Properly instruct Italic Arial or BS Mono at small PPEM sizes

* src/sfnt.c (sfnt_read_simple_glyph): Correct alignment errors.
(PUSH2_UNCHECKED): Don't shift negative signed value to the
left.
(SLOOP): Permit LOOP to be set to 0, which inhibits the
execution of instructions it affects.
(sfnt_address_zp2, sfnt_address_zp1, sfnt_address_zp0): Permit X
and Y to be NULL.
(sfnt_dot_fix_14): Guarantee that the final value is rounded to
negative infinity, not zero.
(sfnt_project_zp1_zp0_org): New function.
(sfnt_interpret_mdrp): Avoid rounding issues by computing
original distance from unscaled coordinates, if at all possible.
(sfnt_interpret_simple_glyph, sfnt_interpret_compound_glyph_2):
Set zone->simple.
(all_tests) <LOOP>: Update test.
(sfnt_identify_instruction, main): Adjust tests.

* src/sfnt.h (struct sfnt_interpreter_zone): New field simple.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/sfnt.h b/src/sfnt.h
index 2b92f9f540a..5b01270e8ce 100644
--- a/src/sfnt.h
+++ b/src/sfnt.h
@@ -1759,6 +1759,10 @@ struct sfnt_interpreter_zone
 
   /* Pointer to the flags associated with this data.  */
   unsigned char *flags;
+
+  /* If this structure was produced from a simple glyph, pointer to
+     the simple glyph itself.  NULL otherwise.  */
+  struct sfnt_simple_glyph *simple;
 };
 
 enum