Viewing file:  Scrolling.php (2.92 KB) -rw-r--r--
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<?php
namespace Laravel\Prompts\Concerns;
use Laravel\Prompts\Themes\Contracts\Scrolling as ScrollingRenderer;
trait Scrolling
{
/**
* The number of items to display before scrolling.
*/
public int $scroll;
/**
* The index of the highlighted option.
*/
public ?int $highlighted;
/**
* The index of the first visible option.
*/
public int $firstVisible = 0;
/**
* Initialize scrolling.
*/
protected function initializeScrolling(?int $highlighted = null): void
{
$this->highlighted = $highlighted;
$this->reduceScrollingToFitTerminal();
}
/**
* Reduce the scroll property to fit the terminal height.
*/
protected function reduceScrollingToFitTerminal(): void
{
$reservedLines = ($renderer = $this->getRenderer()) instanceof ScrollingRenderer ? $renderer->reservedLines() : 0;
$this->scroll = max(1, min($this->scroll, $this->terminal()->lines() - $reservedLines));
}
/**
* Highlight the given index.
*/
protected function highlight(?int $index): void
{
$this->highlighted = $index;
if ($this->highlighted === null) {
return;
}
if ($this->highlighted < $this->firstVisible) {
$this->firstVisible = $this->highlighted;
} elseif ($this->highlighted > $this->firstVisible + $this->scroll - 1) {
$this->firstVisible = $this->highlighted - $this->scroll + 1;
}
}
/**
* Highlight the previous entry, or wrap around to the last entry.
*/
protected function highlightPrevious(int $total, bool $allowNull = false): void
{
if ($total === 0) {
return;
}
if ($this->highlighted === null) {
$this->highlight($total - 1);
} elseif ($this->highlighted === 0) {
$this->highlight($allowNull ? null : ($total - 1));
} else {
$this->highlight($this->highlighted - 1);
}
}
/**
* Highlight the next entry, or wrap around to the first entry.
*/
protected function highlightNext(int $total, bool $allowNull = false): void
{
if ($total === 0) {
return;
}
if ($this->highlighted === $total - 1) {
$this->highlight($allowNull ? null : 0);
} else {
$this->highlight(($this->highlighted ?? -1) + 1);
}
}
/**
* Center the highlighted option.
*/
protected function scrollToHighlighted(int $total): void
{
if ($this->highlighted < $this->scroll) {
return;
}
$remaining = $total - $this->highlighted - 1;
$halfScroll = (int) floor($this->scroll / 2);
$endOffset = max(0, $halfScroll - $remaining);
if ($this->scroll % 2 === 0) {
$endOffset--;
}
$this->firstVisible = $this->highlighted - $halfScroll - $endOffset;
}
}
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