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Unit 11: Graphics

The $size argument is the font size in pixels; $angle is an angle of rotation, in degrees going Notes
counter-clockwise; and /path/to/font.ttf is the pathname to TrueType font file. Unlike
ImageString( ), ($x,$y) are the lower left coordinates of the baseline for the first character. (The
baseline is where the bottom of most characters sits. Characters such as “g” and “j” extend below
the baseline; “a” and “z” sit on the baseline.)
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 cannot 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 colour, you also pass a background
colour to be used in antialiasing calculations. The ($x,$y) positioning is akin to the how the
TrueType library does it. Last, when you are 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, andantialias_steps. You must include all four or none of
the four (i.e., you cannot 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 11.9:
// 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);

Figure 11.9: Words with Extra Space and Tightness

My India

My India

My India

11.6 Dynamically Generated Buttons

You want to create an image based on a existing image template and dynamic data (typically
text). For instance, you want to create a hit counter.

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