canvas

问题 Is it possible to make perspective image transformation in html5 canvas? I am using EaselJS right now and can't find a solution for my need. 回答1: I don't tried the easel.js yet, but every image transformation is done with matrix operations: translate, rotate, skew etc. Looking on the easel.js source code there is a Matrix2D class, and the documentation to it: http://www.createjs.com/Docs/EaselJS/Matrix2D.html. For a perspective transformation you need to use rotation , scaling and skewing .

问题 Is it possible to make perspective image transformation in html5 canvas? I am using EaselJS right now and can't find a solution for my need. 回答1: I don't tried the easel.js yet, but every image transformation is done with matrix operations: translate, rotate, skew etc. Looking on the easel.js source code there is a Matrix2D class, and the documentation to it: http://www.createjs.com/Docs/EaselJS/Matrix2D.html. For a perspective transformation you need to use rotation , scaling and skewing .

问题 I have a small problem using Canvas API in HTML5. I have a text that I have to show on a canvas in an html page. The text example can be "This is an Italic word". So what I have to do is display this text that I take from the database, but to make just one word from the sentence Italic. So I have to display the text like this: "This is an Italic word" So my code looks like this: <script> var canvas = document.getElementById('myCanvas'); var context = canvas.getContext('2d'); //text context

问题 I have an app where users can drag controls around on a Form. But they re asking me for Snap-To lines to make the alignment of controls easier. I have no idea about the snep-to lines and how to implement them - I have looked at: http://msdn.microsoft.com/en-us/library/ms752100.aspx Adorner's, but it says it's only for WPF. And I tried it in WinForms but (as expected) didn't work. How can I get snap-to lines (something like the ones in VS) in my app? Thank you Bael 回答1: Have you seen this

问题 I am retrieving a byte array of a pictureStream from a .net webservice. the JSON byte array response looks like this: [137, 80, 78, 372, 617 more...] I am trying to convert this byte array and draw it into an HTML canvas like this var context = document.getElementById('boxcover').getContext('2d'); context.putImageData(movies.PictureStream, 0, 0); But this doesn't work. I have no access the modify the webservice, so I am looking to convert this byte array into a picture using Javascript only.

问题 i got two servers (prod.example.com and img.example.com) so on "prod" i process images from "img" using canvas in FF and Chrome all is Ok but in Safari i got this SECURITY_ERR: DOM Exception 18: An attempt was made to break through the security policy of the user agent. all images from "img" has Access-Control-Allow-Origin:* in headers so where is padla? 回答1: getImageData which you probably call will raise this if you try to access the one host from the other. You cannot go around this, the

问题 I would like to write a web interface that resembles Prezi.com in its user experience. What would be the best technology for that purpose? Project requirements: Fast implementation (it is a demo) - I'd appreciate a rough estimate Large amounts of data - dynamic content loading/unloading is required. My natural candidates are Flash and HTML5. Prezi.com is an alternative platform for presentations that uses single canvas zoom/pan/rotate controls instead of classic slide-by-slide interface. An

问题 I'm trying to use the following code to save the contents of myCanvas as an image file in the gallery (for Windows Phone 8.1, not Silverlight). When I run the App, the image is saved but it is distorted. What am I doing wrong? I have uploaded the resultant image and the expected result. public async void SaveFileToPhone() { var file = await KnownFolders.PicturesLibrary.CreateFileAsync("bug.png", CreationCollisionOption.GenerateUniqueName); await SaveVisualElementToFile(myCanvas, file); }

问题 I'm trying to use the following code to save the contents of myCanvas as an image file in the gallery (for Windows Phone 8.1, not Silverlight). When I run the App, the image is saved but it is distorted. What am I doing wrong? I have uploaded the resultant image and the expected result. public async void SaveFileToPhone() { var file = await KnownFolders.PicturesLibrary.CreateFileAsync("bug.png", CreationCollisionOption.GenerateUniqueName); await SaveVisualElementToFile(myCanvas, file); }

问题 When looking through the questions I never found a clear answer to the above. I wanted a method that worked with just about every platform. So for the benefit of the community, I thought I'd share my success in getting custom fonts to work in canvas. My main question was, What is a surefire way to get said fonts to work? I tried multiple methods such as just using a CSS stylesheet but it's a bit more complicated than that. Here's what I found: 回答1: Although it doesn't have complete support