ByteScout Premium Suite – JavaScript – Use alpha channel with graphics for pdf with pdf generator sdk for javascript

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ByteScout Premium Suite – JavaScript – Use alpha channel with graphics for pdf with pdf generator sdk for javascript

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ByteScout-Premium-Suite-JavaScript-Use-alpha-channel-with-graphics-for-pdf-with-pdf-generator-sdk-for-javascript.pdf

How to use alpha channel with graphics for pdf with pdf generator sdk for javascript in JavaScript with ByteScout Premium Suite

How to write a robust code in JavaScript to use alpha channel with graphics for pdf with pdf generator sdk for javascript with this step-by-step tutorial

Sample source code below will display you how to manage a complex task like use alpha channel with graphics for pdf with pdf generator sdk for javascript in JavaScript. ByteScout Premium Suite is the bundle that includes twelve SDK products from ByteScout including tools and components for PDF, barcodes, spreadsheets, screen video recording and you can use it to use alpha channel with graphics for pdf with pdf generator sdk for javascript with JavaScript.

These JavaScript code samples for JavaScript guide developers to speed up coding of the application when using ByteScout Premium Suite. Follow the instructions from scratch to work and copy the JavaScript code. If you want to use these JavaScript sample examples in one or many applications then they can be used easily.

All these programming tutorials along with source code samples and ByteScout free trial version are available for download from our website.

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checkdatauri.js

      	// checks if we have datauri support in current browser
        // if we have support for datauri support then we can stream generated PDF right into the browser
        // otherwise we should use Downloadify script to allow user to save PDF file
	function CheckDataURISupport(){

	var result = true;
	var checkDataURISupportImage = new Image();

	checkDataURISupportImage.onload = checkDataURISupportImage.onerror = function(){
		if(this.width != 1 || this.height != 1){
			result = false;
		}
	}
	checkDataURISupportImage.src = "data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=";
	// check if we have datauri support in current browser - end

		return result;
	}

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createpdf.js

      // function that creates BytescoutPDF instance (defined in BytescoutPDF.js script which have to be included into the same page)
// then calls API methods and properties to create PDF document
// and returns created BytescoutPDF object instance
// this CreatePDF() function is called from Sample.html
// IsInternetExplorer8OrLower parameter indicates if we use IE8 or lower so we CAN'T use images (as it requires HTML5 Canvas available in IE9 or higher). Other browsers should be working fine

// IMPORTANT ABOUT IMAGES: 
// When using Firefox or IE, pdf generation may fail because images are not accessible when pdf generation works
// the solution for this issue is to preload images in main HTML document before running PDF generation
// to preload images, put them into hidden div block "pdfreportimages" - you can see it in the sample.html right after <body> opening tag


function CreatePDF(IsInternetExplorer8OrLower) {

    // create BytescoutPDF object instance
    var pdf = new BytescoutPDF();
    // set document properties: Title, subject, keywords, author name and creator name
    pdf.propertiesSet("Sample document title", "Sample subject", "keyword1, keyword 2, keyword3", "Document Author Name", "Document Creator Name");
    
    pdf.pageAdd();

	// draw transparent star
    
    pdf.graphicsSetColor("ffff00");
	pdf.graphicsSetAlpha(125);
	
	var rad=200;
	var cx=300; var cy=300;
	
	pdf.graphicsSetLineWidth(10);
	
	for (var an = 0.0; an < Math.PI; an += Math.PI / 20) 
	{
		var x = rad * Math.sin(an);
		var y = rad * Math.cos(an);
		pdf.graphicsDrawLine(cx + x, cy + y, cx - x, cy - y);
	}
	
    // return BytescoutPDF object instance
    return pdf;
}