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PicArt Cookbook

This page will illustrate some common effects, tricks and strategies to use PicArt-page and its PicArt-Script.

1. Writing Stand-alone Scripts
2. Sample Script
3. inside-border
4. Sample Script
5. fancy
6. ProgrammerHTML & PicArt
7. Metal Letters
8. On The Fly
9. Resources

First of all, how to write standalone scripts:

#!/usr/local/bin/pascript-wrapper

pascript-wrapper is a wrapper to call pascript properly. All command-line arguments will be pushed on the stack. Remember, all is stack oriented so they get them in the reversed order:

% ./test.pa "hello" a.jpg

The possible source might be:

#!/usr/local/bin/pascript-wrapper

printstack  # display the stack to see

xv          # display 2nd argument (the picture)

print       # print out 1st argument (last on the stack)

If the order of the arguments gets to complicate to write code so assign the args to some variables:

/pic exch def

/string exch def

or

/pic = ; /string = ;

both ways do exactly the same. Some programmers who know PostScript may feel more comfortable with exch def, those more coming from C or general procedural languages may prefere = ; way.

Also, the script does nothing unless you write it, the PicArt Script don't give anything out, ie. text or images, you must declare the writing of the image by yourself like:

... tojpeg(85,"my.jpeg");

... togif(255,"my.gif");

... toppm("my.ppm");

The ... indicate you created an image within the source already, three formats are supported, JPEG, GIF and PPM.

Again, since there are so many commands and its arguments, call

% pascript -man tojpeg

to get some info of it.

PicArt Cookbook 2. Sample Script: inside-border

#!/usr/local/bin/pascript-wrapper

"inside-border: [<filename>] <image>" 1 expect

/pic exch def

pic sizeof /h exch def /w exch def

w 10 add h 10 add 5 100 100 100 button

invert

.8 .8 .8 1. gamma

5 5 pic paste

stackdepth 2 lt

{ xv }

{ exch 75 exch tojpeg }

ifelse

Before I comment each line, let me say that this source code is written the 'stack' oriented way unlike the next example below "fancy".

1. The expect command is prompts when the script doesn't get at least 1 argument.
2. /pic exch makes the assigment
3. pic sizeof gives size of the picture
4. then add the args before button define the button, then invert make it go inside looking
5. gamma makes it a bit darker
6. then we paste to original pic into it
7. finally we check if the script was called with 1 or 2 command-line arguments, either create a JPEG or call xv to display it.

Usage:

% ./inside-border SampleImages/albuquerque.jpg

PicArt Cookbook 3. Sample Script: fancy

#!/usr/local/bin/pascript-wrapper

"fancy: <font> <size> <text>" 3 expect

/itxt = ;               # assign last arg <text>

setfontsize();          # set fontsize

setfont();              # set font family

setrgb(0,80,0);         # color dark green

/pic = border(show(itxt), 10,10,0,0,0,255)

# show create bitmap

# and put transparent border

# arround, required for smooth

smooth gamma(1,1,1,.1)  # smooth and put alpha gamma low

# (easy way to make bold)

;

pic sizeof /h = ; /w = ;

/pic1 = pic smooth gamma(1,1,1,.1)

map(255,255,0,0);    # recolor yellow

/pic2 = pic1 smooth(3) gamma(1,1,1,.01)

map(200,0,0,0);      # recolor red

pic                     # use it as base

paste(0,0,pic2);     # paste red

paste(0,0,pic1);     # paste yellow

paste(0,0,pic);      # and top-layer once again

xv                      # display it

As you see, this source code is written in style of function-calls, and the arguments are enclosed in () instead leading before the call.

Near /pic2 assigment there is a mix of it, sequential pipeing through several smooth and finally a gamma adjustment, before maping a new color to it and the assignment ends with <;>. Again, <;> is ignored at the end of the function ie. paste(0,0,pic2);, I just wrote it for likeness of writing C or Perl.

Use the script like:

./fancy 'Times-Bold' 40 'Hello'

PicArt Cookbook 4. ProgrammerHTML & PicArt

ProgrammerHTML is an extension of HTML which you are able to define new tags. Using this feature, as described in ProgrammerHTML Cookbook already, you can use following tag-definition:

<def name=pascript plugin=inline language=perl>

`mkdir phtml-pics` if(!(-d "phtml-pics"));

$arg{type} = 'jpeg' if(!$arg{type});

$arg{cols} = '240' if(!$arg{cols});

$options .= "align=$arg{align} " if($arg{align});

$options .= "hspace=$arg{hspace} " if($arg{hspace});

$options .= "vspace=$arg{vspace} " if($arg{vspace});

$options .= "border=$arg{border} " if($arg{border} ne '');

$rpath = $ENV{REVERSE_PATH};

$base = $ENV{SOURCE_FILENAME}; $base =~ s/\.phtml//; $base =~ s/\//_/g;

$fname = "phtml-pics/pascript-inline-$base-$ENV{'PLUGIN_CALLS'}";

while(<STDIN>) {

$buff .= $_;

}

$fname .= '.jpg', $buff .= " tojpeg(85,$fname);" if($arg{type} eq 'jpeg');

$fname .= '.gif', $buff .= " togif($arg{transp} $arg{cols},$fname);"

if($arg{type} eq 'gif');

`pascript -direct '$buff'`;

print "<img src=\"$rpath/$fname\" $options>";

</def>

To use the plugin, write the PicArt-Script code:

<pascript type=gif transp=0,0,0>

text.font(/Bajoran); text.size(50);

/img = border(text("STAR TREK"),2,2,0,0,0,255);

make(sizeof(img),0,0,0,0);

paste(0,0,map(img smooth(2) gamma(2,2,2,.2),255,0,0,0));

paste(0,0,map(img,blend(img,0,.5,0,1, linear, 250,250,0,0, 200,0,0,0)));

</pascript>

PicArt Cookbook 5. Metal Letters

In this case study a metal shader is implemented without any image-tile. First of all, we define how many colors we need to define a shade, for simplicity we just use two colors.

<pascript type=gif transp=0,0,0>

/col1 = {80 80 120 0};

/col2 = {245 245 255 0};

text.font(Times-Bold); text.size(50); text("Metal Letters");

/t = border(5,5,0,0,0,255);

make(sizeof(t),0,0,0,0);

/t0 = map(t,blend(t,0,.4,0,.8,bilinear,

col1 execstack,col2 execstack)

wavy.noise(1,.8) wavy(3,80));

paste(-2,-2,t0); paste(-1,-1,t0);

paste(1,1,t0); paste(2,2,t0);

paste(0,0,map(t,blend(t,0,.2,0,.8,bilinear,

col1 execstack,col2 execstack) ));

</pascript>

Hint: the execstack is used to expand the { } rgba colors. You may play with the wavy arguments to achieve smoother effects.

PicArt Cookbook 6. On The Fly

Often you need to draw exact things, which are cumbersome to start any drawing tools (like xpaint or GIMP), you can also use pascript for this:

% pascript -direct "background-html.jpg for(0,246,4,{ /i exch def \

draw.rgba(0,0,80,120) draw.line(0,i,1200,i);}); cut(0,0,1200,232); \

draw xv"

This will draw 58 horizontal lines unto a picture with vertical space of 4 pixels, which is this very background of this page. xv is used to display whereas it is manually stores as GIF.

PicArt Cookbook 7. Resources

PicArtScript Reference Reference Manual	PicArt Script Collection Collection of stand-alone & shaders	ProgrammerHTML Cookbook Further infos on ProgrammerHTML
ProgrammerHTML Plugins Collection of plugins

                                                                                                                                   

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