我正在尝试为数据库表播种映射点，映射点反映jpg映射中的每个点。该代码是对3x7小图像的测试，但该应用程序适用于更大的地图，其中地图点信息将与每个点关联并存储在表中。map_terain字段表示给定坐标的颜色十六进制值。但正是相关的x，y值出了问题。
我最终得到了表中map_point_x=7和map_point_y=3的每一行。map_trrain字段的值正确。
这是怎么误入歧途的？
$image_filespec = '../test.jpg';
$map_id = 1;
include_once '../includes/functions.php';
function heximagecolorat($image, $x, $y, $sharp_prefix = TRUE) {
$rgb = imagecolorat($image, $x, $y);
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
If ($sharp_prefix == TRUE) {
$hex = "#";
} else {
$hex = "";
}
$hex .= str_pad(dechex($r), 2, "0", STR_PAD_LEFT);
$hex .= str_pad(dechex($g), 2, "0", STR_PAD_LEFT);
$hex .= str_pad(dechex($b), 2, "0", STR_PAD_LEFT);
return $hex; // returns the hex value including the number sign (#)
}
if ($image_filespec == 'nnn.jpg' ){
echo 'you need to edit teh php file to make this work and alter $image_filespec as appropriate';
return;
}
//$result = query_db('SELECT * FROM users');
//
//while($row = $result->fetch()){
// echo $row['uID'] . " - " . $row['uUsername'] . "<br/>";
//}
$image = imagecreatefromjpeg($image_filespec); // imagecreatefromjpeg/png/
$width = imagesx($image);
$height = imagesy($image);
$colors = array();
for ($y = 0; $y < $height; $y++) {
for ($x = 0; $x < $width; $x++) {
$colors[] = heximagecolorat($image, $x, $y, $sharp_prefix=FALSE) ;
}
}
// connect and insert arrya to database $row in this context is talking about table row as opposed to row from the original image
$dbh = db_connect();
$query = "INSERT INTO map_points ( map_id, map_point_x, map_point_y, map_terrain ) VALUES "; //Prequery
$qPart = array_fill(0, count($colors), "( ?, ?, ?, ?)");
$query .= implode(",",$qPart);
$stmt = $dbh -> prepare($query);
$i = 1;
$point=0;
for ($y = 0; $y < $height; $y++) {
for ($x = 0; $x < $width; $x++) { //bind the values one by one
$stmt -> bindParam($i++, $map_id);
$stmt -> bindParam($i++, $x);
$stmt -> bindParam($i++, $y);
$stmt -> bindParam($i++, $colors[$point]);
$point += 1;
}
}
$temp=$stmt;
$stmt -> execute(); //execute
我认为问题在于PDOStatement::bindParam()的使用：它在查询执行时绑定变量（如$x、$y…）的值。这将是循环之后的最终值，即您的示例中的3和7。
请改用PDOStatement::bindValue()。
此外，如果为每个点执行语句，而不是使用行数尽可能多的元组，则可能更容易阅读和维护代码。换句话说，使用多个INSERT INTO map_points(map_id, map_point_x, map_point_y, map_terrain) VALUES (?, ?, ?, ?)而不是一个INSERT INTO map_points(map_id, map_point_x, map_point_y, map_terrain) VALUES (?, ?, ?, ?), (?, ?, ?, ?), ...。多元组具有更好的性能，但通过将INSERT语句封装在事务中可以达到类似的性能。
$dbh = db_connect();
$stmt = $dbh->prepare('INSERT INTO map_points (map_id, map_point_x, map_point_y, map_terrain) VALUES (?, ?, ?, ?)');
$y = 0;
$x = 0;
$stmt->bindValue(1, $map_id);
$stmt->bindParam(2, $x);
$stmt->bindParam(3, $y);
$dbh->beginTransaction();
for (; $y < $height; $y++) {
for (; $x < $width; $x++) {
$stmt->bindValue(4, heximagecolorat($image, $x, $y, $sharp_prefix=FALSE));
$stmt->execute();
}
}
$dbh->commit();