325 lines
8.8 KiB
Vue
325 lines
8.8 KiB
Vue
<!-- 子组件 transform-canvas.vue -->
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<template>
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<view>
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<canvas
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id="myCanvas"
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canvas-id="myCanvas"
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type="2d"
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:style="{
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width: `${canvasDisplayWidth}px`,
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height: `${canvasDisplayHeight}px`,
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border: '1px solid #eee'
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}"
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></canvas>
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</view>
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</template>
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<script>
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export default {
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props: {
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width: Number, // 画布实际宽度(像素)
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height: Number, // 画布实际高度(像素)
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imgUrl: String, // 图片URL
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matrix: { // 变换矩阵
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type: Object,
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default: () => ({
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a: 1, b: 0, c: 0, d: 1, tx: 0, ty: 0
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})
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},
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areaData:{}
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},
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data() {
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return {
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canvasContext: null,
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image: null,
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dpr: 1,
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canvasDisplayWidth: 800, // 默认显示尺寸
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canvasDisplayHeight: 600,
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canvasActualWidth: 800, // 实际像素尺寸
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canvasActualHeight: 600
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};
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},
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watch: {
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imgUrl: {
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handler(newUrl) {
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if (newUrl) this.loadImage(newUrl);
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},
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immediate: true
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},
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width: {
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handler() {
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this.updateCanvasSize();
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},
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immediate: true
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},
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height: {
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handler() {
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this.updateCanvasSize();
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},
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immediate: true
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},
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matrix: {
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deep: true,
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immediate: true, // 添加立即触发
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handler() {
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this.$nextTick(this.redraw); // 确保在下一个tick重绘
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}
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},
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},
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mounted() {
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this.initCanvas();
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},
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methods: {
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// 添加点击检测方法
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checkHitArea(x, y) {
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if (!this.areaData) return null;
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// 转换坐标到原始画布空间
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const inverted = this.matrix.invertPoint(x, y);
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console.log('checkHitArea',inverted)
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// 遍历所有区域检测
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for (const area of this.areaData) {
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if (this.pointInPolygon(inverted.x, inverted.y, area.polygon)) {
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return area.areacode;
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}
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}
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return null;
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},
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// 射线法判断点是否在多边形内
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// pointInPolygon(x, y, polygon) {
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// // console.log('pointInPolygon',x, y, polygon)
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// // 确保多边形有足够的点构成
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// if (!polygon || polygon.length < 6) return false;
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// let inside = false;
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// const length = polygon.length;
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// // 不需要遍历最后一个点，因为它是闭合点（与第一个点相同）
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// for (let i = 0, j = length - 2; i < length; j = i, i += 2) {
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// const xi = polygon[i], yi = polygon[i + 1];
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// const xj = polygon[j], yj = polygon[j + 1];
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// // 检查点是否在边的y值范围内
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// const intersect = ((yi > y) !== (yj > y));
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// // 检查点是否在边的左侧
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// if (intersect) {
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// const slope = (xj - xi) / (yj - yi); // 边的斜率
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// const intersectX = xi + (y - yi) * slope;
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// if (x < intersectX) {
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// inside = !inside;
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// }
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// }
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// }
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// return inside;
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// },
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// 在 transform-canvas.vue 中替换 pointInPolygon 方法
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pointInPolygon(x, y, polygon) {
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// 确保多边形的点数是偶数且至少有3个顶点
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if (!polygon || polygon.length < 6 || polygon.length % 2 !== 0) {
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return false;
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}
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let inside = false;
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// 转换多边形点数为顶点数
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const vertexCount = polygon.length / 2;
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let j = vertexCount - 1;
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for (let i = 0; i < vertexCount; j = i++) {
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// 获取当前顶点和上一个顶点
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const xi = polygon[i * 2];
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const yi = polygon[i * 2 + 1];
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const xj = polygon[j * 2];
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const yj = polygon[j * 2 + 1];
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// 检查点是否在边界上 - 提高精度避免浮点数误差
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const onLine = this.pointOnLineSegment(x, y, xi, yi, xj, yj);
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if (onLine) return true;
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// 检查点是否在两个顶点之间（射线法）
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if ((yi < y && yj >= y) || (yj < y && yi >= y)) {
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// 计算射线与边界的交点
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const slope = (xj - xi) / (yj - yi);
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const intersectX = xi + (y - yi) * slope;
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// 如果交点在点右侧，标记为穿越
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if (x < intersectX) {
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inside = !inside;
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}
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}
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}
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return inside;
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},
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// 添加点是否在线段上的检查
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pointOnLineSegment(x, y, x1, y1, x2, y2) {
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// 线段的长度
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const dx = x2 - x1;
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const dy = y2 - y1;
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const segmentLength = Math.sqrt(dx * dx + dy * dy);
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// 点到线段起点的向量
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const vx = x - x1;
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const vy = y - y1;
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// 向量在方向上的投影
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const dotProduct = vx * dx + vy * dy;
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// 计算参数t (0-1之间表示在线段上)
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const t = dotProduct / (segmentLength * segmentLength);
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// 点在线段上
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if (t >= 0 && t <= 1) {
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// 计算点在线段上的位置
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const projX = x1 + t * dx;
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const projY = y1 + t * dy;
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// 检查点与投影点的距离（容差5px）
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const distance = Math.sqrt((x - projX) ** 2 + (y - projY) ** 2);
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return distance < 5;
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}
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return false;
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},
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initCanvas() {
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const query = uni.createSelectorQuery().in(this);
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query.select('#myCanvas')
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.fields({ node: true, size: true })
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.exec(async (res) => {
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if (!res[0]) return;
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this.canvas = res[0].node;
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this.ctx = res[0].node.getContext('2d');
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// 获取设备像素比
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this.dpr = uni.getSystemInfoSync().pixelRatio;
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// 更新画布尺寸
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this.updateCanvasSize();
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// 如果已有图片URL，加载图片
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if (this.imgUrl) {
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await this.loadImage(this.imgUrl);
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}
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});
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},
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updateCanvasSize() {
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// 显示尺寸使用prop传入的width/height
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this.canvasDisplayWidth = this.width;
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this.canvasDisplayHeight = this.height;
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// 实际像素尺寸考虑DPR
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this.canvasActualWidth = this.width * this.dpr;
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this.canvasActualHeight = this.height * this.dpr;
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if (this.canvas) {
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this.canvas.width = this.canvasActualWidth;
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this.canvas.height = this.canvasActualHeight;
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this.ctx.scale(this.dpr, this.dpr);
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this.redraw();
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}
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},
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async loadImage(src) {
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try {
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// 等待canvas初始化
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if (!this.canvas) {
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await this.initCanvas();
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}
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this.image = await new Promise((resolve, reject) => {
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if (!this.canvas) {
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// reject(new Error("Canvas not initialized"));
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return;
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}
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const image = this.canvas.createImage();
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image.src = src;
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image.onload = () => resolve(image);
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image.onerror = reject;
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});
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this.redraw();
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} catch (e) {
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console.error("图片加载失败:", e);
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this.image = null;
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}
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},
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// async loadImage(src) {
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// try {
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// this.image = await new Promise((resolve, reject) => {
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// const image = this.canvas.createImage();
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// image.src = src;
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// image.onload = () => resolve(image);
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// image.onerror = reject;
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// });
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// this.redraw();
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// } catch (e) {
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// console.error("图片加载失败:", e);
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// this.image = null;
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// this.redraw(); // 加载失败时也需要重绘画布
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// }
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// },
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redraw() {
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if (!this.ctx) return;
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// 保存当前状态
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this.ctx.save();
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// 重置为初始状态
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this.ctx.resetTransform();
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this.ctx.clearRect(0, 0, this.canvasActualWidth, this.canvasActualHeight);
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// 应用设备像素比缩放
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this.ctx.scale(this.dpr, this.dpr);
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// 应用变换矩阵
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const { a, b, c, d, tx, ty } = this.matrix;
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this.ctx.setTransform(a, b, c, d, tx, ty);
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// 绘制图片（或错误信息）
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if (this.image) {
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this.ctx.drawImage(
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this.image,
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0,
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0,
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this.canvasDisplayWidth,
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this.canvasDisplayHeight
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);
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}
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// this.ctx.restore();
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// 恢复上下文状态
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if (this.areaData && this.areaData.length > 0) {
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this.areaData.forEach(area => {
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// if (!area.polygon || area.polygon.length < 6) return;
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this.ctx.beginPath();
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for (let i = 0; i < area.polygon.length; i += 2) {
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// 使用标准API
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if (i === 0) {
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this.ctx.moveTo(area.polygon[i], area.polygon[i + 1]);
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} else {
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this.ctx.lineTo(area.polygon[i], area.polygon[i + 1]);
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}
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}
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this.ctx.closePath();
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this.ctx.strokeStyle = 'rgba(255, 0, 0, 0.7)';
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this.ctx.lineWidth = 2;
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this.ctx.stroke();
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this.ctx.fillStyle = 'rgba(0, 255, 0, 0.2)';
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this.ctx.fill();
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});
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}
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}
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}
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}
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</script> |