Question

如何使用fabricjs进行平移和缩放？我尝试过使用zoomToPoint和setZoom方法，但它们不能用于平移。一旦我开始使用不同的缩放点，我就开始遇到麻烦了。

$('#zoomIn').click(function(){
    canvas.setZoom(canvas.getZoom() * 1.1 ) ;
}) ;

$('#zoomOut').click(function(){
    canvas.setZoom(canvas.getZoom() / 1.1 ) ;
}) ;

$('#goRight').click(function(){
    //Need to implement
}) ;

$('#goLeft').click(function(){
    //Need to implement
}) ;

http://jsfiddle.net/hdramos/ux16013L/

Answer 1

使用：

解决它

relativePan（） absolutePan（）

[更新]

$('#goRight').click(function(){
    var units = 10 ;
    var delta = new fabric.Point(units,0) ;
    canvas.relativePan(delta) ;
}) ;

$('#goLeft').click(function(){
    var units = 10 ;
    var delta = new fabric.Point(-units,0) ;
    canvas.relativePan(delta) ;
}) ;
$('#goUp').click(function(){
    var units = 10 ;
    var delta = new fabric.Point(0,-units) ;
    canvas.relativePan(delta) ;
}) ;

$('#goDown').click(function(){
    var units = 10 ;
    var delta = new fabric.Point(0,units) ;
    canvas.relativePan(delta) ;
});

http://jsfiddle.net/ux16013L/2/

Answer 2

我知道它已经回答了，但我不得不做一个鼠标平移，所以我调整了接受答案的小提琴。我在这里发布给任何必须做这样的事情的人。这只是主要想法：

On Holy Wars and a Plea for Peace 
Cohen, D. 
Computer

这是小提琴：http://jsfiddle.net/gncabrera/hkee5L6d/5/

Answer 3

这是我的画布缩放（使用鼠标滚轮）和平移（使用左/上/右/下键或Shift键+鼠标左下+鼠标移动）的解决方案。

https://jsfiddle.net/milanhlinak/7s4w0uLy/8/

<!DOCTYPE html>
<html>

<head>
    <script type="text/javascript" src="lib/jquery-3.1.1.min.js"></script>
    <script type="text/javascript" src="lib/fabric.min.js"></script>
</head>

<body>

    <canvas id="canvas" style="border: 1px solid #cccccc"></canvas>

    <script>
        var Direction = {
            LEFT: 0,
            UP: 1,
            RIGHT: 2,
            DOWN: 3
        };

        var zoomLevel = 0;
        var zoomLevelMin = 0;
        var zoomLevelMax = 3;

        var shiftKeyDown = false;
        var mouseDownPoint = null;

        var canvas = new fabric.Canvas('canvas', {
            width: 500,
            height: 500,
            selectionKey: 'ctrlKey'
        });

        canvas.add(new fabric.Rect({
            left: 100,
            top: 100,
            width: 50,
            height: 50,
            fill: '#faa'

        }));
        canvas.add(new fabric.Rect({
            left: 300,
            top: 300,
            width: 50,
            height: 50,
            fill: '#afa'
        }));

        canvas.on('mouse:down', function (options) {
            var pointer = canvas.getPointer(options.e, true);
            mouseDownPoint = new fabric.Point(pointer.x, pointer.y);
        });
        canvas.on('mouse:up', function (options) {
            mouseDownPoint = null;
        });
        canvas.on('mouse:move', function (options) {
            if (shiftKeyDown && mouseDownPoint) {
                var pointer = canvas.getPointer(options.e, true);
                var mouseMovePoint = new fabric.Point(pointer.x, pointer.y);
                canvas.relativePan(mouseMovePoint.subtract(mouseDownPoint));
                mouseDownPoint = mouseMovePoint;
                keepPositionInBounds(canvas);
            }
        });
        fabric.util.addListener(document.body, 'keydown', function (options) {
            if (options.repeat) {
                return;
            }
            var key = options.which || options.keyCode; // key detection
            if (key == 16) { // handle Shift key
                canvas.defaultCursor = 'move';
                canvas.selection = false;
                shiftKeyDown = true;
            } else if (key === 37) { // handle Left key
                move(Direction.LEFT);
            } else if (key === 38) { // handle Up key
                move(Direction.UP);
            } else if (key === 39) { // handle Right key
                move(Direction.RIGHT);
            } else if (key === 40) { // handle Down key
                move(Direction.DOWN);
            }
        });
        fabric.util.addListener(document.body, 'keyup', function (options) {
            var key = options.which || options.keyCode; // key detection
            if (key == 16) { // handle Shift key
                canvas.defaultCursor = 'default';
                canvas.selection = true;
                shiftKeyDown = false;
            }
        });
        jQuery('.canvas-container').on('mousewheel', function (options) {
            var delta = options.originalEvent.wheelDelta;
            if (delta != 0) {
                var pointer = canvas.getPointer(options.e, true);
                var point = new fabric.Point(pointer.x, pointer.y);
                if (delta > 0) {
                    zoomIn(point);
                } else if (delta < 0) {
                    zoomOut(point);
                }
            }
        });

        function move(direction) {
            switch (direction) {
            case Direction.LEFT:
                canvas.relativePan(new fabric.Point(-10 * canvas.getZoom(), 0));
                break;
            case Direction.UP:
                canvas.relativePan(new fabric.Point(0, -10 * canvas.getZoom()));
                break;
            case Direction.RIGHT:
                canvas.relativePan(new fabric.Point(10 * canvas.getZoom(), 0));
                break;
            case Direction.DOWN:
                canvas.relativePan(new fabric.Point(0, 10 * canvas.getZoom()));
                break;
            }
            keepPositionInBounds(canvas);
        }


        function zoomIn(point) {
            if (zoomLevel < zoomLevelMax) {
                zoomLevel++;
                canvas.zoomToPoint(point, Math.pow(2, zoomLevel));
                keepPositionInBounds(canvas);
            }
        }

        function zoomOut(point) {
            if (zoomLevel > zoomLevelMin) {
                zoomLevel--;
                canvas.zoomToPoint(point, Math.pow(2, zoomLevel));
                keepPositionInBounds(canvas);
            }
        }

        function keepPositionInBounds() {
            var zoom = canvas.getZoom();
            var xMin = (2 - zoom) * canvas.getWidth() / 2;
            var xMax = zoom * canvas.getWidth() / 2;
            var yMin = (2 - zoom) * canvas.getHeight() / 2;
            var yMax = zoom * canvas.getHeight() / 2;

            var point = new fabric.Point(canvas.getWidth() / 2, canvas.getHeight() / 2);
            var center = fabric.util.transformPoint(point, canvas.viewportTransform);

            var clampedCenterX = clamp(center.x, xMin, xMax);
            var clampedCenterY = clamp(center.y, yMin, yMax);

            var diffX = clampedCenterX - center.x;
            var diffY = clampedCenterY - center.y;

            if (diffX != 0 || diffY != 0) {
                canvas.relativePan(new fabric.Point(diffX, diffY));
            }
        }

        function clamp(value, min, max) {
            return Math.max(min, Math.min(value, max));
        }
    </script>

</body>

</html>

Answer 4

我在Github上有一个使用fabric.js Canvas平移和缩放的示例：https://sabatinomasala.github.io/fabric-clipping-demo/

负责平移行为的代码如下：https://github.com/SabatinoMasala/fabric-clipping-demo/blob/master/src/classes/Panning.js

它是MyTuple上的一个简单扩展程序，可让您切换“拖动模式”＆＃39;在画布上如下：

fabric.Canvas.prototype

请查看以下代码段，整个代码中都提供了文档。

＆＃13;

canvas.toggleDragMode(true); // Start panning
canvas.toggleDragMode(false); // Stop panning

＆＃13;

const STATE_IDLE = 'idle';
const STATE_PANNING = 'panning';
fabric.Canvas.prototype.toggleDragMode = function(dragMode) {
  // Remember the previous X and Y coordinates for delta calculations
  let lastClientX;
  let lastClientY;
  // Keep track of the state
  let state = STATE_IDLE;
  // We're entering dragmode
  if (dragMode) {
    // Discard any active object
    this.discardActiveObject();
    // Set the cursor to 'move'
    this.defaultCursor = 'move';
    // Loop over all objects and disable events / selectable. We remember its value in a temp variable stored on each object
    this.forEachObject(function(object) {
      object.prevEvented = object.evented;
      object.prevSelectable = object.selectable;
      object.evented = false;
      object.selectable = false;
    });
    // Remove selection ability on the canvas
    this.selection = false;
    // When MouseUp fires, we set the state to idle
    this.on('mouse:up', function(e) {
      state = STATE_IDLE;
    });
    // When MouseDown fires, we set the state to panning
    this.on('mouse:down', (e) => {
      state = STATE_PANNING;
      lastClientX = e.e.clientX;
      lastClientY = e.e.clientY;
    });
    // When the mouse moves, and we're panning (mouse down), we continue
    this.on('mouse:move', (e) => {
      if (state === STATE_PANNING && e && e.e) {
        // let delta = new fabric.Point(e.e.movementX, e.e.movementY); // No Safari support for movementX and movementY
        // For cross-browser compatibility, I had to manually keep track of the delta

        // Calculate deltas
        let deltaX = 0;
        let deltaY = 0;
        if (lastClientX) {
          deltaX = e.e.clientX - lastClientX;
        }
        if (lastClientY) {
          deltaY = e.e.clientY - lastClientY;
        }
        // Update the last X and Y values
        lastClientX = e.e.clientX;
        lastClientY = e.e.clientY;

        let delta = new fabric.Point(deltaX, deltaY);
        this.relativePan(delta);
        this.trigger('moved');
      }
    });
  } else {
    // When we exit dragmode, we restore the previous values on all objects
    this.forEachObject(function(object) {
      object.evented = (object.prevEvented !== undefined) ? object.prevEvented : object.evented;
      object.selectable = (object.prevSelectable !== undefined) ? object.prevSelectable : object.selectable;
    });
    // Reset the cursor
    this.defaultCursor = 'default';
    // Remove the event listeners
    this.off('mouse:up');
    this.off('mouse:down');
    this.off('mouse:move');
    // Restore selection ability on the canvas
    this.selection = true;
  }
};

// Create the canvas

let canvas = new fabric.Canvas('fabric')
canvas.backgroundColor = '#f1f1f1';

// Add a couple of rects

let rect = new fabric.Rect({
  width: 100,
  height: 100,
  fill: '#f00'
});
canvas.add(rect)

rect = new fabric.Rect({
  width: 200,
  height: 200,
  top: 200,
  left: 200,
  fill: '#f00'
});
canvas.add(rect)

// Handle dragmode change

let dragMode = false;
$('#dragmode').change(_ => {
  dragMode = !dragMode;
  canvas.toggleDragMode(dragMode);
});

＆＃13;

Answer 5

如果您只想在显示中平移画布，而不是更改元素的位置，你可以使用this solution。

我们的想法是拥有一个固定大小的容器，其中css为var cargo = async.queue(function (task, callback) { setTimeout( connectStream(task) , 50000); callback(); }, 1); for(var j = 0; j < TeamList.length; j++) { cargo.push(TeamList[j], function (err) { });，其中包含一个展开的画布。平移将在容器内移动画布，以便用户每次都能看到展开画布的不同区域。

Fabricjs平移和缩放

5 个答案: