Some fonts, even monospaced ones, have a negative line gap (line
height < ascent + descent).
Using the font's line height as cell height will result in some glyphs
overflowing into the cell above or below.
Workaround by using which ever value is the largest: the line height
or ascent + descent.
For now, this behavior is controlled with an ifdef. At least kwin
seems very buggy when the decorations are positioned like this (but
normally you'd use server-side decorations with kwin anyway).
This commit also changes 'use_csd' to be a tri-state variable;
when instantiating a window it is set to 'unknown'.
If there's no decoration manager available (e.g. weston), we
immediately set it to 'yes' (use CSDs).
Otherwise, we wait for the decoration manager callback to indicate
whether we should use CSDs or not.
We draw the CSDs in a darker color when we're inactive.
Weston seems to be buggy with synchronized subsurfaces, so temporarily
reconfigure them to desynchronized surfaces.
This is needed to handle pointer motion and button events correctly,
since mouse actions in e.g. CSD surfaces are very different from mouse
actions in the main window.
In unhook, add the generated image to a list of finished sixel images,
along with positioning and size information.
When rendering, loop this list of images, and render the images (or
parts of) that are visible.
When scrolling, check if any part of the images cover the re-cycled
lines, and if so, remove the *entire* image from the list.
This means we have the following limitations:
* The renderer always renders the whole (visible area of) the
image(s). There are times when this isn't necessary - for example,
when the image is scrolled inside the visible area.
* It would be nice if we could crop the image when parts of it is
scrolled out.
This function reloads the font *if* the DPI has changed. To handle
user run-time adjusted font sizes, we record the number of adjustments
made.
Then, when re-loading the font, we first load the font as specified in
the configuration. Then, we re-apply the size adjustment using
font_size_adjust().
Note that this means we end up loading the fonts twice; first using
the default size (but with adjusted DPI), and then again with the
adjusted size. This can probably be improved upon.
The existing font code has been refactored to avoid code
duplication. For example, term_init() now calls
term_font_dpi_changed() to load the initial fonts, instead of directly
instantiating them.
Finally, the way we calculate the DPI to use has changed: instead of
using the highest DPI of all available outputs, we use the highest DPI
of the output's we're actually mapped on. If we're not mapped at all,
we use the globally highest DPI.
Doing it this way means we usually only have to load the fonts
once. Otherwise, we'd end up using the default DPI of 96 when the
terminal is first instantiated (since it's not mapped at that time).
On a single monitor system, we'll use the globally highest DPI at
first, before being mapped. Then when we get mapped, we re-load the
fonts using the highest mapped DPI. But since they'll be the same,
we can skip actually reloading the fonts.
To do text reflow, we only need to know if a line has been explicitly
linebreaked or not. If not, that means it wrapped, and that we
should *not* insert a linebreak when reflowing text.
When reflowing text, when reaching the end of a row in the old grid,
only insert a linebreak in the new grid if the old row had been
explicitly linebreaked.
Furthermore, when reflowing text and wrapping a row in the new grid,
mark the previous row as linebreaked if either the last cell was
(the last column in the last row) empty, or the current cell (the
first column in the new row) is empty. If both are non-empty, then we
assume a linewrap.
When cursor.lcf is set, that means the cursor column was *not*
incremented when we printed the last character. Thus, we should *not*
decrement the column before setting the linefeed bit.
To handle text reflow correctly when a line has a printable character
in the last column, but was still line breaked, we need to track the
fact that the slave inserted a line break here.
Otherwise, when the window width is increased, we'll end up pulling up
the next line, when we really should have inserted a line break.
When term_print() was implemented, it introduced a regression where
printing a character when the last cursor was in the last column on a
line would print the character in the wrong column.
This is because term_print() retrieved a pointer to the current
cell *before* line wrapping (and possibly inserting empty cells).
