Page 571 - Beginning PHP 5.3

Chapter 17: Generating Images with PHP

Next the script sets up a for loop to iterate through each of the five built-in system fonts:
for ( $i = 1; $i <= 5; $i++ ) {
Within the loop, the text is drawn using the system font with an index of $i. The text is positioned 5
pixels from the left edge of the image. The $yOffset variable positions it vertically in the image.

imagestring( $textImage, $i, 5, $yOffset, “This is system font $i”, $black );
Next, $yOffset is increased by the height of the current font to position the next line below the
current line. It uses the imagefontheight() function to return the height of a character in the font, in
pixels. (If you want to get the width of a character in a font, use the imagefontwidth() function.)

$yOffset += imagefontheight( $i );
After the loop, the script outputs the image and cleans up:

}

header( “Content-type: image/png” );
imagepng( $textImage );
imagedestroy( $textImage );
?>

Using TrueType Fonts

When drawing basic charts and graphs you may prefer to use the built - in system fonts because they are
nonproportional fonts — all of the character widths are the same — so it makes layout and positioning
easier. However, if you ’ d like your text to look more elegant, you probably want to use a TrueType font.
These fonts offer a lot more versatility — not only can you control what your text looks like by choosing
from a wide range of available fonts, but you can also specify the size of the text and an angle at
which to draw it.

The preferred function to draw TrueType text is imagefttext() , which uses the FreeType 2 library. The
function takes the following arguments, in order:

❑ The image resource containing the image to write the text on
❑ The font size in points
❑ The angle at which to rotate the text, in degrees. Zero degrees is the three o ’ clock position,
90 degrees is the twelve o ’ clock position, and so on. A value of zero produces standard left - to -
right text. (Notice that, unlike the corresponding imagearc() parameter, this angle works in a
counterclockwise direction rather than clockwise.)
❑ The x and y position where you want the text to start. That ’ s the bottom - left corner of the
bounding box around the text. This is different from the imagestring() function, where the
coordinates represent the top - left corner of the bounding box

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