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<template>
<div>
<div class="tool-style">
<el-button type="primary" size="mini" @click="reset">复位</el-button>
</div>
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<div
:style="{
cursor: isDragging ? 'pointer' : 'default',
top: canvasTop + 'px',
left: canvasLeft + 'px',
}"
@wheel.prevent="onWheel"
@mousedown="onMouseDown"
@mousemove="onMouseMove"
@mouseup="onMouseUp"
>
<canvas
id="canvasId"
width="1200"
height="1000"
style="border: 1px solid #000"
></canvas>
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</div>
</div>
</template>
<script>
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import { fabric } from "fabric";
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export default {
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name: "DrawModule",
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data() {
return {
canvas: null,
zoomLevel: 1, // 初始缩放比例
isDragging: false, // 标记是否正在拖动
lastPointer: null, // 记录上次鼠标位置
canvasTop: 0, // 画布的顶部偏移
canvasLeft: 0, // 画布的左部偏移
};
},
props: {
isActive: {
type: Boolean,
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default: false,
},
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},
mounted() {
this.$nextTick(() => {
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this.canvas = new fabric.Canvas("canvasId");
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// 添加一个矩形
const rect = new fabric.Rect({
left: 100,
top: 100,
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fill: "red",
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width: 50,
height: 50,
selectable: false, // 禁止拖动
});
const rect2 = new fabric.Rect({
left: 300,
top: 400,
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fill: "blue",
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width: 50,
height: 50,
selectable: false, // 禁止拖动
});
this.canvas.add(rect);
this.canvas.add(rect2);
});
},
methods: {
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reset() {
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this.zoomLevel = 1;
this.canvas.setZoom(this.zoomLevel);
this.canvasLeft = 0;
this.canvasTop = 0;
},
onWheel(event) {
// event.preventDefault(); // 阻止默认滚动行为
// const delta = event.deltaY; // 获取滚轮滚动的距离
// const zoomFactor = 0.1; // 缩放因子
// if (delta > 0) {
// this.zoomLevel = Math.max(this.zoomLevel - zoomFactor, 0.1); // 缩小
// } else {
// this.zoomLevel += zoomFactor; // 放大
// }
// this.canvas.setZoom(this.zoomLevel);
// this.canvas.renderAll(); // 重新渲染画布
event.preventDefault(); // 阻止默认滚动行为
const delta = event.deltaY; // 获取滚轮滚动的距离
const zoomFactor = 0.1; // 缩放因子
const minZoom = 0.5; // 最小缩放比例
const maxZoom = 5; // 最大缩放比例
const oldZoom = this.zoomLevel;
if (delta > 0) {
this.zoomLevel = Math.max(this.zoomLevel - zoomFactor, minZoom); // 缩小
} else {
this.zoomLevel = Math.min(this.zoomLevel + zoomFactor, maxZoom); // 放大
}
const pointer = this.canvas.getPointer(event); // 获取鼠标指针位置
// 只有当缩放级别发生变化时才进行缩放操作
if (this.zoomLevel !== oldZoom) {
const zoomRatio = this.zoomLevel / oldZoom;
// 获取当前画布的视口变换矩阵
const viewport = this.canvas.viewportTransform;
// 计算缩放中心相对于画布左上角的偏移量
const offsetX = pointer.x - viewport[4];
const offsetY = pointer.y - viewport[5];
// 缩放视口变换矩阵
viewport[0] *= zoomRatio; // 缩放 X 轴
viewport[3] *= zoomRatio; // 缩放 Y 轴
// 调整视口变换矩阵的偏移量，以保持缩放中心不变
viewport[4] = pointer.x - offsetX * zoomRatio;
viewport[5] = pointer.y - offsetY * zoomRatio;
// 更新画布的视口变换矩阵
this.canvas.setViewportTransform(viewport);
}
this.canvas.renderAll(); // 重新渲染画布
},
onMouseDown(event) {
this.isDragging = true;
this.lastPointer = this.canvas.getPointer(event);
},
onMouseMove(event) {
if (this.isDragging) {
const currentPointer = this.canvas.getPointer(event);
const deltaX = currentPointer.x - this.lastPointer.x;
const deltaY = currentPointer.y - this.lastPointer.y;
// 更新 canvasTop 和 canvasLeft
this.canvasTop += deltaY;
this.canvasLeft += deltaX;
const viewport = this.canvas.viewportTransform;
viewport[4] += deltaX;
viewport[5] += deltaY;
this.canvas.setViewportTransform(viewport);
this.canvas.renderAll();
this.lastPointer = currentPointer;
}
},
onMouseUp() {
this.isDragging = false;
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},
},
};
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</script>
<style scoped>
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.tool-style {
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position: absolute;
/* left: 0px;
top: 0px; */
margin: 10px;
z-index: 99999;
}
</style>
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