Re: 2.10.3 BW renderer changes

[Alexei Podtelezhnikov]

Hi Davide,

Thank you. I don't know how much you know about hinting vs rendering.
You seem to be confused about FT_LOAD flags.

> FT_Load_Char(face, 'e', FT_LOAD_DEFAULT | FT_LOAD_TARGET_LIGHT | 
> FT_LOAD_MONOCHROME | FT_LOAD_NO_BITMAP);

FT_LOAD_DEFAULT is just 0 and is meaningless in the OR-chain.
FT_LOAD_NO_BITMAP mean no embedded bitmaps, which Arial does not have,
if I am not mistaken
FT_LOAD_MONOCHROME is a selector of rendering algorithm, but you
postpone it until later. It has no effect
FT_LOAD_TARGET_LIGHTis the only flag that does a lot here: it enables
autohinting but only vertically, bytecode is disabled.

As a result you might indeed use wrong hinting (or without horizontal
hinting) for a mono rendering. Please try FT_LOAD_TARGET_MONO as our
documentation clearly suggests for monochrome rendering. See
https://freetype.org/freetype2/docs/reference/ft2-base_interface.html#ft_load_xxx.

> FT_Render_Glyph(face->glyph, FT_RENDER_MODE_MONO);

You might argue that it used to work. I really do not know how. Again,
you should get an Ok output with just FT_LOAD_TARGET_MONO do not make
it more complicated than that.

Alexei

On Wed, Jan 11, 2023 at 3:29 AM Davide Rizzo <davide.rizzo@eidos.eu> wrote:
>
> Hi,
>
> You're right.
>
> I wrote a very simple test program to evidence the difference in the output.
>
> I attach the program, the font we use (a standard arial.ttf) and the
> different outputs I obtain at size 58.
>
> With freetype up to 2.10.2 I obtain the desired nice bitmap, with
> freetype since 2.10.3 (including the last 2.12.1) I obtain a different
> bitmap.
>
> My question is if it's possible with some parameter to obtain the "old"
> bitmap with freetype 2.12.1.
>
> Thank you
>
> Davide Rizzo
>
>
> Il 10/01/23 00:03, Alexei Podtelezhnikov ha scritto:
> > Davide,
> >
> >> The new output is much worse, most of chars have single dots protruding
> > in the external outline.
> >
> > We won't be able to help you unless you help us to reproduce or see
> > the issue. At the very least you should name the font and the size,
> > and give a screenshot.  Also, in our mind, only bugs in 2.12.1 are
> > worth fixing. You should try this most recent version in case it is
> > fixed already. There could be other software that disabled the hinting
> > too. Therefore, we prefer that you show the issue using freetype demos
> > like ftview or ftgrid.
> >
> > Does this make sense? Your report does not have any details. You can
> > use https://gitlab.freedesktop.org/freetype/freetype/-/issues once you
> > have mode details.
> >
> > Can you help us to help you?
> >
> > Alexei



-- 
Alexei A. Podtelezhnikov, PhD