How to rotate all items as a group? (In a script, Illustrator)

Question

I have an SVG with a few curved paths. I'd like to create n versions of this, by rotating them around as a group (360 / n degrees apart), around the center of the square-shaped canvas they're in, like this:

Then, I'd like to save these into separate SVG files.

Based on some initial research, this should be possible in Illustrator. However, I can't even get it to rotate all objects as a group, I can only rotate each object around its center with:

doc = app.activeDocument;
sel = doc.pageItems;
for (var i = 0; i < sel.length; i++) {
    sel[i].rotate(30);
}

How could I do this? (I'm also open to any software alternative.)

Answer 1

Quick primer into computer graphics programming. Whenever you are trying to do a compound transform it is best to compose the transform onto a matrix operation. Mainly because you can specify a complex transformation in one go.

OK so no we have to compute the bounds. But then you might rotate around a arbitrary point in some case too (this makes it easy).

#target illustrator

var doc = app.activeDocument;
var sel = doc.pageItems;
var bounds = calculate_bounds(sel);
var center = [(bounds[0]+bounds[2])/2,
              (bounds[1]+bounds[3])/2]

for (var i = 0; i < sel.length; i++) {
    rotate_around_global_pos(sel[i], 30, center);
}


/********* Support functions *********/

function rotate_around_global_pos(obj, ang, pos) {
    var rot = app.getRotationMatrix(15);
    var mov = app.getTranslationMatrix(pos[0], pos[1]);
    var inv = app.invertMatrix(mov);
    var mtx = app.concatenateMatrix(inv, rot);
    var mtx = concatenateMatrix(mtx, mov);

    obj.transform(mtx, 1, 1, 1, 1, 1, Transformation.DOCUMENTORIGIN);
}

function calculate_bounds(sel){
    var minX = Number.POSITIVE_INFINITY;
    var maxX = Number.NEGATIVE_INFINITY;
    var minY = Number.POSITIVE_INFINITY;
    var maxY = Number.NEGATIVE_INFINITY;


    for (i = 0; i < sel.length; i++){
        var item = sel[i];
        var bounds = sel[i].controlBounds;

        minX = Math.min( minX, bounds[0], bounds[2] );
        maxX = Math.max( maxX, bounds[0], bounds[2] );
        minY = Math.min( minY, bounds[1], bounds[3] );
        maxY = Math.max( maxY, bounds[1], bounds[3] );
    }
    return [maxX, maxY, minX, minY];
}

Answer 2

You could always record an action on one file (Window > Actions) and then run the rest as a batch using that action...

I did a test creating, saving out the first group and then rotating and saving out 7 copies... and it worked just fine:

Here is my action so you can see how I did it:

Answer 3

Combining joojaa's matrix manipulation and Cai's SVG exporting loop, I ended up with this script:

#target illustrator

var doc = app.activeDocument;
var docDir = ( doc.path != '' ) ? doc.path : '~';

var n = 20,
    iterations = n - 1,
    angle = 360 / n,
    destFolder = 'rotated'; // output files are saved in this subfolder

rotateAndExport();

function rotateAndExport() {
    var pos = [doc.width / 2, doc.height / 2];
    var layer = doc.layers[0];
    exportFile(1); // save the original file into the output folder
    for ( var r = 0; r < iterations; r++ ) {
        for ( var j = 0; j < layer.pageItems.length; j++ ) {
            var item = layer.pageItems[j];
            rotate_around_global_pos(item, -angle, pos);
        }
        exportFile(r + 2);
    }
}

function pad(number) { // pad with a leading zero (%02d)
    if (number <= 9) number = "0" + number;
    return number;
}

function exportFile( iteration ) {
    // create folder if it doesn't exist
    var destPath = docDir + '/' + destFolder;
    if ( false == Folder( destPath ).exists ) {
        new Folder( destPath ).create();
    }

    // export options
    var destFile;
    var type;
    var exportOptions;

    var svgPath = destPath + '/';
    destFile = new File( svgPath + '/output_' + pad(iteration) + ".svg");

    type = ExportType.SVG;
    exportOptions = new ExportOptionsSVG();
    exportOptions.preserveEditability   = false;
    exportOptions.embedRasterImages     = true;
    exportOptions.embedAllFonts         = false;
    exportOptions.encoding              = SVGDocumentEncoding.UTF8;
    exportOptions.fontType              = SVGFontType.OUTLINEFONT;

    doc.exportFile( destFile, type, exportOptions );
}

function rotate_around_global_pos(obj, ang, pos) {
    var rot = app.getRotationMatrix(ang);
    var mov = app.getTranslationMatrix(pos[0], pos[1]);
    var inv = app.invertMatrix(mov);
    var mtx = app.concatenateMatrix(inv, rot);
    var mtx = concatenateMatrix(mtx, mov);

    obj.transform(mtx, 1, 1, 1, 1, 1, Transformation.DOCUMENTORIGIN);
}

This script creates a subfolder next to the file currently open, and saves n states, each of which are rotated clockwise with the same angle one after another. (The paths don't need to be grouped, and no additional rectangle needs to be added.)

Answer 4

If you are using an SVG file, you can open it in Adobe Illustrator. Then select all of your objects that you wish to rotate. Ctrl + A should do. Then right click and group them. Now, you can easily rotate them as one.

You can ungroup them later as well.

Answer 5

In addition to the answer by @Yash Sheth, your question does not need be scripted per se. You can perform it quite efficiently without. Illustrator has the 'transform again' function, (CMD or CTRL + D).

So, you could:

1. Group the items
2. Object --> Transform --> Rotate
3. Choose 360/n degress
4. Press 'Copy' (not APPLY)
5. Now, press CMD+D an n amount of times.

Additionally (though not tested), you could create a series of n equally spaced artboards, place the first 0º copy and the last 360º-360º/n copy on the first and last artboard, and use the 'distribute objects' functionality to place one copy on each artboard.Export each artboard individually.