RebGUI Cookbook

Author : Ashley G Trüter
Updated: 21-Apr-2007
Purpose: RebGUI tricks, tips & code examples.

Contents:

1. Using SQLite with widgets

1.1 Flat versus blocked data

RebGUI widgets that accept a block of values expect the block to be 'flat', that is, all values in a single block. This contrasts with the way in which database data is often represented, that is, a block of blocks with each block containing row values.

>> describe "names"          ; two column table
== ["Name" string! "Age" integer!]
>> SQL "select * from names" ; 'blocked' data
== [["Bob" 19] ["Pete" 26] ["Jane" 23]]
>> SQL "select * from names" ; 'flat' data
== ["Bob" 19 "Pete" 26 "Jane" 23]

You can still use a database/driver that returns blocked data, just be aware that you must flatten the block prior to passing it to a RebGUI widget.

SQLite Driver

The remainder of this section assumes you are using the SQLite Driver. The sample database used in this example can be created with the following script:

REBOL []

do %sqlite.r

CONNECT/create %my_db.db

SQL "create table names (name,age)"

foreach [name age] ["Bob" 19 "Pete" 26 "Jane" 23] [
    SQL reduce ["insert into names values (?,?)" name age]
]

DISCONNECT

1.2 Establishing a SQLite connection

First we must include both the RebGUI and SQLite libraries, then connect to our database with the /flat refinement:

REBOL []

do %rebgui.r
do %sqlite.r

CONNECT/flat %my_db.db

display ...

do-events

1.3 Composing query data into a widget

Using compose/only is a handy way of assigning the block returned from a query as the widget's data block, as in:

display "Test" compose/only [
    text-list data (SQL "select name from names")
    drop-list data (SQL "select age from names")
]

Composing data into a table widget requires that you match the column specifications with the return set, as in:

display "Test" compose/only [
    table options ["Name" left .7 "Age" right .3] data (sql "select * from names")
]

1.4 Dynamically updating a widget with query data

Performing similar operations at runtime is then as simple as:

display "Test" [
    t: text-list
    button "Append" [
        insert t/data SQL "select name from names"
        t/redraw
    ]
    button "Replace" [
        insert clear t/data SQL "select name from names"
        t/redraw
    ]
]

Note that the only difference between appending and replacing data is the use of clear.

2. Creating a RebGUI application using the SDK

2.1 Include files

Your script needs to include the following files (change paths to suit):

REBOL [
    Encap: [title ""]
]

#include %/c/rebol/rebol-sdk/source/gfx-colors.r
#include %/c/rebol/rebol-sdk/source/gfx-funcs.r
#include %rebgui.r

2.2 Calling enface from another script

You can call enface from another script as follows:

script: request-file/only/filter ["*.r"]

call reduce [%/c/rebol/rebol-sdk/tools/enface.exe script]

2.3 Windows Icons & Version information

2.3.1 ResHacker

On Windows an indispensable tool for changing an executable's resources is Resource Hacker, which can be called from a script to replace icons and/or version information as follows:

call "ResHacker.exe -addoverwrite app.exe,app.exe,app.ico,ICONGROUP,REBOL,1033"

call "ResHacker.exe -addoverwrite app.exe,app.exe,app.res,VERSIONINFO,1,1033"

To see your icon change(s) you may have to highlight your executable (in Explorer) and select View|Refresh from the menu.

2.3.2 .ico file

The .ico file must be a multiple icon file containing 9 icons as follows:

1. 48 x 48 (16 colors)
2. 32 x 32 (16 colors)
3. 16 x 16 (16 colors)
4. 48 x 48 (256 colors)
5. 32 x 32 (256 colors)
6. 16 x 16 (256 colors)
7. 48 x 48 (16.8mil colors)
8. 32 x 32 (16.8mil colors)
9. 16 x 16 (16.8mil colors)

2.3.3 .res file

The .res file is created by using Resource Hacker to open (File|Open) your newly created executable and:

1. Navigating to Version Info|1|1033
2. Changing text details as appropriate
3. Clicking Compile Script
4. Clicking Action|Save Resource as a .res file

Note

The most common cause of problems are incompatible .ico and/or .res files. The .ico file should be around 24.6 KB in size, the .res file about 712 bytes.

2.4 Mac OS/X application bundles

2.4.1 Bundle directory layout

Creating an application bundle on Mac is easy, just follow these steps:

1. Create a directory named MyApp.app
2. Ctrl-click the directory and select Show Package Contents
3. Now create the following file layout:

MyApp.app
    Contents
        Info.plist
        MacOS
            MyApp
        Resources
            Icon.icns

2.4.2 Info.plist

Info.plist is an XML file of key/string pairs similar to the following:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>CFBundleExecutable</key>
    <string>MyApp</string>
    <key>CFBundleIconFile</key>
    <string>Icon.icns</string>
    <key>CFBundleIdentifier</key>
    <string>com.mydomain.MyApp</string>
    <key>CFBundlePackageType</key>
    <string>APPL</string>
    <key>CFBundleShortVersionString</key>
    <string>1.0.0</string>
</dict>
</plist>

Full documentation on all plist keys can be found at developer.apple.com.

2.4.3 .icns file

A .icns file is similar to a Windows .ico file, but typically only needs the following four file formats:

1. 128 x 128 (16.8mil colors)
2. 48 x 48 (16.8mil colors)
3. 32 x 32 (16.8mil colors)
4. 16 x 16 (16.8mil colors)

A great utility for creating .icns files is FastIcns.

2.4.4 Working directory

You may want to package your application to support the following structure:

MyApp.zip
    Logo.png    ; Shared logo
    MyApp       ; Linux binary
    MyApp.app/  ; Mac OS/X bundle
    MyApp.exe   ; Windows executable
    MyApp.ini   ; Shared ini settings
    Resources/  ; Shared resources

in which case it is desirable to have your encapped Mac OS/X script set its working directory to the same directory where the app bundle resides. This can be done with the following line of code at the start of your script:

all [2 = fourth system/version change-dir join first split-path system/options/boot %../../..]

Note

This allows you to ship one zip file that works on multiple platforms. Now that's what I call a universal binary!