Renders the item region.
Object.defineProperty(ImageViewer.prototype,'renderItemRegion',
get: function(),
set: function(value)
)
renderItemRegion: LeadEvent;
During this part of the rendering cycle, the viewer will check if the image of this item contains a valid region. If this is true and the value of ImageRegionRenderMode is other than ControlRegionRenderMode.None then the viewer will render the outline of the region on top of the image.
For more information, refer to Image Viewer Rendering.
import { ImageViewer_Example } from "../ImageViewer";
export class ImageViewer_PostRenderExample {
private viewerExample;
constructor() {
this.viewerExample = new ImageViewer_Example(this.run);
}
private run = (viewer: lt.Controls.ImageViewer) => {
// Clear all the images already the viewer
viewer.items.clear();
// Use vertical view layout
viewer.viewLayout = new lt.Controls.ImageViewerVerticalViewLayout();
// Make sure the item size is larger than the image size (thumbnails mode)
viewer.itemPadding = lt.Controls.ControlPadding.create(8, 8, 8, 20);
viewer.itemBorderThickness = 3;
viewer.itemMargin = lt.Controls.ControlPadding.createAll(10);
// Add 4 items to the viewer
for (let i = 0; i < 4; i++) {
const item: lt.Controls.ImageViewerItem = new lt.Controls.ImageViewerItem();
item.url = "https://demo.leadtools.com/images/jpeg/cannon.jpg";
item.text = "Item " + i;
viewer.items.add(item);
}
// Render on the view
viewer.postRender.add((sender, e) => {
// Rendering the whole view
const ctx: CanvasRenderingContext2D = e.context;
// Blue ellipse at fixed position. This will stay the same and will not scroll or zoom
ctx.beginPath();
ctx.arc(50, 50, 30, 0, Math.PI * 2);
ctx.closePath();
ctx.fillStyle = "rgba(0, 0, 255, .5)";
ctx.fill();
// Red ellipse at relative position, this will scroll and zoom with the view
ctx.save();
const t: lt.LeadMatrix = viewer.viewTransform;
ctx.transform(t.m11, t.m12, t.m21, t.m22, t.offsetX, t.offsetY);
ctx.beginPath();
ctx.arc(50, 50, 30, 0, Math.PI * 2);
ctx.closePath();
ctx.fillStyle = "rgba(255, 0, 0, .5)";
ctx.fill();
ctx.restore();
});
// Render on each item
viewer.postRenderItem.add((sender, e) => {
const item: lt.Controls.ImageViewerItem = e.item;
const ctx: CanvasRenderingContext2D = e.context;
ctx.save();
// Get the bounding rectangle for the image
const bounds: lt.LeadRectD = lt.LeadRectD.create(0, 0, item.size.width, item.size.height);
// Add the image transform to the graphics
const t: lt.LeadMatrix = viewer.getItemImageTransform(item);
ctx.transform(t.m11, t.m12, t.m21, t.m22, t.offsetX, t.offsetY);
// Red hilight on right half of each item image
ctx.fillStyle = "rgba(255, 0, 0, .5)";
ctx.fillRect(bounds.x + (bounds.width / 2), bounds.y, bounds.width / 2, bounds.height);
ctx.restore();
});
}
}
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 ImageViewer_PostRenderExample {
viewerExample;
constructor() {
this.viewerExample = new ImageViewer_Example(this.run);
}
run = (viewer) => {
// Clear all the images already the viewer
viewer.items.clear();
// Use vertical view layout
viewer.viewLayout = new lt.Controls.ImageViewerVerticalViewLayout();
// Make sure the item size is larger than the image size (thumbnails mode)
viewer.itemPadding = lt.Controls.ControlPadding.create(8, 8, 8, 20);
viewer.itemBorderThickness = 3;
viewer.itemMargin = lt.Controls.ControlPadding.createAll(10);
// Add 4 items to the viewer
for (let i = 0; i < 4; i++) {
const item = new lt.Controls.ImageViewerItem();
item.url = "https://demo.leadtools.com/images/jpeg/cannon.jpg";
item.text = "Item " + i;
viewer.items.add(item);
}
// Render on the view
viewer.postRender.add((sender, e) => {
// Rendering the whole view
const ctx = e.context;
// Blue ellipse at fixed position. This will stay the same and will not scroll or zoom
ctx.beginPath();
ctx.arc(50, 50, 30, 0, Math.PI * 2);
ctx.closePath();
ctx.fillStyle = "rgba(0, 0, 255, .5)";
ctx.fill();
// Red ellipse at relative position, this will scroll and zoom with the view
ctx.save();
const t = viewer.viewTransform;
ctx.transform(t.m11, t.m12, t.m21, t.m22, t.offsetX, t.offsetY);
ctx.beginPath();
ctx.arc(50, 50, 30, 0, Math.PI * 2);
ctx.closePath();
ctx.fillStyle = "rgba(255, 0, 0, .5)";
ctx.fill();
ctx.restore();
});
// Render on each item
viewer.postRenderItem.add((sender, e) => {
const item = e.item;
const ctx = e.context;
ctx.save();
// Get the bounding rectangle for the image
const bounds = lt.LeadRectD.create(0, 0, item.size.width, item.size.height);
// Add the image transform to the graphics
const t = viewer.getItemImageTransform(item);
ctx.transform(t.m11, t.m12, t.m21, t.m22, t.offsetX, t.offsetY);
// Red hilight on right half of each item image
ctx.fillStyle = "rgba(255, 0, 0, .5)";
ctx.fillRect(bounds.x + (bounds.width / 2), bounds.y, bounds.width / 2, bounds.height);
ctx.restore();
});
}
}
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 | PostRender</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.ImageViewer.PostRender();
};
</script>
</html>
Parameter | Type | Description |
---|---|---|
sender | var | The source of the event. |
e | ImageViewerRenderEventArgs | The event data. |
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