The Becasso Scripting API

Like all well-behaved BeOS applications, Becasso implements scripting in the form of a set of messages. The examples in this document use Attila Mezei's freely avaiable scripting application called hey, version 1.2 or greater. Hey is available from BeBits. For example, to make the WinGrab window be "always on top" (which can be handy if you are grabbing a lot of (partial) windows when writing documentation for an application), you can say

    hey Becasso set Feel of Window "WinGrab" to 3

    hey Becasso get Mode

    hey Becasso set tool to "spray can"
    hey Becasso set Tool to "Spray Can"

Note: This is different from the Mode and Tool properties, because these can also function as specifiers when scripting mode or tool parameters (see Scripting Tool Parameters, below).

    hey Becasso set Foreground to "rgb_color(85,107,47,255)"
    hey Becasso set Foreground to DarkOliveGreen

The color names are matched case-insensitively and also allow for variants with spaces, so

    hey Becasso set background to lightslategrey
    hey Becasso set Background to "Light Slate Grey"
    hey Becasso set Background to LightSlateGrey"
    hey Becasso set Background to "Light slate GREY"

Note: To find out all the names Becasso recognizes as colors, run Becasso from a terminal with the command line switch -c, i.e.

    Becasso -c

and it will print out all the color names to the terminal, preceded by the red, green, and blue components. Note that there are 752 entries, so the list is quite long. The color names are the ones that are in the file rgb.txt in most XWindow distributions.

    hey Becasso set ColorRatio of Tool Spraycan to 0.5

All option names are case independent.

Scripting Filter Properties

    hey Becasso set Method of Filter De-Interlace to Interpolate

    hey Becasso let Canvas Foo do ApplyFilter "Gaussian Blur"

    hey Becasso ApplyFilter "Gaussian Blur"

The TabletArea is a BRect that specifies the rectangle and aspect ratio to be used by Becasso's internal Wacom tablet code. You can ask for the current active table area with

    hey Becasso get TabletArea

    hey Becasso set TabletArea to 'BRect(l,t,r,b)'

To prevent the Export Format Window from popping up during scripted export of a canvas to a non-native format, Becasso uses a default export format which can be set via the ExportFormat property:

    hey Becasso set ExportFormat to image/jpeg
    hey Becasso set ExportFormat to 'JPG '

To actually have Becasso export the canvas, send it an Export command:

    hey Becasso Export with Name=foo.jpg

As a more elaborate example, the following snippet will convert all JPEG images in the current directory to PNG:

    hey Becasso set ExportFormat to image/png
    for x in *.jpg
    do
        hey Becasso load file\($x\)
        hey Becasso Export with Name=${x%.jpg}.png
    done

    hey Becasso set Scriptee to 'foobar (100%)'
    hey Becasso set Scriptee to 6

Normally when Becasso loads a file, it performs a sanity check on the alpha channel of the new image. Many Translator add-ons have in the past used the alpha channel to denote transparency instead of opacity (even some by Be themselves), and images originating from other systems might suffer from the same inconvenient inversion of the alpha channel. Becasso uses a simple heuristic to guess whether a newly loaded image file might have this inversion of the alpha channel, and pops up an alert box offering to invert it for you. You can prevent Becasso from popping up that alert, if for example you want to minimize the risk of a script blocking on user input, by specifying the AskForAlpha flag:

    hey Becasso load file[foo.png] with AskForAlpha=bool[false]

There are other commands you can send to Becasso or to a specific canvas. For instance, you can do:

    hey Becasso let Canvas "foo" do Crop BRect[10,10,50,50]

    hey Becasso Crop BRect[10,10,50,50]

You can also send the commands Rotate90, Rotate180, and Rotate270 to a canvas.

Canvases

    hey Becasso create Canvas with Name=foo and Size=BRect'(100,150,400,350)'

    hey Becasso set Look of Canvas "Untitled 1" to 20

You can query a canvas for its aspect ratio:

    hey Becasso get AspectRatio of Canvas "foo"

Canvases have Layer as sub-specifier, so you can say

    hey Becasso create Layer of Canvas "foo" with Name=MyLayer

    hey Becasso set ActiveLayer of Canvas "foo" to MyLayer

    hey Becasso delete Layer "Bar" of Canvas "foo"

    for x in 0 50 100 150 200 255
    do
        hey Becasso set GlobalAlpha of Layer Background of Canvas foo to $x
    done

    hey Becasso set Contents of Layer "bar" of Canvas "foo" to file[image.jpg]