PHP: color hyperlink before create image

Question

I am taking an xml feed and creating an image from the text. What I would like to do it color the link text a different color than the regular text. I am looping through the text to find the link, but cannot figure out how to color that text.

Answer 1

imagetttftext() can only draw in a single color. You can't change it, or embed html-ish color codes, to dynamically change the text color. You'll have to split your text into multiple chunks, each drawn with a single color.

This means you'll have to calculate where each string chunk starts/stops using imagettfbbox() and adjust your coordinates in imagetttftext() accordingly.

comment followup:

Ok, so individual tag contents, with links being different colors. First step will be to pre-process the string and split it up along link boundaries, so you end up with a series of "text / link / text / link / text" chunks. After that, it's just a loop:

$start_x = 5;
$start_y = 20; // initial x/y coords of text
$fontsize = 14;
$font = 'font.ttf';
$angle = 0;

$black = imagecolorallocate($im, 0, 0, 0);
$linkcolor = imagecolorallocate($im, ?, ? ,?);

foreach ($string_chunks as $chunk) {
   // get coordinates of bounding box containing text
   $coords = imagegettfbbox($fontsize, $angle, $font, $chunk);

   $end_x = $coords[4]; // as per imagetttfbbox() doc page
   $end_y = $coords[5]; // x,y coords of top right corner of bounding box

   // figure out which color to draw in
   $color_to_draw = is_link($chunk) ? $linkcolor : $black; 

   // draw the text chunk
   imagettftext($im, $fontsize, $angle, $start_x, $start_y, $color_to_draw, $font, $chunk);

   // adjust starting coordinates to the END of the just-drawn text
   $start_x += $end_x;
   $start_y += $end_y;
}

You might need to adjust the coordinates as you go, if there isn't enough space between each chunk of text, or put a space into the string before you get its bounding box.

Answer 2

I know there's imagefontwidth() and imagefontheight() to get the height and width of a character of a font. However, that only works with built-in fonts or fonts loaded with imageloadfont(), which I don't think support TTF files. But if you used this, it would be fairly easy to calculate the coordinates of each chunk.

For instance:

<?php
// Image:
$image = imagecreatetruecolor(200, 200);

// First built-in font:
$font = 1;

// X and Y coordinates of the 5th character in the 7th row:
$x = imagefontwidth($font) * 4;
$y = imagefontheight($font) * 6;

// Put character onto image, with white color:
imagestring($image, $font, $x, $y, 'H', 0xffffff);
?>

(note that even though I used 0xffffff as a color in my code, it's recommended to use imagecolorallocate() instead whenever possible)