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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