Html canvas text

This text provides an overview of the HTML5 canvas basic usage. The overview is split into two parts: Declaring an HTML5 canvas element. Drawing graphics on the canvas element.Declaring a Canvas Element First, let's see how to declare a canvas element in an HTML page: HTML5 Canvas not supported The code above declares a single canvas element with width set to 500, height set to 150, and style set to a 1 pixel border with color #cccccc. The text inside the canvas element is ignored, if the browser supports the HTML5 canvas element. If the HTML5 canvas element is not supported, the text will probably be displayed as ordinary text by the browser. You should put the canvas HTML code in your page at the location where you want the canvas to be visible. Just like any other HTML element (e.g. a div element).Drawing Graphics on a Canvas Element Graphics drawn on an HTML5 canvas is drawn in immediate mode. Immediate mode means, that as soon as you have drawn a shape on the canvas, the canvas no longer knows anything about that shape. The shape is visible, but you cannot manipulate that shape individually. It is like a real canvas for a painting. Once painted, all you have left is color pigments / pixels. This is contrary to SVG, where you can manipulate the shapes individually, and have the whole diagram redrawn. In HTML5 you will have to redraw everything yourself, if you want to change the drawn figure. Drawing graphics on an HTML5 canvas element is done using JavaScript, following these steps: Wait for the page to be fully loaded. Obtain a reference to the canvas element. Obtain a 2D context from the canvas element. Draw graphics using the draw functions of 2D context. Here is a simple code example that shows the above steps: // 1. wait for the page to be fully loaded. window.onload = function() { drawExamples(); } function drawExamples(){ // 2. Obtain a reference to the canvas element. var canvas = document.getElementById("ex1"); // 3. Obtain a 2D context from the canvas element. var context = canvas.getContext("2d"); // 4. Draw graphics. context.fillStyle = "#ff0000"; context.fillRect(10,10, 100,100); } First, an event listener function is attached to the window. This event listener function is executed when the page is loaded. This function calls another function I have defined, called drawExamples(). Second, the drawExamples() function obtains a reference to the canvas element using document.getElementById() function, passing the id of the canvas element, as defined in the declaration of the canvas element. Third, the drawExamples() function obtains a reference to a 2D context from the canvas element, by calling canvas.getContext("2d") on the canvas element obtained earlier. Fourth, the drawExamples() function calls various drawing functions on the 2D context object, which results in graphics being drawn on the canvas. Here is how the code looks when executed: HTML5 Canvas not supported

Has been assigned with a JavaScriptonclick event handler to call the ConvertToImage JavaScript function. jQuery Sketch plugin implementation Inside the View,the following jQuery and Sketch JS files are inherited. 1. jquery.min.js 2. sketch.min.js Inside the jQuerydocument ready event handler, the jQuery Sketch plugin is applied to the HTML5 Canvas element. Anchor element for selecting Marker is applied with the Style .i.e. color:#000 and when any of the Anchor link is clicked the Style is removed from the Anchor elements and applied to only that element which was clicked. ConvertToImage Inside the ConvertToImage JavaScript function, the HTML5 Canvas Image is converted into Base64 string using toDataURL method and then saved into the Hidden Field. Submitting the Form When the Submit button is clicked, the Form is submitted to the Controllers POST Action Method. @addTagHelper*, Microsoft.AspNetCore.Mvc.TagHelpers @{ Layout = null; } !DOCTYPE html> html> head> meta name="viewport" content="width=device-width" /> title>Indextitle> script type="text/javascript" src=" script type="text/javascript" src=" script type="text/javascript"> $(function () { $('#colors_sketch').sketch(); $(".tools a").eq(0).attr("style", "color:#000"); $(".tools a").click(function () { $(".tools a").removeAttr("style"); $(this).attr("style", "color:#000"); }); }); function ConvertToImage() { $("[id*=hfImageData]").val($('#colors_sketch')[0].toDataURL()); }; script> head> body> form method="post" asp-controller="Home" asp-action="Index"> div class="tools"> a href="#colors_sketch" data-tool="marker">Markera> a href="#colors_sketch" data-tool="eraser">Erasera> div> br /> canvas id="colors_sketch" width="500" height="200" style="border: 1px solid;">canvas> br /> input type="hidden" ID="hfImageData" name="imageData" /> input type="submit" value="Save" onclick="ConvertToImage()" /> form> body> html> Screenshot Creating Signature and saving Uploaded HTML5 Canvas Image Demo Downloads

The Canvas element is a popular HTML 5 tag that can be embedded inside an HTML document for the purpose of drawing and displaying graphics. In this article, we will see how to use the HTML 5 canvas element in an ASP.NET Page to draw shapes and save them to an ASP.NET Image object.Let’s get started. Open Visual Studio 2010/2012 and create a blank ASP.NET Website. Now add a page ‘default.aspx’ to the site. Set it’s target schema for validation as HTML 5 by going to Tools > Options > Text Editor > HTML > Validation. If you do not see the HTML 5 option, make sure you have installed Visual Studio 2010 Service Pack 1and Web Standards Update for Microsoft Visual Studio 2010 SP1.Declare a HTML 5 canvas element of dimensions 400x400, add a Save button and an ASP.NET Image element to the form. We will draw some simple rectangles on this canvas using two functions – fillStyle and fillRectfillRect(float x, float y, float w, float h) – where x & y represent the upper-left corner of the rectangle and w & h represent the width and height of the rectangle you want.fillStyle = “rgba(R, G, B, V)” - we will fill color in this rectangle by using the fillStyle attribute. As you might have guessed, the RGB stand for red, green, and blue values (0–255) of the color you’re creating. ‘V’ represents the visibility factor 0 & 1, where 0 indicates invisibility, and 1 indicates visibility.To draw graphics on a Canvas, you require a JavaScript API that HTML 5 provides. We will be using jQuery to do our client script. Declare the following JavaScript code inside the element of your pagesrc=" $(function () { var canvas = document.getElementById('canasp'); var context = canvas.getContext('2d'); });Note: $(function(){} ensures that code is run only after the Canvas element is fully loaded by the browser. This is better than built-in Javascript event window.onload which has some quirks across browsers (FF/IE6/IE8/Opera) and waits for the entire page, including images to be loaded.We get a reference to the Canvas from the DOM by using getElementById (you can use jQuery code too, but I will stick to the old getElementById for now). We then ask the Canvas to give us a context to draw on. This is done by using the variable context that sets a reference to the 2D context of the canvas, which is used for all drawing purposes. We will now use the fillRect() and fillStyle() function to draw two rectangles. Add this code below the context codecontext.fillStyle = "rgba(156, 170, 193, 1)"; context.fillRect(30, 30, 70, 90); context.fillStyle = "rgba(0, 109, 141, 1)"; context.fillRect(10, 10, 70, 90);The code is pretty simple. We are