famo.us - famo.us：结合 2 个变换同时运行

Question

当用户第一次访问我的应用程序时，我有一个徽标，我想将其从屏幕中心移动到顶部，但随着它的移动，我也希望它缩小到其原始大小的 1/2。是否可以通过 famo.us 做到这一点？

Answer 1

有几种方法可以实现这一点。为了清晰和简单起见，我建议使用 ModifierChain 类。这允许您将影响单个可渲染对象的修改器链接在一起。这是您要实现的目标的示例。

祝你好运！

var Engine              = require("famous/core/Engine");
var Surface             = require("famous/core/Surface");
var StateModifier       = require("famous/modifiers/StateModifier");
var Transform           = require("famous/core/Transform");
var ModifierChain       = require("famous/modifiers/ModifierChain");
var Easing              = require("famous/transitions/Easing");

var context = Engine.createContext();

var surface = new Surface({
  size:[200,200],
  properties: { backgroundColor: 'green'}
})

surface.chain = new ModifierChain();

surface.state = new StateModifier({ origin:[0.5,0.5] });
surface.sizeState = new StateModifier();

surface.chain.addModifier(surface.sizeState);
surface.chain.addModifier(surface.state);

context.add(surface.chain).add(surface);

surface.on('click', function(){

  transition = {duration:1000,curve:Easing.inOutQuad};

  surface.sizeState.setTransform(Transform.scale(0.5,0.5,1),transition);
  surface.state.setOrigin([0.5,0],transition);

});

Answer 2

如果一定要找到组合多个Transforms效果的矩阵

    finalTransform = Transform.multiply4x4(Transform.scale(scaleX, scaleY, scaleZ),
                          Transform.translate(translateX, translateY, translateZ));

    finalTransform = Transform.multiply4x4(finalTransform, 
                         Transform.rotate(rotateX, rotateY, rotateZ));

这结合了旋转、缩放和平移的效果。您也可以包括偏斜。

Answer 3

这是我类似于 johntraver 的优雅解决方案

var Engine = famous.core.Engine;
var Modifier = famous.core.Modifier;
var Transform = famous.core.Transform;
var ImageSurface = famous.surfaces.ImageSurface;

// create the main context
var mainContext = Engine.createContext();

// your app here
var logo = new ImageSurface({
    size: [200, 200],
    content: 'img/famousLogo.svg',
    classes: ['double-sided']
});

var initialTime = Date.now();

var centerModifier = new Modifier({
    origin: [0.5, 0.5],
    align: [0.5, 0.5]
});

var spinYModifier = new Modifier({
    transform: function () {
        return Transform.rotateY(.001 * (Date.now() - initialTime));
    }
});

var spinXModifier = new Modifier({
    transform: function () {
        return Transform.rotateX(.001 * (Date.now() - initialTime));
    }
});

mainContext.add(centerModifier).add(spinXModifier).add(spinYModifier).add(logo);