More about image filters

Image filters can be plugged in to enhance images during album generation, adding watermarking, logos etc. Image filters can be applied to closeup images, thumbnail images or both. Several filters can be chained to produce the desired effect. Imagine first applying red-eye reduction, then sharpening images and finally adding your logo to a corner. An open API and source code example are provided so developers easily can add new filters.

An effects panel was added in jalbum 12. From this panel, you can easily add watermarks (text and/or logo), greyscale, contrasts and a few arty filters. All available filters are not added in the user interface, they can be controlled with some fairly simple settings in the "User defined variables" section of the Advanced page.


Contents

Quick example

Note, in the detailed sections below the '|' character represents 'or', so true|false means the value can be true or false

Learning by example is powerful, so let's start by applying a grayscale filter to each thumbnail and add a copyright notice to the corner of each closeup image. (For a formal description of available filter features, see below.)

Start the jAlbum application and prepare a project for album creation. Now go to the Advanced page of jAlbum. There you will find a section called "User defined variables". We will use this section to set the properties of our filters. Enter exactly as this example shows. Pay attention to capitalization, ("GrayscaleFilter" is different to Grayscalefilter").

ImageFilters1.png
Setting filter properties on the Advanced page

Now go to the Main page and press "Rebuild all" to have the album generated and filters applied. (Pressing "Rebuild all" is important as pressing "Make album" does not process images if they already exist from a previous album generation.) The resulting thumbnails and closeup images should now look something like this:

ImageFilters1Applied.png
Thumbnail and closeup images processed through grayscale and text filters

The filters are applied in the order they are numbered (filter1, filter2 etc). The filter settings gets saved with the album project so don't forget to save your project when you are happy with your settings.

The filters

Below is a list of the initially provided filters and their properties (features). New filters can be installed by putting their Java class files inside the plugins directory of jAlbum. All filters require the class property to be specified as filter identifier. All filters accept the thumbnails and closeups property that controls if the filter is to be applied to thumbnails only, closeups only or both. Default is both.

Note, the '|' character represents 'or', so true|false means the value can be true or false

glödlampa.png

Missing a filter? Please also look for filters made by jAlbum users in the forum.

Grayscale filter

BeforeAfter.jpg
Converts images to grayscale.
Property Value Meaning
class GrayscaleFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?


Example

class=GrayscaleFilter

Applies the grayscale filter to both thumbnails and closeups.

Tint filter

BeforeAfter2.jpg
Adjusts the color of an image.
Property Value Meaning
class TintFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?
redPercent Strength in percent Red tone (100)
greenPercent Strength in percent Green tone (100)
bluePercent Strength in percent Blue tone (100)


Example

class=TintFilter redPercent=100 greenPercent=60 bluePercent=60

Applies a redish tint to images.

glödlampa.png

You can get interresting effects by combining the tint filter with the grayscale filter.

Logotype filter

BeforeAfter3.jpg
Adds image/logotype of your choice on top of album images.
Property Value Meaning
class LogoFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?
src URL to image Any valid URL will do (http:// file:/// etc)
angle Angle of logo in degrees, rotated around the center of the logo (0)
strengthPercent Opaqueness in percent Controls logo visibility. (100)
align left|center|right Horizontal alignment of logotype (left)
valign top|center|bottom Vertical alignment of logotype. (top)
margin Margin in pixels Distance from edge of logotype to edge of image. (0)
offset Horizontal offset in pixels Fine tuning of placement. (0)
voffset Vertical offset in pixels Fine tuning of placement. (0)


Examples

class=LogoFilter src="http://blog.jalbum.net/dor.png" strengthPercent="50" closeups

Add a semi transparent jAlbum logo from the jAlbum web site to center of closeups.

class=LogoFilter src="file:///C:/adir/anotherdir/animage.jpg" closeups

Pick an image from the local hard disk instead from a remote location.

Text filter

BeforeAfter4.jpg
Adds texts to album images.
Property Value Meaning
class TextFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?
src URL to image Any valid URL will do (http:// file:/// etc)
text Text to display Allows jAlbum $variables like $originalDate and $comment to be embedded for dynamic content
color HTML color definition Understands common Netscape and Explorer color names like "pink", #rrggbb and r,g,b,a format
face Name of font Valid font names from your system like "Helvetica", "Verdana", "Courier New" etc
style plain|bold|italic|bolditalic Font style (bold)
size Font size in pixels (16)
angle Angle of text in degrees, rotated around the center of the text (0)
antialias true|false Antialiasing gives smoother edges. (true)
align left|center|right Horizontal alignment of text (left)
valign top|center|bottom Vertical alignment of text. (top)
margin Margin in pixels Distance from edge of text to edge of image. (5)
offset Horizontal offset in pixels

Fine tuning of placement. (0)

voffset Vertical offset in pixels Fine tuning of placement. (0)

Example

class=TextFilter text="Date: $fileDate" size=20 color=#aaffaa closeups

Add the file date of the image on top of the image in a light green color

Shadow text filter

BeforeAfter5.jpg
Like text filter but also adds a drop shadow.

Extended properties (see TextFilter for the others):

Property Value Meaning
class ShadowTextFilter Identifying filter name (required)
shadowColor HTML color definition Color of shadow. Understands common Netscape and Explorer color names like "pink", #rrggbb and r,g,b,a format
shadowDistance Distance in pixels (2)


Example

class=ShadowTextFilter text="Date: $fileDate" size=20 color=#aaffaa closeups

Add the file date of the image on top of the image in a light green color with a black shadow.

Watermark filter

BeforeAfter6.jpg
Like text filter but with a watermark effect.
Property Value Meaning
class WatermarkFilter Identifying filter name (required)
strengthPercent Strength in percent Controls watermark visibility. (20)


Example

class=WatermarkFilter text="jAlbum" size=30  closeups valign=bottom margin=0

Add a "jAlbum" watermark to the lower left edge

Zoom filter

BeforeAfter7.jpg
Zooms into images. Good for making thumbnails more interpretable.
Property Value Meaning
class ZoomFilter Identifying filter name (required)
zoomPercent How far to zoom into center of image (30)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?


Example

class=ZoomFilter prescale thumbnails zoomPercent=30

Applies the zoom filter to thumbnails. Note the very important prescale attribute

Fixed shape filter

BeforeAfter8.jpg
Crops images if needed so they exactly fit the dimensions set for "thumbnail size" or "max image size" in the user interface. This makes all images and/or thumbnails the same shape (portrait, squary etc).
Property Value Meaning
class FixedShapeFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?


Example

class=FixedShapeFilter prescale thumbnails

Applies the fixed shape filter to thumbnails. Note the very important prescale attribute.

Sharpen filter

BeforeAfter9.jpg
Sharpen images.
Property Value Meaning
class SharpenFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?


Example

class=SharpenFilter closeups

Applies the sharpen filter to closeups.

Blur filter

BeforeAfter10.jpg
Blur images.
Property Value Meaning
class BlurFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?
radius 0-100 Amount of blurriness. 30 is default


Example

class=BlurFilter closeups

Applies the blur filter to closeups.

Rotation filter

BeforeAfter11.jpg
Rotates images a specified degree or a random degree (per image)
Property Value Meaning
class RotationFilter Identifying filter name (required)
thumbnails true|false Apply to thumbnails?
closeups true|false Apply to closeups?
prescale true|false Apply filter before scaling?
angle Angle in degrees Angle to rotate images (or bounds for random rotation if random is set) (15)
random true|false If to rotate each image individually at a random degree (bounded by the angle attribute)


Example

class=RotationFilter angle=10 random thumbnails prescale

Rotates thumbnails -10 to 10 degrees randomly

eXtended Border filter

BeforeAfter12.jpg
Adds borders. frames and shadows of your choice on album images.
Property Value Meaning
class XBorderFilter identifying filter name (required)
thumbnails true|false apply to thumbnails
closeups true|false apply to closeups
prescale true|false apply filter before scaling
bgCol HTML color definition background color for tranparent parts of shadows and frames
bgFile URL to jpeg, png or gif image background graphics file to use for tranparent parts of shadows and frames
bgOffX x offset in pixels x offset for bgFile (new with V0.95 β)
bgOffY y offset in pixels y offset for bgFile (new with V0.95 β)
boBlend true|false blend border color bands
boClip border clip radius in pixels the border may have rounded corners
boCol (list of) HTML color definition(s) border color
boMargin border margin in pixels margin between image edges and border
boTrans (list of) frame transpareny(ies) 0 is opaque, 100 fully transparent (invisible)
boWidth border width in pixels all directions are set to the same value
boWidthE eastern border width in pixels only E
boWidthN nothern border width in pixels only N
boWidthS southern border width in pixels only S
boWidthW western border width in pixels only W
brCol bracket line color (new with V0.96)
brStyle bracket style (new with V0.96)
brThick bracket line thickness (new with V0.96)
brX horizontal bracket length (new with V0.96)
brY vertical bracket length (new with V0.96)
clip clip radius in pixels a rounded corner
debug enables debug output for developers only
frBlend true|false blend frame color bands
frCol (list of) HTML color definition(s) frame color
frTrans (list of) frame transpareny(ies) 0 is opaque, 100 fully transparent (invisible)
frWidth frame width in pixels all directions are set to the same value
frWidthE eastern frame width in pixels only E
frWidthN northern frame width in pixels only N
frWidthS southern frame width in pixels only S
frWidthW western frame width in pixels only W
shCol HTML color definition shadow color
shDir NE|SE|NW|SW shadow direction
shDrop hard|norm|soft shadow drop falloff
shTrans minimum shadow transparency shadow transparency near the edge of the image
shWidth shadow width in pixels both directions are set to the same value
shWidthX x shadow width in pixels only x
shWidthY y shadow width in pixels only y
shExX x shadow excess in pixels excess shadow with on the opposite side
shExY y shadow excess in pixels excess shadow width on the opposite side


Examples

class=XBorderFilter frWidth=20 frCol=ivory shWidth=15 closeups

Adds a frame and a drop shadow to your closeups.

class=XBorderFilter boWidth=20 boCol=ivory closeups

Adds a border to your closeups.

Adding filters to skins

This section is for Java programmers who wish to extend jAlbum with new image filters.

jAlbum image filters are java classes added to the plugins directory that implement the small se.datadosen.jalbum.JAFilter interface. A jAlbum filter should also adhere to the JavaBean specification, meaning:

  • Provide a no-args constructor
  • Getters and setter methods should follow the JavaBean naming convention.
  • The filter should be serializable

A se.datadosen.jalbum.JAFilter interface must provide getter methods for name and description pretty much like an Applet. The third method is the filter method that takes a BufferedImage and a java.util.Map as arguments and returns a modified BufferedImage. A filter is allowed to directly manipulate the passed BufferedImage. The Map object contains jAlbum $variables that may be useful for the filter implementer.

The preferred way to pass parameters to a filter is to implement setter methods for them. By using a smart BeanShell script in the init.hsh file in the jAlbum program directory, jAlbum is capable of passing attributes from the user defined variables section of the Advanced tab page to the corresponding setter method of a filter.

The plugins jAlbum directory contains not only the filter classes but also the source code for the filters described on this page. Feel free to use them as base for your own filters. You will probably find the SimpleFilter below a good base for your own filters. The plugins folder also contains a compile.bat file that simplifies compilation for you. As you develop filters, please note that you do not need to restart jAlbum in order to refresh the filter classes as they are dynamically loaded every time an album is being processed. Finally, if you make a cool filter, please send it to me for inclusion.

Sample filter source code

The following simple filter adds a jAlbum logo to the corner of images:

import se.datadosen.jalbum.JAFilter;
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;

/**
 * jAlbum simple image filter adding a jAlbum logo to the
 * corner of images
 * @author David Ekholm
 * @version 1.0
 */
public class SimpleFilter implements JAFilter {

    // Implements JAFilter
    public String getName() {
        return "Simple filter";
    }

    // Implements JAFilter
    public String getDescription() {
        return "Add a jAlbum logo to the corner of images";
    }

    // Implements JAFilter
    public BufferedImage filter(BufferedImage bi, java.util.Map vars) {
        Graphics2D g = bi.createGraphics();
        ImageIcon windowIcon =
         new ImageIcon(se.datadosen.jalbum.JAlbumFrame.class.getResource(
          "smallicon.gif"));
        g.drawImage(windowIcon.getImage(), 0, 0, null);
        return bi;
    }
}

More Examples

Adding a 30px tall red box to the bottom of slide images with a web address in white text.

Name Value
filter1 class=XBorderFilter frWidth=0 frWidthS=30 frCol=#ff0000 closeups
filter2 class=TextFilter text="MyWebsite.com" size=24 align=center valign=bottom margin=0 color=white closeups