Colors and Color Spaces

Embedded File Streams Page Formats and Boundaries

Colors and Color Spaces Using Colors in SetaPDF

Introduction
Colors
Color Spaces

Introduction

Colors could be defined and used in various ways in a PDF file. The SetaPDF-Core component offers several classes to handle a wide range of available color spaces and values.

Colors

Color values are represented by color classes. These instances are mostly used internal by a component to use such color for drawing in or writing text to a canvas object.

If a components class offers a method to define a color, it requires a color instance or it will forward the argument to a static method which will create a component by the given color components:

Description

public static SetaPDF_Core_DataStructure_Color::createByComponents (

int|float|string|array|SetaPDF_Core_Type_Array $components

): SetaPDF_Core_DataStructure_Color

Create an instance by a PDF array object, PHP array or a hexadecimal string of an RGB value.

Parameters

$components : int|float|string|array|SetaPDF_Core_Type_Array

Exceptions

Throws InvalidArgumentException

For sure it is possible to initiate a color object manually by passing the components to its constructor. Common color values could be created with the SetaPDF_Core_DataStructure_Color_Gray, SetaPDF_Core_DataStructure_Color_Rgb, SetaPDF_Core_DataStructure_Color_Cmyk classes:

PHP

$red = new \SetaPDF_Core_DataStructure_Color_Rgb(1, 0, 0);
// the components could also be passed as array
$green = new \SetaPDF_Core_DataStructure_Color_Rgb(array(0, 1, 0));
$blue = new \SetaPDF_Core_DataStructure_Color_Rgb(0, 0, 1);

$gray = new \SetaPDF_Core_DataStructure_Color_Gray(.3);

$orange = new \SetaPDF_Core_DataStructure_Color_Cmyk(0, .35, 1, 0);
$violet = new \SetaPDF_Core_DataStructure_Color_Cmyk(array(.07, .39, 0, .4));

$limegreen = \SetaPDF_Core_DataStructure_Color::createByComponents('#32CD32');

Color Spaces

The SetaPDF-Core component offers classes for defining color spaces. The color classes mentioned earlier will define their own color space when they were invoked by an operator in a content stream.

In the PDF format it is also possible to declare color components for a currently activated color space. This is needed for example for a Separation color space (see PDF 32000-1:2008 - 8.6.6.4 Separation Colour Spaces):

PHP

<?php
require_once('library/SetaPDF/Autoload.php');

// get a document instance
$writer = new \SetaPDF_Core_Writer_Http('separation.pdf', true);
$document = new \SetaPDF_Core_Document($writer);

// create a blank page
$page = $document->getCatalog()->getPages()->create(\SetaPDF_Core_PageFormats::A4);

// get the canvas object
$canvas = $page->getCanvas();

// define some spot colors
$yellow = \SetaPDF_Core_ColorSpace_Separation::createSpotColor($document, 'PANTONE 130', 0, 22/100, 90/100, 0);
$blue = \SetaPDF_Core_ColorSpace_Separation::createSpotColor($document, 'PANTONE 3005', 100/100, 20/100, 0, 0);
$orange = \SetaPDF_Core_ColorSpace_Separation::createSpotColor($document, 'PANTONE 144', 0, 50/100, 100/100, 0);

// Set the non stroking color space and tint value
$canvas->setNonStrokingColorSpace($yellow)
       ->setNonStrokingColor(new \SetaPDF_Core_DataStructure_Color_Special(1));

// Set the stroking color space and tint value
$canvas->setStrokingColorSpace($orange)
       ->setStrokingColor(new \SetaPDF_Core_DataStructure_Color_Special(1));

// let's draw a rect
$canvas->path()->setLineWidth(5);
$canvas->draw()->rect(20, 500, 200, 200, \SetaPDF_Core_Canvas_Draw::STYLE_DRAW_AND_FILL);

// set the non stroking color space and tint value
$canvas->setNonStrokingColorSpace($blue)
       ->setNonStrokingColor(new \SetaPDF_Core_DataStructure_Color_Special(1));

// change the tint value of the stroking color space
$canvas->setStrokingColor(new \SetaPDF_Core_DataStructure_Color_Special(.5));

// draw a circle
$canvas->draw()->circle(190, 540, 60, \SetaPDF_Core_Canvas_Draw::STYLE_DRAW_AND_FILL);

$document->save()->finish();

 Code
 Run

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