[cc] Initial checkin of cc-frame-viewer

tools/cc-frame-viewer/src/quad_view_viewport.js

+/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+'use strict';
+
+base.require('base.range');
+base.require('ui.event_target');
+
+base.exportTo('ccfv', function() {
+  function QuadViewViewport(bbox,
+                            opt_scale,
+                            opt_dontPadBbox, opt_devicePixelRatio) {
+    ui.EventTarget.call(this);
+    if (bbox.isEmpty)
+      throw new Error('Cannot initialize a viewport with an empty bbox');
+
+    this.setWorldBBox(bbox, opt_dontPadBbox);
+
+    var devicePixelRatio;
+    if (opt_devicePixelRatio)
+      devicePixelRatio = opt_devicePixelRatio;
+    else
+      devicePixelRatio = window.devicePixelRatio || 1;
+
+    var scale;
+    if (opt_scale) {
+      scale = opt_scale;
+    } else {
+      if (devicePixelRatio > 1)
+        scale = 0.25;
+      else
+        scale = 0.125;
+    }
+    this.scale_ = scale;
+    this.updateScale_();
+  }
+
+  QuadViewViewport.prototype = {
+
+    __proto__: ui.EventTarget.prototype,
+
+    set scale(scale) {
+      this.scale_ = scale;
+      this.updateScale_();
+      this.didChange_();
+    },
+
+    get scale() {
+      return this.scale_;
+    },
+
+    updateScale_: function() {
+      this.worldPixelsPerDevicePixel_ = this.scale_;
+      this.devicePixelsPerLayoutPixel_ = 1 / devicePixelRatio;
+
+      this.deviceWidth =
+        this.worldRect.width * this.worldPixelsPerDevicePixel_;
+      this.deviceHeight =
+        this.worldRect.height * this.worldPixelsPerDevicePixel_;
+
+      this.layoutWidth = this.deviceWidth * this.devicePixelsPerLayoutPixel_;
+      this.layoutHeight = this.deviceHeight * this.devicePixelsPerLayoutPixel_;
+
+      this.transformWorldToDevicePixels_ = mat2d.create();
+      this.transformDevicePixelsToWorld_ = mat2d.create();
+      this.updateTransform_();
+    },
+
+    setWorldBBox: function(bbox, opt_dontPadBbox) {
+      var world_rect = bbox.asRect();
+      var world_pad;
+      if (opt_dontPadBbox) {
+        world_pad = 0;
+      } else {
+        world_pad = Math.min(world_rect.width,
+                             world_rect.height) * 0.10;
+      }
+
+      world_rect.enlarge(world_pad);
+      this.worldRect = world_rect;
+      this.updateTransform_();
+      this.didChange_();
+    },
+
+    updateTransform_: function() {
+      if (!this.transformWorldToDevicePixels_)
+        return;
+
+      mat2d.identity(this.transformWorldToDevicePixels_);
+      mat2d.translateInplaceXY(
+        this.transformWorldToDevicePixels_,
+          -this.worldRect.left, -this.worldRect.top);
+      mat2d.scaleInplaceXY(this.transformWorldToDevicePixels_,
+                           this.worldPixelsPerDevicePixel_,
+                           this.worldPixelsPerDevicePixel_);
+
+      mat2d.invert(this.transformDevicePixelsToWorld_,
+                   this.transformWorldToDevicePixels_);
+    },
+
+    layoutPixelsToWorldPixels2: function(v) {
+      var tmp = this.layoutPixelsToDevicePixels2(v);
+      return this.devicePixelsToWorldPixels2(tmp);
+    },
+
+    layoutPixelsToDevicePixels2: function(v) {
+      var res = vec2.create();
+      return vec2.scale(res, v, 1 / this.devicePixelsPerLayoutPixel_);
+    },
+
+    devicePixelsToWorldPixels2: function(v) {
+      var res = vec2.create();
+      vec2.transformMat2d(res, v, this.transformDevicePixelsToWorld_);
+      return res;
+    },
+
+    getWorldToDevicePixelTransform: function() {
+      return this.transformDevicePixelsToWorld_;
+    },
+
+    getDeviceLineWidthAssumingTransformIsApplied: function(
+        desired_device_line_width) {
+      return desired_device_line_width / this.worldPixelsPerDevicePixel_;
+    },
+
+    applyTransformToContext: function(ctx) {
+      var transform = this.transformWorldToDevicePixels_;
+      ctx.transform(transform[0], transform[1], transform[2],
+                    transform[3], transform[4], transform[5]);
+    },
+
+    didChange_: function() {
+      base.dispatchSimpleEvent(this, 'change', false, false);
+    }
+  };
+
+  return {
+    QuadViewViewport: QuadViewViewport,
+  }
+});
+