Some programs use the alternative screen (vi, less, ...), whose
content is different of the main screen. If you select text in one of
the screen, you don't wait the box selection is painted in the other
screen, so it is necessary check if the selection was done in the same
screen we are going to paint. Before to this commit, you could do
something like:

	$ LESS="" ls | less
	(select some code)
	q

and selection box remains drawing in the main screen, but the content
of selection keeps text of the alternate screen.
---
 st.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

---
 st.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

When it is called DECSCNM all lines become dirty, because it is necessary
redraw all lines for getting the new colors. It is easy see the problem
running 'echo ^[[?5h'.

In order to get a correct flash when running tput flash is necessary wait
after DECSCNM, until the changes are displayed, because in other case the
switch between reverse on/reverse off will be too much fast and nothing will
happen.
---
 st.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

This is a theorical feature listed in http://st.suckless.org/goals. All the
input/output of the terminal will be written to a file, which can be very
useful for debugging, and also allow interconnect st to other process
through named pipes.
---
 st.1 |    6 ++++++
 st.c |   14 +++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

SM and RM can receive multiple parameters, but the code only was accepting
only one. This patch join the code of set and reset modes (SM and RM) in a
common function and uses a loop which deals with all the arguments of the
sequence. This patch improves xterm and vt100 compability.
---
 st.c |  180 ++++++++++++++++++++++++++++--------------------------------------
 1 file changed, 76 insertions(+), 104 deletions(-)

This will really be needed when there is a full 256 color support.

This sequence performs "Cursor Forward Tabulation <n> tab stops", which
although is not present in vt100 or vt102, xterm accepts it.
---
 st.c |    5 +++++
 1 file changed, 5 insertions(+)

This sequence clears tab stops in the terminal. If the argument is not present
or is zero, then removes the tab stop of the current horizontal position. If
the argument is 3 then removes all the tab stops of the terminal. It was
necessary modify the terminfo entry tbc, because it has \E[2g instead of the
correct \E[3g.

Signed-off-by: Roberto E. Vargas Caballero <k0ga@shike2.com>
---
 st.c    |   12 ++++++++++++
 st.info |    2 +-
 2 files changed, 13 insertions(+), 1 deletion(-)

This sequence adds a new tab stop in the current horizontal position. This
means that tputtab must be look for the next tab stop in the tabs array
instead of using a hard coded value offset. Also, CHT sequence XXX message
is removed because it is not a vt10x sequence (as far as I know it is a
vt50x sequence), and it is not implemented by linux virtual terminal neither
by xterm.

Signed-off-by: Roberto E. Vargas Caballero <k0ga@shike2.com>
---
 st.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Tabs stop are simulated in st using a fixed size of 8, always, without be
worried about sequences changing the tab stops. A user can put a tab stop in
each horizontal position of the screen, so we need at least one flag for
each column of the screen. In the same way as dirty flags is used for the
rows, it is used a bool dinamic array.

Signed-off-by: Roberto E. Vargas Caballero <k0ga@shike2.com>
---
 st.c |   22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

* add a timeout value (SELECT_TIMEOUT) of 20ms in the select() call
* wait at least 20ms (DRAW_TIMEOUT) between draw() calls
* only copy dirty lines from the buffer to the screen

what draw() does:
* clears dirty lines in the buffer
* draws the longest same-attributes string of each
  dirty line to the buffer with multiple xdraws() call
* copies the current dirty line from buffer to the screen with a single
  xcopy() call

this changeset makes st run ~10x faster.