/
LabelCollection.js
645 lines (578 loc) · 24.3 KB
/
LabelCollection.js
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/*global define*/
define([
'../Core/Cartesian2',
'../Core/defaultValue',
'../Core/defined',
'../Core/defineProperties',
'../Core/destroyObject',
'../Core/DeveloperError',
'../Core/Matrix4',
'../Core/writeTextToCanvas',
'./BillboardCollection',
'./HorizontalOrigin',
'./Label',
'./LabelStyle',
'./TextureAtlas',
'./VerticalOrigin'
], function(
Cartesian2,
defaultValue,
defined,
defineProperties,
destroyObject,
DeveloperError,
Matrix4,
writeTextToCanvas,
BillboardCollection,
HorizontalOrigin,
Label,
LabelStyle,
TextureAtlas,
VerticalOrigin) {
"use strict";
// A glyph represents a single character in a particular label. It may or may
// not have a billboard, depending on whether the texture info has an index into
// the the label collection's texture atlas. Invisible characters have no texture, and
// no billboard. However, it always has a valid dimensions object.
function Glyph() {
this.textureInfo = undefined;
this.dimensions = undefined;
this.billboard = undefined;
}
// GlyphTextureInfo represents a single character, drawn in a particular style,
// shared and reference counted across all labels. It may or may not have an
// index into the label collection's texture atlas, depending on whether the character
// has both width and height, but it always has a valid dimensions object.
function GlyphTextureInfo(labelCollection, index, dimensions) {
this.labelCollection = labelCollection;
this.index = index;
this.dimensions = dimensions;
}
// reusable object for calling writeTextToCanvas
var writeTextToCanvasParameters = {};
function createGlyphCanvas(character, font, fillColor, outlineColor, outlineWidth, style, verticalOrigin) {
writeTextToCanvasParameters.font = font;
writeTextToCanvasParameters.fillColor = fillColor;
writeTextToCanvasParameters.strokeColor = outlineColor;
writeTextToCanvasParameters.strokeWidth = outlineWidth;
if (verticalOrigin === VerticalOrigin.BOTTOM) {
writeTextToCanvasParameters.textBaseline = 'bottom';
} else if (verticalOrigin === VerticalOrigin.TOP) {
writeTextToCanvasParameters.textBaseline = 'top';
} else {
// VerticalOrigin.CENTER
writeTextToCanvasParameters.textBaseline = 'middle';
}
writeTextToCanvasParameters.fill = style === LabelStyle.FILL || style === LabelStyle.FILL_AND_OUTLINE;
writeTextToCanvasParameters.stroke = style === LabelStyle.OUTLINE || style === LabelStyle.FILL_AND_OUTLINE;
return writeTextToCanvas(character, writeTextToCanvasParameters);
}
function unbindGlyph(labelCollection, glyph) {
glyph.textureInfo = undefined;
glyph.dimensions = undefined;
var billboard = glyph.billboard;
if (defined(billboard)) {
billboard.show = false;
billboard.image = undefined;
labelCollection._spareBillboards.push(billboard);
glyph.billboard = undefined;
}
}
function addGlyphToTextureAtlas(textureAtlas, id, canvas, glyphTextureInfo) {
textureAtlas.addImage(id, canvas).then(function(index, id) {
glyphTextureInfo.index = index;
});
}
function rebindAllGlyphs(labelCollection, label) {
var text = label._text;
var textLength = text.length;
var glyphs = label._glyphs;
var glyphsLength = glyphs.length;
var glyph;
var glyphIndex;
var textIndex;
// if we have more glyphs than needed, unbind the extras.
if (textLength < glyphsLength) {
for (glyphIndex = textLength; glyphIndex < glyphsLength; ++glyphIndex) {
unbindGlyph(labelCollection, glyphs[glyphIndex]);
}
}
// presize glyphs to match the new text length
glyphs.length = textLength;
var glyphTextureCache = labelCollection._glyphTextureCache;
// walk the text looking for new characters (creating new glyphs for each)
// or changed characters (rebinding existing glyphs)
for (textIndex = 0; textIndex < textLength; ++textIndex) {
var character = text.charAt(textIndex);
var font = label._font;
var fillColor = label._fillColor;
var outlineColor = label._outlineColor;
var outlineWidth = label._outlineWidth;
var style = label._style;
var verticalOrigin = label._verticalOrigin;
// retrieve glyph dimensions and texture index (if the canvas has area)
// from the glyph texture cache, or create and add if not present.
var id = JSON.stringify([
character,
font,
fillColor.toRgba(),
outlineColor.toRgba(),
outlineWidth,
+style,
+verticalOrigin
]);
var glyphTextureInfo = glyphTextureCache[id];
if (!defined(glyphTextureInfo)) {
var canvas = createGlyphCanvas(character, font, fillColor, outlineColor, outlineWidth, style, verticalOrigin);
glyphTextureInfo = new GlyphTextureInfo(labelCollection, -1, canvas.dimensions);
glyphTextureCache[id] = glyphTextureInfo;
if (canvas.width > 0 && canvas.height > 0) {
addGlyphToTextureAtlas(labelCollection._textureAtlas, id, canvas, glyphTextureInfo);
}
}
glyph = glyphs[textIndex];
if (defined(glyph)) {
// clean up leftover information from the previous glyph
if (glyphTextureInfo.index === -1) {
// no texture, and therefore no billboard, for this glyph.
// so, completely unbind glyph.
unbindGlyph(labelCollection, glyph);
} else {
// we have a texture and billboard. If we had one before, release
// our reference to that texture info, but reuse the billboard.
if (defined(glyph.textureInfo)) {
glyph.textureInfo = undefined;
}
}
} else {
// create a glyph object
glyph = new Glyph();
glyphs[textIndex] = glyph;
}
glyph.textureInfo = glyphTextureInfo;
glyph.dimensions = glyphTextureInfo.dimensions;
// if we have a texture, configure the existing billboard, or obtain one
if (glyphTextureInfo.index !== -1) {
var billboard = glyph.billboard;
if (!defined(billboard)) {
if (labelCollection._spareBillboards.length > 0) {
billboard = labelCollection._spareBillboards.pop();
} else {
billboard = labelCollection._billboardCollection.add({
collection : labelCollection
});
}
glyph.billboard = billboard;
}
billboard.show = label._show;
billboard.position = label._position;
billboard.eyeOffset = label._eyeOffset;
billboard.pixelOffset = label._pixelOffset;
billboard.horizontalOrigin = HorizontalOrigin.LEFT;
billboard.verticalOrigin = label._verticalOrigin;
billboard.scale = label._scale;
billboard.pickPrimitive = label;
billboard.id = label._id;
billboard.image = id;
billboard.translucencyByDistance = label._translucencyByDistance;
billboard.pixelOffsetScaleByDistance = label._pixelOffsetScaleByDistance;
}
}
// changing glyphs will cause the position of the
// glyphs to change, since different characters have different widths
label._repositionAllGlyphs = true;
}
// reusable Cartesian2 instance
var glyphPixelOffset = new Cartesian2();
function repositionAllGlyphs(label, resolutionScale) {
var glyphs = label._glyphs;
var glyph;
var dimensions;
var totalWidth = 0;
var maxHeight = 0;
var glyphIndex = 0;
var glyphLength = glyphs.length;
for (glyphIndex = 0; glyphIndex < glyphLength; ++glyphIndex) {
glyph = glyphs[glyphIndex];
dimensions = glyph.dimensions;
totalWidth += dimensions.width;
maxHeight = Math.max(maxHeight, dimensions.height);
}
var scale = label._scale;
var horizontalOrigin = label._horizontalOrigin;
var widthOffset = 0;
if (horizontalOrigin === HorizontalOrigin.CENTER) {
widthOffset -= totalWidth / 2 * scale;
} else if (horizontalOrigin === HorizontalOrigin.RIGHT) {
widthOffset -= totalWidth * scale;
}
glyphPixelOffset.x = widthOffset * resolutionScale;
glyphPixelOffset.y = 0;
var verticalOrigin = label._verticalOrigin;
for (glyphIndex = 0; glyphIndex < glyphLength; ++glyphIndex) {
glyph = glyphs[glyphIndex];
dimensions = glyph.dimensions;
if (verticalOrigin === VerticalOrigin.BOTTOM || dimensions.height === maxHeight) {
glyphPixelOffset.y = -dimensions.descent * scale;
} else if (verticalOrigin === VerticalOrigin.TOP) {
glyphPixelOffset.y = -(maxHeight - dimensions.height) * scale - dimensions.descent * scale;
} else if (verticalOrigin === VerticalOrigin.CENTER) {
glyphPixelOffset.y = -(maxHeight - dimensions.height) / 2 * scale - dimensions.descent * scale;
}
glyphPixelOffset.y *= resolutionScale;
if (defined(glyph.billboard)) {
glyph.billboard._setTranslate(glyphPixelOffset);
}
glyphPixelOffset.x += dimensions.width * scale * resolutionScale;
}
}
function destroyLabel(labelCollection, label) {
var glyphs = label._glyphs;
for ( var i = 0, len = glyphs.length; i < len; ++i) {
unbindGlyph(labelCollection, glyphs[i]);
}
label._labelCollection = undefined;
destroyObject(label);
}
/**
* A renderable collection of labels. Labels are viewport-aligned text positioned in the 3D scene.
* Each label can have a different font, color, scale, etc.
* <br /><br />
* <div align='center'>
* <img src='images/Label.png' width='400' height='300' /><br />
* Example labels
* </div>
* <br /><br />
* Labels are added and removed from the collection using {@link LabelCollection#add}
* and {@link LabelCollection#remove}.
*
* @alias LabelCollection
* @constructor
*
* @param {Object} [options] Object with the following properties:
* @param {Matrix4} [options.modelMatrix=Matrix4.IDENTITY] The 4x4 transformation matrix that transforms each label from model to world coordinates.
* @param {Boolean} [options.debugShowBoundingVolume=false] For debugging only. Determines if this primitive's commands' bounding spheres are shown.
*
* @performance For best performance, prefer a few collections, each with many labels, to
* many collections with only a few labels each. Avoid having collections where some
* labels change every frame and others do not; instead, create one or more collections
* for static labels, and one or more collections for dynamic labels.
*
* @see LabelCollection#add
* @see LabelCollection#remove
* @see Label
* @see BillboardCollection
*
* @demo {@link http://cesiumjs.org/Cesium/Apps/Sandcastle/index.html?src=Labels.html|Cesium Sandcastle Labels Demo}
*
* @example
* // Create a label collection with two labels
* var labels = new Cesium.LabelCollection();
* labels.add({
* position : { x : 1.0, y : 2.0, z : 3.0 },
* text : 'A label'
* });
* labels.add({
* position : { x : 4.0, y : 5.0, z : 6.0 },
* text : 'Another label'
* });
*/
var LabelCollection = function(options) {
options = defaultValue(options, defaultValue.EMPTY_OBJECT);
this._textureAtlas = undefined;
this._billboardCollection = new BillboardCollection();
this._billboardCollection.destroyTextureAtlas = false;
this._spareBillboards = [];
this._glyphTextureCache = {};
this._labels = [];
this._labelsToUpdate = [];
this._totalGlyphCount = 0;
this._resolutionScale = undefined;
/**
* The 4x4 transformation matrix that transforms each label in this collection from model to world coordinates.
* When this is the identity matrix, the labels are drawn in world coordinates, i.e., Earth's WGS84 coordinates.
* Local reference frames can be used by providing a different transformation matrix, like that returned
* by {@link Transforms.eastNorthUpToFixedFrame}.
*
* @type Matrix4
* @default {@link Matrix4.IDENTITY}
*
* @example
* var center = Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883);
* labels.modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(center);
* labels.add({
* position : new Cesium.Cartesian3(0.0, 0.0, 0.0),
* text : 'Center'
* });
* labels.add({
* position : new Cesium.Cartesian3(1000000.0, 0.0, 0.0),
* text : 'East'
* });
* labels.add({
* position : new Cesium.Cartesian3(0.0, 1000000.0, 0.0),
* text : 'North'
* });
* labels.add({
* position : new Cesium.Cartesian3(0.0, 0.0, 1000000.0),
* text : 'Up'
* });
*/
this.modelMatrix = Matrix4.clone(defaultValue(options.modelMatrix, Matrix4.IDENTITY));
/**
* This property is for debugging only; it is not for production use nor is it optimized.
* <p>
* Draws the bounding sphere for each draw command in the primitive.
* </p>
*
* @type {Boolean}
*
* @default false
*/
this.debugShowBoundingVolume = defaultValue(options.debugShowBoundingVolume, false);
};
defineProperties(LabelCollection.prototype, {
/**
* Returns the number of labels in this collection. This is commonly used with
* {@link LabelCollection#get} to iterate over all the labels
* in the collection.
* @memberof LabelCollection.prototype
* @type {Number}
*/
length : {
get : function() {
return this._labels.length;
}
}
});
/**
* Creates and adds a label with the specified initial properties to the collection.
* The added label is returned so it can be modified or removed from the collection later.
*
* @param {Object}[options] A template describing the label's properties as shown in Example 1.
* @returns {Label} The label that was added to the collection.
*
* @performance Calling <code>add</code> is expected constant time. However, the collection's vertex buffer
* is rewritten; this operations is <code>O(n)</code> and also incurs
* CPU to GPU overhead. For best performance, add as many billboards as possible before
* calling <code>update</code>.
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
* @see LabelCollection#remove
* @see LabelCollection#removeAll
*
* @example
* // Example 1: Add a label, specifying all the default values.
* var l = labels.add({
* show : true,
* position : Cesium.Cartesian3.ZERO,
* text : '',
* font : '30px sans-serif',
* fillColor : Cesium.Color.WHITE,
* outlineColor : Cesium.Color.BLACK,
* style : Cesium.LabelStyle.FILL,
* pixelOffset : Cesium.Cartesian2.ZERO,
* eyeOffset : Cesium.Cartesian3.ZERO,
* horizontalOrigin : Cesium.HorizontalOrigin.LEFT,
* verticalOrigin : Cesium.VerticalOrigin.BOTTOM,
* scale : 1.0
* });
*
* @example
* // Example 2: Specify only the label's cartographic position,
* // text, and font.
* var l = labels.add({
* position : Cesium.Cartesian3.fromRadians(longitude, latitude, height),
* text : 'Hello World',
* font : '24px Helvetica',
* });
*/
LabelCollection.prototype.add = function(options) {
var label = new Label(options, this);
this._labels.push(label);
this._labelsToUpdate.push(label);
return label;
};
/**
* Removes a label from the collection. Once removed, a label is no longer usable.
*
* @param {Label} label The label to remove.
* @returns {Boolean} <code>true</code> if the label was removed; <code>false</code> if the label was not found in the collection.
*
* @performance Calling <code>remove</code> is expected constant time. However, the collection's vertex buffer
* is rewritten - an <code>O(n)</code> operation that also incurs CPU to GPU overhead. For
* best performance, remove as many labels as possible before calling <code>update</code>.
* If you intend to temporarily hide a label, it is usually more efficient to call
* {@link Label#show} instead of removing and re-adding the label.
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
* @see LabelCollection#add
* @see LabelCollection#removeAll
* @see Label#show
*
* @example
* var l = labels.add(...);
* labels.remove(l); // Returns true
*/
LabelCollection.prototype.remove = function(label) {
if (defined(label) && label._labelCollection === this) {
var index = this._labels.indexOf(label);
if (index !== -1) {
this._labels.splice(index, 1);
destroyLabel(this, label);
return true;
}
}
return false;
};
/**
* Removes all labels from the collection.
*
* @performance <code>O(n)</code>. It is more efficient to remove all the labels
* from a collection and then add new ones than to create a new collection entirely.
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
* @see LabelCollection#add
* @see LabelCollection#remove
*
* @example
* labels.add(...);
* labels.add(...);
* labels.removeAll();
*/
LabelCollection.prototype.removeAll = function() {
var labels = this._labels;
for ( var i = 0, len = labels.length; i < len; ++i) {
destroyLabel(this, labels[i]);
}
labels.length = 0;
};
/**
* Check whether this collection contains a given label.
*
* @param {Label} label The label to check for.
* @returns {Boolean} true if this collection contains the label, false otherwise.
*
* @see LabelCollection#get
*/
LabelCollection.prototype.contains = function(label) {
return defined(label) && label._labelCollection === this;
};
/**
* Returns the label in the collection at the specified index. Indices are zero-based
* and increase as labels are added. Removing a label shifts all labels after
* it to the left, changing their indices. This function is commonly used with
* {@link LabelCollection#length} to iterate over all the labels
* in the collection.
*
* @param {Number} index The zero-based index of the billboard.
*
* @returns {Label} The label at the specified index.
*
* @performance Expected constant time. If labels were removed from the collection and
* {@link Scene#render} was not called, an implicit <code>O(n)</code>
* operation is performed.
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
* @see LabelCollection#length
*
* @example
* // Toggle the show property of every label in the collection
* var len = labels.length;
* for (var i = 0; i < len; ++i) {
* var l = billboards.get(i);
* l.show = !l.show;
* }
*/
LabelCollection.prototype.get = function(index) {
//>>includeStart('debug', pragmas.debug);
if (!defined(index)) {
throw new DeveloperError('index is required.');
}
//>>includeEnd('debug');
return this._labels[index];
};
/**
* @private
*/
LabelCollection.prototype.update = function(context, frameState, commandList) {
var billboardCollection = this._billboardCollection;
billboardCollection.modelMatrix = this.modelMatrix;
billboardCollection.debugShowBoundingVolume = this.debugShowBoundingVolume;
if (!defined(this._textureAtlas)) {
this._textureAtlas = new TextureAtlas({
context : context
});
billboardCollection.textureAtlas = this._textureAtlas;
}
var uniformState = context.uniformState;
var resolutionScale = uniformState.resolutionScale;
var resolutionChanged = this._resolutionScale !== resolutionScale;
this._resolutionScale = resolutionScale;
var labelsToUpdate;
if (resolutionChanged) {
labelsToUpdate = this._labels;
} else {
labelsToUpdate = this._labelsToUpdate;
}
for (var i = 0, len = labelsToUpdate.length; i < len; ++i) {
var label = labelsToUpdate[i];
if (label.isDestroyed()) {
continue;
}
var preUpdateGlyphCount = label._glyphs.length;
if (label._rebindAllGlyphs) {
rebindAllGlyphs(this, label);
label._rebindAllGlyphs = false;
}
if (resolutionChanged || label._repositionAllGlyphs) {
repositionAllGlyphs(label, resolutionScale);
label._repositionAllGlyphs = false;
}
var glyphCountDifference = label._glyphs.length - preUpdateGlyphCount;
this._totalGlyphCount += glyphCountDifference;
}
this._labelsToUpdate.length = 0;
billboardCollection.update(context, frameState, commandList);
};
/**
* Returns true if this object was destroyed; otherwise, false.
* <br /><br />
* If this object was destroyed, it should not be used; calling any function other than
* <code>isDestroyed</code> will result in a {@link DeveloperError} exception.
*
* @returns {Boolean} True if this object was destroyed; otherwise, false.
*
* @see LabelCollection#destroy
*/
LabelCollection.prototype.isDestroyed = function() {
return false;
};
/**
* Destroys the WebGL resources held by this object. Destroying an object allows for deterministic
* release of WebGL resources, instead of relying on the garbage collector to destroy this object.
* <br /><br />
* Once an object is destroyed, it should not be used; calling any function other than
* <code>isDestroyed</code> will result in a {@link DeveloperError} exception. Therefore,
* assign the return value (<code>undefined</code>) to the object as done in the example.
*
* @returns {undefined}
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
* @see LabelCollection#isDestroyed
*
* @example
* labels = labels && labels.destroy();
*/
LabelCollection.prototype.destroy = function() {
this.removeAll();
this._billboardCollection = this._billboardCollection.destroy();
this._textureAtlas = this._textureAtlas && this._textureAtlas.destroy();
return destroyObject(this);
};
return LabelCollection;
});