Resizing document without losing colored pixels

[Feast]

I've been using Photoshop's Trim and Resize image and I realized that it always deletes unwanted pixels of my .psd document.

What can I do to have a more accurate Trim / Resize on my documents? I believe the cause of this is due to Resize.

The script is very simple:

    doc = app.activeDocument;
    // trim
    doc.trim(TrimType.TRANSPARENT);
    // ========== set units to pixels ==========//
    var oldPrefs = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;
    DocTrimmedWidth = doc.width;
    DocTrimmedHeight = doc.height;
    // resize algorithm
    if (DocTrimmedHeight > DocTrimmedWidth) {
        doc.resizeImage(undefined, UnitValue(1024, "px"),72, ResampleMethod.BICUBIC, 100);
    }
    else {
        doc.resizeImage(UnitValue(1024, "px"), undefined, 72, ResampleMethod.BICUBIC, 100);
    }
    doc.activeLayer.applyOffset(0,512, OffsetUndefinedAreas.WRAPAROUND);

I tried different kinds of ResampleMethods to no avail. Here's the .psd I'm using it on:
ImproperResize.psd - Google Drive

There are always transparents pixels appearing on the .psd. What can I do about this problem?
https://i.imgur.com/TZc36yG.png

[r-bin · Accepted solution]

Try using this plugin for the resize

C3C Image Size – Telegraph

[r-bin]

You can call this plugin in the script using the following function

)

function c3c_resize(w, h, sharp, use_contrast)
    {   
    try {
        if (sharp == undefined) sharp = 0;
        if (use_contrast == undefined) use_contrast = false;
        var old_units = app.preferences.rulerUnits;
        app.preferences.rulerUnits = Units.PIXELS;
        var doc = app.activeDocument;
        var w0 = Number(doc.width.value);
        var h0 = Number(doc.height.value);
        while (w > w0 || h > h0) 
            {
            doc.resizeImage(UnitValue(4*w0,"px"), UnitValue(4*h0,"px"), doc.resolution, ResampleMethod.NEARESTNEIGHBOR);
            w0 = Number(doc.width.value);
            h0 = Number(doc.height.value);
            }
        app.preferences.rulerUnits = old_units;
        var d = new ActionDescriptor();
        d.putInteger( charIDToTypeID( "Wdth" ), w );
        d.putInteger( charIDToTypeID( "Hght" ), h );
        d.putBoolean( charIDToTypeID( "cC3P" ), true );
        d.putBoolean( charIDToTypeID( "cC3F" ), false );
        d.putEnumerated( charIDToTypeID( "uc3S" ), charIDToTypeID( "tc3U" ), charIDToTypeID( "uc30" ) );
        if (use_contrast == true)
            d.putEnumerated( charIDToTypeID( "mc3S" ), charIDToTypeID( "tc3M" ), charIDToTypeID( "rc31" ) );
        else
            d.putEnumerated( charIDToTypeID( "mc3S" ), charIDToTypeID( "tc3M" ), charIDToTypeID( "rc30" ) );
        d.putInteger( charIDToTypeID( "pC3S" ), sharp );
        d.putInteger( charIDToTypeID( "pC3W" ), w );
        d.putInteger( charIDToTypeID( "pC3H" ), h );
        executeAction( stringIDToTypeID( "5f3d6843-d895-44c2-bbb7-b71ca0cb8c01" ), d, DialogModes.NO );
        return true;
        }
    catch (e) { alert(e); return false; }
    }

[Feast]

Great, thanks for the help r-bin. I'll try this out in an hour when I'm back home.

[r-bin]

Please change the line in the function

d.putBoolean( charIDToTypeID( "cC3P" ), true );

to

d.putBoolean( charIDToTypeID( "cC3P" ), false );

This guarantees the exact final dimensions W and H that you set.

This parameter tries to keep the proportions fitting on only the width

[Feast]

It works great, thanks Much appreciated!

[Geppetto Luis]

I tried to use it on mac

with photoshop  cs6 cc cc2014 does not work?

[r-bin]

It's strange. On a mac I can not say anything. Write to the author.