如何使用 FabricJS 在分组后取消对多个折线的组合?
我们可以通过创建fabric.Polyline的实例来创建一个折线对象。折线对象可以由一组连接的直线段来表示。由于它是 FabricJS 的基本元素之一,因此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。对于取消组合多个折线对象,我们可以使用toActiveSelection()方法。
语法
toActiveSelection(): fabric.ActiveSelection
示例 1:一键组合所有折线
在了解如何取消组合之前,让我们先看看如何组合对象。在本例中,我们将有一个按钮,点击它所有折线将被组合成一个对象。因此,移动该对象将移动所有折线,并且在调整大小或倾斜时,它也将表现为一个对象。
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组合成一个对象。
<!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>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 2:一键取消组合所有已组合的折线
在本例中,我们将有一个按钮,点击它已组合的折线将被取消组合。因此,该对象将表现为单独的对象。首先,我们将所有对象组合成一个对象。此外,当按下取消组合按钮时,我们将使用toActiveSelection()来取消组合对象。
<!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 all the 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 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: 100 }, { x: 150, y: 60 }, { x: 250, y: 10 }, ], { stroke: "green", fill: "white", strokeWidth: 5, }); // Initiate another Polyline object var polyLine3 = new fabric.Polyline([ { x: 400, y: 200 }, { x: 250, y: 160 }, { x: 150, y: 200 }, ], { stroke: "green", fill: "white", strokeWidth: 5, }); // Add them to the canvas instance canvas.add(polyLine1); canvas.add(polyLine2); canvas.add(polyLine3); // 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(); // Function to ungroup the grouped polyline objects function ungroup() { canvas.getActiveObject().toActiveSelection(); } </script> </body> </html>
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