Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
445 views
in Technique[技术] by (71.8m points)

How to scale an imageData in HTML canvas?

I have a canvas in my webpage; I create a new Image data in this canvas then I modify some pixel through myImgData.data[] array. Now I would like to scale this image and make it bigger. I tried by scaling the context but the image remains small. Is it possible to do this? Thanks

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

You could draw the imageData to a new canvas, scale the original canvas and then draw the new canvas to the original canvas.

Something like this should work:

var imageData = context.getImageData(0, 0, 100, 100);
var newCanvas = $("<canvas>")
    .attr("width", imageData.width)
    .attr("height", imageData.height)[0];

newCanvas.getContext("2d").putImageData(imageData, 0, 0);

context.scale(1.5, 1.5);
context.drawImage(newCanvas, 0, 0);

Here's a functioning demo http://jsfiddle.net/Hm2xq/2/.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...