Question

我想在点击按钮时启动相机并通过javascript显示预览。

 function emitStream() {
    // Asking permission to get the user media.
    // If permission granted, assign the stream to the HTML 5 video element.
    navigator.webkitGetUserMedia({
        video: true,
        audio: true
    }, function(stream) {
        that._video = document.querySelector('video');
        that._video.src = window.URL.createObjectURL(stream);
    });


    function takePicture() {
        // Assigning the video stream to the canvas to create a picture.
        that._canvas = document.querySelector('canvas');
        var context = that._canvas.getContext('2d');
        context.clearRect(0, 0, 0, 0);
        context.drawImage(that._video, 0, 0, 400, 300);
    }
}

Answer 1

此代码由David Walsh - Camera and Video Control with HTML5发布或编写。请尝试以下代码----

 window.addEventListener("DOMContentLoaded", function() {
        // Grab elements, create settings, etc.
        var canvas = document.getElementById("canvas"),
            context = canvas.getContext("2d"),
            video = document.getElementById("video"),
            videoObj = { "video": true },
            errBack = function(error) {
                console.log("Video capture error: ", error.code); 
            };

        // Put video listeners into place
        if(navigator.getUserMedia) { // Standard
            navigator.getUserMedia(videoObj, function(stream) {
                video.src = stream;
                video.play();
            }, errBack);
        } else if(navigator.webkitGetUserMedia) { // WebKit-prefixed
            navigator.webkitGetUserMedia(videoObj, function(stream){
                video.src = window.webkitURL.createObjectURL(stream);
                video.play();
            }, errBack);
        }
        else if(navigator.mozGetUserMedia) { // Firefox-prefixed
            navigator.mozGetUserMedia(videoObj, function(stream){
                video.src = window.URL.createObjectURL(stream);
                video.play();
            }, errBack);
        }
    }, false);

触发器如下：---

document.getElementById("snap").addEventListener("click", function() {
    context.drawImage(video, 0, 0, 640, 480);
});

在javascript中单击按钮时捕获图像

1 个答案: