如何在使用 FabricJS 分组后仅取消分组选定的多段线?
我们可以通过创建fabric.Polyline的实例来创建一个多段线对象。多段线对象可以由一组连接的直线段来表征。由于它是 FabricJS 的基本元素之一,我们也可以通过应用角度、不透明度等属性轻松地自定义它。对于取消分组已分组的多段线对象,我们可以使用toActiveSelection()方法。
语法
toActiveSelection(): fabric.ActiveSelection
示例 1:一键分组所有多段线
在了解如何取消分组之前,让我们看看如何对对象进行分组。在这个例子中,我们将有一个按钮,点击它后所有多段线将被分组到单个对象中。因此,移动该对象将移动所有多段线,并且在调整大小或倾斜时,它也将表现为单个对象。
我们将创建一个函数,该函数获取画布中的所有对象并将它们分组到单个对象中。
<!DOCTYPE html> <html> <head> <!-- Adding the Fabric JS Library--> <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script> </head> <body> <h2>Grouping all the Polyline objects using one click</h2> <p>Click on the `Group` Button to group all the Polyline objects in the canvas </p> <canvas id="canvas"></canvas> <button type="button" onclick="group()">Group</button> <script> // Initiate a canvas instance var canvas = new fabric.Canvas("canvas"); canvas.setWidth(document.body.scrollWidth); canvas.setHeight(250); // Initiate a Polyline object var polyLine1 = new fabric.Polyline([ { x: 500, y: 200 }, { x: 550, y: 60 }, { x: 350, y: 100 }, ], { stroke: "green", fill: "white", strokeWidth: 5, }); // Initiate another Polyline object var polyLine2 = new fabric.Polyline([ { x: 300, y: 200 }, { x: 150, y: 60 }, { x: 250, y: 100 }, ], { stroke: "green", fill: "white", strokeWidth: 5, }); // Add them to the canvas instance canvas.add(polyLine1); canvas.add(polyLine2); // Function to group all the polyline objects into single object function group() { // Get all the objects as selection var sel = new fabric.ActiveSelection(canvas.getObjects(), { canvas: canvas, }); // Make the objects active canvas.setActiveObject(sel); // Group the objects canvas.getActiveObject().toGroup(); } </script> </body> </html>
示例 2:一键取消分组选定的已分组多段线
在这个例子中,我们将有一个按钮,点击它后,选定的已分组多段线将被取消分组。因此,对象将表现为单独的对象。首先,我们将创建两组多段线,每组将有两个多段线对象。
此外,当选择一个组并按下取消分组按钮时,我们将使用toActiveSelection()来取消分组对象。
<!DOCTYPE html> <html> <head> <!-- Adding the Fabric JS Library--> <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script> </head> <body> <h2>Ungrouping the selected grouped Polylines using one click</h2> <p>Click on the grouped object and click on `Ungroup` button to ungroup the objects, further click in empty space to discard the selection </p> <canvas id="canvas"></canvas> <button type="button" onclick="ungroup()">Ungroup</button> <script> // Initiate a canvas instance var canvas = new fabric.Canvas("canvas"); canvas.setWidth(document.body.scrollWidth); canvas.setHeight(250); // Initiate another Polyline object var polyLine1 = new fabric.Polyline([ { x: 300, y: 100 }, { x: 150, y: 60 }, { x: 250, y: 10 }, ], { stroke: "green", fill: "white", strokeWidth: 5, }); // Initiate another Polyline object var polyLine2 = new fabric.Polyline([ { x: 400, y: 200 }, { x: 250, y: 160 }, { x: 150, y: 200 }, ], { stroke: "blue", fill: "white", strokeWidth: 5, }); // Group two objects and add to canvas var group1 = new fabric.Group([polyLine1, polyLine2]); canvas.add(group1); // Initiate another Polyline object var polyLine4 = new fabric.Polyline([ { x: 400, y: 10 }, { x: 350, y: 60 }, { x: 450, y: 10 }, ], { stroke: "pink", fill: "white", strokeWidth: 5, }); // Initiate a Polyline object var polyLine3 = new fabric.Polyline([ { x: 500, y: 200 }, { x: 550, y: 60 }, { x: 350, y: 100 }, ], { stroke: "red", fill: "white", strokeWidth: 5, }); // Group two objects and add to canvas var group2 = new fabric.Group([polyLine3, polyLine4]); canvas.add(group2); // Function to ungroup the selected grouped polyline objects function ungroup() { canvas.getActiveObject().toActiveSelection(); } </script> </body> </html>
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