imageftbbox()
(PHP 4 >= 4.0.7, PHP 5, PHP 7)
给出一个使用 FreeType 2 字体的文本框
说明
imageftbbox(float $size,float $angle,string $fontfile,string $text[,array $extrainfo]): array
This function calculates and returns the bounding box in pixels for a FreeType text.
参数
- $size
字体的尺寸。根据 GD 的版本,为像素尺寸(GD1)或点(磅)尺寸(GD2)。
- $angle
Angle in degrees in which$textwill be measured.
- $fontfile
The name of the TrueType font file(can be a URL). Depending on which version of the GD library that PHP is using, it may attempt to search for files that do not begin with a leading '/' by appending '.ttf' to the filename and searching along a library-defined font path.
- $text
The string to be measured.
- $extrainfo
Possible array indexes for$extrainfo Key Type Meaning linespacing float Defines drawing linespacing
返回值
imageftbbox() 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 thetextregardless of the$angle, so "upper left" means in the top left-hand corner seeing the text horizontally.
范例
imageftbbox() example
<?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
Note:此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。
Note:此函数仅在PHP 编译时加入 freetype 支持时有效(--with-freetype-dir=DIR)。
更新日志
版本 | 说明 |
---|---|
4.3.5 | $extrainfowas made optional. |
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.
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);
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 ($im);
//EXAMPLE - Center text function newText($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); }
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.)
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
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($bbox[5]); // distance from top to bottom
For alignment i used this method: if($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);