Example 1. Translation of the coordinate system
<?php
function rectangle($ps) {
ps_moveto($ps, 0, 0);
ps_lineto($ps, 0, 50);
ps_lineto($ps, 50, 50);
ps_lineto($ps, 50, 0);
ps_lineto($ps, 0, 0);
ps_stroke($ps);
}
$ps = ps_new();
if (!ps_open_file($ps, "translate.ps")) {
print "Cannot open PostScript file\n";
exit;
}
ps_set_info($ps, "Creator", "translate.php");
ps_set_info($ps, "Author", "Uwe Steinmann");
ps_set_info($ps, "Title", "Translated example");
ps_set_info($ps, "BoundingBox", "0 0 596 842");
$psfont = ps_findfont($ps, "Helvetica", "", 0);
ps_begin_page($ps, 596, 842);
ps_set_text_pos($ps, 100, 100);
ps_translate($ps, 500, 750);
rectangle($ps);
ps_translate($ps, -500, -750);
ps_setfont($ps, $psfont, 8.0);
ps_show($ps, "Text at initial position");
ps_end_page($ps);
ps_begin_page($ps, 596, 842);
ps_set_text_pos($ps, 100, 100);
ps_save($ps);
ps_translate($ps, 500, 750);
rectangle($ps);
ps_restore($ps);
ps_setfont($ps, $psfont, 8.0);
ps_show($ps, "Text at initial position");
ps_end_page($ps);
ps_delete($ps);
?>
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The above example demonstrates two possible ways to place
a graphic (in this case just a rectangle) at any position on the page,
while the graphic itself uses its own coordinate system. The trick is
to change the origin of the current coordinate system before drawing
the rectangle. The translation has to undone after the graphic has
been drawn.
On the second page a slightly different and more elegant approach is
applied. Instead of undoing the translation with a second call of
ps_translate() the graphics context is saved before
modifying the coordinate system and restored after drawing the rectangle.
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