)>>8] * 0x101;
+                    int mask = interp16(mask_tr_fn, *mask_curr_ptr++);
                     mask += mask>>15;
                     pix_alpha = (pix_alpha * mask + 0x8000)>>16;
                 } else {
@@ -3854,7 +3859,7 @@ compose_group16_nonknockout_nonblend_isolated_nomask_common(uint16_t *tos_ptr, b
               uint16_t shape, gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3871,7 +3876,7 @@ compose_group16_nonknockout_nonblend_nonisolated_mask_common(uint16_t *tos_ptr,
               uint16_t shape, gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3888,7 +3893,7 @@ compose_group16_nonknockout_nonblend_nonisolated_nomask_common(uint16_t *tos_ptr
               uint16_t shape, gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3905,7 +3910,7 @@ compose_group16_nonknockout_noblend_general(uint16_t *tos_ptr, bool tos_isolated
               gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3922,7 +3927,7 @@ compose_group16_alphaless_knockout(uint16_t *tos_ptr, bool tos_isolated, int tos
               gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3939,7 +3944,7 @@ compose_group16_alphaless_nonknockout(uint16_t *tos_ptr, bool tos_isolated, int
               gs_blend_mode_t blend_mode, bool tos_has_shape, int tos_shape_offset, int tos_alpha_g_offset, int tos_tag_offset, bool tos_has_tag,
               uint16_t *nos_ptr, bool nos_isolated, int nos_planestride, int nos_rowstride, uint16_t *nos_alpha_g_ptr, bool nos_knockout,
               int nos_shape_offset, int nos_tag_offset,
-              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, byte *mask_tr_fn,
+              uint16_t *mask_row_ptr, int has_mask, pdf14_buf *maskbuf, uint16_t mask_bg_alpha, const uint16_t *mask_tr_fn,
               uint16_t *backdrop_ptr,
               bool has_matte, int n_chan, bool additive, int num_spots, bool overprint, gx_color_index drawn_comps, int x0, int y0, int x1, int y1,
               const pdf14_nonseparable_blending_procs_t *pblend_procs, pdf14_device *pdev)
@@ -3983,7 +3988,7 @@ do_compose_group16(pdf14_buf *tos, pdf14_buf *nos, pdf14_buf *maskbuf,
     int nos_shape_offset = n_chan * nos_planestride;
     int nos_alpha_g_offset = nos_shape_offset + (nos->has_shape ? nos_planestride : 0);
     int nos_tag_offset = nos_planestride * (nos->n_planes - 1);
-    byte *mask_tr_fn = NULL; /* Quiet compiler. */
+    const uint16_t *mask_tr_fn = NULL; /* Quiet compiler. */
     bool has_mask = false;
     uint16_t *backdrop_ptr = NULL;
     pdf14_device *pdev = (pdf14_device *)dev;
@@ -4021,7 +4026,8 @@ do_compose_group16(pdf14_buf *tos, pdf14_buf *nos, pdf14_buf *maskbuf,
         overprint = false;
 
     if (maskbuf != NULL) {
-        mask_tr_fn = maskbuf->transfer_fn;
+        unsigned int tmp;
+        mask_tr_fn = (uint16_t *)maskbuf->transfer_fn;
         /* Make sure we are in the mask buffer */
         if (maskbuf->data != NULL) {
             mask_row_ptr =
@@ -4036,9 +4042,9 @@ do_compose_group16(pdf14_buf *tos, pdf14_buf *nos, pdf14_buf *maskbuf,
         mask_bg_alpha = maskbuf->alpha;
         /* Adjust alpha by the mask background alpha.   This is only used
            if we are outside the soft mask rect during the filling operation */
-        mask_bg_alpha = mask_tr_fn[mask_bg_alpha>>8] * 0x101;
-        mask_bg_alpha += mask_bg_alpha>>8;
-        mask_bg_alpha = (alpha * mask_bg_alpha + 0x8000)>>16;
+        mask_bg_alpha = interp16(mask_tr_fn, mask_bg_alpha);
+        tmp = alpha * mask_bg_alpha + 0x8000;
+        mask_bg_alpha = (tmp + (tmp >> 8)) >> 8;
     }
     n_chan--; /* Now the true number of colorants (i.e. not including alpha)*/
 #if RAW_DUMP
@@ -4187,7 +4193,7 @@ do_compose_alphaless_group(pdf14_buf *tos, pdf14_buf *nos,
     int nos_shape_offset = n_chan * nos_planestride;
     int nos_alpha_g_offset = nos_shape_offset + (nos->has_shape ? nos_planestride : 0);
     int nos_tag_offset = nos_planestride * (nos->n_planes - 1);
-    byte *mask_tr_fn = NULL; /* Quiet compiler. */
+    const byte *mask_tr_fn = NULL; /* Quiet compiler. */
     bool has_mask = false;
     byte *backdrop_ptr = NULL;
 #if RAW_DUMP
@@ -4319,7 +4325,6 @@ do_compose_alphaless_group16(pdf14_buf *tos, pdf14_buf *nos,
     int nos_shape_offset = n_chan * nos_planestride;
     int nos_alpha_g_offset = nos_shape_offset + (nos->has_shape ? nos_planestride : 0);
     int nos_tag_offset = nos_planestride * (nos->n_planes - 1);
-    byte *mask_tr_fn = NULL; /* Quiet compiler. */
     bool has_mask = false;
     uint16_t *backdrop_ptr = NULL;
 #if RAW_DUMP
@@ -4405,7 +4410,7 @@ do_compose_alphaless_group16(pdf14_buf *tos, pdf14_buf *nos,
                   tos_shape_offset>>1, tos_alpha_g_offset>>1, tos_tag_offset>>1, tos_has_tag,
                   nos_ptr, nos_isolated, nos_planestride>>1, nos->rowstride>>1, nos_alpha_g_ptr, nos_knockout,
                   nos_shape_offset>>1, nos_tag_offset>>1,
-                  mask_row_ptr, has_mask, /* maskbuf */ NULL, mask_bg_alpha, mask_tr_fn,
+                  mask_row_ptr, has_mask, /* maskbuf */ NULL, mask_bg_alpha, NULL,
                   backdrop_ptr,
                   /* has_matte */ 0, n_chan, additive, num_spots, overprint, drawn_comps, x0, y0, x1, y1,
                   pdev->blend_procs, pdev);