ghostty/website/app/vt/ri/page.mdx
2023-10-10 15:15:53 -07:00

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import VTSequence from "@/components/VTSequence";
# Reverse Index (RI)
<VTSequence sequence={["ESC", "M"]} />
Move the cursor up one cell, scrolling if necessary.
This sequence does not unset the pending wrap state.
If the cursor is exactly on the [top margin](/vt/decstbm) and is within
[left and right margins](/vt/decslrm), invoke [scroll down (SD)](/vt/sd)
with `n = 1`. The operation is complete.
Otherwise, scrolling isn't necessary. Perform a
[cursor up](/vt/cuu) operation with `n = 1`.
## Validation
### RI V-1: No Scroll Region, Top of Screen
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[1;1H" # move to top-left
printf "\033M" # reverse index
printf "X"
```
```
|Xc________|
|A_________|
|B_________|
|C_________|
```
### RI V-2: No Scroll Region, Not Top of Screen
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;1H"
printf "\033M" # reverse index
printf "X"
```
```
|Xc________|
|B_________|
|C_________|
```
### RI V-3: Top/Bottom Scroll Region
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;3r" # scroll region
printf "\033[2;1H"
printf "\033M" # reverse index
```
```
|A_________|
|c_________|
|B_________|
```
### RI V-4: Outside of Top/Bottom Scroll Region
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;3r" # scroll region
printf "\033[1;1H"
printf "\033M" # reverse index
```
```
|A_________|
|B_________|
|C_________|
```
### RI V-5: Left/Right Scroll Region
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[?69h" # enable left/right margins
printf "\033[2;3s" # scroll region left/right
printf "\033[1;2H"
printf "\033M"
```
```
|A_________|
|DBC_______|
|GEF_______|
|_HI_______|
```
### RI V-6: Outside Left/Right Scroll Region
```bash
printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[?69h" # enable left/right margins
printf "\033[2;3s" # scroll region left/right
printf "\033[2;1H"
printf "\033M"
```
```
|ABC_______|
|DEF_______|
|GHI_______|
```
Cursor on the `A`.