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terminal: don't overwrite last column until eol

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Introduce a new _overflowed state variable to indicate whether the
horizontal boundary was reached already and to omit subsequent character
output.

This state is necessary to maintain a valid cursor position at all
times. The _overflowed attribute is reset once the cursor is moved into
a valid position again.

To harmonise the bounds checking for _cursor_pos modifications, the
`constrain()` method was added.

Fixes genodelabs/genode#4093

Also fixes a bug in `vpa()` and `vpb()` which moved the cursor
horizontally instead of vertically.
This commit is contained in:
Johannes Schlatow 2021-04-26 17:21:52 +02:00 committed by Norman Feske
parent 9cb8c37e3a
commit 1c49da8ce4
2 changed files with 32 additions and 22 deletions
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44
repos/os/include/terminal/char_cell_array_character_screen.h
View File

@ -94,6 +94,8 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
bool _wrap = false;
bool _overflowed = false;
enum { DEFAULT_COLOR_INDEX_BG = 0, DEFAULT_COLOR_INDEX = 7, DEFAULT_TAB_SIZE = 8 };
struct Cursor_guard
@ -116,8 +118,14 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
cs._char_cell_array.cursor(old_cursor_pos, true);
/* if cursor position changed, move cursor */
Terminal::Position &new_cursor_pos = cs._cursor_pos;
Terminal::Position &new_cursor_pos = cs._cursor_pos;
Terminal::Boundary const &boundary = cs._boundary;
if (old_cursor_pos != new_cursor_pos) {
cs._overflowed = (new_cursor_pos.x >= boundary.width);
/* make sure cursor pos is within range */
new_cursor_pos.constrain(boundary);
cs._char_cell_array.cursor(old_cursor_pos, false, true);
cs._char_cell_array.cursor(
new_cursor_pos, cs._cursor_visibility != CURSOR_INVISIBLE, true);
@ -179,8 +187,9 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
void cursor_pos(Terminal::Position pos)
{
_cursor_pos.x = Genode::min(_boundary.width - 1, pos.x);
_cursor_pos.y = Genode::min(_boundary.height - 1, pos.y);
Cursor_guard guard(*this);
_cursor_pos = pos;
}
void output(Terminal::Character c) override
@ -219,7 +228,7 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
}
default:
if (c.value > 0x1f) {
if (c.value > 0x1f && !_overflowed) {
Cursor_guard guard(*this);
_char_cell_array.set_cell(_cursor_pos.x, _cursor_pos.y,
Char_cell(c, Font_face::REGULAR,
@ -229,19 +238,17 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
break;
}
if (_cursor_pos.x >= _boundary.width) {
if (_wrap) {
_new_line();
} else {
_cursor_pos.x = _boundary.width-1;
}
if (_wrap && _overflowed) {
_new_line();
}
}
void cha(int pn) override
{
using namespace Genode;
Cursor_guard guard(*this);
_cursor_pos.x = Genode::max(pn - 1, _boundary.width);
_cursor_pos.x = pn - 1;
}
void civis() override
@ -280,7 +287,6 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
Cursor_guard guard(*this);
_cursor_pos.x -= dx;
_cursor_pos.x = Genode::max(0, _cursor_pos.x);
}
void cud(int dy) override
@ -288,7 +294,6 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
Cursor_guard guard(*this);
_cursor_pos.y += dy;
_cursor_pos.y = Genode::min(_boundary.height - 1, _cursor_pos.y);
}
void cuf(int dx) override
@ -296,7 +301,6 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
Cursor_guard guard(*this);
_cursor_pos.x += dx;
_cursor_pos.x = Genode::min(_boundary.width - 1, _cursor_pos.x);
}
void cup(int y, int x) override
@ -307,10 +311,6 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
x--;
y--;
using namespace Genode;
x = max(0, min(x, _boundary.width - 1));
y = max(0, min(y, _boundary.height - 1));
_cursor_pos = Terminal::Position(x, y);
}
@ -319,7 +319,6 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
Cursor_guard guard(*this);
_cursor_pos.y -= dy;
_cursor_pos.y = Genode::max(0, _cursor_pos.y);
}
void da(int) override { _missing(__func__); }
@ -429,7 +428,8 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
void ich(int pn) override
{
pn = Genode::min(_boundary.width - _cursor_pos.x, pn);
using namespace Genode;
pn = max(0, min(_boundary.width - _cursor_pos.x, pn));
for (int x = _boundary.width-1; _cursor_pos.x+pn < x; --x) {
_char_cell_array.set_cell(x, _cursor_pos.y,
@ -565,13 +565,13 @@ class Char_cell_array_character_screen : public Terminal::Character_screen
void vpa(int pn) override
{
Cursor_guard guard(*this);
_cursor_pos.x = pn;
_cursor_pos.y = pn - 1;
}
void vpb(int pn) override
{
Cursor_guard guard(*this);
_cursor_pos.x = Genode::min(0, _cursor_pos.x - pn);
_cursor_pos.y -= pn;
}
void decsc() override

10
repos/os/include/terminal/types.h
View File

@ -102,6 +102,16 @@ struct Terminal::Position
&& y >= 0 && y < boundary.height;
}
/**
* Make sure that position lies within specified boundaries
*/
void constrain(Boundary const &boundary)
{
using namespace Genode;
x = max(0, min(boundary.width - 1, x));
y = max(0, min(boundary.height - 1, y));
}
void print(Genode::Output &out) const {
Genode::print(out, y, ",", x); }
};