在 Photoshop 脚本中获取一个像素的颜色

Posted 2023-02-16

【中文标题】在 Photoshop 脚本中获取一个像素的颜色

【英文标题】：Get the color of one pixel at Photoshop scripts

【发布时间】：2018-06-19 17:11:02

【问题描述】：

我正在尝试弄清楚如何获得一个已定义像素的颜色。

在我的想象中应该是这样的：

color = get.color.Pixel(x,y);

也许有人可以帮助我处理这段代码？

【参考方案1】：

Photoshop 的 javascript API 没有提供您在问题中想象的机制。

您需要使用Document.colorSamplers.add([x, y]) 方法，然后通过其属性读取每个组件的颜色值：

以下要点显示如何获取给定x,y 坐标的rgb 或cmyk 值：

#target photoshop

// Define the x and y coordinates for the pixel to sample.
var x = 1;
var y = 1;

// Add a Color Sampler at a given x and y coordinate in the image.
var pointSample = app.activeDocument.colorSamplers.add([(x - 1),(y - 1)]);

// Obtain array of RGB values.
var rgb = [
    pointSample.color.rgb.red,
    pointSample.color.rgb.green,
    pointSample.color.rgb.blue
];

// Obtain array of rounded CMYK values.
var cmyk = [
    Math.round(pointSample.color.cmyk.cyan),
    Math.round(pointSample.color.cmyk.magenta), 
    Math.round(pointSample.color.cmyk.yellow),
    Math.round(pointSample.color.cmyk.black)
];

// Remove the Color Sampler.
pointSample.remove();

// Display the complete RGB values and each component color.
alert('RGB: ' + rgb)
alert('red: ' + rgb[0])
alert('green: ' + rgb[1])
alert('blue: ' + rgb[2])

// Display the complete CMYK values and each component color.
alert('CMYK: ' + cmyk)
alert('cyan: ' + cmyk[0])
alert('magenta: ' + cmyk[1])
alert('yellow: ' + cmyk[2])
alert('black: ' + cmyk[3])

【讨论】：

如果您需要扫描大面积而不是一个像素（（（您将等待数小时扫描 1000x1000 像素图像

@bodich colorSamplers 可以移动 - 如果你移动而不是为每个像素重新创建它，它仍然很慢吗？

@darda 我刚刚测量了 100x100 像素区域的时间。重新创建颜色采样器时，需要 60 秒才能完成循环。移动颜色采样器时，需要 32 秒。速度快了两倍，但速度仍然非常慢。如果您移动颜色采样器，12 兆像素的图片将在 10 小时内处理完毕。 PS：8核Intel i7

【参考方案2】：

这是一个使用ColorSampler 的简单脚本。它设置为返回 RGB 值。

function PixelSampler(doc) 
    this.doc = doc
    this.doc.colorSamplers.removeAll();
    this.sampler = this.doc.colorSamplers.add([0, 0]);


// Return an array of R, G, B pixel values for a particular coordinate.
PixelSampler.prototype.get = function (x, y) 
    this.sampler.move([x, y]);
    const R = this.sampler.color.rgb.red;
    const G = this.sampler.color.rgb.green;
    const B = this.sampler.color.rgb.blue;
    return [R, G, B];


////////////////////////////////////////////////////////
/// SOME TESTS /////////////////////////////////////////
////////////////////////////////////////////////////////

const p = new PixelSampler(app.activeDocument);
alert("Pixel 0 =\n\n" + p.get(0, 0));

$.hiresTimer;
var n = 1000; //p.width * p.height;
for (var i = 0; i < n; i++) p.get(i, 0);
sec = ($.hiresTimer / 1000 / 1000);
alert("Got " + (n / 1000) + " kilopixels in " + sec.toFixed(2) + " seconds.");

这使我的机器上的像素值约为 100 像素/秒。

我找到了this 并稍微清理了脚本。基本上，这个想法是：

将当前图像保存为原始位图。 重新读入，但在 javascript 端。 在 javascript 端对像素进行所有访问。

这为我提供了大约 72,000 像素每秒的像素值，不包括将原始数据写入磁盘并将其读回的开销。它还有一个额外的好处是您可以设置像素值，也是。

// Adapted from https://community.adobe.com/t5/photoshop/get-index-of-each-pixel/td-p/10022899?page=1
// The purpose is to query (and change) pixel values quickly.
//
// The secret to speed is doing everything on the script side rather than ask Photoshop to do things.
// We use files on disk as an intermediary; on the script side, we read / write it as a binary file; on the
// Photoshop side, we save / open it as a raw bitmap.
//
// Only works on RGB 8bpp images, but this could be easily extended to support others.
function RawPixels(doc) 
    this.doc = doc;

    const currentActiveDoc = app.activeDocument;

    // Obtain the width and height in pixels of the desired document.
    const currentRulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;
    app.activeDocument = doc;
    this.width = Number(doc.width.value);
    this.height = Number(doc.height.value);
    this.length = this.width * this.height;
    this.pixelData = "";

    // Return the ruler to its previous state.
    app.preferences.rulerUnits = currentRulerUnits;

    try 
        // We're going to save this document as a raw bitmap to be able to read back in the pixel values
        // themselves.
        const file = new File(Folder.temp.fsName + "/" + Math.random().toString().substr(2) + ".raw");

        // Set up the save action.
        // See https://helpx.adobe.com/photoshop/using/file-formats.html#photoshop_raw_format for some info,
        // and more technical at https://www.adobe.com/devnet-apps/photoshop/fileformatashtml/
        var rawFormat = new ActionDescriptor();
        rawFormat.putString(stringIDToTypeID("fileCreator"), "8BIM");
        rawFormat.putBoolean(stringIDToTypeID("channelsInterleaved"), true);
        
        var saveAction = new ActionDescriptor();
        saveAction.putObject(stringIDToTypeID("as"), stringIDToTypeID("rawFormat"), rawFormat);
        saveAction.putPath(stringIDToTypeID("in"), file);
        saveAction.putBoolean(stringIDToTypeID("copy"), false);
        executeAction(stringIDToTypeID("save"), saveAction, DialogModes.NO);

        // File is saved; now read it back in as raw bytes.
        file.open("r");
        file.encoding = "BINARY";
        this.pixelData = file.read();

        const err = file.error;
        file.close();
        file.remove();
        file = null;
        if (err) alert(err);
    
    catch (e)  alert(e); 

    // Return focus to whatever the user had.
    app.activeDocument = currentActiveDoc;


// Calculate offset from x, y coordinates. Does not check for valid bounds.
getOffset = function(x, y) 
    if (y == undefined) 
        // allow linear indices too
        y = Math.floor(x / this.width); 
        x = x - y * this.width;
    
    return (y * this.width + x) * 3;


// Return an array of R, G, B pixel values for a particular coordinate.
RawPixels.prototype.get = function (x, y) 
    const off = getOffset(x, y);
    const R = this.pixelData.charCodeAt(off + 0);
    const G = this.pixelData.charCodeAt(off + 1);
    const B = this.pixelData.charCodeAt(off + 2);
    return [R, G, B];


// Set the pixel at x, y to the values in RGB.
RawPixels.prototype.set = function (RGB, x, y) 
    const off = getOffset(x, y);
    // note: note checking that length of p = 3!
    const R = String.fromCharCode(RGB[0]);
    const G = String.fromCharCode(RGB[1]);
    const B = String.fromCharCode(RGB[2]);

    this.pixelData = this.pixelData.substr(0, off) + R + G + B + this.pixelData.substr(off + 3);


// If any changes were made to the pixels, we need to save them to disk and have Photoshop read that file back in.
// We do that by creating a new layer in the desired document.
RawPixels.prototype.create_layer = function () 
    try 
        const file = new File(Folder.temp.fsName + "/" + Math.random().toString().substr(2) + ".raw");
        file.open("w");
        file.encoding = "BINARY";
        file.write(this.pixelData);

        const err = file.error;
        file.close();
        if (err)  file.remove(); alert(err); return; 

        var rawFormat = new ActionDescriptor();
        rawFormat.putInteger(stringIDToTypeID("width"), this.width);
        rawFormat.putInteger(stringIDToTypeID("height"), this.height);
        rawFormat.putInteger(stringIDToTypeID("channels"), 3);
        rawFormat.putBoolean(stringIDToTypeID("channelsInterleaved"), true);
        rawFormat.putInteger(stringIDToTypeID("depth"), 8);

        var openAction = new ActionDescriptor();
        openAction.putPath(stringIDToTypeID("null"), file);
        openAction.putObject(stringIDToTypeID("as"), stringIDToTypeID("rawFormat"), rawFormat);
        executeAction(stringIDToTypeID("open"), openAction, DialogModes.NO);
        file.remove();

        // The new active document is the file we just opened. Duplicate its contents into 
        // a new layer in our desired document, then close this temporary file.
        app.activeDocument.activeLayer.duplicate(this.doc.layers[0], ElementPlacement.PLACEBEFORE);
        const tempDoc = app.activeDocument;
        app.activeDocument = this.doc;
        this.doc.layers[0].name = "Pixels";
        app.activeDocument = tempDoc;
        app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
        app.activeDocument = this.doc;
    
    catch (e)  alert(e); 


////////////////////////////////////////////////////////
/// SOME TESTS /////////////////////////////////////////
////////////////////////////////////////////////////////

$.hiresTimer;
const p = new RawPixels(app.activeDocument);
var sec = ($.hiresTimer / 1000 / 1000);
alert("Init RawPixels in " + sec.toFixed(2) + " seconds");

alert("Pixel 0 =\n\n" + p.get(0));
var a = new Array();
for (var i = 0; i < 100; i++) a.push(p.get(i));
alert("Pixel 0-99 = \n\n" + a.toSource());

p.set(0, [1, 200, 3]);
alert("New Pixel 0=\n\n" + p.get(0));

$.hiresTimer;
var n = p.width * p.height;
for (var i = 0; i < n; i++) p.get(i);
sec = ($.hiresTimer / 1000 / 1000);
alert("Got " + (n / 1000 / 1000) + " megapixels in " + sec.toFixed(2) + " seconds.");

$.hiresTimer;
n = 10;
for (var i = 0; i < n; i++) p.set([255, i * 20, i * 10], 1 + i * 2);
sec = ($.hiresTimer / 1000 / 1000);
//alert("Set " + n + " pixels in " + sec.toFixed(2) + " seconds");

p.create_layer();
alert("New layer created  with new pixels");