Occurs when a picture object has been finished loading its source image.
Object.defineProperty(AnnRenderingEngine.prototype,'loadPicture',
get: function(),
set: function(value)
)
loadPicture: LeadEvent;
AnnLoadPictureEventArgs
In the LEADTOOLS Annotation framework, the source image in picture objects is not loaded till render time. For example, when you first render an annotation object that contains a picture, such as the AnnHotspotObject or AnnPointObject, the framework will load the image in AnnPicture.Source in the background. While the image is loading, the framework will use a placeholder rectangle to render the object position and size. When the image is fully loaded, the framework will fire the LoadPicture event and renders the new image instead of the placeholder.
LoadingPictureStroke and LoadingPictureFill are the objects to use for stroking and filling the placeholder rectangle. Default values are a white stroke on a black background.
The LoadPicture event contains data about the picture that finished loading such as the Picture object itself and the owner AnnObject. Also, the event data contains the Error property that will be populated if an error occurred.
Loading an image in the background is an efficient and easy way to start drawing an annotation object without waiting for all the resources to be available in the browser. This is especially true if the object contains a picture with a source URL on a server machine and takes a few seconds to download.
This example will create a picture from a resource in a remote server and use it with a hotspot annotation object. It will then uses automation to start drawing the object as the image is being loaded.
import { EngineHelper } from "../utilities/EngineHelper";
export class AnnRenderingEngine_LoadPicture {
constructor() {
const helper = new EngineHelper();
helper.run(this.loadPicture);
}
loadPicture = (automation: lt.Annotations.Automation.AnnAutomation) => {
// get the current rendering engine
let renderingEngine: lt.Annotations.Engine.AnnRenderingEngine = automation.automationControl.renderingEngine;
// Change the default loading object placeholder to be a green border with semi-transparent background
const stroke: lt.Annotations.Engine.AnnStroke = lt.Annotations.Engine.AnnStroke.create(
lt.Annotations.Engine.AnnSolidColorBrush.create("green"),
lt.LeadLengthD.create(1));
const fill: lt.Annotations.Engine.AnnBrush = lt.Annotations.Engine.AnnSolidColorBrush.create("rgba(0, 0, 0, 0.5)");
renderingEngine.loadingPictureStroke = stroke;
renderingEngine.loadingPictureFill = fill;
// Hook to the LoadPicture event
renderingEngine.add_loadPicture((sender, e) => {
// e is AnnLoadPictureEventArgs
// Check if an error occurred
if (e.error != null) {
// Show info about the error
let str = e.error.message;
str += "\nSource: " + e.picture.source;
str += "\nOwner object: " + e.annObject.friendlyName;
alert(str);
}
// Re-render the container after picture get loaded
automation.invalidate(lt.LeadRectD.empty);
});
// Create a new AnnHotspotObject with a picture from a remote server
const inch: number = 720;
const hotspot: lt.Annotations.Engine.AnnHotspotObject = new lt.Annotations.Engine.AnnHotspotObject();
// Add the object at location 1,1 inch with size 4,2 inches
hotspot.rect = lt.LeadRectD.create(1 * inch, 1 * inch, 4 * inch, 2 * inch);
// Set its picture
const picture: lt.Annotations.Engine.AnnPicture = new lt.Annotations.Engine.AnnPicture("");
picture.source = "https://www.leadtools.com/images/page_graphics/leadlogo.png";
//NOTE: CORS can cause toDataUrl to fail
// Alternatively, use a local resource
//picture.source = "Resources/leadlogo.png";
hotspot.picture = picture;
// Add it to the container
const container: lt.Annotations.Engine.AnnContainer = automation.container;
container.children.add(hotspot);
// Render the container
automation.invalidate(lt.LeadRectD.empty);
}
}
export class EngineHelper {
// Automation object
protected _automation: lt.Annotations.Automation.AnnAutomation = null;
// Image viewer
protected _viewer: lt.Controls.ImageViewer = null;
constructor() {
// Set the LEADTOOLS license. Replace this with your actual license file
lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null);
}
public run(callback?: (automation: lt.Annotations.Automation.AnnAutomation, viewer: lt.Controls.ImageViewer) => void): void {
// Create the viewer
const imageViewerDiv = document.getElementById("imageViewerDiv");
const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv);
const viewer: lt.Controls.ImageViewer = new lt.Controls.ImageViewer(createOptions);
viewer.autoCreateCanvas = true;
this._viewer = viewer;
// PanZoom interactive mode
const panZoom: lt.Controls.ImageViewerPanZoomInteractiveMode = new lt.Controls.ImageViewerPanZoomInteractiveMode();
// Create an instance of the Automation control object that works with LEADTOOLS ImageViewer
const imageViewerAutomationControl: lt.Demos.Annotations.ImageViewerAutomationControl = new lt.Demos.Annotations.ImageViewerAutomationControl();
// Attach our image viewer
imageViewerAutomationControl.imageViewer = viewer;
// Set the image viewer interactive mode
const automationInteractiveMode: lt.Demos.Annotations.AutomationInteractiveMode = new lt.Demos.Annotations.AutomationInteractiveMode();
automationInteractiveMode.automationControl = imageViewerAutomationControl;
// Set the image URL
viewer.imageUrl = "http://demo.leadtools.com/images/png/pngimage.png";
// Create and set up the automation manager using the HTML5 rendering engine
const renderingEngine: lt.Annotations.Rendering.AnnHtml5RenderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine();
const manager: lt.Annotations.Automation.AnnAutomationManager = lt.Annotations.Automation.AnnAutomationManager.create(renderingEngine);
// Create default automation objects
manager.createDefaultObjects();
// Add the objects to the objects select element
const currentObjectIdSelect = document.getElementById("currentObjectIdSelect") as HTMLSelectElement;
// Add the PanZoom option
currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option("Pan/Zoom", lt.Annotations.Engine.AnnObject.none.toString());
const automationObjCount: number = manager.objects.count;
for (let i = 0; i < automationObjCount; i++) {
// Get the object
const automationObj: lt.Annotations.Automation.AnnAutomationObject = manager.objects.item(i);
// Add its name to the select element
const name: string = automationObj.name;
const id: string = automationObj.id.toString();
currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option(name, id);
}
// Hook to its change event
currentObjectIdSelect.addEventListener("change", () => {
// Get the object ID
const id: number = parseInt(currentObjectIdSelect.options[currentObjectIdSelect.selectedIndex].value);
// Set it as the current object in the manager
manager.currentObjectId = id;
// If this is the "Pan/Zoom" option, then back to pan zoom, otherwise, set our automation control
if (id == lt.Annotations.Engine.AnnObject.none) {
viewer.defaultInteractiveMode = panZoom;
}
else {
viewer.defaultInteractiveMode = automationInteractiveMode;
}
});
// When the current object ID changes, we need to update our select
manager.add_currentObjectIdChanged((sender, e) => {
const currentObjectId: number = manager.currentObjectId;
for (let i = 0; i < currentObjectIdSelect.options.length; i++) {
const id: number = parseInt(currentObjectIdSelect.options[i].value);
if (id === currentObjectId) {
currentObjectIdSelect.selectedIndex = i;
break;
}
}
});
// Pan zoom by default
viewer.defaultInteractiveMode = panZoom;
// set up the automation (will create the container as well)
const automation: lt.Annotations.Automation.AnnAutomation = new lt.Annotations.Automation.AnnAutomation(manager, imageViewerAutomationControl);
this._automation = automation;
// Add handler to update the container size when the image size changes
viewer.itemChanged.add((sender, e) => {
const container: lt.Annotations.Engine.AnnContainer = automation.container;
container.size = container.mapper.sizeToContainerCoordinates(viewer.imageSize);
//Create new canvas data provider for the new image
const canvasDataProvider: lt.Demos.Annotations.CanvasDataProvider = new lt.Demos.Annotations.CanvasDataProvider(viewer.activeItem.canvas);
imageViewerAutomationControl.automationDataProvider = canvasDataProvider;
});
// set up this automation as the active one
this._automation.active = true;
const exampleButton = document.getElementById("exampleButton");
exampleButton.onclick = () => {
if(callback)
callback(this._automation, this._viewer);
}
}
}
import { EngineHelper } from "../utilities/EngineHelper";
export class AnnRenderingEngine_LoadPicture {
constructor() {
const helper = new EngineHelper();
helper.run(this.loadPicture);
}
loadPicture = (automation) => {
// get the current rendering engine
let renderingEngine = automation.automationControl.renderingEngine;
// Change the default loading object placeholder to be a green border with semi-transparent background
const stroke = lt.Annotations.Engine.AnnStroke.create(
lt.Annotations.Engine.AnnSolidColorBrush.create("green"),
lt.LeadLengthD.create(1));
const fill = lt.Annotations.Engine.AnnSolidColorBrush.create("rgba(0, 0, 0, 0.5)");
renderingEngine.loadingPictureStroke = stroke;
renderingEngine.loadingPictureFill = fill;
// Hook to the LoadPicture event
renderingEngine.add_loadPicture((sender, e) => {
// e is AnnLoadPictureEventArgs
// Check if an error occurred
if (e.error != null) {
// Show info about the error
let str = e.error.message;
str += "\nSource: " + e.picture.source;
str += "\nOwner object: " + e.annObject.friendlyName;
alert(str);
}
// Re-render the container after picture get loaded
automation.invalidate(lt.LeadRectD.empty);
});
// Create a new AnnHotspotObject with a picture from a remote server
const inch = 720;
const hotspot = new lt.Annotations.Engine.AnnHotspotObject();
// Add the object at location 1,1 inch with size 4,2 inches
hotspot.rect = lt.LeadRectD.create(1 * inch, 1 * inch, 4 * inch, 2 * inch);
// Set its picture
const picture = new lt.Annotations.Engine.AnnPicture("");
picture.source = "https://www.leadtools.com/images/page_graphics/leadlogo.png";
//NOTE: CORS can cause toDataUrl to fail
// Alternatively, use a local resource
//picture.source = "Resources/leadlogo.png";
hotspot.picture = picture;
// Add it to the container
const container = automation.container;
container.children.add(hotspot);
// Render the container
automation.invalidate(lt.LeadRectD.empty);
}
}
export class EngineHelper {
// Automation object
_automation = null;
// Image viewer
_viewer = null;
constructor() {
// Set the LEADTOOLS license. Replace this with your actual license file
lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/v200/LEADTOOLSEVAL.txt", "EVAL", null);
}
run(callback) {
// Create the viewer
const imageViewerDiv = document.getElementById("imageViewerDiv");
const createOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv);
const viewer = new lt.Controls.ImageViewer(createOptions);
viewer.autoCreateCanvas = true;
this._viewer = viewer;
// PanZoom interactive mode
const panZoom = new lt.Controls.ImageViewerPanZoomInteractiveMode();
// Create an instance of the Automation control object that works with LEADTOOLS ImageViewer
const imageViewerAutomationControl = new lt.Demos.Annotations.ImageViewerAutomationControl();
// Attach our image viewer
imageViewerAutomationControl.imageViewer = viewer;
// Set the image viewer interactive mode
const automationInteractiveMode = new lt.Demos.Annotations.AutomationInteractiveMode();
automationInteractiveMode.automationControl = imageViewerAutomationControl;
// Set the image URL
viewer.imageUrl = "http://demo.leadtools.com/images/png/pngimage.png";
// Create and set up the automation manager using the HTML5 rendering engine
const renderingEngine = new lt.Annotations.Rendering.AnnHtml5RenderingEngine();
const manager = lt.Annotations.Automation.AnnAutomationManager.create(renderingEngine);
// Create default automation objects
manager.createDefaultObjects();
// Add the objects to the objects select element
const currentObjectIdSelect = document.getElementById("currentObjectIdSelect");
// Add the PanZoom option
currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option("Pan/Zoom", lt.Annotations.Engine.AnnObject.none.toString());
const automationObjCount = manager.objects.count;
for (let i = 0; i < automationObjCount; i++) {
// Get the object
const automationObj = manager.objects.item(i);
// Add its name to the select element
const name = automationObj.name;
const id = automationObj.id.toString();
currentObjectIdSelect.options[currentObjectIdSelect.options.length] = new Option(name, id);
}
// Hook to its change event
currentObjectIdSelect.addEventListener("change", () => {
// Get the object ID
const id = parseInt(currentObjectIdSelect.options[currentObjectIdSelect.selectedIndex].value);
// Set it as the current object in the manager
manager.currentObjectId = id;
// If this is the "Pan/Zoom" option, then back to pan zoom, otherwise, set our automation control
if (id == lt.Annotations.Engine.AnnObject.none) {
viewer.defaultInteractiveMode = panZoom;
}
else {
viewer.defaultInteractiveMode = automationInteractiveMode;
}
});
// When the current object ID changes, we need to update our select
manager.add_currentObjectIdChanged((sender, e) => {
const currentObjectId = manager.currentObjectId;
for (let i = 0; i < currentObjectIdSelect.options.length; i++) {
const id = parseInt(currentObjectIdSelect.options[i].value);
if (id === currentObjectId) {
currentObjectIdSelect.selectedIndex = i;
break;
}
}
});
// Pan zoom by default
viewer.defaultInteractiveMode = panZoom;
// set up the automation (will create the container as well)
const automation = new lt.Annotations.Automation.AnnAutomation(manager, imageViewerAutomationControl);
this._automation = automation;
// Add handler to update the container size when the image size changes
viewer.itemChanged.add((sender, e) => {
const container = automation.container;
container.size = container.mapper.sizeToContainerCoordinates(viewer.imageSize);
//Create new canvas data provider for the new image
const canvasDataProvider = new lt.Demos.Annotations.CanvasDataProvider(viewer.activeItem.canvas);
imageViewerAutomationControl.automationDataProvider = canvasDataProvider;
});
// set up this automation as the active one
this._automation.active = true;
const exampleButton = document.getElementById("exampleButton");
exampleButton.onclick = () => {
if(callback)
callback(this._automation, this._viewer);
}
}
}
<!doctype html>
<html lang="en">
<title>AnnRenderingEngine Example | LoadPicture</title>
<head>
<script src="https://code.jquery.com/jquery-2.2.4.min.js"
integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script>
<script src="../LT/Leadtools.js"></script>
<script src="../LT/Leadtools.Controls.js"></script>
<script src="../LT/Leadtools.Annotations.Engine.js"></script>
<script src="../LT/Leadtools.Annotations.Designers.js"></script>
<script src="../LT/Leadtools.Annotations.Rendering.Javascript.js"></script>
<script src="../LT/Leadtools.Annotations.Automation.js"></script>
<script src="../LT/Leadtools.Annotations.BatesStamp.js"></script>
<script src="../LT/Leadtools.Demos.js"></script>
<script src="../LT/Leadtools.Demos.Annotations.js"></script>
<style>
#imageViewerDiv {
border: 1px solid #000000;
width: 800px;
height: 800px;
background-color: #7F7F7F;
}
</style>
<!-- All demo files are bundled and appended to the window -->
<script src="../../bundle.js" type="text/javascript"></script>
</head>
<body>
<p>Either Pan/Zoom or Annotations mode. In annotations mode, draw new objects or edit them.</p>
<div>
<select id="currentObjectIdSelect"></select>
</div>
<div>
<input type="button" id="exampleButton" value="Example" />
<label id="exampleLabel" />
</div>
<div id="imageViewerDiv" />
</body>
<script>
window.onload = () => new window.examples.AnnRenderingEngine.LoadPicture();
</script>
</html>
Parameter | Type | Description |
---|---|---|
sender | var | The source of the event. |
e | AnnLoadPictureEventArgs | The event data. |
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