Programming PHP, 3rd Edition

Images with Text

Often it is necessary to add text to images. GD has built-in fonts for this purpose. Example 9-5 adds some text to our black square image.

Example 9-5. Adding text to an image

<?php
$image = imagecreate(200, 200);
$white = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
$black = imagecolorallocate($image, 0x00, 0x00, 0x00);

imagefilledrectangle($image, 50, 50, 150, 150, $black);
imagestring($image, 5, 50, 160, "A Black Box", $black);

header("Content-Type: image/png");
imagepng($image);

Figure 9-3 shows the output of Example 9-5.

Figure 9-3. The black box image with added text

The imagestring() function adds text to an image. Specify the top-left point of the text, as well as the color and the font (by GD font identifier) to use:

imagestring(image, font_id, x, y, text, color);

Fonts

GD identifies fonts by an ID. Five fonts are built-in, and you can load additional fonts through the imageloadfont() function. The five built-in fonts are shown in Figure 9-4.

Figure 9-4. Native GD fonts

The code used to show you these fonts follows:

<?php
$image = imagecreate(200, 200);
$white = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
$black = imagecolorallocate($image, 0x00, 0x00, 0x00);

imagestring($image, 1, 10, 10, "Font 1: ABCDEfghij", $black);
imagestring($image, 2, 10, 30, "Font 2: ABCDEfghij" ...