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Digg imageftbbox
Give the bounding box of a text using fonts via freetype2
(PHP 4 >= 4.0.7, PHP 5)
Code Examples / Notes » imageftbboxphpimageftbbox
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); fernando
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. groomed
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 theo v e
IF we accept the idea that a bouding box is returned then: $bbox= imageftbbox ( $size, $angle, $font, $txt); $width = abs($bbox[4] - $bbox[0]); $height = abs($bbox[1] - $bbox[5]); may be a better kind of math. But it depends... You may want to subtract yet another '1' from both the width and the height. But try drawing a "p" and next try a "d". Their bounding boxes differ 1 px in height. Of course the respective boxes, by imagefttext(), are placed at a different y coordinate. I noticed that if a "p" or a "b" is drawn at (0, 30) the first character of the string actually starts on, fills, the third horizontal pixel. Also: if your image is only 30 pixels in heigth, drawing text at (0, 30) means that the bottoms parts of "p", "q", "y" and alike are somewhere else... ta
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 brian
I noticed that PHP's True Type functions do not allow you to create text blocks with multiple lines that automatically adjust for alignment. I wrote a function that will allow you to generate images with multiple lines, control the alignment, and handle rotation. I hope it helps someone. There was too much code to paste on this message post so you can grab it off of my webserver. I also created an example page so that you can see the code in action. Example Page: http://www.PrintsMadeEasy.com/code_samples/php/text_generation.php Download the Text file: http://www.PrintsMadeEasy.com /code_samples/php/text_generation.txt sectionthirty1
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); theo v e -2
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.) |
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