Question

我如何将圆圈调整为更小？我复制了这个来源，但没有找到。这个圆圈用画布绘制。我尝试更改某些值，但结果无法正确显示。 HTML：

<div style='position: absolute: top: 0px; left: 0px; background-color: #FFFFFF; width: 300px; height: 2000px'>
                <div id='mainDiv' style='position: absolute; width: 250px; height: 250px; visibility: hidden; cursor: pointer'>
                    <canvas id='g2'></canvas>
                    <canvas id='luminosity' width='250' height='250' style='position: absolute; left: 0px; top: 0px'></canvas>
                    <canvas id='hue-selector' width='15' height='15' style='position: absolute'></canvas>
                    <canvas id='luminosity-selector' width='15' height='15' style='position: absolute'></canvas>
                </div>       
            </div>

                <canvas id='selColor' width='15' height='15' style='position: absolute; border: 1px solid #000'></canvas>

Javascript：

    $('#selColor').click(function(e) {
    onMenuForegroundColor();
});

function HSB2RGB(j, d, c) {
    var e, g, l, h, k, b, a, m;
    if (c == 0) {
        return [0, 0, 0]
    }
    j *= 0.016666667;
    d *= 0.01;
    c *= 0.01;
    h = Math.floor(j);
    k = j - h;
    b = c * (1 - d);
    a = c * (1 - (d * k));
    m = c * (1 - (d * (1 - k)));
    switch (h) {
        case 0:
            e = c;
            g = m;
            l = b;
            break;
        case 1:
            e = a;
            g = c;
            l = b;
            break;
        case 2:
            e = b;
            g = c;
            l = m;
            break;
        case 3:
            e = b;
            g = a;
            l = c;
            break;
        case 4:
            e = m;
            g = b;
            l = c;
            break;
        case 5:
            e = c;
            g = b;
            l = a;
            break
    }
    return [e, g, l]
}

function RGB2HSB(c, d, k) {
    var j, h, e, g, b, a;
    j = Math.min(Math.min(c, d), k);
    a = Math.max(Math.max(c, d), k);
    if (j == a) {
        return [0, 0, a * 100]
    }
    h = (c == j) ? d - k : ((d == j) ? k - c : c - d);
    e = (c == j) ? 3 : ((d == j) ? 5 : 1);
    g = Math.floor((e - h / (a - j)) * 60) % 360;
    b = Math.floor(((a - j) / a) * 100);
    a = Math.floor(a * 100);
    return [g, b, a]
}

function ColorSelector(a) {
    this.init(a)
}

ColorSelector.prototype = {
    container: null,
    color: [0, 0, 0],
    hueSelector: null,
    luminosity: null,
    luminosityData: null,
    luminositySelector: null,
    luminosityPosition: null,
    dispatcher: null,
    changeEvent: null,

    init: function(k) {
        var m = this,
            b1, g2, d3;

        this.container = document.getElementById('mainDiv')
        this.container.addEventListener("mousedown", l, false);
        this.container.addEventListener("touchstart", f, false);


        g2 = document.getElementById('g2');
        g2.width = k.width;
        g2.height = k.height;

        b1 = g2.getContext("2d");
        b1.drawImage(k, 0, 0, g2.width, g2.height);
        d3 = b1.getImageData(0, 0, g2.width, g2.height).data;


        this.luminosity = document.getElementById('luminosity');
        this.hueSelector = document.getElementById('hue-selector');
        this.hueSelector.style.left = ((g2.width - 15) / 2) + "px";
        this.hueSelector.style.top = ((g2.height - 15) / 2) + "px";


        b1 = this.hueSelector.getContext("2d");
        b1.lineWidth = 2;
        b1.strokeStyle = "rgba(0, 0, 0, 0.5)";
        b1.beginPath();
        b1.arc(8, 8, 6, 0, Math.PI * 2, true);
        b1.stroke();
        b1.strokeStyle = "rgba(256, 256, 256, 0.8)";
        b1.beginPath();
        b1.arc(7, 7, 6, 0, Math.PI * 2, true);
        b1.stroke();

        this.luminosityPosition = [(k.width - 15), (k.height - 15) / 2];


        this.luminositySelector = document.getElementById('luminosity-selector');
        this.luminositySelector.style.left = (this.luminosityPosition[0] - 7) + "px";
        this.luminositySelector.style.top = (this.luminosityPosition[1] - 7) + "px";
        b1 = this.luminositySelector.getContext("2d");
        b1.drawImage(this.hueSelector, 0, 0, this.luminositySelector.width, this.luminositySelector.height);

        this.dispatcher = document.createElement("div");
        this.changeEvent = document.createEvent("Events");
        this.changeEvent.initEvent("change", true, true);

        function l(n) {
            window.addEventListener("mousemove", c, false);
            window.addEventListener("mouseup", h, false);
            e(n.clientX - m.container.offsetLeft, n.clientY - m.container.offsetTop)
        }

        function c(n) {
            e(n.clientX - m.container.offsetLeft, n.clientY - m.container.offsetTop)
        }

        function h(n) {
            window.removeEventListener("mousemove", c, false);
            window.removeEventListener("mouseup", h, false);
            e(n.clientX - m.container.offsetLeft, n.clientY - m.container.offsetTop)
        }

        function f(n) {
            if (n.touches.length == 1) {
                n.preventDefault();
                window.addEventListener("touchmove", a, false);
                window.addEventListener("touchend", j, false);
                e(n.touches[0].pageX - m.container.offsetLeft, n.touches[0].pageY - m.container.offsetTop)
            }
        }

        function a(n) {
            if (n.touches.length == 1) {
                n.preventDefault();
                e(n.touches[0].pageX - m.container.offsetLeft, n.touches[0].pageY - m.container.offsetTop)
            }
        }

        function j(n) {
            if (n.touches.length == 0) {
                n.preventDefault();
                window.removeEventListener("touchmove", a, false);
                window.removeEventListener("touchend", j, false)
            }
        }

        function e(o, t) {
            var q, p, r, n, s;
            q = o - 125;
            p = t - 125;
            r = Math.sqrt(q * q + p * p);
            if (r < 90) {
                m.hueSelector.style.left = (o - 7) + "px";
                m.hueSelector.style.top = (t - 7) + "px";
                m.updateLuminosity([d3[(o + (t * 250)) * 4], d3[(o + (t * 250)) * 4 + 1], d3[(o + (t * 250)) * 4 + 2]])
            } else {
                if (r > 100) {
                    n = q / r;
                    s = p / r;
                    m.luminosityPosition[0] = (n * 110) + 125;
                    m.luminosityPosition[1] = (s * 110) + 125;
                    m.luminositySelector.style.left = (m.luminosityPosition[0] - 7) + "px";
                    m.luminositySelector.style.top = (m.luminosityPosition[1] - 7) + "px"
                }
            }
            o = Math.floor(m.luminosityPosition[0]);
            t = Math.floor(m.luminosityPosition[1]);
            m.color[0] = m.luminosityData[(o + (t * 250)) * 4];
            m.color[1] = m.luminosityData[(o + (t * 250)) * 4 + 1];
            m.color[2] = m.luminosityData[(o + (t * 250)) * 4 + 2];
            m.dispatchEvent(m.changeEvent)
        }
    },
    show: function() {
        this.container.style.visibility = "visible"
    },
    hide: function() {
        this.container.style.visibility = "hidden"
    },
    getColor: function() {
        return this.color
    },
    setColor: function(c) {
        var a, e, f, d, b = Math.PI / 180;
        this.color = c;
        a = RGB2HSB(c[0] / 255, c[1] / 255, c[2] / 255);
        e = a[0] * b;
        f = (a[1] / 100) * 90;
        this.hueSelector.style.left = ((Math.cos(e) * f + 125) - 7) + "px";
        this.hueSelector.style.top = ((Math.sin(e) * f + 125) - 7) + "px";
        d = HSB2RGB(a[0], a[1], 100);
        d[0] *= 255;
        d[1] *= 255;
        d[2] *= 255;
        this.updateLuminosity(d);
        e = (a[2] / 100) * 360 * b;
        this.luminosityPosition[0] = (Math.cos(e) * 110) + 125;
        this.luminosityPosition[1] = (Math.sin(e) * 110) + 125;
        this.luminositySelector.style.left = (this.luminosityPosition[0] - 7) + "px";
        this.luminositySelector.style.top = (this.luminosityPosition[1] - 7) + "px";
        this.dispatchEvent(this.changeEvent)
    },
    updateLuminosity: function(j) {
        var d, f, l, g, p, b, a, o = 100,
            h = 120,
            k, n = 1080 / 2,
            e = 1 / n,
            c = Math.PI / 180,
            m = (n / 360);
        b = this.luminosity.width / 2;
        a = this.luminosity.height / 2;
        d = this.luminosity.getContext("2d");
        d.lineWidth = 3;
        d.clearRect(0, 0, this.luminosity.width, this.luminosity.height);
        for (k = 0; k < n; k++) {
            f = k / m * c;
            l = Math.cos(f);
            g = Math.sin(f);
            p = 255 - (k * e) * 255;
            d.strokeStyle = "rgb(" + Math.floor(j[0] - p) + "," + Math.floor(j[1] - p) + "," + Math.floor(j[2] - p) + ")";
            d.beginPath();
            d.moveTo(l * o + b, g * o + a);
            d.lineTo(l * h + b, g * h + a);
            d.stroke()
        }
        this.luminosityData = d.getImageData(0, 0, this.luminosity.width, this.luminosity.height).data
    },
    addEventListener: function(b, c, a) {
        this.dispatcher.addEventListener(b, c, a)
    },
    dispatchEvent: function(a) {
        this.dispatcher.dispatchEvent(a)
    },
    removeEventListener: function(b, c, a) {
        this.dispatcher.removeEventListener(b, c, a)
    }
};

function Palette() {
    var e, d, b, a, n = 90,
        m = 1080,
        f = 1 / m,
        l = m / 360,
        c = Math.PI / 180,
        j, h, k, g, o;
    e = document.createElement("canvas");
    e.width = 250;
    e.height = 250;
    b = e.width / 2;
    a = e.height / 2;
    d = e.getContext("2d");
    d.lineWidth = 1;
    for (j = 0; j < m; j++) {
        h = j / l * c;
        k = Math.cos(h);
        g = Math.sin(h);
        d.strokeStyle = "hsl(" + Math.floor((j * f) * 360) + ", 100%, 50%)";
        d.beginPath();
        d.moveTo(k + b, g + a);
        d.lineTo(k * n + b, g * n + a);
        d.stroke()
    }
    o = d.createRadialGradient(b, b, 0, b, b, n);
    o.addColorStop(0, "rgba(255, 255, 255, 1)");
    o.addColorStop(1, "rgba(255, 255, 255, 0)");
    d.fillStyle = o;
    d.fillRect(0, 0, e.width, e.height);
    return e
}

var SCREEN_WIDTH = window.innerWidth,
    SCREEN_HEIGHT = window.innerHeight,
    COLOR = [0, 0, 0],
    i,
    container, foregroundColorSelector, canvas, flattenCanvas, context, isFgColorSelectorVisible = false;
init();

function init() {
    var hash, palette;
    container = document.createElement("div");

    document.body.appendChild(container);
    canvas = document.createElement("canvas");
    canvas.width = SCREEN_WIDTH;
    canvas.height = SCREEN_HEIGHT;
    canvas.style.cursor = "crosshair";
    container.appendChild(canvas);
    context = canvas.getContext("2d");
    palette = new Palette();
    foregroundColorSelector = new ColorSelector(palette);
    foregroundColorSelector.addEventListener("change", onForegroundColorSelectorChange, false);
    container.appendChild(foregroundColorSelector.container);
    onMenuForegroundColor();

    setColorAll(COLOR);

    foregroundColorSelector.setColor(COLOR);
    canvas.addEventListener("mousedown", onCanvasMouseDown, false);
}

function onForegroundColorSelectorChange(a) {
    COLOR = foregroundColorSelector.getColor();
    setColorAll(COLOR);
}

//show palette
function onMenuForegroundColor() {

    hidePalette();
    foregroundColorSelector.show();
    foregroundColorSelector.container.style.left = 0;
    foregroundColorSelector.container.style.top = 0;
    isFgColorSelectorVisible = true
}

function hidePalette() {
    foregroundColorSelector.hide();    
}


/* mouse and touches up down move */
//mouse down canvas
function onCanvasMouseDown(b) {
    hidePalette();
    window.addEventListener("mouseup", onCanvasMouseUp, false)
}

//up on canvas
function onCanvasMouseUp() {
    window.removeEventListener("mouseup", onCanvasMouseUp, false);
}

function setColorAll(color) {
    foregroundColor = document.getElementById('selColor');
    var foregroundCtx = this.foregroundColor.getContext("2d");
    foregroundCtx.fillStyle = "rgb(" + COLOR[0] + "," + COLOR[1] + "," + COLOR[2] + ")";
    foregroundCtx.fillRect(0, 0, foregroundColor.width, foregroundColor.height);   
}

请检查小提琴Here

Answer 1

虽然我不会审核你的300多行小提琴（参见 https://stackoverflow.com/help/mcve），但如果你想缩放画布内容，你可以：

清除画布，
char* sort(char* str){ int len = strlen(str); for (int i = 0; i < len -1; ++i) { for (int j = i + 1; j < len; ++j) { if (str[j]<str[i]) { swap(str[j], str[i]); } } } printf("%s\n", str); return str; }//end of sort缩放后面的所有图纸，
重绘所有画布内容。
通过取消缩放画布来清理：context.scale(scalefactorX,scalefactorY)

Answer 2

添加以下css

#mainDiv {
    transform: scale(.7); //scale down to 70% of the current height
}

如何调整到较小的圆圈

2 个答案: