Draws and pans a spy glass on the viewer.
function lt.Controls.ImageViewerSpyGlassInteractiveMode
extends lt.Controls.ImageViewerInteractiveMode
class lt.Controls.ImageViewerSpyGlassInteractiveMode()
extends ImageViewerInteractiveMode
The ImageViewerSpyGlassInteractiveMode derives from the ImageViewerInteractiveMode and subscribes to the following events of the InteractiveService:
The ImageViewerSpyGlassInteractiveMode interactive mode does not perform any action on the viewer (besides drawing the spy glass). It is up to the user to implement any custom operation required. For example, to implement a magnify glass, ImageViewerMagnifyGlassInteractiveMode derives from the ImageViewerSpyGlassInteractiveMode and overrides the OnDrawImage method to draw a magnified version of the area under the spy glass.
The ImageViewerSpyGlassInteractiveMode works as follows:
When a dragStarted event is received, the InteractiveEventArgs.IsHandled property is set to true and a temporary HTML5 Canvas Element is created on top of the viewer for drawing the spy glass. Note that if you set your own canvas
into the InteractiveModeCanvas property, then this object will not create a canvas
(nor use the above properties). Instead, your canvas
will be used as the surface for the spy glass.
When a dragDelta event is received, the InteractiveEventArgs.isHandled property is set to true and the temporary canvas
is moved to the current position. The ImageViewerSpyGlassInteractiveMode.DrawImage event is fired at this time to allow implementers and listeners to perform any custom operation on the spy glass surface.
When a dragCompleted event is received, the InteractiveEventArgs.isHandled property is set to true and the temporary canvas
is removed.
The ImageViewerSpyGlassInteractiveMode also supports redirecting the output to an external canvas
instead of the viewer surface. For an example, refer to RedirectCanvas.
Neither ImageViewerSpyGlassInteractiveMode nor ImageViewerMagnifyGlassInteractiveMode work when the image viewer is in Elements Mode, since the viewer does not paint the items.
For more information, refer to Image Viewer Interactive Modes.
This example will use the ImageViewerSpyGlassInteractiveMode to show a flipped version of the image under the mouse.
import { ImageViewer_Example } from "../ImageViewer";
export class SpyGlassInteractiveMode_Example {
private viewerExample;
constructor() {
this.viewerExample = new ImageViewer_Example(this.run);
}
private run = (viewer: lt.Controls.ImageViewer) => {
viewer.interactiveModes.clearItems();
viewer.interactiveModes.beginUpdate();
// Create the spyglass
const spyGlass: lt.Controls.ImageViewerSpyGlassInteractiveMode = new lt.Controls.ImageViewerSpyGlassInteractiveMode();
spyGlass.backgroundColor = "rgba(255, 255, 0, 0.5)";
spyGlass.autoItemMode = lt.Controls.ImageViewerAutoItemMode.autoSet;
// On draw, draw the viewer flipped
spyGlass.drawImage.add((sender, e) => {
const rect: lt.LeadRectD = e.destinationRectangle;
const ctx: CanvasRenderingContext2D = e.context;
// Width and height of the canvas
const controlSize: lt.LeadSizeD = viewer.controlSize;
ctx.save();
// Undo offset of the spyglass
ctx.translate(-rect.x, -rect.y);
// Flip the context
ctx.scale(1, -1);
ctx.translate(0, -controlSize.height);
// Draw the view
viewer.renderRedirect(ctx, new lt.Controls.ImageViewerRenderRedirectOptions(), lt.LeadRectD.empty);
ctx.restore();
});
viewer.interactiveModes.add(spyGlass);
viewer.interactiveModes.endUpdate();
}
}
export class ImageViewer_Example {
// LEADTOOLS ImageViewer to be used with this example
protected imageViewer: lt.Controls.ImageViewer = null;
// Generic state value used by the examples
public timesClicked: number = 0;
constructor(callback?: (viewer: lt.Controls.ImageViewer) => void) {
// Set the LEADTOOLS license. Replace this with your actual license file
lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null);
// Create an image viewer inside the imageViewerDiv element
const imageViewerDiv = document.getElementById("imageViewerDiv");
const createOptions: lt.Controls.ImageViewerCreateOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv);
this.imageViewer = new lt.Controls.ImageViewer(createOptions);
this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center;
this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center;
this.imageViewer.autoCreateCanvas = true;
// Add Pan/Zoom interactive mode
// Click and drag to pan, CTRL-Click and drag to zoom in and out
this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode());
// Load an image
this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg";
this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin);
const exampleButton = document.getElementById("exampleButton");
exampleButton.addEventListener("click", () => {
this.timesClicked++;
// Run the example
if (callback)
callback(this.imageViewer);
});
}
}
import { ImageViewer_Example } from "../ImageViewer";
export class SpyGlassInteractiveMode_Example {
viewerExample;
constructor() {
this.viewerExample = new ImageViewer_Example(this.run);
}
run = (viewer) => {
viewer.interactiveModes.clearItems();
viewer.interactiveModes.beginUpdate();
// Create the spyglass
const spyGlass = new lt.Controls.ImageViewerSpyGlassInteractiveMode();
spyGlass.backgroundColor = "rgba(255, 255, 0, 0.5)";
spyGlass.autoItemMode = lt.Controls.ImageViewerAutoItemMode.autoSet;
// On draw, draw the viewer flipped
spyGlass.drawImage.add((sender, e) => {
const rect = e.destinationRectangle;
const ctx = e.context;
// Width and height of the canvas
const controlSize = viewer.controlSize;
ctx.save();
// Undo offset of the spyglass
ctx.translate(-rect.x, -rect.y);
// Flip the context
ctx.scale(1, -1);
ctx.translate(0, -controlSize.height);
// Draw the view
viewer.renderRedirect(ctx, new lt.Controls.ImageViewerRenderRedirectOptions(), lt.LeadRectD.empty);
ctx.restore();
});
viewer.interactiveModes.add(spyGlass);
viewer.interactiveModes.endUpdate();
}
}
export class ImageViewer_Example {
// LEADTOOLS ImageViewer to be used with this example
imageViewer = null;
// Generic state value used by the examples
timesClicked = 0;
constructor(callback) {
// Set the LEADTOOLS license. Replace this with your actual license file
lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null);
// Create an image viewer inside the imageViewerDiv element
const imageViewerDiv = document.getElementById("imageViewerDiv");
const createOptions = new lt.Controls.ImageViewerCreateOptions(imageViewerDiv);
this.imageViewer = new lt.Controls.ImageViewer(createOptions);
this.imageViewer.viewVerticalAlignment = lt.Controls.ControlAlignment.center;
this.imageViewer.viewHorizontalAlignment = lt.Controls.ControlAlignment.center;
this.imageViewer.autoCreateCanvas = true;
// Add Pan/Zoom interactive mode
// Click and drag to pan, CTRL-Click and drag to zoom in and out
this.imageViewer.interactiveModes.add(new lt.Controls.ImageViewerPanZoomInteractiveMode());
// Load an image
this.imageViewer.imageUrl = "https://demo.leadtools.com/images/jpeg/cannon.jpg";
this.imageViewer.zoom(lt.Controls.ControlSizeMode.fit, .9, this.imageViewer.defaultZoomOrigin);
const exampleButton = document.getElementById("exampleButton");
exampleButton.addEventListener("click", () => {
this.timesClicked++;
// Run the example
if (callback)
callback(this.imageViewer);
});
}
}
<!doctype html>
<html lang="en">
<title>Controls Example | SpyGlassInteractiveMode</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.ImageProcessing.Main.js"></script>
<script src="../../LT/Leadtools.ImageProcessing.Color.js"></script>
<script src="../../LT/Leadtools.ImageProcessing.Core.js"></script>
<script src="../../LT/Leadtools.ImageProcessing.Effects.js"></script>
<script src="../../LT/Leadtools.Document.js"></script>
<script src="../../LT/Leadtools.Document.Viewer.js"></script>
<style>
body {
font-family: 'Segoe UI', sans-serif;
}
#imageViewerDiv {
border: 1px solid #888;
width: 500px;
height: 500px;
background-color: #eee;
}
</style>
<!-- All demo files are bundled and appended to the window -->
<script src="../../bundle.js" type="text/javascript"></script>
</head>
<body>
<p>Press and drag on the image to pan.</p>
<p>Hold down the control key and press and drag on the image or pinch with two fingers to zoom in and out.</p>
<div>
<button type="button" id="exampleButton">Run Example</button>
</div>
<div id="imageViewerDiv"></div>
<div id="output"></div>
</body>
<script>
window.onload = () => {
const example = new window.examples.Spyglass.SpyGlassInteractiveMode();
};
</script>
</html>
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