Projects:Go Bible/SymScroll
Contents
Symmetric Scrolling Branch
- New page under construction.
Raison d'être
The motivation for developing the SymScroll branch of Go Bible was to provide support for touch screen only phones that have Java ME. For touch screen phones with a hardware menu button, using SymScroll you can safely get rid of the on-screen virtual keypad and retain full Go Bible functionality, thus taking advantage of the full area of the screen for the application display.
As a sensible prelude for this task, the source code has been refactored. The SymScroll branch of GoBibleCore has been subdivided into many more Java classes than the previous release.
Features
Enhanced/changed features
- Symmetrical scrolling
- Smooth scrolling
- Touch screen full support
New features
- Text added by translators can be displayed (e.g. in italics)
- Line breaks
- Psalm titles
- Other numeral systems (e.g. Arabic, Devanagari, Thai)
- Search next
- Key settings (e.g. for phones with QWERTY keyboard)
Improvements
Several software improvements were implemented in the SymScroll branch.
- The painting code has been reworked. It is much faster than the previous code.
Technical details:
- The original code measured the length of each line character by character, giving speed n (n = number of characters in a verse).
- Because of look ahead and caching, at first the SymScroll branch repeated the above process about 4x, on top of other overheads, slowing it down by about the same factor.
- Now, the code defers measuring any length until an entire word is read, speeding the code up by a factor equal to the average word length.
- For Chinese script, where there is no concept of words and spaces, the code is does a binary search (i.e. log_2(n) ) to find the best breaking point.
Bug fixes
Some existing software bugs are being fixed. Details will be included in the release notes.
Implementation details
Symmetrical scrolling
Pressing 'up' now goes up by one screen, and pressing 'down' still goes down by one screen. This should be much more intuitive than the previous method. [1]
The previous method had its merits, namely speed, which this branch assumes is less relevant in the era of phones that can emulate Nintendo Gameboys.
- ↑ In which 'up' went up to the start of the previous verse.
Smooth scrolling
Touch screen scrolling needed to be smooth. Smooth scrolling is abandonned when a proper 'up' or 'down' key is pressed, after which the application reverts to the original discrete scrolling method.
Touch screen support
The Biblical text display now includes simple book and chapter headings, such that during continued scrolling, there is a better visual feedback for navigating.
The Go Bible Menu is accessed by touching anywhere in the top bar.
Key settings
This new feature facilitates remapping keys to the Go Bible navigation functions, thus making it possible for the user of a phone with a QUERTY keyboard (for example) to assign keys more conveniently. This feature requires several new UI properties.
The new Search next feature is by default assigned to the previously unused "0" key.
Other numeral systems
The new UI property called UI-Digits facilitates using a different numeral system for chapter and verse numbers. The method is to specify a ten character string corresponding to the digits 0 through 9. Examples:
Default (if omitted):
UI-Digits: 0123456789
Eastern Arabic numerals:
UI-Digits: ٠١٢٣٤٥٦٧٨٩
Farsi numerals:
UI-Digits: ۰۱۲۳۴۵۶۷۸۹
Devanagari numerals:
UI-Digits: ०१२३४५६७८९
Thai numerals:
UI-Digits: ๐๑๒๓๔๕๖๗๘๙
Notes:
- Limitations: Currently, there is no error message. Go Bible does not check for uniqueness of characters. If there are less than 10 characters, it will revert to default.
- The transformation is done at the individual digit level for decimal notation.
- The transformation applies only to chapter and verse numbers as used by the application, not to any numbers as might be found within the text of some Bible translations.
- In numeral systems with further special symbols for 20, 30, 50, etc; these are not catered for.
- For right to left languages, how different phones handle the bidirectional algorithm when the numeral system is not the default is outside the control of Go Bible software.
- Some languages do not have a symbol for numerical zero. See [1] which tabulates Numerals in Unicode.
- No semantic check is performed by Go Bible Creator. i.e. The following would be accepted, even though it makes no sense.
UI-Digits: 9876543210
Go Bible Creator
The SymScroll branch of Go Bible Creator supports the new features. Several new UI properties have been defined. Some further properties are available for use in collections text files.
New UI properties
Here is a list of the new and re-used user interface (UI) properties:
UI-Key-Settings: Key Settings UI-Assign-Key: Assign Key UI-Unassign-Key: Unassign Key UI-Action-Next-Book: Next Book UI-Action-Next-Chapter: Next Chapter UI-Action-Next-Screen: Next Screen UI-Action-Next-Verse: Next Verse UI-Action-Next-3-Lines: Next 3 Lines UI-Action-Next-1-Line: Next Line UI-Action-Previous-Book: Previous Book UI-Action-Previous-Chapter: Previous Chapter UI-Action-Previous-Screen: Previous Screen UI-Action-Previous-Verse: Previous Verse UI-Action-Previous-3-Lines: Previous 3 Lines UI-Action-Previous-1-Line: Previous Line UI-Book: Book UI-Chapter: Chapter UI-Verse: Verse UI-Chapter-Reference-%1: Chapter %1 UI-Search-Next: Search Next UI-Delete-All: Delete All
Notes:
- This list is still incomplete.
- Parameter %1 in UI-Chapter-Reference-%1 is a placeholder for the numerical value. This facilitates having a different position for the number in the displayed chapter headings.
- In version 2.4.x, displaying "Delete All" under Bookmarks was a kludge using "UI-Delete" and "UI-All".
Collections text file properties
Here is a list of the new collections text file properties:
UI-Digits: 0123456789
Note:
- This list is still incomplete.
- Although UI-Digits looks like a normal UI property, it does not get copied as such into the internal ui.properties file.
Support for XHTML-TE
The SymScroll branch of Go Bible Creator incorporates the extension to specify XHTML-TE as the source text format. The code is as provided by one of the programmers at SIL in Dallas. It was designed to support their FieldWorks Translation Editor.
Other improvements
Command line options are now available by which one can choose a baseline Manifest file, a baseline ui.properties, and even the GoBibleCore binaries. This should make GoBibleCreator a bit easier to use with different versions of GoBibleCore.
- These new options require documenting.
Refactoring:
The source code has undergone major reorganization. The following are the new/changed Java classes:
- USFMConverter: Supersedes USFM_Utilities. Contains all the USFM-related methods.
- XMLConverter: Contains all the XML-related helper methods.
- GoBibleCreator: USFM- and XML- specific code have been removed and placed in their respective *Converter classes.
Go Bible data format
Go Bible data format already assigned the control character code \x01 to mark both the start and finish as the means to implement the display of red letters for Words of Jesus. As Go Bible makes no standard use of control characters, it had been envisaged that any UTF-8 character up to \x1F might be used for further enhancements to the Go Bible data format.
This method has been extended as follows:
\x01 – Delimit red letters
\x02 – Delimit translators' additions (e.g. as for words shown as italics in the KJV)
\x03 – Delimit the name of deity
\x04 – Delimit OT quotations (e.g. as for words shown in oblique in the NKJV)
\x05 – Delimit a personal name
\x06 – Suppress printing the verse number, if it has not been printed, and change to boldface for titles
\x07 – Breaks a line, prints the verse number, and resumes normal data (see below)
\x08 – Decrements the verse number by one (as opposed to inserting empty verses to increase the verse number by one).
This has to be repeated for every verse for which the numbering is not correct.
\x0A – Line break (see below)
Line breaks
Line breaks are now permitted within Go Bible data format, coded as EOL marker in Unix \n (i.e. \x0A ).
Titles
To accommodate descriptions / titles without making major design changes, the following solution has been adopted. Example for canonical Psalm titles.
<VERSE INDEX 0><\x06>For the director of music. Of David.<\x07> In the <\x03>LORD<\x03> I take refuge. How then can you say to me: ... <VERSE INDEX 1>For look,...
Backwards compatibility
The SymScroll branch of GoBibleCore is backwards compatible with existing Go Bible applications. This means that earlier applications can be changed to SymScroll merely by replacing the file gobiblecore2.jar and using the Update option of Go Bible Creator to rebuild the application. For Go Bible applications that already have a UI translation, then ideally the new UI properties should be translated prior to the rebuild.
Development Status
The SymScroll branch is still being actively developed. Most of the features are already implemented. The branch is at the testing and debug stage. No milestoned release has yet been announced.
