APPENDIX H
1108
Compatibility and Implementation Notes
effect of masked images when printing to LanguageLevel 1 or Lan-
guageLevel 2 output devices; they print the base image without the mask.
The Acrobat 4.0 viewer displays masked images, but only when the
amount of data in the mask is below a certain limit. Above that, the viewer
displays the base image without the mask.
55. All Acrobat viewers ignore the
Name
entry in a form dictionary.
56. Acrobat 6.0 and earlier viewers do not implement reference XObjects. The
proxy is always used for viewing and printing.
57. In Acrobat 4.05 and earlier versions, text-showing operators such as
Tj
first perform the fills for all the glyphs in the string being shown, followed
by the strokes for all the glyphs. This produces incorrect results if glyphs
overlap.
58. In versions of Acrobat earlier than 3.0, the horizontal coordinate of the
text position after the
TJ
operator paints a character glyph and moves by
any specified offset must not be less than it was before the glyph was
painted.
59. In Acrobat 4.0 and earlier viewers, position adjustments specified by num-
bers in a
TJ
array are performed incorrectly if the horizontal scaling pa-
rameter,
T
h
, is different from its default value of 100.
60. All Acrobat viewers ignore the
Name
entry in a font dictionary.
61. Acrobat 5.0 and later viewers use the glyph widths stored in the font dic-
tionary to override the widths of glyphs in the font program itself, which
improves the consistency of the display and printing of the document.
This addresses the situation in which the font program used by the viewer