import { VantComponent } from '../common/component'; import { isObj } from '../common/utils'; import { BLUE, WHITE } from '../common/color'; function format(rate) { return Math.min(Math.max(rate, 0), 100); } const PERIMETER = 2 * Math.PI; const BEGIN_ANGLE = -Math.PI / 2; const STEP = 1; VantComponent({ props: { text: String, lineCap: { type: String, value: 'round' }, value: { type: Number, value: 0, observer: 'reRender' }, speed: { type: Number, value: 50 }, size: { type: Number, value: 100, observer: 'setStyle' }, fill: String, layerColor: { type: String, value: WHITE }, color: { type: [String, Object], value: BLUE, observer: 'setHoverColor' }, strokeWidth: { type: Number, value: 4 }, clockwise: { type: Boolean, value: true } }, data: { style: 'width: 100px; height: 100px;', hoverColor: BLUE }, methods: { getContext() { if (!this.ctx) { this.ctx = wx.createCanvasContext('van-circle', this); } return this.ctx; }, setHoverColor() { const context = this.getContext(); const { color, size } = this.data; let hoverColor = color; if (isObj(color)) { const LinearColor = context.createLinearGradient(size, 0, 0, 0); Object.keys(color) .sort((a, b) => parseFloat(a) - parseFloat(b)) .map(key => LinearColor.addColorStop(parseFloat(key) / 100, color[key])); hoverColor = LinearColor; } this.setData({ hoverColor }); }, setStyle() { const { size } = this.data; const style = `width: ${size}px; height: ${size}px;`; this.setData({ style }); }, presetCanvas(context, strokeStyle, beginAngle, endAngle, fill) { const { strokeWidth, lineCap, clockwise, size } = this.data; const position = size / 2; const radius = position - strokeWidth / 2; context.setStrokeStyle(strokeStyle); context.setLineWidth(strokeWidth); context.setLineCap(lineCap); context.beginPath(); context.arc(position, position, radius, beginAngle, endAngle, !clockwise); context.stroke(); if (fill) { context.setFillStyle(fill); context.fill(); } }, renderLayerCircle(context) { const { layerColor, fill } = this.data; this.presetCanvas(context, layerColor, 0, PERIMETER, fill); }, renderHoverCircle(context, formatValue) { const { clockwise, hoverColor } = this.data; // 结束角度 const progress = PERIMETER * (formatValue / 100); const endAngle = clockwise ? BEGIN_ANGLE + progress : 3 * Math.PI - (BEGIN_ANGLE + progress); this.presetCanvas(context, hoverColor, BEGIN_ANGLE, endAngle); }, drawCircle(currentValue) { const context = this.getContext(); const { size } = this.data; context.clearRect(0, 0, size, size); this.renderLayerCircle(context); const formatValue = format(currentValue); if (formatValue !== 0) { this.renderHoverCircle(context, formatValue); } context.draw(); }, reRender() { // tofector 动画暂时没有想到好的解决方案 const { value, speed } = this.data; if (speed <= 0 || speed > 1000) { this.drawCircle(value); return; } this.clearInterval(); this.currentValue = this.currentValue || 0; this.interval = setInterval(() => { if (this.currentValue !== value) { if (this.currentValue < value) { this.currentValue += STEP; } else { this.currentValue -= STEP; } this.drawCircle(this.currentValue); } else { this.clearInterval(); } }, 1000 / speed); }, clearInterval() { if (this.interval) { clearInterval(this.interval); this.interval = null; } } }, created() { const { value } = this.data; this.currentValue = value; this.drawCircle(value); }, destroyed() { this.ctx = null; this.clearInterval(); } });