foam-framework/js/foam/graphics/DAOListCView.js

MVC metaprogramming framework

/**
 * @license
 * Copyright 2014 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

CLASS({
  package: 'foam.graphics',
  name: 'DAOListCView',
  extends: 'foam.graphics.CView',

  properties: [
    { model_: 'foam.core.types.DAOProperty', name: 'dao' },
    { model_: 'IntProperty', name: 'scrollTop', preSet: function(_,t) { return Math.max(t, 0); }, postSet: function() { this.scroll(); } },
    { name: 'rowRenderer' },
    { name: 'objs', postSet: function() { this.view && this.view.paint(); }, factory: function() { return []; } }
  ],

  methods: {
    init: function(args) {
      this.SUPER(args);
      this.dao.listen(this.scroll);
    },
    paintSelf: function() {
      var renderer = this.rowRenderer;

      var offset = -(this.scrollTop % renderer.height);
      this.canvas.save();
      this.canvas.translate(0, offset);
      for ( var i = 0; i < this.objs.length; i++ ) {
        renderer.render(this.canvas, this.objs[i]);
        this.canvas.translate(0, renderer.height);
      }
      this.canvas.restore();
    }
  },

  listeners: [
    {
      name: 'scroll',
      code: function() {
        var renderer = this.rowRenderer;
        var limit = Math.floor(this.height / renderer.height);
        var skip = Math.floor(this.scrollTop / renderer.height);
        var self = this;
        this.dao.skip(skip).limit(limit).select()(function(objs) {
          self.objs = objs;
        });
      }
    }
  ]
});