情人节炫酷表白神器

 

 

BLUR = false;

 

PULSATION = true;

PULSATION_PERIOD = 600;

PARTICLE_RADIUS = 4;

 

 

 

BLINK = false;

 

GLOBAL_PULSATION = false;

 

QUALITY = 2;

 

 

ARC = true;

 

 

TREMBLING = 0;

 

FANCY_FONT = "Arial";

 

BACKGROUND = "#000";

 

BLENDING = true;

 

 

var TEXT;

num = 0;

TEXTArray = ["你说","你喜", "欢的", "是谁"];

 

QUALITY_TO_FONT_SIZE = [10, 12, 40, 50,100, 350];

QUALITY_TO_SCALE = [20, 6, 4, 2, 0.9, 0.5];

QUALITY_TO_TEXT_POS = [10, 20, 60, 100,370, 280];

 

 

window.onload = function () {

       document.body.style.backgroundColor = BACKGROUND;

 

       var canvas = document.getElementById("canvas");

       var ctx = canvas.getContext("2d");

 

       var W = canvas.width;

       var H = canvas.height;

 

       var tcanvas = document.createElement("canvas");

       var tctx = tcanvas.getContext("2d");

       tcanvas.width = W;

       tcanvas.height = H;

 

       total_area = W * H;

       total_particles = 928;

       single_particle_area = total_area / total_particles;

       area_length = Math.sqrt(single_particle_area);

 

       var particles = [];

       for (var i = 1; i <= total_particles; i++) {

                particles.push(newparticle(i));

       }

 

       function particle(i) {

                this.r =Math.round(Math.random() * 255 | 0);

                this.g =Math.round(Math.random() * 255 | 0);

                this.b =Math.round(Math.random() * 255 | 0);

                this.alpha = 1;

 

                this.x = (i * area_length) % W;

                this.y = (i * area_length) / W* area_length;

 

               

                this.deltaOffset =Math.random() * PULSATION_PERIOD | 0;

 

                this.radius = 0.1 +Math.random() * 2;

       }

 

       var positions = [];

 

       function new_positions() {

 

                TEXT = TEXTArray[num];

 

                if (num < TEXTArray.length -1) {

                        num++;

                } else {

                        num = 0;

                }

                //alert(TEXT);

 

                tctx.fillStyle ="white";

                tctx.fillRect(0, 0, W, H)

                //tctx.fill();

 

                tctx.font = "bold " +QUALITY_TO_FONT_SIZE[QUALITY] + "px " + FANCY_FONT;

 

                //tctx.textAlign='center';//文本水平对齐方式

                //tctx.textBaseline='middle';

 

                //tctx.strokeStyle ="black";

                tctx.fillStyle ="#f00";

                //tctx.strokeText(TEXT,30, 50);

                tctx.fillText(TEXT, 20, 60);

 

                image_data =tctx.getImageData(0, 0, W, H);

                pixels = image_data.data;

                positions = [];

                for (var i = 0; i

                        if (pixels[i] != 255) {

                                position = {

                                        x: (i /2 % W | 0) * QUALITY_TO_SCALE[QUALITY] | 0,

                                        y: (i /2 / W | 0) * QUALITY_TO_SCALE[QUALITY] | 0

                                }

                               positions.push(position);

                        }

                }

 

                get_destinations();

       }

 

       function draw() {

 

                var now = Date.now();

 

                ctx.globalCompositeOperation ="source-over";

 

                if (BLUR) ctx.globalAlpha =0.1;

                else if (!BLUR &&!BLINK) ctx.globalAlpha = 1.0;

 

                ctx.fillStyle = BACKGROUND;

                ctx.fillRect(0, 0, W, H)

 

                if (BLENDING)ctx.globalCompositeOperation = "lighter";

 

                for (var i = 0; i

 

                        p = particles[i];

 

                       

 

                        if (isNaN(p.x))continue

 

                        ctx.beginPath();

                        ctx.fillStyle ="rgb(" + p.r + ", " + p.g + ", " + p.b +")";

                        ctx.fillStyle ="rgba(" + p.r + ", " + p.g + ", " + p.b + "," + p.alpha + ")";

 

                        if (BLINK)ctx.globalAlpha = Math.sin(Math.PI * mod * 1.0);

 

                        if (PULSATION) {

                                var mod =((GLOBAL_PULSATION ? 0 : p.deltaOffset) + now) % PULSATION_PERIOD /PULSATION_PERIOD;

 

                               

                                mod =Math.sin(mod * Math.PI);

                        } else var mod = 1;

 

                        var offset = TREMBLING? TREMBLING * (-1 + Math.random() * 2) : 0;

 

                        var radius =PARTICLE_RADIUS * p.radius;

 

                        if (!ARC) {

                               ctx.fillRect(offset + p.x - mod * radius / 2 | 0, offset + p.y - mod *radius / 2 | 0, radius * mod,

                                        radius * mod);

                        } else {

                                ctx.arc(offset+ p.x | 0, offset + p.y | 0, radius * mod, Math.PI * 2, false);

                                ctx.fill();

                        }

 

                        p.x += (p.dx - p.x) /10;

                        p.y += (p.dy - p.y) /10;

                }

       }

 

       function get_destinations() {

                for (var i = 0; i

                        pa = particles[i];

                        particles[i].alpha = 1;

                        var distance = [];

                        nearest_position = 0;

                        if (positions.length) {

                                for (var n = 0;n < positions.length; n++) {

                                        po =positions[n];

                                       distance[n] = Math.sqrt((pa.x - po.x) * (pa.x - po.x) + (pa.y - po.y) *(pa.y - po.y));

                                        if (n> 0) {

                                               if (distance[n] <= distance[nearest_position]) {

                                                       nearest_position = n;

                                               }

                                        }

                                }

                                particles[i].dx= positions[nearest_position].x;

                                particles[i].dy= positions[nearest_position].y;

                                particles[i].distance= distance[nearest_position];

 

                                var po1 =positions[nearest_position];

                                for (var n = 0;n < positions.length; n++) {

                                        var po2= positions[n];

                                       distance = Math.sqrt((po1.x - po2.x) * (po1.x - po2.x) + (po1.y - po2.y)* (po1.y - po2.y));

                                        if(distance <= 5) {

                                               positions.splice(n, 1);

                                        }

                                }

                        } else {

                               //particles[i].alpha = 0;

                        }

                }

       }

 

       function init() {

                new_positions();

                setInterval(draw, 30);

                setInterval(new_positions,2000);

       }

 

       init();

};

 

 

 

 

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