Image

Object
   |
   +--Image

Defined in Image.js

Constructor Detail

Image

Image(<String> url)

Helma's built-in image object allows you to read, manipulate, and save images.

An image object is created using the Image() constructor.

Example:

 var img = new Image("http://helma.org/image.gif");

Parameters:
url - as String

crop

void crop(<Number> x, <Number> y, <Number> width, <Number> height)

Cuts out (crops) a rectanglular area of an image.

The dimensions of the area are calculated from the xNumber- and yNumber-offsets (ie. from the top left corner of the image as upper left reference point) to xNumber + widthNumber and yNumber + heightNumber as lower right reference point.

Example:

 var img = new Image("http://helma.org/images/original.gif");
 res.write('<:img src="/images/original.gif" />');
  
 
  
 img.crop(58, 9, 48, 21);
 img.saveAs("/www/images/processed.gif");
 res.write('<img src="/images/processed.gif" />');
  
 

Parameters:
x - as Number, offset from the top left corner of the image
y - as Number, offset from the lower right corner of image
width - as Number, the width of the image
height - as Number, the height of the image

dispose

void dispose()

Disposes an Image object that is no longer needed.

If an instance of java.awt.Graphics has been allocated for the Image, the dispose() method is called on it to free its resources.

Example:

 var img = new Image("http://helma.org/images/original.jpg");
 // do something useful or funny with the image
 img.dispose();

drawLine

void drawLine(<Number> xStart, <Number> yStart, <Number> xEnd, <Number> yEnd)

Draws a line onto an image.

The line starts at the reference point defined by the offsets x1Number and y1Number from the top left corner of the image and ends at the reference point defined by the offsets x2Number and y2Number.

Example:

 var img = new Image("http://helma.org/images/original.gif");
 res.write('<img src="/images/original.gif" />');
  
 
  
 img.setColor(204, 0, 0);
 img.drawLine(58, 26, 100, 26);
 img.saveAs("/www/images/processed.gif");
 res.write('<img src="/images/processed.gif" />');
  
 

Parameters:
xStart - as Number, horizontal reference point from top left corner of the image
yStart - as Number, vertical reference point from top left corner of the image
xEnd - as Number, horizontal reference point where the line ends in the image
yEnd - as Number, vertical reference point where the line ends in the image

drawRect

void drawRect(<Number> x, <Number> y, <Number> width, <Number> height)

Draws a rectangle onto an image.

The rectangle's dimensions are calculated from the xNumber- and yNumber-offset (ie. from the top left corner of the image as upper left reference point) to xNumber + widthNumber and yNumber + heightNumber as lower right reference point.

Example:

 var img = new Image("http://helma.org/images/originalgif");
 res.write('<img src="/images/original.gif" />');
  
 
  
 img.setColor(204, 0, 0);
 img.drawRect(57, 8, 46, 20);
 img.saveAs("/www/images/processed.gif");
 res.write('<img src="/images/processed.gif" />');
  
 

Parameters:
x - as Number, as upper left reference point.
y - as Number, as the lower right reference point upperleft
width - as Number, width of the crop
height - as Number, height of the crop

fillRect

void fillRect(<Number> x, <Number> y, <Number> width, <Number> height)

Draws a filled rectangle onto an image.

The rectangle's dimensions are calculated from the xNumber- and yNumber-offset (ie. from the top left corner of the image as upper left reference point) to xNumber + widthNumber and yNumber + heightNumber as lower right reference point.

Example:

 var img = new Image("http://helma.org/images/original.gif");
 res.write('<img src="/images/original.gif" />');
  
 
  
 img.setColor(204, 0, 0);
 img.fillRect(58, 27, 43, 29);
 img.saveAs("/www/images/processed.gif");
 res.write('<img src="/images/processed.gif" />');
  
 

Parameters:
x - as Number, from the top left corner of the image.
y - as Number, from the lower reference point.
width - as Number, width of the rectangle
height - as Number, height of the rectangle

getHeight

Number getHeight()

Returns the height of an image measured in pixels.

Example:

 var img = new Image("http://helma.org/images/hop.gif");
 res.write('<img src="/images/hop.gif" />');
  
 
  
 var height = img.getHeight();
 res.write(height);
 35

Returns:
Number

getInfo

ImageInfo getInfo(<String> pathOfImage)

Returns an ImageInfo object for an image.

This function allows to retrieve image properties such as width, height and MIME type without the need to fully decode the image.

Example:  

 var info = Image.getInfo("http://helma.org/images/hop.gif");
 if (info) {
   res.writeln('width: ' + info.width);
   res.writeln('height: ' + info.height);
 }
  
 width: 174
 height: 35
 


 Note that in contrast to the other Image function, this is called on the 
 constructor rather than on a decoded Image object. This is because the 
 purpose of this function is to avoid the expensive image decoding 
 process if we're just interested in some of the image's properties.
 


 The function returns an instance of Marco Schmidt's ImageInfo object 
 if the image could be read, or null if the image couldn't be read. 
 See the ImageInfo API documentation for the full set of methods. 
 (Remember that you can getters as properties in Rhino as shown in the example above.)

Parameters:
pathOfImage - as String, it can be a path, url, byteArray or inputstream.

Returns:
ImageInfo

getSource

awt.image getSource()

Retrieves a Java-compatible image object from a Helma image object.

To use some of the image filters provided by the JIMI Java image processing package com.sun.jimi.core.filters, a specific Java class of image objects is needed.

Helma wraps the sun.awt.image objects into a custom class. To use Helma image objects with JIMI's filters these have to be "unwrapped" using the getSource() function.

The following filter functions have been successfully applied the way as described in the examples below:

   * Rotate(degreeNumber)
   * Gray()
   * Flip(typeNumber)
   * Oil(intensityNumber)
   * Invert()
   * Smooth(intensityNumber)
   * Shear(degreeNumber)
   * Edges()
   * Shrink(multiplyNumber)
   * Enlarge(divisionNumber)



Please take into account that the quality might suffer depending on the type and amount of filters applied to the image.


Example:

 var img = new Image("http://helma.org/static/original.jpg");
 var filters = Packages.com.sun.jimi.core.filters;
 var rotator = new filters.Rotate(45);
 var processed = new Image(img, rotator);
 processed.saveAs("/path/to/static/processed.jpg");
 res.write('<img src="/static/processed.jpg" />');
  
 
  
 var oil = new filters.Oil(img.getSource(), 3);
 var processed = new Image(img, oil);
 processed.saveAs("/path/to/static/processed.jpg");
 res.write('<img src="/static/processed.jpg" />');
  
 

Returns:
Packages.com.sun.awt.image

See:
- Packages.com.sun.awt.image

getWidth

Number getWidth()

Returns the width of an image measured in pixels.

Example:

 var img = new Image("http://helma.org/images/hop.gif");
 res.write('<img src="/images/hop.gif" />');
  
 
  
 var width = img.getWidth();
 res.write(width);
 174

Returns:
Number

reduceColors

void reduceColors(<Number> colorDepth)

Reduces the number of available colors (color depth) in an image.

Note: GIF images need a color depth of 256 colors maximum. Use this function with caution, generally.

Example:

 var img = new Image("http://helma.org/images/original.jpg");
 res.write('<img src="/images/original.jpg" />');
  
 
  
 img.reduceColors(8);
 img.saveAs("/www/images/processed.jpg");
 res.write('<img src="/images/processed.jpg" />');

Parameters:
colorDepth - as Number, value of color depth in an image.

resize

void resize(<Integer> width, heigth)

Sets the height and width of an image to new values.

The widthNumber and heightNumber arguments need to be integers, so be careful to round the new values eventually.

In case of a GIF image always reduce the image to 256 colors after resizing by using the reduceColors() function.

Example:

 var img = new Image("http://helma.org/images/original.jpg");
 res.write('<img src="/images/original.jpg" />');
  
 
  
 var factor = 0.66;
 var wd = Math.round(img.getWidth() * factor);
 var ht = Math.round(img.getHeight() * factor);
 img.resize(wd, ht);
 img.saveAs("/www/images/processed.jpg");
  
 res.write('<img src="/images/processed.jpg" />');

Parameters:
width - as Number, new width of the image.
height - as Number, new height of the image.

setColor

void setColor(<Number> red, <Number> green, <Number> blue)

Sets the color for current drawing actions.

The colorNumber argument is represented by a 24-bit integer (0-16777215), the redNumber, greenNumber and blueNumber arguments build an RGB tuple with each element ranging from 0 to 255.

Example:

 var img = new Image("http://helma.org/images/original.jpg");
 res.write('<img src="/images/original.jpg" />');
  
 
  
 img.setColor(16777215);
 img.fillRect(80, 50, 30, 30);
 img.setColor(255, 255, 0);
 img.fillRect(65, 15, 30, 30);
 img.saveAs("/www/images/processed.jpg");
 res.write('<img src="/images/processed.jpg" />');
  
 

Parameters:
red - as Number, RGB value ranging from 0 to 255 or if it the only parameter then it can be a 24 bit Integer
green - as Number, RGB value ranging from 0 to 255
blue - as Number, RGB value ranging from 0 to 255.

setFont

void setFont(<String> name, <Number> style, <Number> size)

Determines the typeface font to be used in current drawing actions.

Using this function sets the font to be used in subsequent calls of the drawString() function.

The nameString argument specifies the font face as string (e.g. "sansserif", "dialog").

The integer styleNumber sets the font to normal (0), bold (1), italic (2) or bold and italic (3).

The sizeNumber, an integer as well, refers to the font size in pixels.

Please take a look at the description about adding fonts to the Java runtime for a detailed look onto Java's font mechanics.

Example:

 var img = new Image("http://helma.org/images/original.jpg");
 res.write('<img src="/images/original.jpg" />');
  
 
  
 img.setColor(255, 255, 255);
 img.setFont("serif", 0, 12);
 img.drawString("I shot the serif.", 50, 15);
 img.setFont("sansserif", 1, 14);
 img.drawString("But I didn't shoot", 10, 100);
 img.setFont("monospaced", 2, 16);
 img.drawString("the monotype.", 15, 115);
 img.saveAs("/www/images/processed.png");
 res.write('<img src="/images/processed.png" />');

Parameters:
name - as String, specifies the font face (e.g. "sansserif").
style - as Number, the styleNumber normal (0), bold (1), italic (2) or bold and italic (3).
size - as Number, refers to font size in pixels