圣诞将至:js加html5教你写出动态旋转圣诞树。

js与H5canvas实现动态旋转圣诞树

效果图:

圣诞将至:js加html5教你写出动态旋转圣诞树。

源代码

    <canvas id="c" height="356" width="446">
        <script>
            var collapsed = true;
            function toggle() {
                var fs = top.document.getElementsByTagName('frameset')[0];
                var f = fs.getElementsByTagName('frame');
                if (collapsed) {
                    fs.rows = '250px,*';
                    fs.noResize = false;
                    f[0].noResize = false;
                    f[1].noResize = false;
                }
                else {
                    fs.rows = '30px,*';
                    fs.noResize = true;
                    f[0].noResize = true;
                    f[1].noResize = true;
                }
                collapsed = !collapsed;
            }
        </script>
        <script>
            var b = document.body;
            var c = document.getElementsByTagName('canvas')[0];
            var a = c.getContext('2d');
            document.body.clientWidth;
        </script>
        <script>
            M = Math;
            Q = M.random; J = [];
            U = 16;
            T = M.sin;
            E = M.sqrt;
            for (O = k = 0; x = z = j = i = k < 200;)
                with (M[k] = k ? c.cloneNode(0) : c) {
                    width = height = k ? 32 : W = 446;
                    with (getContext('2d'))
                    if (k > 10 | !k)
                        for (
                            font = '60px Impact',
                            V = 'rgba('; I = i * U, fillStyle = k ? k == 13 ? V + '205,205,215,.15)' :
                                V + (147 + I) + ',' + (k % 2 ? 128 + I : 0) + ',' + I + ',.5)' : '#cca', i < 7;)
                            beginPath(fill(arc(U - i / 3, 24 - i / 2, k == 13 ? 4 - (i++) / 2 : 8 - i++, 0, M.PI * 2, 1)));
                    else for (;
                        x = T(i),
                        y = Q() * 2 - 1,
                        D = x * x + y * y,
                        B = E(D - x / .9 - 1.5 * y + 1),
                        R = 67 * (B + 1) * (L = k / 9 + .8) >> 1,
                        i++ < W;
                    )
                        if (D < 1)
                            beginPath(strokeStyle = V + R + ',' + (R + B * L >> 0) + ',40,.1)'),
                                moveTo(U + x * 8, U + y * 8),
                                lineTo(U + x * U, U + y * U),
                                stroke();
                    for (
                        y = H = k + E(k++) * 25,
                        R = Q() * W;
                        P = 3, j < H;)
                        J[O++] = [
                            x += T(R) * P + Q() * 6 - 3, y += Q() * U - 8,
                            z += T(R - 11) * P + Q() * 6 - 3,
                            j / H * 20 + ((j += U) > H & Q() > .8 ? Q(P = 9) * 4 : 0) >> 1]
                }
            setInterval(function G(m, l) {
                A = T(D - 11);
                if (l)
                    return (
                        m[2] - l[2]) * A + (l[0] - m[0]) * T(D);
                a.clearRect(0, 0, W, W);
                J.sort(G);
                for (
                    i = 0;
                    L = J[i++];
                    a.drawImage(M[L[3] + 1], 207 + L[0] * A + L[2] * T(D) >> 0, L[1] >> 1)) {
                    if (i == 2e3)
                        a.fillText
                            ('Happy Christmas!', U, 345);
                    if (!(i % 7))
                        a.drawImage(M[13],
                            ((157 * (i * i) + T(D * 5 + i * i) * 5) % W) >> 0,
                            ((113 * i + (D * i) / 60) % (290 + i / 99)) >> 0);
                }
                D += .02
            }, 1)
        </script>