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在我的应用程序中,我计划使用 Fabric js 绘制对象。在这里我用鼠标绘制矩形。绘制完矩形后,我想添加一个文本(名称变量)。文本必须位于矩形的顶部。而且我只需要绘制一个矩形。之后绘图心情应该停止并应该激活选择功能。这对于 Fabric js 来说是可能的吗?
var canvas = new fabric.Canvas('canvas1', {
selection: false
});
var Name = "This is a rectangle";
function drawrec() {
var rect, isDown, origX, origY;
removeEvents();
changeObjectSelection(false);
canvas.on('mouse:down', function(o) {
isDown = true;
var pointer = canvas.getPointer(o.e);
origX = pointer.x;
origY = pointer.y;
var pointer = canvas.getPointer(o.e);
rect = new fabric.Rect({
left: origX,
top: origY,
originX: 'left',
originY: 'top',
width: pointer.x - origX,
height: pointer.y - origY,
angle: 0,
selectable:false,
fill: '#07ff11a3',
stroke: 'black',
transparentCorners: false
});
canvas.add(rect);
});
canvas.on('mouse:move', function(o) {
if (!isDown) return;
var pointer = canvas.getPointer(o.e);
if (origX > pointer.x) {
rect.set({
left: Math.abs(pointer.x)
});
}
if (origY > pointer.y) {
rect.set({
top: Math.abs(pointer.y)
});
}
rect.set({
width: Math.abs(origX - pointer.x)
});
rect.set({
height: Math.abs(origY - pointer.y)
});
canvas.renderAll();
});
canvas.on('mouse:up', function(o) {
isDown = false;
rect.setCoords();
});
}
function enableSelection() {
removeEvents();
changeObjectSelection(true);
canvas.selection = true;
}
function changeObjectSelection(value) {
canvas.forEachObject(function (obj) {
obj.selectable = value;
});
canvas.renderAll();
}
function removeEvents() {
canvas.isDrawingMode = false;
canvas.selection = false;
canvas.off('mouse:down');
canvas.off('mouse:up');
canvas.off('mouse:move');
}
<div class="fullpage">
<div class="section">
<a class="thmb" href="#" onclick="drawrec()" style="padding: 0px 10px;margin:5px;border: 2px solid;">Rectangle</a>
<a class="thmb" href="#" onclick="enableSelection()" style="padding: 0px 10px;margin:5px;border: 2px solid;">Selection</a>
<div class="canvas-container">
<canvas id="canvas1" style="border: 1px solid;width: 500px;height: 500px"></canvas>
</div>
</div>
</div>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.6/fabric.min.js'></script>
最佳答案
onmouseup
您可以创建一个文本对象并与矩形对象组成一个组。然后添加到 Canvas 。
演示
var canvas = new fabric.Canvas('canvas1', {
selection: false
});
var Name = "This is a rectangle";
function drawrec() {
var rect, isDown, origX, origY;
removeEvents();
changeObjectSelection(false);
canvas.on('mouse:down', function(o) {
isDown = true;
var pointer = canvas.getPointer(o.e);
origX = pointer.x;
origY = pointer.y;
var pointer = canvas.getPointer(o.e);
rect = new fabric.Rect({
left: origX,
top: origY,
originX: 'left',
originY: 'top',
width: pointer.x - origX,
height: pointer.y - origY,
angle: 0,
selectable:false,
fill: '#07ff11a3',
stroke: 'black',
transparentCorners: false
});
canvas.add(rect);
});
canvas.on('mouse:move', function(o) {
if (!isDown) return;
var pointer = canvas.getPointer(o.e);
if (origX > pointer.x) {
rect.set({
left: Math.abs(pointer.x)
});
}
if (origY > pointer.y) {
rect.set({
top: Math.abs(pointer.y)
});
}
rect.set({
width: Math.abs(origX - pointer.x)
});
rect.set({
height: Math.abs(origY - pointer.y)
});
canvas.renderAll();
});
canvas.on('mouse:up', function(o) {
isDown = false;
rect.setCoords();
var text = new fabric.Text(Name,{
left:rect.left,
top:rect.top,
fontSize: 20
});
var group = new fabric.Group([rect,text]);
canvas.remove(rect);
canvas.add(group);
group.addWithUpdate();
enableSelection();
});
}
function enableSelection() {
removeEvents();
changeObjectSelection(true);
canvas.selection = true;
}
function changeObjectSelection(value) {
canvas.forEachObject(function (obj) {
obj.selectable = value;
});
canvas.renderAll();
}
function removeEvents() {
canvas.isDrawingMode = false;
canvas.selection = false;
canvas.off('mouse:down');
canvas.off('mouse:up');
canvas.off('mouse:move');
}
<div class="fullpage">
<div class="section">
<a class="thmb" href="#" onclick="drawrec()" style="padding: 0px 10px;margin:5px;border: 2px solid;">Rectangle</a>
<a class="thmb" href="#" onclick="enableSelection()" style="padding: 0px 10px;margin:5px;border: 2px solid;">Selection</a>
<div class="canvas-container">
<canvas id="canvas1" width= 400 height= 400 style="border: 1px solid;"></canvas>
</div>
</div>
</div>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.6/fabric.min.js'></script>
关于javascript - 绘制对象后,有没有办法在 Fabric js 中向该对象添加文本,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/51773773/
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