15.5.1 Problem
15.5.2 Solution
ImageString($image, 1, $x, $y, 'I love PHP Cookbook', $text_color);
ImageTTFText($image, $size, 0, $x, $y, $text_color, '/path/to/font.ttf',
'I love PHP Cookbook');
$font = ImagePSLoadFont('/path/to/font.pfb');
ImageString($image, 'I love PHP Cookbook', $font, $size,
$text_color, $background_color, $x, $y);
15.5.3 Discussion
Call ImageString( ) to place text onto the canvas.
Like other GD drawing functions, ImageString( ) needs many inputs: the
image to draw on, the font number, the x and y coordinates of the upper right
position of the first characters, the text string to display, and finally, the
color to use to draw the string.
With ImageString( ), there are five possible font
choices, from 1 to 5. Font number 1 is the smallest, while font 5 is the
largest, as shown in Figure
15-5. Anything above or below that range generates a size equivalent to the
closest legal number.
Figure 15-5. Built-in GD font sizes
To draw text
vertically instead of horizontally, use the function ImageStringUp( ) instead. Figure 15-6 shows the output.
ImageStringUp($image, 1, $x, $y, 'I love PHP Cookbook', $text_color);
Figure 15-6. Vertical text
To use TrueType fonts, you must also
install the FreeType library and configure PHP during
installation to use FreeType. The FreeType main site is http://www.freetype.org. To enable FreeType 1.x support, use
--with-ttf and for FreeType 2.x, pass --with-freetype-dir=DIR.
Like ImageString( ), ImageTTFText( ) prints a string to a canvas, but it takes slightly
different options and needs them in a different order:
ImageTTFText($image, $size, $angle, $x, $y, $text_color, '/path/to/font.ttf',
$text);
The $size argument is the font size in pixels;
$angle is an angle of rotation, in degrees going counter-clockwise; and
/path/to/font.ttf is the pathname to TrueType font file. Unlike
ImageString( ), ($x,$y) are the lower left coordinates of the
baseline for the first character. (The baseline is where the bottom of most
characters sit. Characters such as "g" and "j" extend below the baseline; "a"
and "z" sit on the baseline.)
PostScript Type
1 fonts require t1lib to be installed. It can be
downloaded from ftp://sunsite.unc.edu/pub/Linux/libs/graphics/ and
built into PHP using --with-t1lib.
Again, the syntax for printing text is similar but not the
same:
$font = ImagePSLoadFont('/path/to/font.pfb');
ImagePSText($image, $text, $font, $size, $text_color, $background_color, $x, $y);
ImagePSFreeFont($font);
First, PostScript font names can't be directly passed into
ImagePSText( ). Instead, they must be loaded
using ImagePSLoadFont( ). On success, the function returns a font resource usable
with ImagePSText( ). In addition, besides specifying a text color, you
also pass a background color to be used in antialiasing calculations. The
($x,$y) positioning is akin to the how the TrueType library does it.
Last, when you're done with a font, you can release it from memory by calling
ImagePSFreeFont( ).
Besides the mandatory arguments listed above, ImagePSText(
) also accepts four optional ones, in this order: space , tightness, angle, and
antialias_steps. You must include all four or none of the four (i.e.,
you can't pass one, two, or three of these arguments). The first controls the
size of a physical space (i.e., what's generated by hitting the space bar); the
second is the tightness of the distance between letters; the third is a rotation angle, in degrees, counter-clockwise; and the last
is an antialiasing value. This number must be either 4 or 16. For better
looking, but more computationally expensive graphics, use 16 instead of 4.
By default, space, tightness, and
angle are all 0. A positive number adds more space between words and
letters or rotates the graphic counterclockwise. A negative number kerns words and letters or rotates in the opposite
direction. The following example has the output shown in Figure 15-7:
// normal image
ImagePSText($image, $text, $font, $size, $black, $white, $x, $y,
0, 0, 0, 4);
// extra space between words
ImagePSText($image, $text, $font, $size, $black, $white, $x, $y + 30,
100, 0, 0, 4);
// extra space between letters
ImagePSText($image, $text, $font, $size, $black, $white, $x, $y + 60,
0, 100, 0, 4);
