Pike module:

image

Pontus Hagland law@infovav.se
Per Hedbor per@infovav.se
David Kågedal kg@infovav.se
This package adds two Pike progams:

methods in precompiled/image:

 Methods resulting in a new object:
object clone( [int xsize,int ysize [,int r,int g,int b] ] );

object copy( [int x1,int y1,int x2,int y2 [,int r,int g,int b] ] );
object autocrop( [int border_width [,int left,int right,int top,int bottom] [,int r,int g,int b] ] );

object gray();
object color(int r,int g,int b);
object invert();

object mirrorx(void);
object mirrory(void);
object rotate_cw(void);
object rotate_ccw(void);
object threshold([int r,int g,int b]);
object apply_matrix(array(array(int)) matrix,[int r,int g,int b[,int div]]);

object scale(float factor);
object scale(float factorx,float factory);
object scale(int newx|0,int newy|0);

Methods operating on current object:
string toppm(void);
string|object fromppm(string s);
string togif( [int r,inr g,int b] );

object paste(object img [,int x,int y])
object paste_alpha(object img, int alpha [,int x, int y]);
object paste_mask(object img, object alpha_mask [,int x,int y]);

object setcolor(int r,int g,int b);
object setpixel(int x,int y [,int r,int g,int b] );
object line(int x1,int y1,int x2,int y2 [,int r,int g,int b] );
object box(int x1,int y1,int x2,int y2 [,int r,int g,int b] );
object circle(int x,int y,int radx,int rady [,int r,int b,int g] );
object tuned_box(int x1,int y1,int x2,int y2,array(array(int)) corner_rgb);

Information giving methods:
object xsize();
object ysize();

METHOD
object apply_matrix(array(array(int)) matrix,[int r,int g,int b[,int div]]);
DESCRIPTION
This method applies a matrix on the image. Each surrounding pixel is multiplied with the value of the matrix element in that point, these values are added and divided by the total sum of the matrix values (and the div argument) and stored on the pixel (eventually added to the r,g,b argument given as 'mean' value).

It is possible to use a matrix of RGB groups (ie an array of three integers) instead of the simple values, this making it possible to apply different matrices on red, green and blue channel.

RETURN VALUE
the new object
EXAMPLE
A 'blur' operation (3x3, gaussian): 
blurred=image->apply_matrix( ({ ({1,2,1}), ({2,3,2}), ({1,2,1}) }) );

A 'Emboss' operation (3x3): 

emossed=image->apply_matrix(({ ({0,1,8}), ({-1,0,1}), ({-8,-1,0}) }), 128,128,128, 15 );
Here i'm using 128,128,128 (gray) as a mean, because i get negative values.
A division by 15 is good to give 'normal' edges.
BUGS
not known
METHOD
object autocrop( [int border_width [,int left,int right,int top,int bottom] [,int r,int g,int b] ] );
DESCRIPTION
Crops away unneccesary borders from the image. The border argument is to define the new thickness of the surrounding border and the r,g,b is the newly created border color.

The left, right, ... arguments is used to tell which edges should be autocropped.

RETURN VALUE
the new object
EXAMPLE 
cropped=image->autocrop();
BUGS
now known
METHOD
object box(int x1,int y1,int x2,int y2 [,int r,int g,int b] );
DESCRIPTION
Draw a box of the default or specified color.
RETURN VALUE
the image object
EXAMPLE
BUGS
METHOD
object circle(int x,int y,int radx,int rady [,int r,int b,int g] );
DESCRIPTION
Draw a circle. The coordinates given are the center of the image and the radius in x (horisontal) and y (vertical), this making it possible to draw an ellipse too. :-)
RETURN VALUE
the image object
EXAMPLE
BUGS
METHOD
object clone( [int xsize,int ysize [,int r,int g,int b] ] );
DESCRIPTION
make a new object and return it
RETURN VALUE
the new object
SEE ALSO
copy, clear
EXAMPLE
BUGS
METHOD
object color(int r,int g,int b);
DESCRIPTION
Apply a color filter on the image.
RETURN VALUE
the new object
EXAMPLE 
cyan=image->color(64,255,192);
This function is most usable on a image that has been grayed first.
BUGS
METHOD
object copy( [int x1,int y1,int x2,int y2 [,int r,int g,int b] ] );
DESCRIPTION
Make a copy, or a copy of a part of the image. It is possible to copy more then the image, to extend the image, this area is filled with the current (or given) color.
RETURN VALUE
the new image object
EXAMPLE 
copy=image->copy();

copy=image->copy(-10,-10,image->xsize()+9,image->ysize()+9);
BUGS
METHOD
string|object fromppm(string s);
DESCRIPTION
Import a ppm image.
RETURN VALUE
0 (object) upon success, else the error message (string).
EXAMPLE 
image=clone( (program)"precompiled/image" );
image->fromppm(read_bytes("my_image.ppm",0,10000000));
BUGS
METHOD
object gray([int r,int g,int b]);
DESCRIPTION
Make this image gray (each r,g,b gets the same value).
If a color is given, that specifies the amount of r, g, and b that is used to compute the gray level. Default is 87,127,41.
RETURN VALUE
the new object
EXAMPLE 
gray=image->gray()
BUGS
METHOD
object invert();
DESCRIPTION
Invert the image.
RETURN VALUE
the new object
EXAMPLE 
inverted=image->invert()
BUGS
METHOD
object line(int x1,int y1,int x2,int y2 [,int r,int g,int b] );
DESCRIPTION
Draw a line from x1,y1 to x2,y2.
RETURN VALUE
the image object
EXAMPLE 
image->line(17,100,42,1000);
BUGS
METHOD
object mirrorx(void);
object mirrory(void);
DESCRIPTION
Mirrors the image, horisontally or vertically.
RETURN VALUE
the new image object
EXAMPLE 
mirrored=image->mirrorx();
BUGS
METHOD
object rotate_cw(void);
object rotate_ccw(void);
DESCRIPTION
Rotate the image, clockwise or counterclockwise, 90 degrees.
This operation is very fast compared to rotating any angle.
RETURN VALUE
the new image object
EXAMPLE 
snurr=image->rotate_cw();
BUGS
METHOD
object paste(object img [,int x,int y])
object paste_alpha(object img, int alpha [,int x, int y]);
object paste_mask(object img, object alpha_mask [,int x,int y]);
DESCRIPTION
Paste an image on this image. Use the specified alpha channel value or the second specified image as an alpha channel.
The first argument is the image that will be pasted.
RETURN VALUE
the image object this function doesn't return anything
EXAMPLE 
image->paste(other_smaller_image,17,42);

image->paste_mask(other_image,alpha_channel_image);
Paste a dog on a landscape:
landscape->paste(dog,dog_alpha_channel,xpos,ypos);
Write some text:
text=font->write("some text");
foreground=text->clear(255,255,255); // white
background->paste(foreground,text,xpos,ypos);
BUGS
METHOD
object scale(float factor); (1
object scale(float factorx,float factory); (2
object scale(int newx|0,int newy|0); (3
DESCRIPTION
Scale this image.
  1. scale the image with a (line scale) factor
  2. scale the image with different factors on x and y
  3. scale the image to a new size
    with newx or newy set to zero, just scale the image to fit the x or y size and keep proportions.
RETURN VALUE
the new object this function doesn't return anything
EXAMPLE
BUGS
METHOD
object setcolor(int r,int g,int b);
DESCRIPTION
set the default color used for drawing lines, etc
RETURN VALUE
the image object
EXAMPLE
BUGS
METHOD
object setpixel(int x,int y [,int r,int g,int b] );
DESCRIPTION
set the color of the specified pixel
RETURN VALUE
the image object
EXAMPLE
BUGS
METHOD
object threshold([int r,int g,int b]);
DESCRIPTION
make image black-and-white using the given value as the threshold
RETURN VALUE
the new object
EXAMPLE
BUGS
METHOD
string togif( [int r,inr g,int b] );
DESCRIPTION
export gif
if the color are given, this is the transparent color
RETURN VALUE
the gifimage as a string
EXAMPLE
BUGS
METHOD
string toppm(object);
DESCRIPTION
export ppm
RETURN VALUE
the ppm image as a string
EXAMPLE
BUGS
METHOD
object tuned_box(int x1,int y1,int x2,int y2,array(array(int)) corner_rgb);
DESCRIPTION
draw a box with the specified corner colours, and shade the colors between
RETURN VALUE
the image object
EXAMPLE 
image->tuned_box(0,0,img->xsize()-1,img->ysize()-1,
	        ({({0,0,64}),({16,16,128}),
                  ({16,16,128}),({192,160,128})}));
BUGS
METHOD
object xsize();
object ysize();
DESCRIPTION
RETURN VALUE
Gives the x- or the y-size (horisontal or vertical size) of the image.
EXAMPLE
BUGS

methods in precompiled/font:

 int load(string file_name);
object write(string line, ...);
METHOD
int load(string file_name);
DESCRIPTION
load this font object with the font from the specified file
RETURN VALUE
true on success
EXAMPLE
BUGS
METHOD
object write(string line, ...);
DESCRIPTION
make a new image object from the specified text, each argument representing a line
RETURN VALUE
the new image object
EXAMPLE
BUGS

Example program:

(pike) 

int main()
{
   object txt,o,shad,font;
   int i;

   txt = 
      (font=clone((program)"/precompiled/font"))
      ->load("/usr/local/lib/pike/fonts/64/helvetica_bold_r")
      ->write("The Image Module")
      ->autocrop(20,0,0,0);

   shad=txt->mirrory()->scale(1.0,0.3)->color(64,64,64);

   o=clone((program)"/precompiled/image",
	   txt->xsize(),txt->ysize(), 0,0,100)
        ->tuned_box(0,0,txt->xsize(),txt->ysize(),
		    ({({0,0,0}),({0,0,0}),
		      ({0,0,255}),({128,128,0})}));
   
   o->setcolor(255,255,255,200);
   for (i=0; i<30; i++)
      if (random(2))
	 o->line(random(o->xsize()),o->ysize()-10-random(20+i*3),
		 o->xsize()-1-random(30),o->ysize()-1);
      else
	 o->line(random(o->xsize()),o->ysize()-10-random(20+i),
		 random(30),o->ysize()-1);

   for (i=0; i<10; i++)
      o->box(random(o->xsize()),random(o->ysize()),
	     random(o->xsize()),random(o->ysize()),
	     random(256),random(256),random(256),220);

   o -> paste_mask(txt->clear(0,255,0),
		   shad,0,(int)(font->baseline()*0.7)+shad->ysize()-10)
     -> paste_mask(txt->clear(255,255,0),
		 txt->apply_matrix(({({1,2,1}),({2,4,2}),({1,2,1})}))
		 ->apply_matrix(({({1,2,1}),({2,4,2}),({1,2,1})}))
		 ->modify_by_intensity(1,0,0, 0,255,255,255,255,255))
     -> paste_mask(txt->clone()
		   ->tuned_box(0,0,txt->xsize()-1,txt->ysize()-1,
			       ({({128,128,128}),({64,128,0}),
                                 ({64,128,0}),({255,255,0})})),
		   txt);
   write(o->togif_fs());
   return 0;
}

Undocumented, yet:

object image->select_from(int x,int y);
object image->distancesq(int r,int g,int b);
array(int) image->getpixel(int x,int y);
object image->skewx(int diff,rgb);
object image->skewy(int diff,rgb);
object image->skewx_expand(int diff,rgb);
object image->skewy_expand(int diff,rgb);
object image->rotate(int|float angle,rgb);
object image->rotate_expand(int|float angle,rgb);
object image->turbulence(colorrange,int octaves=3,float scale=1,
			 float xdiff=0,float ydiff=0,float cscale=1);
object image->noise(colorrange,float scale=0.1,
	 	    float xdiff=0,float ydiff=0,float cscale=1);
    where colorrange is ({ float position=0..1, ({r,g,b}),
       			   float position=0..1, ({r,g,b}), ... })