[英]Fabric js: when button is clicked center canvas and zoom to object
我試圖將視口集中在一個對象上,並在單擊按鈕時放大/縮小。 我想要一個動畫。 為此,我使用 setInterval 並像這樣以增量方式移動視口:
const objectCenterCoordenates = {
x: Math.round(rect1.left + rect1.width / 2),
y: Math.round(rect1.top + rect1.height / 2)
};
const centeredCanvasCoordenates = {
x: objectCenterCoordenates.x - canvas.width / 2,
y: objectCenterCoordenates.y - canvas.height / 2
};
let currentPoint = {
x: Math.round(canvas.viewportTransform[4]) * -1,
y: Math.round(canvas.viewportTransform[5]) * -1
};
console.log("Start animation");
let animation = setInterval(() => {
console.log("New frame");
if (canvas.getZoom() !== 2) {
let roundedZoom = Math.round(canvas.getZoom() * 100) / 100;
let zoomStep = roundedZoom > 2 ? -0.01 : 0.01;
let newZoom = roundedZoom + zoomStep;
canvas.zoomToPoint(
new fabric.Point(currentPoint.x, currentPoint.y),
newZoom
);
}
let step = 5;
let vpCenter = {
x: Math.round(canvas.getVpCenter().x),
y: Math.round(canvas.getVpCenter().y)
};
if (
vpCenter.x === objectCenterCoordenates.x &&
vpCenter.y === objectCenterCoordenates.y
) {
console.log("Animation Finish");
clearInterval(animation);
}
let xDif = Math.abs(vpCenter.x - objectCenterCoordenates.x);
let yDif = Math.abs(vpCenter.y - objectCenterCoordenates.y);
let stepX =
Math.round(vpCenter.x) > Math.round(objectCenterCoordenates.x)
? -step
: step;
if (Math.abs(xDif) < step)
stepX =
Math.round(vpCenter.x) > Math.round(objectCenterCoordenates.x)
? -xDif
: xDif;
let stepY =
Math.round(vpCenter.y) > Math.round(objectCenterCoordenates.y)
? -step
: step;
if (Math.abs(yDif) < step)
stepY =
Math.round(vpCenter.y) > Math.round(objectCenterCoordenates.y)
? -yDif
: yDif;
currentPoint = {
x: currentPoint.x + stepX,
y: currentPoint.y + stepY
};
canvas.absolutePan(new fabric.Point(currentPoint.x, currentPoint.y));
}, 4);
但有時,我無法確定原因,它卡在一個循環中,一個方向移動幾個像素,然后返回另一個方向。 並且縮放實現得很好,因為可以在對象完成放大/縮小之前到達對象。
這是我的代碼的代碼筆: https ://codepen.io/nilsilva/pen/vYpPrgq
我將不勝感激有關使我的算法更好的任何建議。
看起來您對 clearInterval 有完全匹配的要求...
if (
vpCenter.x === objectCenterCoordenates.x &&
vpCenter.y === objectCenterCoordenates.y
) {
console.log("Animation Finish");
clearInterval(animation);
}
您描述stuck in a loop moving one way then going back the other
是因為它從未完成的完全匹配,可能是因為您正在采取的步驟,或者它可能是一個舍入問題
您可以使用Math.hypot
檢查兩個點是否足夠接近,請在此處閱讀更多信息:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/hypot
條件將如下所示:
if (Math.hypot(
vpCenter.x - objectCenterCoordenates.x,
vpCenter.y - objectCenterCoordenates.y
) < step) {
console.log("Animation Finish");
clearInterval(animation);
}
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