Hi, I have made an exercise that can be usefull to someone.
On a active image, it builds and draws the histograms on several layers.
This works only on RGB images and if they have more than 8bits/channel, it will reduce to 8bit/channel before proced.
Enjoy or complete and develop it as you want.
addHistogram(true); // this draws a layer with a coloured 8bit RGB histogram
addHistogram(false, false, true); // this draws the Max(, , ) Luminosity RGB histogram (gets the max value of each channel)
addHistogram(false, true); // this draws a layer with 8bit Lightness channel Lab histogram
addHistogram(false, false); // this draws a layer with 8bit Luminosity RGB histogram
/////////////////////////////// HISTOGRAM IN LAYER ///////////////////////////////////
function addHistogram(RGB, Lab, MaxRGB) {
///////////////////////////////////////////////// createProgressWindow
var createProgressWindow = function(title, message, hasCancelButton) {
var win;
if (title == null) title = "Work in progress";
if (message == null) message = "Please wait...";
if (hasCancelButton == null) hasCancelButton = false;
win = new Window("palette", "" + title, undefined);
win.bar = win.add("progressbar", {x: 20, y: 12, width: 300, height: 20 }, 0, 100);
win.stMessage = win.add("statictext", { x: 10, y: 36, width: 320, height: 20 }, "" + message);
win.stMessage.justify = 'center';
if (hasCancelButton) {
win.cancelButton = win.add('button', undefined, 'Cancel');
win.cancelButton.onClick = function() {
win.close();
throw new Error('User canceled the pre-processing!');
};
}
this.reset = function(message) {
win.bar.value = 0;
win.stMessage.text = message;
return win.update();
};
this.updateProgress = function(perc, message) {
if (perc != null) win.bar.value = perc;
if (message != null) win.stMessage.text = message;
return win.update();
};
this.close = function() {
return win.close();
};
win.center(win.parent);
return win.show();
};
//
// the other layer histograms, if exist, should be invisible so the reading is only on the pixels of the image itself
if (getLayer("RGB histogram")) activeDocument.artLayers.getByName ("RGB histogram").visible = false;
if (getLayer("Lightness Lab histogram")) activeDocument.artLayers.getByName ("Lightness Lab histogram").visible = false;
if (getLayer("Luminosity RGB")) activeDocument.artLayers.getByName ("Luminosity RGB").visible = false;
if (getLayer("Luminosity Max")) activeDocument.artLayers.getByName ("Luminosity Max").visible = false;
//
var layerName = (RGB) ? "RGB histogram" : ((Lab) ? "Lightness Lab histogram" : ((MaxRGB) ? "Luminosity Max" : "Luminosity RGB"));
//
if (!getLayer(layerName)) {
// it works only on RGB images
if (activeDocument.mode == DocumentMode.RGB) {
// if the image is 16bit/channel or more it sets 8bits/channel before read the histogram
if (!activeDocument.bitsPerChannel == BitsPerChannelType.EIGHT) activeDocument.bitsPerChannel = BitsPerChannelType.EIGHT;
$.writeln(layerName);
var wasHereLayer = activeDocument.activeLayer;
var unitsAntes = app.preferences.rulerUnits;
var foregroundPreviousColor = app.foregroundColor;
app.preferences.rulerUnits = Units.PIXELS; // importante
activeDocument.quickMaskMode = false;
activeDocument.selection.deselect();
//
// read histogram:
var hL = activeDocument.histogram;
var hR = activeDocument.channels["Red"].histogram;
var hG = activeDocument.channels["Green"].histogram;
var hB = activeDocument.channels["Blue"].histogram;
// if you want the Luminosity of Lab, export it to Lab, read it, and revert it to RGB
if (Lab) {
activeDocument.changeMode (ChangeMode.LAB);
// read Lightness channel histogram of Lab
var hL = activeDocument.channels["Lightness"].histogram;
// revert to RGB
activeDocument.changeMode (ChangeMode.RGB);
} else {
// read Luminosity composite channel histogram of RGB
var hL = activeDocument.histogram;
}
//
var ww = activeDocument.width.as('px');
var hh = activeDocument.height.as('px');
var totalPixels = ww*hh;
var totalPixels1Col = totalPixels/256;
//
var pBar = new createProgressWindow("Histogram building...", "Please wait", false);
//
activeDocument.artLayers.add();
activeDocument.activeLayer.name = layerName;
activeDocument.activeLayer.move( activeDocument, ElementPlacement.PLACEATBEGINNING );
activeDocument.activeLayer.blendMode = BlendMode.NORMAL; // blending mode "normal"
activeDocument.activeLayer.opacity = 60; // opacity 60%
//
var hhGraph = 60;
var hY = 400; // base y of graph
var hX = 100; // base x of graph
// base transparent
app.foregroundColor.rgb.red = 0;
app.foregroundColor.rgb.green = 0;
app.foregroundColor.rgb.blue = 0;
//
drawSelectionScreen (hX-2, hY+2, 258+hX, hY-322);
// fill (filltype [, mode] [, opacity] [, preserveTransparency]) // filltype: SolidColor | mode: ColorBlendMode | opacity: [1..100]
app.activeDocument.selection.fill(app.foregroundColor, ColorBlendMode.SCREEN, 40, false);
activeDocument.selection.deselect();
//
var myHist = [];
//
if (RGB) {
for (var a in activeDocument.componentChannels) {
// criar as 3 cores R, G e B e o graph da cada uma
(a==0) ? app.foregroundColor.rgb.red = 255 : app.foregroundColor.rgb.red = 0;
(a==1) ? app.foregroundColor.rgb.green = 255 : app.foregroundColor.rgb.green = 0;
(a==2) ? app.foregroundColor.rgb.blue = 255 : app.foregroundColor.rgb.blue = 0;
//
if (a==0) myHist = hR;
if (a==1) myHist = hG;
if (a==2) myHist = hB;
//
for ( i = 0; i <= 255; i++ ) {
var col = i+hX;
var YYY = Math.min(Math.floor(myHist*hhGraph/totalPixels1Col), 320);
drawSelectionScreen (col, hY, col+1, hY-YYY);
//
var percent = Math.floor(((i+1)+(a*256))*100/768);
pBar.updateProgress (percent, activeDocument.componentChannels.name.toUpperCase() + " Channel " + percent+ " % completed");
}
// fill (filltype [, mode] [, opacity] [, preserveTransparency]) // filltype: SolidColor | mode: ColorBlendMode | opacity: [1..100]
app.activeDocument.selection.fill(app.foregroundColor, ColorBlendMode.SCREEN, 100, false);
activeDocument.selection.deselect();
}
} else {
app.foregroundColor.rgb.red = 255;
app.foregroundColor.rgb.green = 255;
app.foregroundColor.rgb.blue = 255;
myHist = hL;
for ( i = 0; i <= 255; i++ ) {
var col = i+hX;
if (MaxRGB) {
var YYY = Math.min(Math.floor(Math.max(hR, hG, hB)*hhGraph/totalPixels1Col), 320);
} else {
var YYY = Math.min(Math.floor(myHist*hhGraph/totalPixels1Col), 320);
}
drawSelectionScreen (col, hY, col+1, hY-YYY);
//
var percent = Math.floor((i+1)*100/256);
pBar.updateProgress (percent, "Luminosity Channel " + percent+ " % completed");
}
// fill (filltype [, mode] [, opacity] [, preserveTransparency]) // filltype: SolidColor | mode: ColorBlendMode | opacity: [1..100]
app.activeDocument.selection.fill(app.foregroundColor, ColorBlendMode.SCREEN, 100, false);
activeDocument.selection.deselect();
}
pBar.close();
// activeDocument.activeLayer = wasHereLayer;
app.preferences.rulerUnits = unitsAntes;
app.foregroundColor = foregroundPreviousColor;
$.gc();
} else {
alert("Must be an RGB image");
}
} else {
alert("Already has created this '" + layerName + "' layer!");
return;
}
function drawSelectionScreen(x1, y1, x2, y2) {
$.level = 0;
try {
// SelectionType.SELECTEDAREA | DIMINISH | EXTEND | INTERSECT | REPLACE
activeDocument.selection.select([[ x1, y1], [x2, y1], [x2, y2], [x1,y2]], SelectionType.EXTEND, 0, false);
} catch(e) {}
$.level = 1;
}
function drawLineScreen(x1, y1, x2, y2, width, transparency) {
$.level = 0;
try {
var desc = new ActionDescriptor();
var lineDesc = new ActionDescriptor();
var startDesc = new ActionDescriptor();
startDesc.putUnitDouble( charIDToTypeID('Hrzn'), charIDToTypeID('#Pxl'), x1 );
startDesc.putUnitDouble( charIDToTypeID('Vrtc'), charIDToTypeID('#Pxl'), y1 );
lineDesc.putObject( charIDToTypeID('Strt'), charIDToTypeID('Pnt '), startDesc );
var endDesc = new ActionDescriptor();
endDesc.putUnitDouble( charIDToTypeID('Hrzn'), charIDToTypeID('#Pxl'), x2 );
endDesc.putUnitDouble( charIDToTypeID('Vrtc'), charIDToTypeID('#Pxl'), y2 );
lineDesc.putObject( charIDToTypeID('End '), charIDToTypeID('Pnt '), endDesc );
lineDesc.putUnitDouble( charIDToTypeID('Wdth'), charIDToTypeID('#Pxl'), width ); //
desc.putObject( charIDToTypeID('Shp '), charIDToTypeID('Ln '), lineDesc );
desc.putEnumerated( charIDToTypeID( "Md " ), charIDToTypeID( "BlnM" ), charIDToTypeID( "Scrn" ) ); // mode: Screen
desc.putUnitDouble( charIDToTypeID( "Opct" ), charIDToTypeID( "#Prc" ), transparency ); // [0-100] transparency
desc.putBoolean( charIDToTypeID('AntA'), false ); // important antialias should be false
executeAction( charIDToTypeID('Draw'), desc, DialogModes.NO );
} catch(e) {}
$.level = 1;
}
//////////////////////////////////
function getLayer(layername) {
var result = false;
for (var a=0; a<activeDocument.artLayers.length ; a++) {
if (String(activeDocument.artLayers.name) == layername) {
result = true;
break;
}
}
return result;
}
}
19
Replies
I like visible incement. It works very fast (as far as panels are hidden, but that's normal). The end result makes only last layer is visible. Shouldn't all be checked? Anyway that is ok too 
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