From: "समीर सिंह Sameer Singh" <lumarzeli30@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Implementing Vertical Text support in Emacs
Date: Fri, 30 Sep 2022 01:27:01 +0530 [thread overview]
Message-ID: <CAOR1sLwrMq_L0Xmq1dA-O9TYbPsv0PbxCKPc6ZRoZzWeOSt1bg@mail.gmail.com> (raw)
In-Reply-To: <83leqr9pb4.fsf@gnu.org>
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>
> Before you modify display_line, you need to decide how will the
> vertical-layout display produce glyphs.
Can you please expand more on this?
How to produce glyphs in a column wise order?
I looked at gui_produce_glyphs and that led me to append_glyph, but I could
not figure out how the glyphs are produced.
There is also draw_glyphs but I think working with that will require
editing the low level *term files (if it even is the right function)
Thanks
On Sat, Sep 10, 2022 at 9:47 PM Eli Zaretskii <eliz@gnu.org> wrote:
> > From: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
> > Date: Sat, 10 Sep 2022 21:23:32 +0530
> > Cc: emacs-devel@gnu.org
> >
> > In order to find the "real meat" of the display_line function I started
> to slowly remove most of the lines of the
> > function as long as it does not break emacs and text can be typed.
> >
> > In the end I was left with this a 20-25 lines function (excluding
> comments and spaces):
> > (I have attached this function too)
> >
> > static bool
> > display_line (struct it *it, int cursor_vpos)
> > {
> > struct glyph_row *row = it->glyph_row;
> >
> > /* Clear the result glyph row and enable it. */
> > prepare_desired_row (it->w, row, false);
> >
> > row->y = it->current_y;
> >
> > /* Loop generating characters. The loop is left with IT on the next
> > character to display. */
> > while (true)
> > {
> >
> > /* Retrieve the next thing to display. Value is false if end of
> > buffer reached. */
> > if (!get_next_display_element (it))
> > {
> > break;
> > }
> >
> > PRODUCE_GLYPHS (it);
> >
> > at_end_of_line:
> > /* Is this a line end? If yes, we're also done, after making
> > sure that a non-default face is extended up to the right
> > margin of the window. */
> > if (ITERATOR_AT_END_OF_LINE_P (it))
> > {
> > /* Consume the line end. This skips over invisible lines. */
> > set_iterator_to_next (it, true);
> > break;
> > }
> >
> > set_iterator_to_next (it, true);
> > }
> >
> > /* Compute pixel dimensions of this line. */
> > compute_line_metrics (it);
> >
> > /* Prepare for the next line. This line starts horizontally at (X
> > HPOS) = (0 0). Vertical positions are incremented. As a
> > convenience for the caller, IT->glyph_row is set to the next
> > row to be used. */
> >
> > it->current_y += row->height;
> > ++it->glyph_row;
> > return MATRIX_ROW_DISPLAYS_TEXT_P (row);
> > }
> >
> > Obviously most of the things do not work such as bidi, word wrapping,
> displaying cursor and line numbers but
> > still text is being shown
> > in rows one after the other and it can be scrolled, but now there are no
> lines mentioning the hpos, the
> > x-coordinate, first_visible_x or
> > last_visible_x, does that mean I do not understand the display_line
> function? I thought its function was to fill a
> > row with glyphs in the desired matrix
> > to display it on the glass but now I cannot find a line which fills the
> matrix.
>
> That hides behind the PRODUCE_GLYPHS macro.
>
> > You had advised to swap the x and y
> > coordinates, but here there
> > is no x coordinate present! How can the redisplay still work?
>
> display_line also makes the decisions when the screen line is full and
> the rest should be on the next screen line this is one of its most
> important roles. But you have removed that code, so you don't see it
> in what's left. The parts that deal with the X coordinate that
> exceeds last_visible_x are those which make that decision.
>
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next prev parent reply other threads:[~2022-09-29 19:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-13 15:29 Implementing Vertical Text support in Emacs समीर सिंह Sameer Singh
2022-06-13 16:16 ` [External] : " Drew Adams
2022-06-13 16:30 ` Eli Zaretskii
2022-06-15 10:08 ` Richard Stallman
2022-06-15 10:22 ` Po Lu
2022-06-15 11:09 ` समीर सिंह Sameer Singh
2022-06-16 22:48 ` Richard Stallman
2022-06-17 1:43 ` समीर सिंह Sameer Singh
2022-06-17 6:12 ` Eli Zaretskii
2022-09-08 18:44 ` समीर सिंह Sameer Singh
2022-09-08 19:05 ` Eli Zaretskii
2022-09-10 15:53 ` समीर सिंह Sameer Singh
2022-09-10 16:17 ` Eli Zaretskii
2022-09-29 19:57 ` समीर सिंह Sameer Singh [this message]
2022-09-30 6:30 ` Eli Zaretskii
2022-11-20 11:18 ` समीर सिंह Sameer Singh
2022-11-20 11:43 ` Eli Zaretskii
2022-11-20 12:08 ` समीर सिंह Sameer Singh
2022-11-24 11:39 ` Eli Zaretskii
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