|Revisions to the Picture format in Helix 7.0|
Helix can display images in three distinct places:
Prior to version 7.0, Helix used the Classic PICT (technically, PICT2) format for storing and representing picture data. This format has been obsolete for a few years, and is finally starting to be removed from macOS altogether. We have seen old images that can not be viewed using Apple’s Preview app, but can via Quick Look, and vice versa.
Helix 7.0 uses the PDF format instead, which provides increased sharpness and fidelity to the original. This is Apple’s current official format for image interchange between applications.
When a collection is updated to Helix 7.0, all pictures pasted into label or command rectangles and data stored in fields formatted as Picture type are automatically converted to PDF format. This can not recover lost quality, so if you still have the original images, you may wish to re-apply them. (Note that some very old images may not be convertible and therefore can not be displayed in Helix 7.0. They will not cause a problem; they simply won’t be displayed.)
|Side by Side Comparison||
The image to the right provides one example of the difference in fidelity between Helix 6.2 and Helix 7.0. The center image is the original TIFF image. The Helix 6.2 rendition (on the left) is much darker and less detailed. The Helix 7.0 rendition (on the right) is indistinguishable from the original.
By default, Helix 7.0 renders all images with antialiasing turned on. Users who wish to disable this feature may use the HxEnableImageAntialiasing global preference to turn it off. Be aware that this preference affects all images in all collections opened on the machine where the preference is changed. See Editing Preferences in Helix 7.0 for more information on this (and other) preferences, and for a link to our Preference Editor applet that makes changing preference easier.
The format for stored images in Helix 7.0 is the industry standard PDF format. Using AppleScript, image data can be extracted as encoded data in the content property for template rectangles. (Extracting images from fields and abaci is expected to be added in a future release.)
The current encoding requires further manipulation to convert into the ‘byte stream’ format required to write it directly to a file. Contact tech support for assistance if you want to pursue this.