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(PHP 4, PHP 5)
imagepstext — Ausgabe eines Textes auf einem Bild unter Verwendung von Typ 1 PostScript-Fonts
Size wird in Pixel ausgedrückt.
Foreground ist die Text-Ausgabefarbe (Vordergrund). Background ist die Farbe, zu der ein Farbübergang versucht werden soll. Dabei wird kein Pixel mit der Farbe Background ausgegeben, so dass das Bild im Hintergrund keine festen Farben benötigt.
Die Koordinaten x und y definieren den Ursprung (bzw. den Referenz-Punkt) des ersten Zeichens (ungefähr die linke untere Ecke). Dies ist anders als bei der ImageString()-Funktion, wo x und y die obere linke Ecke des ersten Zeichens angeben. Lesen Sie in der Dokumentation zu PostScript und seines Maßsystems nach, falls Sie die Funktionsweise nicht verstehen.
Space ermöglicht Ihnen, die Standardbreite eines Leerzeichens zu verändern. Der angegebene Wert wird zum Standardwert hinzuaddiert und kann auch negativ sein.
Tightness ermöglicht die Kontrolle über die Breite des Zeichenzwischenräume. Der angegebene Wert wird zur normalen Zeichenbreite hinzuaddiert und kann auch negativ sein.
Angle wird in Grad angegeben und hat die entsprechende Drehung des Ausgabetextes zur Folge.
Antialias_steps erlaubt die Kontrolle über die Anzahl der Farben, mit der der Farbübergang vom Text zum Hintergrundbild vorgenommen werden soll. Möglich sind Werte von 4 bis 16. Der höhere Wert wird empfohlen bei Textgrößen kleiner als 20, wo der Effekt bei der Textqualität deutlich sichtbar ist. Bei größeren Werten als 20 werden 4 Farben empfohlen. Das ist weniger rechenintensiv.
Die Parameter space und tightness werden in 1/1000-stel der Breite des Buchstabens "m" (Einheit 'em') angegeben.
Die Parameter space, tightness, angle und antialias sind optional.
Diese Funktion gibt ein Array mit den folgenden Werten zurück:
| 0 | untere linke X-Koordinate |
| 1 | untere linke Y-Koordinate |
| 2 | obere rechte X-Koordinate |
| 3 | obere rechte Y-Koordinate |
Siehe auch imagepsbbox().
As of PHP 5.2.13 with bundled GD (2.0.34) antialiasing_steps mustn't be "4 to 16", but "4 or 16". Values from 5 to 15 result in a warning.
The documentation above is bad. It says $font:
"Can be 1, 2, 3, 4, 5 for built-in fonts in latin2 encoding (where higher numbers corresponding to larger fonts) or any of your own font identifiers registered with imageloadfont()."
But it can't. When I put in 1,2,3,4,5 I get
"Warning: imagepstext() expects parameter 3 to be resource, integer given"
I get the same thing when using imageloadfont() because imageloadfont() also returns an integer. The documentation should instead say:
"resource returned from imagepsloadfont()."
imagepstext() appears to be quite memory intensive and we had a problem where about 50% of the time the script would error. You need to make sure PHP has enough memory assigned to it - we had to increase PHP's allocation from 8MB to 16MB for a simple "hello world" example to work smoothly.
If the png header was commented out it would sometimes error with a message like:
Warning: imagepstext() [function.imagepstext]: T1Lib Error 11 or 14
and if the png header was there it would sometimes say:
The image [...] cannot be displayed, because it contains errors.
The coordinates given by x, y represent actually a starting point of the text baseline. They represent the lower left corner of the first character only in case that any part of the character doesn't lie below baseline (it works for "Hello" but for "Howdy" it does not - because of letter y). There may be some small differences according to the font and size chosen.
It is important so make shure that the "text" really is a string.
imagepstext ($im, $text, $font, $textsize, $black, $white, 10, 10);
won't work if $text is undefined, so PHP will quit with an error.
so always write it like this:
imagepstext ($im, "$text", $font, $textsize, $black, $white, 10, 10);
I found a way to let imagepstext understand 32-bit colors (RGBA) by replacing in gd.c:PHP_FUNCTION(imagepstext)
int _fg, _bg, x, y, size, space = 0, aa_steps = 4, width = 0;
with
unsigned int _fg, _bg, x, y, size, space = 0, aa_steps = 4, width = 0;
I made a function that makes it easy to align text to the right
of an image. Below you can find the code because for me it
works great. You can also use it to center text as well, if you
like to have that simply remove the -10 and split the result
of $imgwidth and $texwidth
function AlignRight($string, $font, $imgwidth, $fontsize) {
list($lx,$ly,$rx,$ry) = imagepsbbox($string,$font,$fontsize,0,0,0);
$textwidth = $rx - $lx;
$imw = ($imgwidth-10-$textwidth);
return $imw;
}
If you use fonts with special chars, remeber to read in the encoded file *.enc with imagepsencodefont ... etc. for Danish, Swedish, German.....
a note on kernnig:
t1lib tries to load a corresponding afm file in the directory of the font file.
it does this by replacing the extension (.PFB .pfb) with ".afm". note that this has to be a lowercase afm! usually windows-ps-fonts have file names in all-uppercase, so try renaming the *.AFM file to *.afm.
i also noticed that sometimes this gives an error -2. it seems like t1lib chokes on windows-linebreaks in the afm file.
try 'recode dos..lat1 fontfile.afm' and check again.
if it all works, combinations like "Ta" or "Te" should show the second letter slightly moved to the capital T (on normal fonts like Times anyway).
If you have a programming error in your code, using ImagePsText, sometimes t1lib crashes with an unrecoverable error. Because of this, httpd needs to be restarted.
This problem only occurs if there is a programming error, but can drive you crazy when debugging, if you don't know about it. By killing the parent process(httpd) you "reset" t1lib. When debugging, if you get an error then make a code change, restart httpd before testing it again. This will save hours of frustration. Make it a habit to just restart httpd after every error, and you will be much happier.
Also, to see debugging messages, (if you are rendering x's) comment the jpeg header, and the ImageJpeg statement. You will get beautiful error messages. When you get a blank page, your ImagePsText code is working correctly. Uncomment the Header() and ImageJpeg() and see what you have. You might be passing parameters that render a white image with no text, but the code is working!
Numeric t1lib error messages can be decoded using the t1lib_doc.pdf file that comes with t1lib. PHP simply relays these errors from t1lib to the page. Please don't ask the PHP people about these errors... t1lib has beautiful documentation.... use it: )
thx,
Neil
One other thing... variables. It is important to convert variables to the proper type before they hit this function. In this respect, ImageTtfText is easier to work with. IE, if you pass a font size from one page to the next, via GPC, it becomes a string type. Sooo... use IntVal() to convert it to an integer type that ImagePsText can digest. In addition you must convert HTML special characters or use chr() to represent special characters. ImagePsFont will not decode to represent a space, use Chr(32) or a space:
<?php
$fontsize=IntVal($fontsize);
$font=ImagePsLoadFont("fonts/IntR.pfb");
ImagePsText($im, $textstring, $font, $fontsize, $textcolor, $background, 0, $fontsize,'','','',16); //note antialias is set
ImagePsFreeFont($font);
?>
thx,
Neil
with a font included in t1lib:
<?PHP
Header ("Content-type: image/jpeg");
$im = ImageCreate (350, 45);
$black = ImageColorAllocate ($im, 0, 0, 0);
$white = ImageColorAllocate ($im, 255, 255, 255);
$font=ImagePsLoadFont("bchbi.pfb");
ImagePsText($im, "Testing... It worked!",
$font, 32, $white, $black, 32, 32);
ImagePsFreeFont($font);
ImageJpeg($im, "", 100);//for best quality... your mileage may vary
ImageDestroy ($im);
?>
Better than using freetype, but with freetype2, the difference is marginal. To flip backround and foreground colors, alternate the order of ImageColorAllocate statements.
If you get outlines (the antialiasing produces these) reverse the $black and $white color identifiers in the ImagePsText function.
Happy PostScripting!
thx,
Neil
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