FGLIMAGEPATH

FGLIMAGEPATH basics

The FGLIMAGEPATH environment variable is used by the runtime system, to find image resources on the server where the program executes, when the image name specified in the form element is not an URL that can be directly resolved and fetched by the front-end.

Image resources found through FGLIMAGEPATH will be transmitted to the front-end for display.

FGLIMAGEPATH defines a list of directories and/or image-to-font-glyph mapping files: If a path of FGLIMAGEPATH is a directory, it will be used for image file and font file lookup. If the element is a file name, it will be used as an image-to-font-glyph mapping file.

FGLIMAGEPATH setting on mobile devices

When executing on a mobile device, the environment variables must be defined with mobile.environment FGLPROFILE entries. The FGLAPPDIR and FGLDIR environment variables are automatically defined by the front-end component, and can be referenced with the $FGLAPPDIR and $FGLDIR placeholders, when defining FGLIMAGEPATH in FGLPROFILE:

mobile.environment.FGLIMAGEPATH = "$FGLAPPDIR/myimages:$FGLAPPDIR/icons/myimage2font.txt:$FGLDIR/lib/image2font.txt"

For more details about environment variable settings for mobile apps, see Setting environment variables in FGLPROFILE (mobile).

Default behavior when FGLIMAGEPATH is not defined

If the FGLIMAGEPATH environment variable is not defined, the runtime system will by default:

Find image resource files in the current working directory where the BDL program executes.
Note: When executing the app on an iOS device, instead of searching the current working directory, image resources are by default found in the appdir directory.
Use FGLDIR/lib/image2font.txt along with FGLDIR/lib/FontAwesome.ttf, for image to font glyph mapping (to get default icons).

Order of precedence in FGLIMAGEPATH

It is possible to mix several image file directories with several image-to-font-glyph mapping files in FGLIMAGEPATH:

The list of mapping files and directories defines the order of precedence to resolve conflicts, when several image names can resolve to several image resources.

For example, if a form element defines an image as "smiley", and if FGLIMAGEPATH is defined as:

/opt/myapp/images:/opt/myapp/image2font.txt

If the /opt/myapp/images directory contains an image file "smiley.png", and the /opt/myapp/image2font.txt file contains a mapping for "smiley", the "smiley.png" file from /opt/myapp/images will be selected by the runtime system.

If FGLIMAGEPATH is defined as follows:

/opt/myapp/image2font.txt:/opt/myapp/images

The mapping for smiley to font glyph would take precedence.

FGLIMAGEPATH syntax

FGLIMAGEPATH must contain a list of paths, separated by the operating system specific path separator. The path separator is ":" on UNIX™ platforms and ";" on Windows^® platforms.

For example, on UNIX:

$ export FGLIMAGEPATH="/var/myapp/myimages:$FGLDIR/lib/image2font.txt"

Image-to-font-glyph mapping

Image names can be mapped to font glyphs when at least one file path is specified in FGLIMAGEPATH. The runtime system distinguishes file paths (as image-to-font-glyph mapping files), from directory paths (as locations to file plain image files and font files).

Important: The directory and filename to the font file must be specified in FGLIMAGEPATH, except if the font file is located in the same directory as the mapping file.

A default mapping file ("image2font.txt") and its corresponding font file ("FontAwesome.ttf") are provided in FGLDIR/lib. If FGLIMAGEPATH is not defined, the runtime system will use these files to make the image to font glyph mapping.

Important: When providing your own customized font file, it must be a valid TTF file. For example, changing the file name is not sufficient to turn it into a different font: In order to produce a valid TTF file, use font management tools such as FontForge (http://fontforge.github.io/en-US/) or Fontello (http://fontello.com). Furthermore, to target Microsoft^® Internet Explorer (version 11), you will need to patch the generated TTF file to remove embedding limitations from TrueType fonts, by setting the fsType field in the OS/2 table to zero. This modification can be done with freeware tools like ttembed.

The image-to-font-glyph mapping file must have the following syntax:

image-name=font-file:hexa-ordinal[:color-spec]

where:

image-name - is the name of the image to be mapped to a font character.
font-file - is the file name containing the font definitions.
hexa-ordinal - is the font glyph position in the font file, in hexadecimal notation.
color-spec - is the color to be used, in RGB hexadecimal format or as color alias as defined in presentation style colors. This field is optional: If not specified, the glyph will be displayed in a default color used by the front-end platform.

Lines starting with the # sharp character are considered as comment lines and ignored.

For example:

# Common icons
camera=FontAwesome.ttf:f030
file=FontAwesome.ttf:f0f6:#8B0000
smiley=FontAwesome.ttf:f118:yellow
# Traffic lights
circle-red=FontAwesome.ttf:f111:red
circle-orange=FontAwesome.ttf:f111:orange
circle-green=FontAwesome.ttf:f111:green

FGLIMAGEPATH and gICAPI web components

For applications executing on a server and displaying on GDC/GMA/GMI front-ends in client/server mode (not through the GAS), you can use the FGLIMAGEPATH environment variable to locate the HTML files of gICAPI web components on the server. Like image resources, the web component files will be automatically transferred to the front-end.