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
- no arguments -> old image is copied
- size is given -> old image is copied cropped
- color is given -> new default color
- 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.
- scale the image with a (line scale) factor
- scale the image with different factors on x and y
- 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}), ... })