Specifications

{

// We have found a font size that will fit

// Now work out where to put it

$text_x = $width_image/2.0 - $width_text/2.0;

$text_y = $height_image/2.0 - $height_text/2.0 ;

if ($left_text < 0)

$text_x += abs($left_text); // add factor for left overhang

$above_line_text = abs($bbox[7]); // how far above the baseline?

$text_y += $above_line_text; // add baseline factor

$text_y -= 2; // adjustment factor for shape of our template

$white = ImageColorAllocate ($im, 255, 255, 255);

ImageTTFText ($im, $font_size, 0, $text_x, $text_y, $white, “arial.ttf”,

$button_text);

Header (“Content-type: image/png”);

ImagePng ($im);

}

ImageDestroy ($im);

This is one of the longest scripts we’ve looked at so far. Let’s step through it section by sec-

tion. We begin with some basic error checking, and then set up the canvas on which we’re

going to work.

Setting Up the Base Canvas

In Listing 19.2, rather than starting from scratch, we will start with an existing image for the

button. We have a choice of three colors in the basic button: red (red-button.png), green

(green-button.png), and blue (blue-button.png).

The user’s chosen color is stored in the $color variable from the form.

We begin by setting up a new image identifier based on the appropriate button:

$im = imagecreatefrompng (“$color-button.png”);

Advanced PHP Techniques

ART IV

414

LISTING 19.2 Continued

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