Randomly deleting parts of image/pixels - photoshop

Question

I'm wondering whether anyone knows how I might randomly delete/remove certain parts of an image. Is there some sort of filter for this where I can specify the % of the picture that I want to be deleted? (I'm coming up short with my Google searches.)

Answer 1

You could right something like this:
It's not very efficient! As it's looping over a selection and then deleting those pixels. Over and over again.
I tried it with an 1 MB image and a setting of 50 % deletion it took a couple of minutes. So you're warned.
// call the source document
var srcDoc = app.activeDocument;
// Get original width and height
var imageWidth = srcDoc.width.value;
var imageHeight = srcDoc.height.value;
// Selection size for deleting pixels
// You could make these random
var sizeX = 20;
var sizeY = 20;
// Define the number of parts you want to delete
// Area of image = imageWidth * imageHeight
// Example image 1600 x 1200, area = 1920000 pixels
// To delete 50% would be the same as selecting
// an area that's (sizeX * sizeY) *2400 times
var pcent = 0.1; //10% of image
var area = imageWidth * imageHeight;
var selArea = sizeX * sizeY; //selection area
var numParts = pcent * (area/ selArea);
numParts = parseInt(numParts);
for (var i = 0; i < numParts; i++)
{
var randX = Math.floor(Math.random() * (imageWidth-sizeX));
var randY = Math.floor(Math.random() * (imageHeight-sizeY));
// deselect EVERYTHING first
srcDoc.selection.deselect();
// select random position of selection
selectRectangle(randY, randX, randY+sizeY, randX+sizeX);
// Delete those pixels
srcDoc.selection.clear();
// deselect EVERYTHING first
srcDoc.selection.deselect();
}
// function SELECT RECTANGLE(top, left, bottom, right)
//
// Note: co-ordinates are same as script listener
// and not so human-friendly as t,l,r,b.
// --------------------------------------------------------
function selectRectangle(top, left, bottom, right)
{
// =======================================================
var id1 = charIDToTypeID( "setd" );
var desc1 = new ActionDescriptor();
var id2 = charIDToTypeID( "null" );
var ref1 = new ActionReference();
var id3 = charIDToTypeID( "Chnl" );
var id4 = charIDToTypeID( "fsel" );
ref1.putProperty( id3, id4 );
desc1.putReference( id2, ref1 );
var id5 = charIDToTypeID( "T " );
var desc2 = new ActionDescriptor();
var id6 = charIDToTypeID( "Top " );
var id7 = charIDToTypeID( "#Pxl" );
desc2.putUnitDouble( id6, id7, top );
var id8 = charIDToTypeID( "Left" );
var id9 = charIDToTypeID( "#Pxl" );
desc2.putUnitDouble( id8, id9, left );
var id10 = charIDToTypeID( "Btom" );
var id11 = charIDToTypeID( "#Pxl" );
desc2.putUnitDouble( id10, id11, bottom );
var id12 = charIDToTypeID( "Rght" );
var id13 = charIDToTypeID( "#Pxl" );
desc2.putUnitDouble( id12, id13, right );
var id16 = charIDToTypeID( "Rctn" );
desc1.putObject( id5, id16, desc2 );
executeAction( id1, desc1, DialogModes.NO );
}