gistfile1.js

// (shift control cmd c)

function theFunction() {
    var color = null,
    results = 0,
    referenceColor = null,
    selected = null;

    if (selection.count() == 1) {

        // get the selected layer
        selected = selection[0];

        // get color of selected layer
        referenceColor = getColorOf(selected);

        // loop through all layers of the page
        var layers = doc.currentPage().children().objectEnumerator();

        while (layer = layers.nextObject()) {
          // get color of layer
            try {
                color = getColorOf(layer);

                if (areEqual(color, referenceColor)) {
                    // select layer if colors are equal
                    layer.setIsSelected(true);
                    results++;
                }
            } catch (error) {
                log("error comparing colors");
            }
        }

        doc.showMessage(results + " layers of " + doc.currentPage().children().count() + " selected. " + referenceColor);
    } else {
        doc.showMessage("Please select a reference layer.");
    }
};

function getColorOf(_layer) {
    var color = null,
    fill = null,
    style = null,
    fills = null,
    className = String(_layer.className());

    switch (className) {

        case "MSTextLayer":

            try {
                // get the text color
                color = _layer.textColor();

                // check if the text layer has a fill color
                fill = layer.style().fills().firstObject();
                if (fill != undefined && fill.isEnabled()) {
                    color = fill.color();
                }
            } catch (error) {
                log(error);
            }
        break;
            case "MSOvalShape":
            case "MSShapeGroup":
            case "MSShapePathLayer":
            case "MSRectangleShape":
                try {
                    // try to determin the fill type
                    style = _layer.style();
                    if (style.fills()) {
                        fills = style.fills();
                        if (fills.count() > 0) {
                            fill = fills.firstObject();
                            if (fill != null && fill.isEnabled()) {
                                if(fill.fillType() == 0) {
                                    // solid color
                                    color = fill.color();
                                } else {
                                    // any other fill
                                    color = fill;
                                }
                            }
                        }
                    }
                } catch (error) {
                    log("could not get color");
                }
        break;
        }
    return color;
}

theFunction();

function areEqual(a, b) {

    var ca = null;
    var cb = null;
    var hex_a = null;
    var hex_b = null;

    try {
        ca = String(a.className());
        cb = String(b.className());

        log("received classnames " + ca + " / " + cb);
    } catch (error) {
        log("could not receive classnames");
    }

    try {
      if (ca === "MSColor" && cb === "MSColor") {
          try {
              hex_a = String(a.hexValue());
          } catch (error) {
              log("couldn’t get hex a");
          }

          try {
              hex_b = String(b.hexValue());
          } catch (error) {
              log("couldn’t get hex a");
          }

          if (hex_a && hex_b) {
              return hex_a === hex_b;
          }
      } else if (ca === "MSStyleFill" && cb === "MSStyleFill") {
          switch (a.fillType()) {
              // pattern
              case 4:
                  if (a.image() == b.image()) return true;
              break;
              // gradient
              case 1:
                  // check if both gradients have the same number of stops
                  var stopsA = a.gradient().stops();
                  var stopsB = b.gradient().stops();

                  if (stopsA.count() == stopsB.count()) {
                      for (var i = 0; i < stopsA.count(); i++) {
                          if (stopsA.objectAtIndex(i).color() != stopsB.objectAtIndex(i).color() || stopsA.objectAtIndex(i).position() != stopsB.objectAtIndex(i).position()) {
                              return false;
                          }
                      }
                      return true;
                  }
              break;

              default:
                  log("default");
              break;
          }
      }
    } catch (error) {
        log("error comparing " + a.fillType() + " / " + b.fillType());
    }
    return false;
}