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    imageftbbox

    (PHP 4 >= 4.0.7, PHP 5, PHP 7, PHP 8)

    imageftbbox — 通过 freetype2 使用字体给出文本的边界框

    说明

    imageftbbox(
        float $size,
        float $angle,
        string $font_filename,
        string $string,
        array $options = []
    ): array|false

    此函数计算并返回 FreeType 文本的边界框（以像素为单位）。

    注意:

    在 PHP 8.0.0 之前，imageftbbox() 是 imagettfbbox() 的扩展变体，它还支持 options。 自 PHP 8.0.0 起，imagettfbbox() 是 imageftbbox() 的别名。

    参数

    size

    字体的尺寸，单位：点（磅）。

    angle

    测量的 string 的角度（以度为单位）。

    font_filename

    TrueType 字体文件的名称（可以是 URL）。根据 PHP 使用的 GD 库的版本，可能会尝试搜索没有以“/”开头并会在末尾追加“.ttf”的文件名，并沿着库定义的字体路径搜索。

    string

    要测量的字符串。

    options

    options 可能的数组索引
    键 类型 含义
    linespacing float 定义绘制行距

    返回值

    imageftbbox() 返回包含 8 个元素的数组，代表构成文本边界框的四个点：

    0 左下角，X 坐标
    1 左下角，Y 坐标
    2 右下角，X 坐标
    3 右下角，Y 坐标
    4 右上角，X 坐标
    5 右上角， Y 坐标
    6 左上角，X 坐标
    7 左上角，Y 坐标

    无论 angle 如何，这些点都是相对于 text，因此“左上角”意味着在左上角水平地看到文本。

    失败时，返回 false。

    示例

    示例 #1 imageftbbox() 示例

    <?php
    // Create a 300x150 image
    $im = imagecreatetruecolor(300, 150);
    $black = imagecolorallocate($im, 0, 0, 0);
    $white = imagecolorallocate($im, 255, 255, 255);

    // Set the background to be white
    imagefilledrectangle($im, 0, 0, 299, 299, $white);

    // Path to our font file
    $font = './arial.ttf';

    // First we create our bounding box
    $bbox = imageftbbox(10, 0, $font, 'The PHP Documentation Group');

    // This is our cordinates for X and Y
    $x = $bbox[0] + (imagesx($im) / 2) - ($bbox[4] / 2) - 5;
    $y = $bbox[1] + (imagesy($im) / 2) - ($bbox[5] / 2) - 5;

    imagefttext($im, 10, 0, $x, $y, $black, $font, 'The PHP Documentation Group');

    // Output to browser
    header('Content-Type: image/png');

    imagepng($im);
    imagedestroy($im);
    ?>

    注释

    注意: 此函数仅在 PHP 编译时加入 freetype 支持时有效（--with-freetype-dir=DIR）。

    参见

    add a note add a note

    User Contributed Notes 8 notes

    up
    2
    fernando
    19 years ago
    imagettfbbox() returns an array with 8 elements representing four points making the bounding box of the text:

    0 lower left corner, X position
    1 lower left corner, Y position
    2 lower right corner, X position
    3 lower right corner, Y position
    4 upper right corner, X position
    5 upper right corner, Y position
    6 upper left corner, X position
    7 upper left corner, Y position

    The points are relative to the text regardless of the angle, so "upper left" means in the top left-hand corner seeing the text horizontally.
    up
    1
    phpimageftbbox at juggernaut dot com dot au
    22 years ago
    This function can be used to generate right-aligned text. Just work out how wide the text image is and position it accordingly. Example:

    $i_width  = 200;
    $i_height = 40;

    $string = "Hello World!";
    $pointsize = 10;
    $fontfile = "/usr/local/lib/ttf/Helve.ttf";

    $im = imagecreate($i_width, $i_height);
    $black = imagecolorallocate ($im, 0, 0, 0);
    $white = imagecolorallocate ($im, 255, 255, 255);

    $string_size = ImageFtBbox($pointsize, 0, $fontfile, $string, array("linespacing" => 1));
    $s_width  = $string_size[4];
    $s_height = $string_size[5];

    ImageFtText($im, $pointsize, 0, $i_width - $s_width - 1,  0 - $s_height, $white, $fontfile, $string, array("linespacing" => 1));

    Header ("Content-type: image/png");
    ImagePNG ($im);
    ImageDestroy ($im);
    up
    1
    sectionthirty1 at yahoo dot com
    20 years ago
    Here is a handy example I used to center "dynamic text" onto an image. 

    Ex. Say you want to center a clients IP Address onto a picture. 

    $ip=$_SERVER['REMOTE_ADDR'];   

    $details = imageftbbox($fontsize, 0, $font, $ip, array("linespacing" => 1));

    $xcoord = ($imgwidth - $details[4]) / 2;  // this will return the x coordinate centered to your specific image.  Make sure  you set $imgwidth to the width of the image you are using.     

    imagettftext($image, $fontsize, 0, $xcoord, $ycoord, $fontcolor, $font, $ip);
    up
    0
    theo v e -2
    19 years ago
    ah... the problem between imageftbbox() and imagefttext() lies in the mirroring of the y-axes.
    Below you see, for a font-size 16 the boudingboxes of "b", "p" and "bp":
    < b: w=9 h=15
    b(0,-1)
    b(9,-1)
    b(9,-16)
    b(0,-16)
    < p: w=9 h=16
    p(0,4)
    p(9,4)
    p(9,-12)
    p(0,-12)
    < bp: w=20 h=20
    bp(0,4)
    bp(20,4)
    bp(20,-16)
    bp(0,-16)
    If drawing "bp" using imagefttext() at y=0, the the top of "bp" indeed is at y=-16, and the bottom of "bp" at y=4. (Plus or minus a pixel here and there, because at y=0 there actually is a vissible pixel.)
    up
    -1
    pablocorezzola at gmail dot com
    7 years ago
    //EXAMPLE - Center text

    function newText($im, $size, $angle= 0, $x, $y, $color, $font, $text,$align = "left",$border=false,$width=0,$height=0){
       
        if($align == "center")
        {
            if ($border == true ){
               imagerectangle($im, $x, $y, $x +$width, $y + $height, $color);
            }
            $bbox = imageftbbox($size, 0, $font, $text);

            // Marcamos el ancho y alto
            $s_width  = $bbox[4];
            $s_height = $bbox[5]; 
           
            $y = $y + ($height-$s_height)/2;
            $x = $x + ($width-$s_width)/2;

        }
        
        imagettftext($im, $size, $angle, $x, $y, $color, $font, $text);
    }
    up
    -1
    Johan
    17 years ago
    For alignment i used this method:

    if($align == "center" || $align == "right")
        {
            $verticaltxtspace = $backwidth - (2 * $posx);       
            $spacepositions = imagettfbbox($size, $angle, "fonts/verdanaz.ttf", " ");        
            $spacepx = $spacepositions[4] - $spacepositions[0];       
           
            // Split text in lines
            $lines = split("[\r][\n]", $text);       
            for($count = 0; $count < count($lines); $count++)
            {
                $textpositions = imagettfbbox($size, $angle, "fonts/verdanaz.ttf", $lines[$count]);           
                $textpx = $textpositions[2] - $textpositions[0];
               
                if($align == "right")
                {
                    $spaces = ($verticaltxtspace - $textpx) / $spacepx;
                }
                else if($align == "center")
                {
                    $spaces = (($verticaltxtspace - $textpx)/2) / $spacepx;
                }
               
                // Add spaces
                $line = $lines[$count];
                for($i = 0; $i < $spaces; $i++)
                {
                    $line = " " . $line;
                }
                $lines[$count] = $line;
            }
           
            // Create new text of lines
            $text = "";
            for($count = 0; $count < count($lines); $count++)
            {
                $text .= $lines[$count] . "\r\n";
            }       
        }
       
           
        //    Draw the shadow text on de shadow
        imagettftext($background, $size, $angle, $posx, $posy, $textcolor, "fonts/verdanaz.ttf",  $text);
    up
    -2
    ta at NOSPAM dot magicsquare dot info
    22 years ago
    i've found a work around for this situation

    it seems that height is directly proportional to line spacing so you just have to apply the same factor to image height

    for example :

    $spacing = 0.7;
    $params = array("linespacing" => $spacing);

    $box = imageftbbox ($size, 0, $font, $text, $params);
    $tw=$box[4]-$box[0]; //image width
    $th=($box[1]-$box[5])*$spacing; //image height
    up
    -3
    groomed at users dot sf dot net
    20 years ago
    ImageFTBBox returns a bounding box, not metrics, as some (most?) of the notes above seem to assume. The 8 values it returns specify the 4 corners of this bounding box. So to properly determine the width and height of a string you need to do:

    $bbox = ImageFTBBox(...);
    $width = abs($bbox[0]) + abs($bbox[2]); // distance from left to right
    $height = abs($bbox[1]) + abs($bbox[5]); // distance from top to bottom
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