How to reset Scale percentage using script

Hi Loïc,

That's probably one of the best examples of invoking a MenuAction!

In terms of transformations, “Redefine Scaling as 100%” is much more complex than I imagined. There are probably good solutions using resize() and/or (horizontal/vertical)Scale properties. But from an educational standpoint it's interesting to implement that function strictly using the transformation and coordinate space API.

What is required here is:

(0) backup the original scaling factors,

(1) apply a 100% scaling with ajustScalingPercentage turned on,

(2) restore the original scaling factors with applyToContent turned on.

Surprisingly complicated! I did not manage to emulate the command in a more compact way:

function redefineScalingAs100(/*Image|<ImageContainer>*/sel,  img,p,orig,mx,pf,t)
//----------------------------------
// Emulate the "Redefine Scaling as 100%" menu action through
// detailed transform steps. As shown by Loic Aigon, invoking
// `app.menuActions.itemByName("$ID/RedefineScalingMenuString")`
// does the entire job in one single command. The present snippet
// attempts to reach the same outcome from pure transformations.
{
    // Checkpoint.
    // ---
    if( !sel ){ alert("Select an image."); return; }
    // ---
    ( sel instanceof Image )
    ? ( p=(img=sel).parent )
    : ( img=(p=sel).hasOwnProperty('images') && p.images[0] );
    // ---
    if( !img.isValid ){ alert("No image found."); return; }
    // Constants.
    // ---
    const CS_REF = +CoordinateSpaces.parentCoordinates;
    const CS_INN = +CoordinateSpaces.innerCoordinates;
    const CS_PBD = +CoordinateSpaces.pasteboardCoordinates;
    // ---
    const BB_VIS = +BoundingBoxLimits.OUTER_STROKE_BOUNDS;
    // ---
    const WS_SCA = +WhenScalingOptions.adjustScalingPercentage;
    const WS_RSZ = +WhenScalingOptions.applyToContent;
    // ---
    const MC_SCA = +MatrixContent.scaleValues;
    // Visible box center in *pasteboard* coordinates (because
    // we want that location to remain invariant.)
    // ---
    orig = p.resolve([AnchorPoint.centerAnchor, BB_VIS, CS_INN], CS_PBD)[0];
    
    // Matrix of `p` relative to its parent space--i.e, affine map.
    // (The whole purpose of `mx` is to backup scaling factors.)
    // ---
    mx = p.transformValuesOf(CS_REF)[0];
    if( 1==mx.horizontalScaleFactor && 1==mx.verticalScaleFactor ) return;
    // 1. Reset `p` scaling to 100% relative to its parent space.
    //    (`adjustScalingPercentage` is temporarily required.)
    // ---
    t = +(pf=app.transformPreferences).whenScaling;
    t==WS_SCA ? ( t=0 ) : ( pf.whenScaling=WS_SCA );
    p.transform( CS_REF, orig, [1,0,0,1,0,0], MC_SCA );
    t && (pf.whenScaling=t);
    
    // 2. Recover the original size by applying `mx` scale values.
    //    (`applyToContent` is temporarily required.)
    // ---
    t ? (t=0) : ( pf.whenScaling=t=WS_RSZ );
    p.transform( CS_REF, orig, mx, MC_SCA );
    t && (pf.whenScaling=t);
}
// Test.
// ---
redefineScalingAs100(app.selection[0]);

Best,

Marc