PHP | imagickpixeliterator setIteratorFirstRow()函数

ImagickPixelIterator::setIteratorFirstRow()函数是PHP中的一个内置函数，用于将像素迭代器设置为第一个像素行。

句法：

bool ImagickPixelIterator::setIteratorFirstRow( void )

参数：此函数不接受任何参数。

返回值：此函数在成功时返回 TRUE。

下面的程序说明了PHP中的ImagickPixelIterator::setIteratorFirstRow()函数：

方案一：

getPixelIterator();
    
// Set the pixel iterator to 50
$pixelIterator->setIteratorRow(50);
   
// Get the current iterator row
echo "Current row is " . $pixelIterator->getIteratorRow();
   
// Set the iterator to first row
$pixelIterator->setIteratorFirstRow();
   
// Get the current iterator row
echo "
Current row is " . $pixelIterator->getIteratorRow();
?>

输出：

Current row is 50
Current row is 0

方案二：

getPixelIterator();
  
$pixelIterator->setIteratorRow(40);
   
// Get the current iterator row
$row = $pixelIterator->getCurrentIteratorRow();
echo "Colors of 61th and 62nd pixel from 40th row are:
";
print("Pixel 60:" . "
".print_r($row[60]->getColor(), true)."
");
print("Pixel 61:" . "
".print_r($row[61]->getColor(), true)."
");
  
// Set the iterator to first row
$pixelIterator->setIteratorFirstRow();
  
// Get the current iterator row
$row = $pixelIterator->getCurrentIteratorRow();
echo "First two colors of pixels from first row are:
";
print("Pixel 1:" . "
".print_r($row[0]->getColor(), true)."
");
print("Pixel 2:" . "
".print_r($row[1]->getColor(), true)."
");
?>

输出：

Colors of 61th and 62nd pixel from 40th row are:
Pixel 60:
Array
(
    [r] => 110
    [g] => 199
    [b] => 131
    [a] => 1
)
Pixel 61:
Array
(
    [r] => 23
    [g] => 165
    [b] => 57
    [a] => 1
)
First two colors of pixels from first row are:
Pixel 1:
Array
(
    [r] => 255
    [g] => 255
    [b] => 255
    [a] => 1
)
Pixel 2:
Array
(
    [r] => 255
    [g] => 255
    [b] => 255
    [a] => 1
)

参考： https://www. PHP.net/manual/en/imagickpixeliterator.setiteratorfirstrow。 PHP