Problems in writing text on an image

developer

02-27-2008, 10:34 AM

I am using a function that write text on image, the problem is that it sometimes do not center align text and sometimes some characters missed. I use the following logic in the function, i set no of pixels for one character and multiply it with the total no of characters and divide it with the width in pixels of an image, but it is not working accurate at sometime because, i set the character pixels myself if know some way how to get pixels of a character because some characters takes more pixels and some less i.e caps characters. the code is as follows plz suggest a solution

function writeOnImage($filePath, $title, $author, $subtitle, $title_R, $title_G, $title_B, $subtitle_R, $subtitle_G, $subtitle_B, $title_fontsize, $subtitle_fontsize, $author_R, $author_G, $title_B, $author_fontsize,$finalImage)
{
//$existingImage = substr($existingImage, 3);
$im = imagecreatetruecolor(90, 30);
$title_fontColor = imagecolorallocate($im, $title_R, $title_G, $title_B);
$subtitle_fontColor = imagecolorallocate($im, $subtitle_R, $subtitle_G, $subtitle_B);
$author_fontColor = imagecolorallocate($im, $author_R, $author_G, $author_B);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// Replace path by your own font path
$font = 'arial.ttf';
$im_bg = @imagecreatefromjpeg($filePath);
//imagejpeg($im,"New.jpeg", 100);
list($width, $height) = getimagesize($filePath);
$pixels_for_one_char = 16;
$available_pixels = (int) $width ;
//echo "ONE: ".pixels_for_one_char;
//echo " TITLE::". $title;
$title_length = strlen($title);
$pixels_for_whole_title = $title_length*$pixels_for_one_char;
if($pixels_for_whole_title > $available_pixels)
{
$no_of_lines = ceil($pixels_for_whole_title/$available_pixels);
}
else
{
$no_of_lines =1;
}
//echo "LINES".$no_of_lines ;
$y = 70;
$from=0;
$chars_in_one_line = round($available_pixels/$pixels_for_one_char);
$limit = $chars_in_one_line;
$white = imagecolorallocate($im_bg, 255, 255, 255);
$str = wordwrap($title,$chars_in_one_line,"#");
$title_in_lines = explode("#",$str);

for($i=0; $i<count($title_in_lines); $i++)
{
//echo "loop".$title_in_lines[$i];
//$text_to_write = substr($title,$from,$limit);
$total_pixels_for_title = strlen($title_in_lines[$i])*$pixels_for_one_char;
$xPosition = ( $available_pixels - $total_pixels_for_title)/2 ;
//$from = ($i+1)*$chars_in_one_line;
//$limit = $from + $chars_in_one_line;
imagettftext($im_bg, $title_fontsize, 0, $xPosition, $y, $title_fontColor, $font, $title_in_lines[$i]);
imagettftext($im_bg, $title_fontsize, 0, ($xPosition), $y-1, $title_fontColor, $font, $title_in_lines[$i]);
$y= $y+50;

}
////////////// write subtitle//////////////////////
$y = $y - 18;
$pixels_for_one_char = 8;
$available_pixels = (int) $width ;
//echo "ONE: ".pixels_for_one_char;
//echo " TITLE::". $title;
$title_length = strlen($subtitle);
$pixels_for_whole_title = $title_length*$pixels_for_one_char;
if($pixels_for_whole_title > $available_pixels)
{
$no_of_lines = ceil($pixels_for_whole_title/$available_pixels);
}
else
{
$no_of_lines =1;
}
//echo "LINES".$no_of_lines ;

$chars_in_one_line = round($available_pixels/$pixels_for_one_char);
$limit = $chars_in_one_line;
$white = imagecolorallocate($im_bg, 255, 255, 255);
$str = wordwrap($subtitle,$chars_in_one_line,"#");
$title_in_lines = explode("#",$str);

for($i=0; $i<count($title_in_lines); $i++)
{
//echo "loop".$title_in_lines[$i];
//$text_to_write = substr($title,$from,$limit);
$total_pixels_for_title = strlen($title_in_lines[$i])*$pixels_for_one_char;
$xPosition = ( $available_pixels - $total_pixels_for_title)/2 ;
//$from = ($i+1)*$chars_in_one_line;
//$limit = $from + $chars_in_one_line;
imagettftext($im_bg, $subtitle_fontsize, 0, $xPosition, $y, $subtitle_fontColor, $font, $title_in_lines[$i]);
imagettftext($im_bg, $subtitle_fontsize, 0, ($xPosition), $y-1, $subtitle_fontColor, $font, $title_in_lines[$i]);
$y= $y+50;

}

///////////////////////// write author/////////////
//$xPosition = (int) $width / 4;
$pixels_for_one_char = 16;
$available_pixels = (int) $width ;
$author_length = strlen($author);
$total_pixels_for_author = $author_length*$pixels_for_one_char;
$xPosition = ( $available_pixels - $total_pixels_for_author)/2 ;

$yPosition = $height - 10;
$path_parts = pathinfo($filePath);
//echo "<br> Extension".$path_parts['extension'];

imagettftext($im_bg, $author_fontsize, 0, $xPosition, $yPosition-89, $author_fontColor, $font, $author);
imagettftext($im_bg, $author_fontsize, 0, ($xPosition), ($yPosition - 90), $author_fontColor, $font, $author);

//header("Content-type: image/jpeg");
imagejpeg($im_bg, $finalImage, 100);
}// end write

rafiki

02-27-2008, 05:35 PM

Inigoesdr

02-27-2008, 07:27 PM

Here is an example of how to center the text by getting the bounding box of the text:
$text = 'Some Text to Center';
$color = imagecolorallocate($image, 255, 255, 255);
$font = 'arial.ttf';
$fontSize = 8;
$ret = imagettfbbox($fontSize, 0, $font, $text);
imagettftext($image, $fontSize, 0, ($imageWidth - $ret[4]) / 2, 12, $color, $font, $text);
You can get $imageWidth from imagex() (http://php.net/imagex) or getimagesize() (http://php.net/getimagesize) if you're creating the image object from a file. The 12 in imagettftext() is the vertical offset, so you'll probably want to change that.

developer

02-29-2008, 01:16 PM

Thankyou rafiki and Inigoesdr for the response, i am able to solve my problem.