Fabric.js loadFromJSON 不适用于 rgba 填充

Question

我有一个简单的画布，我在上面添加形状（三角形、圆形、矩形）。我使用了支持 rgba 的光谱颜色选择器，并且我正在根据所选颜色设置形状的填充。至此，一切正常。现在我将画布导出为 JSON，

var json = JSON.stringify(canvas);
console.log(json);

此 JSON 输出稍后将保存到数据库中，但出于测试目的，我从控制台复制 json 并按如下方式使用它，

canvas.loadFromJSON('{"objects":[{"type":"circle","originX":"center","originY":"center","left":400,"top":200,"width":100,"height":100,"fill":{"_originalInput":{"h":"0%","s":"100%","v":"100%","a":0.13},"_r":255,"_g":0,"_b":0,"_a":0.13,"_roundA":0.13,"_format":"rgb","_ok":true,"_tc_id":3288},"stroke":{"_originalInput":{"h":"0%","s":"0%","v":"0%","a":1},"_r":0,"_g":0,"_b":0,"_a":1,"_roundA":1,"_format":"rgb","_ok":true,"_tc_id":3783},"strokeWidth":1,"strokeDashArray":null,"strokeLineCap":"butt","strokeLineJoin":"miter","strokeMiterLimit":10,"scaleX":1,"scaleY":1,"angle":0,"flipX":false,"flipY":false,"opacity":0.4,"shadow":null,"visible":true,"clipTo":null,"backgroundColor":"","fillRule":"nonzero","globalCompositeOperation":"source-over","transformMatrix":null,"skewX":0,"skewY":0,"radius":50,"startAngle":0,"endAngle":6.283185307179586},{"type":"triangle","originX":"left","originY":"top","left":583,"top":89,"width":50,"height":50,"fill":{"_originalInput":{"h":"17.374213836477992%","s":"86.88524590163934%","v":"95.68627450980392%","a":0.34},"_r":235.01046366720004,"_g":243.98400000000004,"_b":32.01070080000003,"_a":0.34,"_roundA":0.34,"_format":"hex","_ok":true,"_tc_id":2503},"stroke":"rgb(0, 0, 0)","strokeWidth":6,"strokeDashArray":null,"strokeLineCap":"butt","strokeLineJoin":"miter","strokeMiterLimit":10,"scaleX":1,"scaleY":1,"angle":0,"flipX":false,"flipY":false,"opacity":1,"shadow":null,"visible":true,"clipTo":null,"backgroundColor":"","fillRule":"nonzero","globalCompositeOperation":"source-over","transformMatrix":null,"skewX":0,"skewY":0},{"type":"rect","originX":"left","originY":"top","left":485,"top":196,"width":50,"height":50,"fill":"#1d128f","stroke":null,"strokeWidth":1,"strokeDashArray":null,"strokeLineCap":"butt","strokeLineJoin":"miter","strokeMiterLimit":10,"scaleX":1,"scaleY":1,"angle":0,"flipX":false,"flipY":false,"opacity":0.4,"shadow":null,"visible":true,"clipTo":null,"backgroundColor":"","fillRule":"nonzero","globalCompositeOperation":"source-over","transformMatrix":null,"skewX":0,"skewY":0,"rx":0,"ry":0}],"background":""}');
canvas.renderAll();

我面临的问题是，由于导出的 JSON 具有 rgba 值，因此当在画布上呈现形状时，填充为黑色。画布忽略了 JSON 字符串中存在的 rgba 值。

但是，当我使用以下 JSON 字符串（填充“绿色”和“红色”）时，形状会以绿色和红色呈现良好。

canvas.loadFromJSON('{"objects":[{"type":"rect","left":50,"top":50,"width":20,"height":20,"fill":"green","overlayFill":null,"stroke":null,"strokeWidth":1,"strokeDashArray":null,"scaleX":1,"scaleY":1,"angle":0,"flipX":false,"flipY":false,"opacity":1,"selectable":true,"hasControls":true,"hasBorders":true,"hasRotatingPoint":false,"transparentCorners":true,"perPixelTargetFind":false,"rx":0,"ry":0},{"type":"circle","left":100,"top":100,"width":100,"height":100,"fill":"red","overlayFill":null,"stroke":null,"strokeWidth":1,"strokeDashArray":null,"scaleX":1,"scaleY":1,"angle":0,"flipX":false,"flipY":false,"opacity":1,"selectable":true,"hasControls":true,"hasBorders":true,"hasRotatingPoint":false,"transparentCorners":true,"perPixelTargetFind":false,"radius":50}],"background":"rgba(0, 0, 0, 0)"}');

这是 fabric.js 中的错误还是我做错了什么？

Answer 1

好的。我已经发现它为什么会发生。问题是我如何设置形状对象的颜色。我正在使用光谱颜色选择器并使用以下代码来初始化光谱并添加代码，当在光谱颜色选择器上选择颜色时，它也会针对画布上选定的形状对象进行更改。

$(".spectrumColor").spectrum({
        showAlpha: true,
        showButtons: false,
        showPalette: true,
        palette: defaultPallete,
        allowEmpty: true,
        showInput: true,
        move: function (color) {

            var selectedObject = canvas.getActiveObject();
            if (selectedObject != null) {
                if ($(this).attr('id') == "FillColor") {
                    selectedObject.set('fill', color);
                    canvas.renderAll();
                }
                else if ($(this).attr('id') == "StrokeColor") {
                    selectedObject.set('stroke', color);
                    canvas.renderAll();
                }
            }
        }
    });

问题出在这一行，

selectedObject.set('stroke', color);

我已将整个颜色对象从光谱传递到织物形状对象。当我在控制台中检查颜色值时，它是简单的 rgb 字符串“rgb(255, 0, 0)”，但是当整个对象分配给 Fabric 的形状对象时，它会添加 hsv（色调、饱和度和亮度）像这样将RGB字符串与Fabric形状对象一起，

fill":{"_originalInput":{"h":"0%","s":"100%","v":"100%","a":0.13},"_r":255,"_g":0,"_b":0,"_a":0.13

由于 Fabric.js 无法识别 HSV，因此它将形状对象呈现为黑色。为了解决这个问题，我不得不更换，

    selectedObject.set('stroke', color);

与

    selectedObject.set('stroke', color.toRgbString());