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Participating Frequently
February 14, 2019
Answered

Find extrema of an irregular shape to place guides

  • February 14, 2019
  • 1 reply
  • 609 views

Hi,

I want to use a script to find the extrema (x,y) of irregular shapes (on a white background) to place four guides automatically (inscribing the shape in a rectangle).

My idea is to scan the RGB values line per line horizontally and vertically - the position of the top horizontal guide therefore

should be the one, where the values are continously 255, 255, 255 through the entire width of the image for the last time (from the top) and so forth.

This is how it should look finally:

What would the code for such a task look like?

Thanks.

This topic has been closed for replies.
Correct answer r-bin

Direct function for scanning pixels is not in Photoshop.

But you can do something like this.

// click magicwand at point [0,0] px
var d = new ActionDescriptor();
var r = new ActionReference();
r.putProperty(stringIDToTypeID("channel"), stringIDToTypeID("selection"));
d.putReference(stringIDToTypeID("null"), r);
var d1 = new ActionDescriptor();
d1.putUnitDouble(stringIDToTypeID("horizontal"), stringIDToTypeID("pixelsUnit"), 0);
d1.putUnitDouble(stringIDToTypeID("vertical"),   stringIDToTypeID("pixelsUnit"), 0);
d.putObject(stringIDToTypeID("to"), stringIDToTypeID("point"), d1);
d.putInteger(stringIDToTypeID("tolerance"), 0);
d.putBoolean(stringIDToTypeID("antiAlias"), false);
d.putBoolean(stringIDToTypeID("merged"), true);
executeAction(stringIDToTypeID("set"), d, DialogModes.NO);
// invert selection
activeDocument.selection.invert();
// create guides
if (preferences.rulerUnits == Units.PERCENT) preferences.rulerUnits = Units.CM;
activeDocument.guides.add(Direction.HORIZONTAL, activeDocument.selection.bounds[1]);
activeDocument.guides.add(Direction.VERTICAL,   activeDocument.selection.bounds[0]);
activeDocument.guides.add(Direction.HORIZONTAL, activeDocument.selection.bounds[3]);
activeDocument.guides.add(Direction.VERTICAL,   activeDocument.selection.bounds[2]);
// deselect selection
activeDocument.selection.deselect();

1 reply

R
r-binCorrect answer
Legend
February 14, 2019

Direct function for scanning pixels is not in Photoshop.

But you can do something like this.

// click magicwand at point [0,0] px
var d = new ActionDescriptor();
var r = new ActionReference();
r.putProperty(stringIDToTypeID("channel"), stringIDToTypeID("selection"));
d.putReference(stringIDToTypeID("null"), r);
var d1 = new ActionDescriptor();
d1.putUnitDouble(stringIDToTypeID("horizontal"), stringIDToTypeID("pixelsUnit"), 0);
d1.putUnitDouble(stringIDToTypeID("vertical"),   stringIDToTypeID("pixelsUnit"), 0);
d.putObject(stringIDToTypeID("to"), stringIDToTypeID("point"), d1);
d.putInteger(stringIDToTypeID("tolerance"), 0);
d.putBoolean(stringIDToTypeID("antiAlias"), false);
d.putBoolean(stringIDToTypeID("merged"), true);
executeAction(stringIDToTypeID("set"), d, DialogModes.NO);
// invert selection
activeDocument.selection.invert();
// create guides
if (preferences.rulerUnits == Units.PERCENT) preferences.rulerUnits = Units.CM;
activeDocument.guides.add(Direction.HORIZONTAL, activeDocument.selection.bounds[1]);
activeDocument.guides.add(Direction.VERTICAL,   activeDocument.selection.bounds[0]);
activeDocument.guides.add(Direction.HORIZONTAL, activeDocument.selection.bounds[3]);
activeDocument.guides.add(Direction.VERTICAL,   activeDocument.selection.bounds[2]);
// deselect selection
activeDocument.selection.deselect();
B
black_squareAuthor
Participating Frequently
February 14, 2019

Kudos, that does exactly what I want. Thank you.

One more question:

If I selected the rectangular formed by the guides automatically,

how would it be done?

R
r-bin
Legend
February 14, 2019

Instead of 

activeDocument.selection.deselect(); 

use

preferences.rulerUnits = Units.PIXELS;  
var x0 = activeDocument.selection.bounds[0];
var y0 = activeDocument.selection.bounds[1];
var x1 = activeDocument.selection.bounds[2];
var y1 = activeDocument.selection.bounds[3];
activeDocument.selection.select([[x0,y0], [x1,y0], [x1,y1], [x0,y1]]);
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